/* vi: set sw=4 ts=4: */ /* * sh.c -- a prototype Bourne shell grammar parser * Intended to follow the original Thompson and Ritchie * "small and simple is beautiful" philosophy, which * incidentally is a good match to today's BusyBox. * * Copyright (C) 2000,2001 Larry Doolittle <larry@doolittle.boa.org> * * Credits: * The parser routines proper are all original material, first * written Dec 2000 and Jan 2001 by Larry Doolittle. The * execution engine, the builtins, and much of the underlying * support has been adapted from busybox-0.49pre's lash, which is * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> * written by Erik Andersen <andersen@codepoet.org>. That, in turn, * is based in part on ladsh.c, by Michael K. Johnson and Erik W. * Troan, which they placed in the public domain. I don't know * how much of the Johnson/Troan code has survived the repeated * rewrites. * * Other credits: * b_addchr() derived from similar w_addchar function in glibc-2.2 * setup_redirect(), redirect_opt_num(), and big chunks of main() * and many builtins derived from contributions by Erik Andersen * miscellaneous bugfixes from Matt Kraai * * There are two big (and related) architecture differences between * this parser and the lash parser. One is that this version is * actually designed from the ground up to understand nearly all * of the Bourne grammar. The second, consequential change is that * the parser and input reader have been turned inside out. Now, * the parser is in control, and asks for input as needed. The old * way had the input reader in control, and it asked for parsing to * take place as needed. The new way makes it much easier to properly * handle the recursion implicit in the various substitutions, especially * across continuation lines. * * Bash grammar not implemented: (how many of these were in original sh?) * $_ * ! negation operator for pipes * &> and >& redirection of stdout+stderr * Brace Expansion * Tilde Expansion * fancy forms of Parameter Expansion * aliases * Arithmetic Expansion * <(list) and >(list) Process Substitution * reserved words: case, esac, select, function * Here Documents ( << word ) * Functions * Major bugs: * job handling woefully incomplete and buggy (improved --vda) * reserved word execution woefully incomplete and buggy * to-do: * port selected bugfixes from post-0.49 busybox lash - done? * finish implementing reserved words: for, while, until, do, done * change { and } from special chars to reserved words * builtins: break, continue, eval, return, set, trap, ulimit * test magic exec * handle children going into background * clean up recognition of null pipes * check setting of global_argc and global_argv * control-C handling, probably with longjmp * follow IFS rules more precisely, including update semantics * figure out what to do with backslash-newline * explain why we use signal instead of sigaction * propagate syntax errors, die on resource errors? * continuation lines, both explicit and implicit - done? * memory leak finding and plugging - done? * more testing, especially quoting rules and redirection * document how quoting rules not precisely followed for variable assignments * maybe change charmap[] to use 2-bit entries * (eventually) remove all the printf's * * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. */ #include <glob.h> /* glob, of course */ /* #include <dmalloc.h> */ #include "busybox.h" /* for APPLET_IS_NOFORK/NOEXEC */ #if !BB_MMU && ENABLE_HUSH_TICK //#undef ENABLE_HUSH_TICK //#define ENABLE_HUSH_TICK 0 #warning On NOMMU, hush command substitution is dangerous. #warning Dont use it for commands which produce lots of output. #warning For more info see shell/hush.c, generate_stream_from_list(). #endif #if !BB_MMU && ENABLE_HUSH_JOB #undef ENABLE_HUSH_JOB #define ENABLE_HUSH_JOB 0 #endif #if !ENABLE_HUSH_INTERACTIVE #undef ENABLE_FEATURE_EDITING #define ENABLE_FEATURE_EDITING 0 #undef ENABLE_FEATURE_EDITING_FANCY_PROMPT #define ENABLE_FEATURE_EDITING_FANCY_PROMPT 0 #endif /* If you comment out one of these below, it will be #defined later * to perform debug printfs to stderr: */ #define debug_printf(...) do {} while (0) /* Finer-grained debug switches */ #define debug_printf_parse(...) do {} while (0) #define debug_print_tree(a, b) do {} while (0) #define debug_printf_exec(...) do {} while (0) #define debug_printf_jobs(...) do {} while (0) #define debug_printf_expand(...) do {} while (0) #define debug_printf_clean(...) do {} while (0) #ifndef debug_printf #define debug_printf(...) fprintf(stderr, __VA_ARGS__) #endif #ifndef debug_printf_parse #define debug_printf_parse(...) fprintf(stderr, __VA_ARGS__) #endif #ifndef debug_printf_exec #define debug_printf_exec(...) fprintf(stderr, __VA_ARGS__) #endif #ifndef debug_printf_jobs #define debug_printf_jobs(...) fprintf(stderr, __VA_ARGS__) #define DEBUG_SHELL_JOBS 1 #endif #ifndef debug_printf_expand #define debug_printf_expand(...) fprintf(stderr, __VA_ARGS__) #define DEBUG_EXPAND 1 #endif /* Keep unconditionally on for now */ #define ENABLE_HUSH_DEBUG 1 #ifndef debug_printf_clean /* broken, of course, but OK for testing */ static const char *indenter(int i) { static const char blanks[] ALIGN1 = " "; return &blanks[sizeof(blanks) - i - 1]; } #define debug_printf_clean(...) fprintf(stderr, __VA_ARGS__) #define DEBUG_CLEAN 1 #endif /* * Leak hunting. Use hush_leaktool.sh for post-processing. */ #ifdef FOR_HUSH_LEAKTOOL void *xxmalloc(int lineno, size_t size) { void *ptr = xmalloc((size + 0xff) & ~0xff); fprintf(stderr, "line %d: malloc %p\n", lineno, ptr); return ptr; } void *xxrealloc(int lineno, void *ptr, size_t size) { ptr = xrealloc(ptr, (size + 0xff) & ~0xff); fprintf(stderr, "line %d: realloc %p\n", lineno, ptr); return ptr; } char *xxstrdup(int lineno, const char *str) { char *ptr = xstrdup(str); fprintf(stderr, "line %d: strdup %p\n", lineno, ptr); return ptr; } void xxfree(void *ptr) { fprintf(stderr, "free %p\n", ptr); free(ptr); } #define xmalloc(s) xxmalloc(__LINE__, s) #define xrealloc(p, s) xxrealloc(__LINE__, p, s) #define xstrdup(s) xxstrdup(__LINE__, s) #define free(p) xxfree(p) #endif #define SPECIAL_VAR_SYMBOL 3 #define PARSEFLAG_EXIT_FROM_LOOP 1 #define PARSEFLAG_SEMICOLON (1 << 1) /* symbol ';' is special for parser */ #define PARSEFLAG_REPARSING (1 << 2) /* >= 2nd pass */ typedef enum { REDIRECT_INPUT = 1, REDIRECT_OVERWRITE = 2, REDIRECT_APPEND = 3, REDIRECT_HEREIS = 4, REDIRECT_IO = 5 } redir_type; /* The descrip member of this structure is only used to make debugging * output pretty */ static const struct { int mode; signed char default_fd; char descrip[3]; } redir_table[] = { { 0, 0, "()" }, { O_RDONLY, 0, "<" }, { O_CREAT|O_TRUNC|O_WRONLY, 1, ">" }, { O_CREAT|O_APPEND|O_WRONLY, 1, ">>" }, { O_RDONLY, -1, "<<" }, { O_RDWR, 1, "<>" } }; typedef enum { PIPE_SEQ = 1, PIPE_AND = 2, PIPE_OR = 3, PIPE_BG = 4, } pipe_style; /* might eventually control execution */ typedef enum { RES_NONE = 0, #if ENABLE_HUSH_IF RES_IF = 1, RES_THEN = 2, RES_ELIF = 3, RES_ELSE = 4, RES_FI = 5, #endif #if ENABLE_HUSH_LOOPS RES_FOR = 6, RES_WHILE = 7, RES_UNTIL = 8, RES_DO = 9, RES_DONE = 10, RES_IN = 11, #endif RES_XXXX = 12, RES_SNTX = 13 } reserved_style; enum { FLAG_END = (1 << RES_NONE ), #if ENABLE_HUSH_IF FLAG_IF = (1 << RES_IF ), FLAG_THEN = (1 << RES_THEN ), FLAG_ELIF = (1 << RES_ELIF ), FLAG_ELSE = (1 << RES_ELSE ), FLAG_FI = (1 << RES_FI ), #endif #if ENABLE_HUSH_LOOPS FLAG_FOR = (1 << RES_FOR ), FLAG_WHILE = (1 << RES_WHILE), FLAG_UNTIL = (1 << RES_UNTIL), FLAG_DO = (1 << RES_DO ), FLAG_DONE = (1 << RES_DONE ), FLAG_IN = (1 << RES_IN ), #endif FLAG_START = (1 << RES_XXXX ), }; /* This holds pointers to the various results of parsing */ struct p_context { struct child_prog *child; struct pipe *list_head; struct pipe *pipe; struct redir_struct *pending_redirect; smallint res_w; smallint parse_type; /* bitmask of PARSEFLAG_xxx, defines type of parser : ";$" common or special symbol */ int old_flag; /* bitmask of FLAG_xxx, for figuring out valid reserved words */ struct p_context *stack; /* How about quoting status? */ }; struct redir_struct { struct redir_struct *next; /* pointer to the next redirect in the list */ redir_type type; /* type of redirection */ int fd; /* file descriptor being redirected */ int dup; /* -1, or file descriptor being duplicated */ char **glob_word; /* *word.gl_pathv is the filename */ }; struct child_prog { pid_t pid; /* 0 if exited */ char **argv; /* program name and arguments */ struct pipe *group; /* if non-NULL, first in group or subshell */ smallint subshell; /* flag, non-zero if group must be forked */ smallint is_stopped; /* is the program currently running? */ struct redir_struct *redirects; /* I/O redirections */ struct pipe *family; /* pointer back to the child's parent pipe */ //sp counting seems to be broken... so commented out, grep for '//sp:' //sp: int sp; /* number of SPECIAL_VAR_SYMBOL */ //seems to be unused, grep for '//pt:' //pt: int parse_type; }; /* argv vector may contain variable references (^Cvar^C, ^C0^C etc) * and on execution these are substituted with their values. * Substitution can make _several_ words out of one argv[n]! * Example: argv[0]=='.^C*^C.' here: echo .$*. */ struct pipe { struct pipe *next; int num_progs; /* total number of programs in job */ int running_progs; /* number of programs running (not exited) */ int stopped_progs; /* number of programs alive, but stopped */ #if ENABLE_HUSH_JOB int jobid; /* job number */ pid_t pgrp; /* process group ID for the job */ char *cmdtext; /* name of job */ #endif char *cmdbuf; /* buffer various argv's point into */ struct child_prog *progs; /* array of commands in pipe */ int job_context; /* bitmask defining current context */ smallint followup; /* PIPE_BG, PIPE_SEQ, PIPE_OR, PIPE_AND */ smallint res_word; /* needed for if, for, while, until... */ }; /* On program start, environ points to initial environment. * putenv adds new pointers into it, unsetenv removes them. * Neither of these (de)allocates the strings. * setenv allocates new strings in malloc space and does putenv, * and thus setenv is unusable (leaky) for shell's purposes */ #define setenv(...) setenv_is_leaky_dont_use() struct variable { struct variable *next; char *varstr; /* points to "name=" portion */ int max_len; /* if > 0, name is part of initial env; else name is malloced */ smallint flg_export; /* putenv should be done on this var */ smallint flg_read_only; }; typedef struct { char *data; int length; int maxlen; smallint o_quote; smallint nonnull; } o_string; #define NULL_O_STRING {NULL,0,0,0,0} /* used for initialization: o_string foo = NULL_O_STRING; */ /* I can almost use ordinary FILE *. Is open_memstream() universally * available? Where is it documented? */ struct in_str { const char *p; /* eof_flag=1: last char in ->p is really an EOF */ char eof_flag; /* meaningless if ->p == NULL */ char peek_buf[2]; #if ENABLE_HUSH_INTERACTIVE smallint promptme; smallint promptmode; /* 0: PS1, 1: PS2 */ #endif FILE *file; int (*get) (struct in_str *); int (*peek) (struct in_str *); }; #define b_getch(input) ((input)->get(input)) #define b_peek(input) ((input)->peek(input)) enum { CHAR_ORDINARY = 0, CHAR_ORDINARY_IF_QUOTED = 1, /* example: *, # */ CHAR_IFS = 2, /* treated as ordinary if quoted */ CHAR_SPECIAL = 3, /* example: $ */ }; #define HUSH_VER_STR "0.02" /* "Globals" within this file */ /* Sorted roughly by size (smaller offsets == smaller code) */ struct globals { #if ENABLE_HUSH_INTERACTIVE /* 'interactive_fd' is a fd# open to ctty, if we have one * _AND_ if we decided to act interactively */ int interactive_fd; const char *PS1; const char *PS2; #endif #if ENABLE_FEATURE_EDITING line_input_t *line_input_state; #endif #if ENABLE_HUSH_JOB int run_list_level; pid_t saved_task_pgrp; pid_t saved_tty_pgrp; int last_jobid; struct pipe *job_list; struct pipe *toplevel_list; smallint ctrl_z_flag; #endif smallint fake_mode; /* these three support $?, $#, and $1 */ char **global_argv; int global_argc; int last_return_code; const char *ifs; const char *cwd; unsigned last_bg_pid; struct variable *top_var; /* = &shell_ver (set in main()) */ struct variable shell_ver; #if ENABLE_FEATURE_SH_STANDALONE struct nofork_save_area nofork_save; #endif #if ENABLE_HUSH_JOB sigjmp_buf toplevel_jb; #endif unsigned char charmap[256]; char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2]; }; #define G (*ptr_to_globals) #if !ENABLE_HUSH_INTERACTIVE enum { interactive_fd = 0 }; #endif #if !ENABLE_HUSH_JOB enum { run_list_level = 0 }; #endif #if ENABLE_HUSH_INTERACTIVE #define interactive_fd (G.interactive_fd ) #define PS1 (G.PS1 ) #define PS2 (G.PS2 ) #endif #if ENABLE_FEATURE_EDITING #define line_input_state (G.line_input_state) #endif #if ENABLE_HUSH_JOB #define run_list_level (G.run_list_level ) #define saved_task_pgrp (G.saved_task_pgrp ) #define saved_tty_pgrp (G.saved_tty_pgrp ) #define last_jobid (G.last_jobid ) #define job_list (G.job_list ) #define toplevel_list (G.toplevel_list ) #define toplevel_jb (G.toplevel_jb ) #define ctrl_z_flag (G.ctrl_z_flag ) #endif /* JOB */ #define global_argv (G.global_argv ) #define global_argc (G.global_argc ) #define last_return_code (G.last_return_code) #define ifs (G.ifs ) #define fake_mode (G.fake_mode ) #define cwd (G.cwd ) #define last_bg_pid (G.last_bg_pid ) #define top_var (G.top_var ) #define shell_ver (G.shell_ver ) #if ENABLE_FEATURE_SH_STANDALONE #define nofork_save (G.nofork_save ) #endif #if ENABLE_HUSH_JOB #define toplevel_jb (G.toplevel_jb ) #endif #define charmap (G.charmap ) #define user_input_buf (G.user_input_buf ) #define INIT_G() do { \ SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \ } while (0) #define B_CHUNK 100 #define B_NOSPAC 1 #define JOB_STATUS_FORMAT "[%d] %-22s %.40s\n" #if 1 /* Normal */ static void syntax(const char *msg) { /* Was using fancy stuff: * (interactive_fd ? bb_error_msg : bb_error_msg_and_die)(...params...) * but it SEGVs. ?! Oh well... explicit temp ptr works around that */ void (*fp)(const char *s, ...); fp = (interactive_fd ? bb_error_msg : bb_error_msg_and_die); fp(msg ? "%s: %s" : "syntax error", "syntax error", msg); } #else /* Debug */ static void syntax_lineno(int line) { void (*fp)(const char *s, ...); fp = (interactive_fd ? bb_error_msg : bb_error_msg_and_die); fp("syntax error hush.c:%d", line); } #define syntax(str) syntax_lineno(__LINE__) #endif /* Index of subroutines: */ /* o_string manipulation: */ static int b_check_space(o_string *o, int len); static int b_addchr(o_string *o, int ch); static void b_reset(o_string *o); static int b_addqchr(o_string *o, int ch, int quote); /* in_str manipulations: */ static int static_get(struct in_str *i); static int static_peek(struct in_str *i); static int file_get(struct in_str *i); static int file_peek(struct in_str *i); static void setup_file_in_str(struct in_str *i, FILE *f); static void setup_string_in_str(struct in_str *i, const char *s); /* "run" the final data structures: */ #if !defined(DEBUG_CLEAN) #define free_pipe_list(head, indent) free_pipe_list(head) #define free_pipe(pi, indent) free_pipe(pi) #endif static int free_pipe_list(struct pipe *head, int indent); static int free_pipe(struct pipe *pi, int indent); /* really run the final data structures: */ static int setup_redirects(struct child_prog *prog, int squirrel[]); static int run_list(struct pipe *pi); static void pseudo_exec_argv(char **argv) ATTRIBUTE_NORETURN; static void pseudo_exec(struct child_prog *child) ATTRIBUTE_NORETURN; static int run_pipe(struct pipe *pi); /* extended glob support: */ static char **globhack(const char *src, char **strings); static int glob_needed(const char *s); static int xglob(o_string *dest, char ***pglob); /* variable assignment: */ static int is_assignment(const char *s); /* data structure manipulation: */ static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input); static void initialize_context(struct p_context *ctx); static int done_word(o_string *dest, struct p_context *ctx); static int done_command(struct p_context *ctx); static int done_pipe(struct p_context *ctx, pipe_style type); /* primary string parsing: */ static int redirect_dup_num(struct in_str *input); static int redirect_opt_num(o_string *o); #if ENABLE_HUSH_TICK static int process_command_subs(o_string *dest, /*struct p_context *ctx,*/ struct in_str *input, const char *subst_end); #endif static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch); static const char *lookup_param(const char *src); static int handle_dollar(o_string *dest, /*struct p_context *ctx,*/ struct in_str *input); static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input0, const char *end_trigger); /* setup: */ static int parse_and_run_stream(struct in_str *inp, int parse_flag); static int parse_and_run_string(const char *s, int parse_flag); static int parse_and_run_file(FILE *f); /* job management: */ static int checkjobs(struct pipe* fg_pipe); #if ENABLE_HUSH_JOB static int checkjobs_and_fg_shell(struct pipe* fg_pipe); static void insert_bg_job(struct pipe *pi); static void remove_bg_job(struct pipe *pi); static void delete_finished_bg_job(struct pipe *pi); #else int checkjobs_and_fg_shell(struct pipe* fg_pipe); /* never called */ #endif /* local variable support */ static char **expand_strvec_to_strvec(char **argv); /* used for eval */ static char *expand_strvec_to_string(char **argv); /* used for expansion of right hand of assignments */ static char *expand_string_to_string(const char *str); static struct variable *get_local_var(const char *name); static int set_local_var(char *str, int flg_export); static void unset_local_var(const char *name); static char **add_strings_to_strings(int need_xstrdup, char **strings, char **add) { int i; unsigned count1; unsigned count2; char **v; v = strings; count1 = 0; if (v) { while (*v) { count1++; v++; } } count2 = 0; v = add; while (*v) { count2++; v++; } v = xrealloc(strings, (count1 + count2 + 1) * sizeof(char*)); v[count1 + count2] = NULL; i = count2; while (--i >= 0) v[count1 + i] = need_xstrdup ? xstrdup(add[i]) : add[i]; return v; } /* 'add' should be a malloced pointer */ static char **add_string_to_strings(char **strings, char *add) { char *v[2]; v[0] = add; v[1] = NULL; return add_strings_to_strings(0, strings, v); } static void free_strings(char **strings) { if (strings) { char **v = strings; while (*v) free(*v++); free(strings); } } /* Function prototypes for builtins */ static int builtin_cd(char **argv); static int builtin_echo(char **argv); static int builtin_eval(char **argv); static int builtin_exec(char **argv); static int builtin_exit(char **argv); static int builtin_export(char **argv); #if ENABLE_HUSH_JOB static int builtin_fg_bg(char **argv); static int builtin_jobs(char **argv); #endif #if ENABLE_HUSH_HELP static int builtin_help(char **argv); #endif static int builtin_pwd(char **argv); static int builtin_read(char **argv); static int builtin_test(char **argv); static int builtin_set(char **argv); static int builtin_shift(char **argv); static int builtin_source(char **argv); static int builtin_umask(char **argv); static int builtin_unset(char **argv); //static int builtin_not_written(char **argv); /* Table of built-in functions. They can be forked or not, depending on * context: within pipes, they fork. As simple commands, they do not. * When used in non-forking context, they can change global variables * in the parent shell process. If forked, of course they cannot. * For example, 'unset foo | whatever' will parse and run, but foo will * still be set at the end. */ struct built_in_command { const char *cmd; /* name */ int (*function) (char **argv); /* function ptr */ #if ENABLE_HUSH_HELP const char *descr; /* description */ #define BLTIN(cmd, func, help) { cmd, func, help } #else #define BLTIN(cmd, func, help) { cmd, func } #endif }; /* For now, echo and test are unconditionally enabled. * Maybe make it configurable? */ static const struct built_in_command bltins[] = { BLTIN("[" , builtin_test, "Test condition"), BLTIN("[[" , builtin_test, "Test condition"), #if ENABLE_HUSH_JOB BLTIN("bg" , builtin_fg_bg, "Resume a job in the background"), #endif // BLTIN("break" , builtin_not_written, "Exit for, while or until loop"), BLTIN("cd" , builtin_cd, "Change working directory"), // BLTIN("continue", builtin_not_written, "Continue for, while or until loop"), BLTIN("echo" , builtin_echo, "Write strings to stdout"), BLTIN("eval" , builtin_eval, "Construct and run shell command"), BLTIN("exec" , builtin_exec, "Exec command, replacing this shell with the exec'd process"), BLTIN("exit" , builtin_exit, "Exit from shell"), BLTIN("export", builtin_export, "Set environment variable"), #if ENABLE_HUSH_JOB BLTIN("fg" , builtin_fg_bg, "Bring job into the foreground"), BLTIN("jobs" , builtin_jobs, "Lists the active jobs"), #endif // TODO: remove pwd? we have it as an applet... BLTIN("pwd" , builtin_pwd, "Print current directory"), BLTIN("read" , builtin_read, "Input environment variable"), // BLTIN("return", builtin_not_written, "Return from a function"), BLTIN("set" , builtin_set, "Set/unset shell local variables"), BLTIN("shift" , builtin_shift, "Shift positional parameters"), // BLTIN("trap" , builtin_not_written, "Trap signals"), BLTIN("test" , builtin_test, "Test condition"), // BLTIN("ulimit", builtin_not_written, "Controls resource limits"), BLTIN("umask" , builtin_umask, "Sets file creation mask"), BLTIN("unset" , builtin_unset, "Unset environment variable"), BLTIN("." , builtin_source, "Source-in and run commands in a file"), #if ENABLE_HUSH_HELP BLTIN("help" , builtin_help, "List shell built-in commands"), #endif BLTIN(NULL, NULL, NULL) }; #if ENABLE_HUSH_JOB /* Signals are grouped, we handle them in batches */ static void set_fatal_sighandler(void (*handler)(int)) { bb_signals(0 + (1 << SIGILL) + (1 << SIGTRAP) + (1 << SIGABRT) + (1 << SIGFPE) + (1 << SIGBUS) + (1 << SIGSEGV) /* bash 3.2 seems to handle these just like 'fatal' ones */ + (1 << SIGHUP) + (1 << SIGPIPE) + (1 << SIGALRM) , handler); } static void set_jobctrl_sighandler(void (*handler)(int)) { bb_signals(0 + (1 << SIGTSTP) + (1 << SIGTTIN) + (1 << SIGTTOU) , handler); } static void set_misc_sighandler(void (*handler)(int)) { bb_signals(0 + (1 << SIGINT) + (1 << SIGQUIT) + (1 << SIGTERM) , handler); } /* SIGCHLD is special and handled separately */ static void set_every_sighandler(void (*handler)(int)) { set_fatal_sighandler(handler); set_jobctrl_sighandler(handler); set_misc_sighandler(handler); signal(SIGCHLD, handler); } static void handler_ctrl_c(int sig ATTRIBUTE_UNUSED) { debug_printf_jobs("got sig %d\n", sig); // as usual we can have all kinds of nasty problems with leaked malloc data here siglongjmp(toplevel_jb, 1); } static void handler_ctrl_z(int sig ATTRIBUTE_UNUSED) { pid_t pid; debug_printf_jobs("got tty sig %d in pid %d\n", sig, getpid()); pid = fork(); if (pid < 0) /* can't fork. Pretend there was no ctrl-Z */ return; ctrl_z_flag = 1; if (!pid) { /* child */ if (ENABLE_HUSH_JOB) die_sleep = 0; /* let nofork's xfuncs die */ setpgrp(); debug_printf_jobs("set pgrp for child %d ok\n", getpid()); set_every_sighandler(SIG_DFL); raise(SIGTSTP); /* resend TSTP so that child will be stopped */ debug_printf_jobs("returning in child\n"); /* return to nofork, it will eventually exit now, * not return back to shell */ return; } /* parent */ /* finish filling up pipe info */ toplevel_list->pgrp = pid; /* child is in its own pgrp */ toplevel_list->progs[0].pid = pid; /* parent needs to longjmp out of running nofork. * we will "return" exitcode 0, with child put in background */ // as usual we can have all kinds of nasty problems with leaked malloc data here debug_printf_jobs("siglongjmp in parent\n"); siglongjmp(toplevel_jb, 1); } /* Restores tty foreground process group, and exits. * May be called as signal handler for fatal signal * (will faithfully resend signal to itself, producing correct exit state) * or called directly with -EXITCODE. * We also call it if xfunc is exiting. */ static void sigexit(int sig) ATTRIBUTE_NORETURN; static void sigexit(int sig) { /* Disable all signals: job control, SIGPIPE, etc. */ sigprocmask_allsigs(SIG_BLOCK); if (interactive_fd) tcsetpgrp(interactive_fd, saved_tty_pgrp); /* Not a signal, just exit */ if (sig <= 0) _exit(- sig); kill_myself_with_sig(sig); /* does not return */ } /* Restores tty foreground process group, and exits. */ static void hush_exit(int exitcode) ATTRIBUTE_NORETURN; static void hush_exit(int exitcode) { fflush(NULL); /* flush all streams */ sigexit(- (exitcode & 0xff)); } #else /* !JOB */ #define set_fatal_sighandler(handler) ((void)0) #define set_jobctrl_sighandler(handler) ((void)0) #define set_misc_sighandler(handler) ((void)0) #define hush_exit(e) exit(e) #endif /* JOB */ static const char *set_cwd(void) { if (cwd == bb_msg_unknown) cwd = NULL; /* xrealloc_getcwd_or_warn(arg) calls free(arg)! */ cwd = xrealloc_getcwd_or_warn((char *)cwd); if (!cwd) cwd = bb_msg_unknown; return cwd; } /* built-in 'test' handler */ static int builtin_test(char **argv) { int argc = 0; while (*argv) { argc++; argv++; } return test_main(argc, argv - argc); } /* built-in 'test' handler */ static int builtin_echo(char **argv) { int argc = 0; while (*argv) { argc++; argv++; } return echo_main(argc, argv - argc); } /* built-in 'eval' handler */ static int builtin_eval(char **argv) { int rcode = EXIT_SUCCESS; if (argv[1]) { char *str = expand_strvec_to_string(argv + 1); parse_and_run_string(str, PARSEFLAG_EXIT_FROM_LOOP | PARSEFLAG_SEMICOLON); free(str); rcode = last_return_code; } return rcode; } /* built-in 'cd <path>' handler */ static int builtin_cd(char **argv) { const char *newdir; if (argv[1] == NULL) { // bash does nothing (exitcode 0) if HOME is ""; if it's unset, // bash says "bash: cd: HOME not set" and does nothing (exitcode 1) newdir = getenv("HOME") ? : "/"; } else newdir = argv[1]; if (chdir(newdir)) { printf("cd: %s: %s\n", newdir, strerror(errno)); return EXIT_FAILURE; } set_cwd(); return EXIT_SUCCESS; } /* built-in 'exec' handler */ static int builtin_exec(char **argv) { if (argv[1] == NULL) return EXIT_SUCCESS; /* bash does this */ // FIXME: if exec fails, bash does NOT exit! We do... pseudo_exec_argv(argv + 1); /* never returns */ } /* built-in 'exit' handler */ static int builtin_exit(char **argv) { // TODO: bash does it ONLY on top-level sh exit (+interacive only?) //puts("exit"); /* bash does it */ // TODO: warn if we have background jobs: "There are stopped jobs" // On second consecutive 'exit', exit anyway. if (argv[1] == NULL) hush_exit(last_return_code); /* mimic bash: exit 123abc == exit 255 + error msg */ xfunc_error_retval = 255; /* bash: exit -2 == exit 254, no error msg */ hush_exit(xatoi(argv[1]) & 0xff); } /* built-in 'export VAR=value' handler */ static int builtin_export(char **argv) { const char *value; char *name = argv[1]; if (name == NULL) { // TODO: // ash emits: export VAR='VAL' // bash: declare -x VAR="VAL" // (both also escape as needed (quotes, $, etc)) char **e = environ; if (e) while (*e) puts(*e++); return EXIT_SUCCESS; } value = strchr(name, '='); if (!value) { /* They are exporting something without a =VALUE */ struct variable *var; var = get_local_var(name); if (var) { var->flg_export = 1; putenv(var->varstr); } /* bash does not return an error when trying to export * an undefined variable. Do likewise. */ return EXIT_SUCCESS; } set_local_var(xstrdup(name), 1); return EXIT_SUCCESS; } #if ENABLE_HUSH_JOB /* built-in 'fg' and 'bg' handler */ static int builtin_fg_bg(char **argv) { int i, jobnum; struct pipe *pi; if (!interactive_fd) return EXIT_FAILURE; /* If they gave us no args, assume they want the last backgrounded task */ if (!argv[1]) { for (pi = job_list; pi; pi = pi->next) { if (pi->jobid == last_jobid) { goto found; } } bb_error_msg("%s: no current job", argv[0]); return EXIT_FAILURE; } if (sscanf(argv[1], "%%%d", &jobnum) != 1) { bb_error_msg("%s: bad argument '%s'", argv[0], argv[1]); return EXIT_FAILURE; } for (pi = job_list; pi; pi = pi->next) { if (pi->jobid == jobnum) { goto found; } } bb_error_msg("%s: %d: no such job", argv[0], jobnum); return EXIT_FAILURE; found: // TODO: bash prints a string representation // of job being foregrounded (like "sleep 1 | cat") if (*argv[0] == 'f') { /* Put the job into the foreground. */ tcsetpgrp(interactive_fd, pi->pgrp); } /* Restart the processes in the job */ debug_printf_jobs("reviving %d procs, pgrp %d\n", pi->num_progs, pi->pgrp); for (i = 0; i < pi->num_progs; i++) { debug_printf_jobs("reviving pid %d\n", pi->progs[i].pid); pi->progs[i].is_stopped = 0; } pi->stopped_progs = 0; i = kill(- pi->pgrp, SIGCONT); if (i < 0) { if (errno == ESRCH) { delete_finished_bg_job(pi); return EXIT_SUCCESS; } else { bb_perror_msg("kill (SIGCONT)"); } } if (*argv[0] == 'f') { remove_bg_job(pi); return checkjobs_and_fg_shell(pi); } return EXIT_SUCCESS; } #endif /* built-in 'help' handler */ #if ENABLE_HUSH_HELP static int builtin_help(char **argv ATTRIBUTE_UNUSED) { const struct built_in_command *x; printf("\nBuilt-in commands:\n"); printf("-------------------\n"); for (x = bltins; x->cmd; x++) { printf("%s\t%s\n", x->cmd, x->descr); } printf("\n\n"); return EXIT_SUCCESS; } #endif #if ENABLE_HUSH_JOB /* built-in 'jobs' handler */ static int builtin_jobs(char **argv ATTRIBUTE_UNUSED) { struct pipe *job; const char *status_string; for (job = job_list; job; job = job->next) { if (job->running_progs == job->stopped_progs) status_string = "Stopped"; else status_string = "Running"; printf(JOB_STATUS_FORMAT, job->jobid, status_string, job->cmdtext); } return EXIT_SUCCESS; } #endif /* built-in 'pwd' handler */ static int builtin_pwd(char **argv ATTRIBUTE_UNUSED) { puts(set_cwd()); return EXIT_SUCCESS; } /* built-in 'read VAR' handler */ static int builtin_read(char **argv) { char *string; const char *name = argv[1] ? argv[1] : "REPLY"; string = xmalloc_reads(STDIN_FILENO, xasprintf("%s=", name), NULL); return set_local_var(string, 0); } /* built-in 'set [VAR=value]' handler */ static int builtin_set(char **argv) { char *temp = argv[1]; struct variable *e; if (temp == NULL) for (e = top_var; e; e = e->next) puts(e->varstr); else set_local_var(xstrdup(temp), 0); return EXIT_SUCCESS; } /* Built-in 'shift' handler */ static int builtin_shift(char **argv) { int n = 1; if (argv[1]) { n = atoi(argv[1]); } if (n >= 0 && n < global_argc) { global_argv[n] = global_argv[0]; global_argc -= n; global_argv += n; return EXIT_SUCCESS; } return EXIT_FAILURE; } /* Built-in '.' handler (read-in and execute commands from file) */ static int builtin_source(char **argv) { FILE *input; int status; if (argv[1] == NULL) return EXIT_FAILURE; /* XXX search through $PATH is missing */ input = fopen(argv[1], "r"); if (!input) { bb_error_msg("cannot open '%s'", argv[1]); return EXIT_FAILURE; } close_on_exec_on(fileno(input)); /* Now run the file */ /* XXX argv and argc are broken; need to save old global_argv * (pointer only is OK!) on this stack frame, * set global_argv=argv+1, recurse, and restore. */ status = parse_and_run_file(input); fclose(input); return status; } static int builtin_umask(char **argv) { mode_t new_umask; const char *arg = argv[1]; char *end; if (arg) { new_umask = strtoul(arg, &end, 8); if (*end != '\0' || end == arg) { return EXIT_FAILURE; } } else { new_umask = umask(0); printf("%.3o\n", (unsigned) new_umask); } umask(new_umask); return EXIT_SUCCESS; } /* built-in 'unset VAR' handler */ static int builtin_unset(char **argv) { /* bash always returns true */ unset_local_var(argv[1]); return EXIT_SUCCESS; } //static int builtin_not_written(char **argv) //{ // printf("builtin_%s not written\n", argv[0]); // return EXIT_FAILURE; //} static int b_check_space(o_string *o, int len) { /* It would be easy to drop a more restrictive policy * in here, such as setting a maximum string length */ if (o->length + len > o->maxlen) { /* assert(data == NULL || o->maxlen != 0); */ o->maxlen += (2*len > B_CHUNK ? 2*len : B_CHUNK); o->data = xrealloc(o->data, 1 + o->maxlen); } return o->data == NULL; } static int b_addchr(o_string *o, int ch) { debug_printf("b_addchr: '%c' o->length=%d o=%p\n", ch, o->length, o); if (b_check_space(o, 1)) return B_NOSPAC; o->data[o->length] = ch; o->length++; o->data[o->length] = '\0'; return 0; } static void b_reset(o_string *o) { o->length = 0; o->nonnull = 0; if (o->data) o->data[0] = '\0'; } static void b_free(o_string *o) { free(o->data); memset(o, 0, sizeof(*o)); } /* My analysis of quoting semantics tells me that state information * is associated with a destination, not a source. */ static int b_addqchr(o_string *o, int ch, int quote) { if (quote && strchr("*?[\\", ch)) { int rc; rc = b_addchr(o, '\\'); if (rc) return rc; } return b_addchr(o, ch); } static int static_get(struct in_str *i) { int ch = *i->p++; if (ch == '\0') return EOF; return ch; } static int static_peek(struct in_str *i) { return *i->p; } #if ENABLE_HUSH_INTERACTIVE #if ENABLE_FEATURE_EDITING static void cmdedit_set_initial_prompt(void) { #if !ENABLE_FEATURE_EDITING_FANCY_PROMPT PS1 = NULL; #else PS1 = getenv("PS1"); if (PS1 == NULL) PS1 = "\\w \\$ "; #endif } #endif /* EDITING */ static const char* setup_prompt_string(int promptmode) { const char *prompt_str; debug_printf("setup_prompt_string %d ", promptmode); #if !ENABLE_FEATURE_EDITING_FANCY_PROMPT /* Set up the prompt */ if (promptmode == 0) { /* PS1 */ free((char*)PS1); PS1 = xasprintf("%s %c ", cwd, (geteuid() != 0) ? '$' : '#'); prompt_str = PS1; } else { prompt_str = PS2; } #else prompt_str = (promptmode == 0) ? PS1 : PS2; #endif debug_printf("result '%s'\n", prompt_str); return prompt_str; } static void get_user_input(struct in_str *i) { int r; const char *prompt_str; prompt_str = setup_prompt_string(i->promptmode); #if ENABLE_FEATURE_EDITING /* Enable command line editing only while a command line * is actually being read */ do { r = read_line_input(prompt_str, user_input_buf, BUFSIZ-1, line_input_state); } while (r == 0); /* repeat if Ctrl-C */ i->eof_flag = (r < 0); if (i->eof_flag) { /* EOF/error detected */ user_input_buf[0] = EOF; /* yes, it will be truncated, it's ok */ user_input_buf[1] = '\0'; } #else fputs(prompt_str, stdout); fflush(stdout); user_input_buf[0] = r = fgetc(i->file); /*user_input_buf[1] = '\0'; - already is and never changed */ i->eof_flag = (r == EOF); #endif i->p = user_input_buf; } #endif /* INTERACTIVE */ /* This is the magic location that prints prompts * and gets data back from the user */ static int file_get(struct in_str *i) { int ch; /* If there is data waiting, eat it up */ if (i->p && *i->p) { #if ENABLE_HUSH_INTERACTIVE take_cached: #endif ch = *i->p++; if (i->eof_flag && !*i->p) ch = EOF; } else { /* need to double check i->file because we might be doing something * more complicated by now, like sourcing or substituting. */ #if ENABLE_HUSH_INTERACTIVE if (interactive_fd && i->promptme && i->file == stdin) { do { get_user_input(i); } while (!*i->p); /* need non-empty line */ i->promptmode = 1; /* PS2 */ i->promptme = 0; goto take_cached; } #endif ch = fgetc(i->file); } debug_printf("file_get: got a '%c' %d\n", ch, ch); #if ENABLE_HUSH_INTERACTIVE if (ch == '\n') i->promptme = 1; #endif return ch; } /* All the callers guarantee this routine will never be * used right after a newline, so prompting is not needed. */ static int file_peek(struct in_str *i) { int ch; if (i->p && *i->p) { if (i->eof_flag && !i->p[1]) return EOF; return *i->p; } ch = fgetc(i->file); i->eof_flag = (ch == EOF); i->peek_buf[0] = ch; i->peek_buf[1] = '\0'; i->p = i->peek_buf; debug_printf("file_peek: got a '%c' %d\n", *i->p, *i->p); return ch; } static void setup_file_in_str(struct in_str *i, FILE *f) { i->peek = file_peek; i->get = file_get; #if ENABLE_HUSH_INTERACTIVE i->promptme = 1; i->promptmode = 0; /* PS1 */ #endif i->file = f; i->p = NULL; } static void setup_string_in_str(struct in_str *i, const char *s) { i->peek = static_peek; i->get = static_get; #if ENABLE_HUSH_INTERACTIVE i->promptme = 1; i->promptmode = 0; /* PS1 */ #endif i->p = s; i->eof_flag = 0; } /* squirrel != NULL means we squirrel away copies of stdin, stdout, * and stderr if they are redirected. */ static int setup_redirects(struct child_prog *prog, int squirrel[]) { int openfd, mode; struct redir_struct *redir; for (redir = prog->redirects; redir; redir = redir->next) { if (redir->dup == -1 && redir->glob_word == NULL) { /* something went wrong in the parse. Pretend it didn't happen */ continue; } if (redir->dup == -1) { char *p; mode = redir_table[redir->type].mode; p = expand_string_to_string(redir->glob_word[0]); openfd = open_or_warn(p, mode); free(p); if (openfd < 0) { /* this could get lost if stderr has been redirected, but bash and ash both lose it as well (though zsh doesn't!) */ return 1; } } else { openfd = redir->dup; } if (openfd != redir->fd) { if (squirrel && redir->fd < 3) { squirrel[redir->fd] = dup(redir->fd); } if (openfd == -3) { //close(openfd); // close(-3) ??! } else { dup2(openfd, redir->fd); if (redir->dup == -1) close(openfd); } } } return 0; } static void restore_redirects(int squirrel[]) { int i, fd; for (i = 0; i < 3; i++) { fd = squirrel[i]; if (fd != -1) { /* We simply die on error */ xmove_fd(fd, i); } } } /* Called after [v]fork() in run_pipe(), or from builtin_exec(). * Never returns. * XXX no exit() here. If you don't exec, use _exit instead. * The at_exit handlers apparently confuse the calling process, * in particular stdin handling. Not sure why? -- because of vfork! (vda) */ static void pseudo_exec_argv(char **argv) { int i, rcode; char *p; const struct built_in_command *x; for (i = 0; is_assignment(argv[i]); i++) { debug_printf_exec("pid %d environment modification: %s\n", getpid(), argv[i]); // FIXME: vfork case?? p = expand_string_to_string(argv[i]); putenv(p); } argv += i; /* If a variable is assigned in a forest, and nobody listens, * was it ever really set? */ if (!argv[0]) _exit(EXIT_SUCCESS); argv = expand_strvec_to_strvec(argv); /* * Check if the command matches any of the builtins. * Depending on context, this might be redundant. But it's * easier to waste a few CPU cycles than it is to figure out * if this is one of those cases. */ for (x = bltins; x->cmd; x++) { if (strcmp(argv[0], x->cmd) == 0) { debug_printf_exec("running builtin '%s'\n", argv[0]); rcode = x->function(argv); fflush(stdout); _exit(rcode); } } /* Check if the command matches any busybox applets */ #if ENABLE_FEATURE_SH_STANDALONE if (strchr(argv[0], '/') == NULL) { int a = find_applet_by_name(argv[0]); if (a >= 0) { if (APPLET_IS_NOEXEC(a)) { debug_printf_exec("running applet '%s'\n", argv[0]); // is it ok that run_applet_no_and_exit() does exit(), not _exit()? run_applet_no_and_exit(a, argv); } /* re-exec ourselves with the new arguments */ debug_printf_exec("re-execing applet '%s'\n", argv[0]); execvp(bb_busybox_exec_path, argv); /* If they called chroot or otherwise made the binary no longer * executable, fall through */ } } #endif debug_printf_exec("execing '%s'\n", argv[0]); execvp(argv[0], argv); bb_perror_msg("cannot exec '%s'", argv[0]); _exit(1); } /* Called after [v]fork() in run_pipe() */ static void pseudo_exec(struct child_prog *child) { // FIXME: buggy wrt NOMMU! Must not modify any global data // until it does exec/_exit, but currently it does // (puts malloc'ed stuff into environment) if (child->argv) pseudo_exec_argv(child->argv); if (child->group) { #if !BB_MMU bb_error_msg_and_die("nested lists are not supported on NOMMU"); #else int rcode; #if ENABLE_HUSH_INTERACTIVE // run_list_level now takes care of it? // debug_printf_exec("pseudo_exec: setting interactive_fd=0\n"); // interactive_fd = 0; /* crucial!!!! */ #endif debug_printf_exec("pseudo_exec: run_list\n"); rcode = run_list(child->group); /* OK to leak memory by not calling free_pipe_list, * since this process is about to exit */ _exit(rcode); #endif } /* Can happen. See what bash does with ">foo" by itself. */ debug_printf("trying to pseudo_exec null command\n"); _exit(EXIT_SUCCESS); } #if ENABLE_HUSH_JOB static const char *get_cmdtext(struct pipe *pi) { char **argv; char *p; int len; /* This is subtle. ->cmdtext is created only on first backgrounding. * (Think "cat, <ctrl-z>, fg, <ctrl-z>, fg, <ctrl-z>...." here...) * On subsequent bg argv is trashed, but we won't use it */ if (pi->cmdtext) return pi->cmdtext; argv = pi->progs[0].argv; if (!argv || !argv[0]) return (pi->cmdtext = xzalloc(1)); len = 0; do len += strlen(*argv) + 1; while (*++argv); pi->cmdtext = p = xmalloc(len); argv = pi->progs[0].argv; do { len = strlen(*argv); memcpy(p, *argv, len); p += len; *p++ = ' '; } while (*++argv); p[-1] = '\0'; return pi->cmdtext; } static void insert_bg_job(struct pipe *pi) { struct pipe *thejob; int i; /* Linear search for the ID of the job to use */ pi->jobid = 1; for (thejob = job_list; thejob; thejob = thejob->next) if (thejob->jobid >= pi->jobid) pi->jobid = thejob->jobid + 1; /* Add thejob to the list of running jobs */ if (!job_list) { thejob = job_list = xmalloc(sizeof(*thejob)); } else { for (thejob = job_list; thejob->next; thejob = thejob->next) continue; thejob->next = xmalloc(sizeof(*thejob)); thejob = thejob->next; } /* Physically copy the struct job */ memcpy(thejob, pi, sizeof(struct pipe)); thejob->progs = xzalloc(sizeof(pi->progs[0]) * pi->num_progs); /* We cannot copy entire pi->progs[] vector! Double free()s will happen */ for (i = 0; i < pi->num_progs; i++) { // TODO: do we really need to have so many fields which are just dead weight // at execution stage? thejob->progs[i].pid = pi->progs[i].pid; /* all other fields are not used and stay zero */ } thejob->next = NULL; thejob->cmdtext = xstrdup(get_cmdtext(pi)); /* We don't wait for background thejobs to return -- append it to the list of backgrounded thejobs and leave it alone */ printf("[%d] %d %s\n", thejob->jobid, thejob->progs[0].pid, thejob->cmdtext); last_bg_pid = thejob->progs[0].pid; last_jobid = thejob->jobid; } static void remove_bg_job(struct pipe *pi) { struct pipe *prev_pipe; if (pi == job_list) { job_list = pi->next; } else { prev_pipe = job_list; while (prev_pipe->next != pi) prev_pipe = prev_pipe->next; prev_pipe->next = pi->next; } if (job_list) last_jobid = job_list->jobid; else last_jobid = 0; } /* remove a backgrounded job */ static void delete_finished_bg_job(struct pipe *pi) { remove_bg_job(pi); pi->stopped_progs = 0; free_pipe(pi, 0); free(pi); } #endif /* JOB */ /* Checks to see if any processes have exited -- if they have, figure out why and see if a job has completed */ static int checkjobs(struct pipe* fg_pipe) { int attributes; int status; #if ENABLE_HUSH_JOB int prognum = 0; struct pipe *pi; #endif pid_t childpid; int rcode = 0; attributes = WUNTRACED; if (fg_pipe == NULL) { attributes |= WNOHANG; } /* Do we do this right? * bash-3.00# sleep 20 | false * <ctrl-Z pressed> * [3]+ Stopped sleep 20 | false * bash-3.00# echo $? * 1 <========== bg pipe is not fully done, but exitcode is already known! */ //FIXME: non-interactive bash does not continue even if all processes in fg pipe //are stopped. Testcase: "cat | cat" in a script (not on command line) // + killall -STOP cat wait_more: // TODO: safe_waitpid? while ((childpid = waitpid(-1, &status, attributes)) > 0) { const int dead = WIFEXITED(status) || WIFSIGNALED(status); #ifdef DEBUG_SHELL_JOBS if (WIFSTOPPED(status)) debug_printf_jobs("pid %d stopped by sig %d (exitcode %d)\n", childpid, WSTOPSIG(status), WEXITSTATUS(status)); if (WIFSIGNALED(status)) debug_printf_jobs("pid %d killed by sig %d (exitcode %d)\n", childpid, WTERMSIG(status), WEXITSTATUS(status)); if (WIFEXITED(status)) debug_printf_jobs("pid %d exited, exitcode %d\n", childpid, WEXITSTATUS(status)); #endif /* Were we asked to wait for fg pipe? */ if (fg_pipe) { int i; for (i = 0; i < fg_pipe->num_progs; i++) { debug_printf_jobs("check pid %d\n", fg_pipe->progs[i].pid); if (fg_pipe->progs[i].pid == childpid) { /* printf("process %d exit %d\n", i, WEXITSTATUS(status)); */ if (dead) { fg_pipe->progs[i].pid = 0; fg_pipe->running_progs--; if (i == fg_pipe->num_progs - 1) /* last process gives overall exitstatus */ rcode = WEXITSTATUS(status); } else { fg_pipe->progs[i].is_stopped = 1; fg_pipe->stopped_progs++; } debug_printf_jobs("fg_pipe: running_progs %d stopped_progs %d\n", fg_pipe->running_progs, fg_pipe->stopped_progs); if (fg_pipe->running_progs - fg_pipe->stopped_progs <= 0) { /* All processes in fg pipe have exited/stopped */ #if ENABLE_HUSH_JOB if (fg_pipe->running_progs) insert_bg_job(fg_pipe); #endif return rcode; } /* There are still running processes in the fg pipe */ goto wait_more; } } /* fall through to searching process in bg pipes */ } #if ENABLE_HUSH_JOB /* We asked to wait for bg or orphaned children */ /* No need to remember exitcode in this case */ for (pi = job_list; pi; pi = pi->next) { prognum = 0; while (prognum < pi->num_progs) { if (pi->progs[prognum].pid == childpid) goto found_pi_and_prognum; prognum++; } } #endif /* Happens when shell is used as init process (init=/bin/sh) */ debug_printf("checkjobs: pid %d was not in our list!\n", childpid); goto wait_more; #if ENABLE_HUSH_JOB found_pi_and_prognum: if (dead) { /* child exited */ pi->progs[prognum].pid = 0; pi->running_progs--; if (!pi->running_progs) { printf(JOB_STATUS_FORMAT, pi->jobid, "Done", pi->cmdtext); delete_finished_bg_job(pi); } } else { /* child stopped */ pi->stopped_progs++; pi->progs[prognum].is_stopped = 1; } #endif } /* wait found no children or failed */ if (childpid && errno != ECHILD) bb_perror_msg("waitpid"); return rcode; } #if ENABLE_HUSH_JOB static int checkjobs_and_fg_shell(struct pipe* fg_pipe) { pid_t p; int rcode = checkjobs(fg_pipe); /* Job finished, move the shell to the foreground */ p = getpgid(0); /* pgid of our process */ debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p); if (tcsetpgrp(interactive_fd, p) && errno != ENOTTY) bb_perror_msg("tcsetpgrp-4a"); return rcode; } #endif /* run_pipe() starts all the jobs, but doesn't wait for anything * to finish. See checkjobs(). * * return code is normally -1, when the caller has to wait for children * to finish to determine the exit status of the pipe. If the pipe * is a simple builtin command, however, the action is done by the * time run_pipe returns, and the exit code is provided as the * return value. * * The input of the pipe is always stdin, the output is always * stdout. The outpipe[] mechanism in BusyBox-0.48 lash is bogus, * because it tries to avoid running the command substitution in * subshell, when that is in fact necessary. The subshell process * now has its stdout directed to the input of the appropriate pipe, * so this routine is noticeably simpler. * * Returns -1 only if started some children. IOW: we have to * mask out retvals of builtins etc with 0xff! */ static int run_pipe(struct pipe *pi) { int i; int nextin; int pipefds[2]; /* pipefds[0] is for reading */ struct child_prog *child; const struct built_in_command *x; char *p; /* it is not always needed, but we aim to smaller code */ int squirrel[] = { -1, -1, -1 }; int rcode; const int single_fg = (pi->num_progs == 1 && pi->followup != PIPE_BG); debug_printf_exec("run_pipe start: single_fg=%d\n", single_fg); #if ENABLE_HUSH_JOB pi->pgrp = -1; #endif pi->running_progs = 1; pi->stopped_progs = 0; /* Check if this is a simple builtin (not part of a pipe). * Builtins within pipes have to fork anyway, and are handled in * pseudo_exec. "echo foo | read bar" doesn't work on bash, either. */ child = &(pi->progs[0]); if (single_fg && child->group && child->subshell == 0) { debug_printf("non-subshell grouping\n"); setup_redirects(child, squirrel); debug_printf_exec(": run_list\n"); rcode = run_list(child->group) & 0xff; restore_redirects(squirrel); debug_printf_exec("run_pipe return %d\n", rcode); return rcode; } if (single_fg && child->argv != NULL) { char **argv_expanded; char **argv = child->argv; for (i = 0; is_assignment(argv[i]); i++) continue; if (i != 0 && argv[i] == NULL) { /* assignments, but no command: set the local environment */ for (i = 0; argv[i] != NULL; i++) { debug_printf("local environment set: %s\n", argv[i]); p = expand_string_to_string(argv[i]); set_local_var(p, 0); } return EXIT_SUCCESS; /* don't worry about errors in set_local_var() yet */ } for (i = 0; is_assignment(argv[i]); i++) { p = expand_string_to_string(argv[i]); //sp: child->sp--; putenv(p); } for (x = bltins; x->cmd; x++) { if (strcmp(argv[i], x->cmd) == 0) { if (x->function == builtin_exec && argv[i+1] == NULL) { debug_printf("magic exec\n"); setup_redirects(child, NULL); return EXIT_SUCCESS; } debug_printf("builtin inline %s\n", argv[0]); /* XXX setup_redirects acts on file descriptors, not FILEs. * This is perfect for work that comes after exec(). * Is it really safe for inline use? Experimentally, * things seem to work with glibc. */ setup_redirects(child, squirrel); debug_printf_exec(": builtin '%s' '%s'...\n", x->cmd, argv[i+1]); //sp: if (child->sp) /* btw we can do it unconditionally... */ argv_expanded = expand_strvec_to_strvec(argv + i); rcode = x->function(argv_expanded) & 0xff; free(argv_expanded); restore_redirects(squirrel); debug_printf_exec("run_pipe return %d\n", rcode); return rcode; } } #if ENABLE_FEATURE_SH_STANDALONE { int a = find_applet_by_name(argv[i]); if (a >= 0 && APPLET_IS_NOFORK(a)) { setup_redirects(child, squirrel); save_nofork_data(&nofork_save); argv_expanded = argv + i; //sp: if (child->sp) argv_expanded = expand_strvec_to_strvec(argv + i); debug_printf_exec(": run_nofork_applet '%s' '%s'...\n", argv_expanded[0], argv_expanded[1]); rcode = run_nofork_applet_prime(&nofork_save, a, argv_expanded); free(argv_expanded); restore_redirects(squirrel); debug_printf_exec("run_pipe return %d\n", rcode); return rcode; } } #endif } /* Disable job control signals for shell (parent) and * for initial child code after fork */ set_jobctrl_sighandler(SIG_IGN); /* Going to fork a child per each pipe member */ pi->running_progs = 0; nextin = 0; for (i = 0; i < pi->num_progs; i++) { child = &(pi->progs[i]); if (child->argv) debug_printf_exec(": pipe member '%s' '%s'...\n", child->argv[0], child->argv[1]); else debug_printf_exec(": pipe member with no argv\n"); /* pipes are inserted between pairs of commands */ pipefds[0] = 0; pipefds[1] = 1; if ((i + 1) < pi->num_progs) xpipe(pipefds); child->pid = BB_MMU ? fork() : vfork(); if (!child->pid) { /* child */ if (ENABLE_HUSH_JOB) die_sleep = 0; /* let nofork's xfuncs die */ #if ENABLE_HUSH_JOB /* Every child adds itself to new process group * with pgid == pid_of_first_child_in_pipe */ if (run_list_level == 1 && interactive_fd) { pid_t pgrp; /* Don't do pgrp restore anymore on fatal signals */ set_fatal_sighandler(SIG_DFL); pgrp = pi->pgrp; if (pgrp < 0) /* true for 1st process only */ pgrp = getpid(); if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) { /* We do it in *every* child, not just first, * to avoid races */ tcsetpgrp(interactive_fd, pgrp); } } #endif xmove_fd(nextin, 0); xmove_fd(pipefds[1], 1); /* write end */ if (pipefds[0] > 1) close(pipefds[0]); /* read end */ /* Like bash, explicit redirects override pipes, * and the pipe fd is available for dup'ing. */ setup_redirects(child, NULL); /* Restore default handlers just prior to exec */ set_jobctrl_sighandler(SIG_DFL); set_misc_sighandler(SIG_DFL); signal(SIGCHLD, SIG_DFL); pseudo_exec(child); /* does not return */ } if (child->pid < 0) { /* [v]fork failed */ /* Clearly indicate, was it fork or vfork */ bb_perror_msg(BB_MMU ? "fork" : "vfork"); } else { pi->running_progs++; #if ENABLE_HUSH_JOB /* Second and next children need to know pid of first one */ if (pi->pgrp < 0) pi->pgrp = child->pid; #endif } if (i) close(nextin); if ((i + 1) < pi->num_progs) close(pipefds[1]); /* write end */ /* Pass read (output) pipe end to next iteration */ nextin = pipefds[0]; } if (!pi->running_progs) { debug_printf_exec("run_pipe return 1 (all forks failed, no children)\n"); return 1; } debug_printf_exec("run_pipe return -1 (%u children started)\n", pi->running_progs); return -1; } #ifndef debug_print_tree static void debug_print_tree(struct pipe *pi, int lvl) { static const char *PIPE[] = { [PIPE_SEQ] = "SEQ", [PIPE_AND] = "AND", [PIPE_OR ] = "OR" , [PIPE_BG ] = "BG" , }; static const char *RES[] = { [RES_NONE ] = "NONE" , #if ENABLE_HUSH_IF [RES_IF ] = "IF" , [RES_THEN ] = "THEN" , [RES_ELIF ] = "ELIF" , [RES_ELSE ] = "ELSE" , [RES_FI ] = "FI" , #endif #if ENABLE_HUSH_LOOPS [RES_FOR ] = "FOR" , [RES_WHILE] = "WHILE", [RES_UNTIL] = "UNTIL", [RES_DO ] = "DO" , [RES_DONE ] = "DONE" , [RES_IN ] = "IN" , #endif [RES_XXXX ] = "XXXX" , [RES_SNTX ] = "SNTX" , }; int pin, prn; pin = 0; while (pi) { fprintf(stderr, "%*spipe %d res_word=%s followup=%d %s\n", lvl*2, "", pin, RES[pi->res_word], pi->followup, PIPE[pi->followup]); prn = 0; while (prn < pi->num_progs) { struct child_prog *child = &pi->progs[prn]; char **argv = child->argv; fprintf(stderr, "%*s prog %d", lvl*2, "", prn); if (child->group) { fprintf(stderr, " group %s: (argv=%p)\n", (child->subshell ? "()" : "{}"), argv); debug_print_tree(child->group, lvl+1); prn++; continue; } if (argv) while (*argv) { fprintf(stderr, " '%s'", *argv); argv++; } fprintf(stderr, "\n"); prn++; } pi = pi->next; pin++; } } #endif /* NB: called by pseudo_exec, and therefore must not modify any * global data until exec/_exit (we can be a child after vfork!) */ static int run_list(struct pipe *pi) { struct pipe *rpipe; #if ENABLE_HUSH_LOOPS char *for_varname = NULL; char **for_lcur = NULL; char **for_list = NULL; int flag_rep = 0; #endif int flag_skip = 1; int rcode = 0; /* probably for gcc only */ int flag_restore = 0; #if ENABLE_HUSH_IF int if_code = 0, next_if_code = 0; /* need double-buffer to handle elif */ #else enum { if_code = 0, next_if_code = 0 }; #endif reserved_style rword; reserved_style skip_more_for_this_rword = RES_XXXX; debug_printf_exec("run_list start lvl %d\n", run_list_level + 1); #if ENABLE_HUSH_LOOPS /* check syntax for "for" */ for (rpipe = pi; rpipe; rpipe = rpipe->next) { if ((rpipe->res_word == RES_IN || rpipe->res_word == RES_FOR) && (rpipe->next == NULL) ) { syntax("malformed for"); /* no IN or no commands after IN */ debug_printf_exec("run_list lvl %d return 1\n", run_list_level); return 1; } if ((rpipe->res_word == RES_IN && rpipe->next->res_word == RES_IN && rpipe->next->progs[0].argv != NULL) || (rpipe->res_word == RES_FOR && rpipe->next->res_word != RES_IN) ) { /* TODO: what is tested in the first condition? */ syntax("malformed for"); /* 2nd condition: not followed by IN */ debug_printf_exec("run_list lvl %d return 1\n", run_list_level); return 1; } } #else rpipe = NULL; #endif #if ENABLE_HUSH_JOB /* Example of nested list: "while true; do { sleep 1 | exit 2; } done". * We are saving state before entering outermost list ("while...done") * so that ctrl-Z will correctly background _entire_ outermost list, * not just a part of it (like "sleep 1 | exit 2") */ if (++run_list_level == 1 && interactive_fd) { if (sigsetjmp(toplevel_jb, 1)) { /* ctrl-Z forked and we are parent; or ctrl-C. * Sighandler has longjmped us here */ signal(SIGINT, SIG_IGN); signal(SIGTSTP, SIG_IGN); /* Restore level (we can be coming from deep inside * nested levels) */ run_list_level = 1; #if ENABLE_FEATURE_SH_STANDALONE if (nofork_save.saved) { /* if save area is valid */ debug_printf_jobs("exiting nofork early\n"); restore_nofork_data(&nofork_save); } #endif if (ctrl_z_flag) { /* ctrl-Z has forked and stored pid of the child in pi->pid. * Remember this child as background job */ insert_bg_job(pi); } else { /* ctrl-C. We just stop doing whatever we were doing */ bb_putchar('\n'); } rcode = 0; goto ret; } /* ctrl-Z handler will store pid etc in pi */ toplevel_list = pi; ctrl_z_flag = 0; #if ENABLE_FEATURE_SH_STANDALONE nofork_save.saved = 0; /* in case we will run a nofork later */ #endif signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z); signal(SIGINT, handler_ctrl_c); } #endif /* JOB */ for (; pi; pi = flag_restore ? rpipe : pi->next) { //why? int save_num_progs; rword = pi->res_word; #if ENABLE_HUSH_LOOPS if (rword == RES_WHILE || rword == RES_UNTIL || rword == RES_FOR) { flag_restore = 0; if (!rpipe) { flag_rep = 0; rpipe = pi; } } #endif debug_printf_exec(": rword=%d if_code=%d next_if_code=%d skip_more=%d\n", rword, if_code, next_if_code, skip_more_for_this_rword); if (rword == skip_more_for_this_rword && flag_skip) { if (pi->followup == PIPE_SEQ) flag_skip = 0; continue; } flag_skip = 1; skip_more_for_this_rword = RES_XXXX; #if ENABLE_HUSH_IF if (rword == RES_THEN || rword == RES_ELSE) if_code = next_if_code; if (rword == RES_THEN && if_code) continue; if (rword == RES_ELSE && !if_code) continue; if (rword == RES_ELIF && !if_code) break; #endif #if ENABLE_HUSH_LOOPS if (rword == RES_FOR && pi->num_progs) { if (!for_lcur) { /* first loop through for */ /* if no variable values after "in" we skip "for" */ if (!pi->next->progs->argv) continue; /* create list of variable values */ for_list = expand_strvec_to_strvec(pi->next->progs->argv); for_lcur = for_list; for_varname = pi->progs->argv[0]; pi->progs->argv[0] = NULL; flag_rep = 1; } free(pi->progs->argv[0]); if (!*for_lcur) { /* for loop is over, clean up */ free(for_list); for_lcur = NULL; flag_rep = 0; pi->progs->argv[0] = for_varname; continue; } /* insert next value from for_lcur */ /* vda: does it need escaping? */ pi->progs->argv[0] = xasprintf("%s=%s", for_varname, *for_lcur++); } if (rword == RES_IN) continue; if (rword == RES_DO) { if (!flag_rep) continue; } if (rword == RES_DONE) { if (flag_rep) { flag_restore = 1; } else { rpipe = NULL; } } #endif if (pi->num_progs == 0) continue; //why? save_num_progs = pi->num_progs; debug_printf_exec(": run_pipe with %d members\n", pi->num_progs); rcode = run_pipe(pi); if (rcode != -1) { /* We only ran a builtin: rcode was set by the return value * of run_pipe(), and we don't need to wait for anything. */ } else if (pi->followup == PIPE_BG) { /* What does bash do with attempts to background builtins? */ /* Even bash 3.2 doesn't do that well with nested bg: * try "{ { sleep 10; echo DEEP; } & echo HERE; } &". * I'm NOT treating inner &'s as jobs */ #if ENABLE_HUSH_JOB if (run_list_level == 1) insert_bg_job(pi); #endif rcode = EXIT_SUCCESS; } else { #if ENABLE_HUSH_JOB if (run_list_level == 1 && interactive_fd) { /* waits for completion, then fg's main shell */ rcode = checkjobs_and_fg_shell(pi); } else #endif { /* this one just waits for completion */ rcode = checkjobs(pi); } debug_printf_exec(": checkjobs returned %d\n", rcode); } debug_printf_exec(": setting last_return_code=%d\n", rcode); last_return_code = rcode; //why? pi->num_progs = save_num_progs; #if ENABLE_HUSH_IF if (rword == RES_IF || rword == RES_ELIF) next_if_code = rcode; /* can be overwritten a number of times */ #endif #if ENABLE_HUSH_LOOPS if (rword == RES_WHILE) flag_rep = !last_return_code; if (rword == RES_UNTIL) flag_rep = last_return_code; #endif if ((rcode == EXIT_SUCCESS && pi->followup == PIPE_OR) || (rcode != EXIT_SUCCESS && pi->followup == PIPE_AND) ) { skip_more_for_this_rword = rword; } checkjobs(NULL); } #if ENABLE_HUSH_JOB if (ctrl_z_flag) { /* ctrl-Z forked somewhere in the past, we are the child, * and now we completed running the list. Exit. */ exit(rcode); } ret: if (!--run_list_level && interactive_fd) { signal(SIGTSTP, SIG_IGN); signal(SIGINT, SIG_IGN); } #endif debug_printf_exec("run_list lvl %d return %d\n", run_list_level + 1, rcode); return rcode; } /* return code is the exit status of the pipe */ static int free_pipe(struct pipe *pi, int indent) { char **p; struct child_prog *child; struct redir_struct *r, *rnext; int a, i, ret_code = 0; if (pi->stopped_progs > 0) return ret_code; debug_printf_clean("%s run pipe: (pid %d)\n", indenter(indent), getpid()); for (i = 0; i < pi->num_progs; i++) { child = &pi->progs[i]; debug_printf_clean("%s command %d:\n", indenter(indent), i); if (child->argv) { for (a = 0, p = child->argv; *p; a++, p++) { debug_printf_clean("%s argv[%d] = %s\n", indenter(indent), a, *p); } free_strings(child->argv); child->argv = NULL; } else if (child->group) { debug_printf_clean("%s begin group (subshell:%d)\n", indenter(indent), child->subshell); ret_code = free_pipe_list(child->group, indent+3); debug_printf_clean("%s end group\n", indenter(indent)); } else { debug_printf_clean("%s (nil)\n", indenter(indent)); } for (r = child->redirects; r; r = rnext) { debug_printf_clean("%s redirect %d%s", indenter(indent), r->fd, redir_table[r->type].descrip); if (r->dup == -1) { /* guard against the case >$FOO, where foo is unset or blank */ if (r->glob_word) { debug_printf_clean(" %s\n", r->glob_word[0]); free_strings(r->glob_word); r->glob_word = NULL; } } else { debug_printf_clean("&%d\n", r->dup); } rnext = r->next; free(r); } child->redirects = NULL; } free(pi->progs); /* children are an array, they get freed all at once */ pi->progs = NULL; #if ENABLE_HUSH_JOB free(pi->cmdtext); pi->cmdtext = NULL; #endif return ret_code; } static int free_pipe_list(struct pipe *head, int indent) { int rcode = 0; /* if list has no members */ struct pipe *pi, *next; for (pi = head; pi; pi = next) { debug_printf_clean("%s pipe reserved mode %d\n", indenter(indent), pi->res_word); rcode = free_pipe(pi, indent); debug_printf_clean("%s pipe followup code %d\n", indenter(indent), pi->followup); next = pi->next; /*pi->next = NULL;*/ free(pi); } return rcode; } /* Select which version we will use */ static int run_and_free_list(struct pipe *pi) { int rcode = 0; debug_printf_exec("run_and_free_list entered\n"); if (!fake_mode) { debug_printf_exec(": run_list with %d members\n", pi->num_progs); rcode = run_list(pi); } /* free_pipe_list has the side effect of clearing memory. * In the long run that function can be merged with run_list, * but doing that now would hobble the debugging effort. */ free_pipe_list(pi, /* indent: */ 0); debug_printf_exec("run_nad_free_list return %d\n", rcode); return rcode; } /* Whoever decided to muck with glob internal data is AN IDIOT! */ /* uclibc happily changed the way it works (and it has rights to do so!), all hell broke loose (SEGVs) */ /* The API for glob is arguably broken. This routine pushes a non-matching * string into the output structure, removing non-backslashed backslashes. * If someone can prove me wrong, by performing this function within the * original glob(3) api, feel free to rewrite this routine into oblivion. * XXX broken if the last character is '\\', check that before calling. */ static char **globhack(const char *src, char **strings) { int cnt; const char *s; char *v, *dest; for (cnt = 1, s = src; s && *s; s++) { if (*s == '\\') s++; cnt++; } v = dest = xmalloc(cnt); for (s = src; s && *s; s++, dest++) { if (*s == '\\') s++; *dest = *s; } *dest = '\0'; return add_string_to_strings(strings, v); } /* XXX broken if the last character is '\\', check that before calling */ static int glob_needed(const char *s) { for (; *s; s++) { if (*s == '\\') s++; if (strchr("*[?", *s)) return 1; } return 0; } static int xglob(o_string *dest, char ***pglob) { /* short-circuit for null word */ /* we can code this better when the debug_printf's are gone */ if (dest->length == 0) { if (dest->nonnull) { /* bash man page calls this an "explicit" null */ *pglob = globhack(dest->data, *pglob); } return 0; } if (glob_needed(dest->data)) { glob_t globdata; int gr; memset(&globdata, 0, sizeof(globdata)); gr = glob(dest->data, 0, NULL, &globdata); debug_printf("glob returned %d\n", gr); if (gr == GLOB_NOSPACE) bb_error_msg_and_die("out of memory during glob"); if (gr == GLOB_NOMATCH) { debug_printf("globhack returned %d\n", gr); /* quote removal, or more accurately, backslash removal */ *pglob = globhack(dest->data, *pglob); globfree(&globdata); return 0; } if (gr != 0) { /* GLOB_ABORTED ? */ bb_error_msg("glob(3) error %d", gr); } if (globdata.gl_pathv && globdata.gl_pathv[0]) *pglob = add_strings_to_strings(1, *pglob, globdata.gl_pathv); globfree(&globdata); return gr; } *pglob = globhack(dest->data, *pglob); return 0; } /* expand_strvec_to_strvec() takes a list of strings, expands * all variable references within and returns a pointer to * a list of expanded strings, possibly with larger number * of strings. (Think VAR="a b"; echo $VAR). * This new list is allocated as a single malloc block. * NULL-terminated list of char* pointers is at the beginning of it, * followed by strings themself. * Caller can deallocate entire list by single free(list). */ /* Helpers first: * count_XXX estimates size of the block we need. It's okay * to over-estimate sizes a bit, if it makes code simpler */ static int count_ifs(const char *str) { int cnt = 0; debug_printf_expand("count_ifs('%s') ifs='%s'", str, ifs); while (1) { str += strcspn(str, ifs); if (!*str) break; str++; /* str += strspn(str, ifs); */ cnt++; /* cnt += strspn(str, ifs); - but this code is larger */ } debug_printf_expand(" return %d\n", cnt); return cnt; } static void count_var_expansion_space(int *countp, int *lenp, char *arg) { char first_ch; int i; int len = *lenp; int count = *countp; const char *val; char *p; while ((p = strchr(arg, SPECIAL_VAR_SYMBOL))) { len += p - arg; arg = ++p; p = strchr(p, SPECIAL_VAR_SYMBOL); first_ch = arg[0]; switch (first_ch & 0x7f) { /* high bit in 1st_ch indicates that var is double-quoted */ case '$': /* pid */ case '!': /* bg pid */ case '?': /* exitcode */ case '#': /* argc */ len += sizeof(int)*3 + 1; /* enough for int */ break; case '*': case '@': for (i = 1; global_argv[i]; i++) { len += strlen(global_argv[i]) + 1; count++; if (!(first_ch & 0x80)) count += count_ifs(global_argv[i]); } break; default: *p = '\0'; arg[0] = first_ch & 0x7f; if (isdigit(arg[0])) { i = xatoi_u(arg); val = NULL; if (i < global_argc) val = global_argv[i]; } else val = lookup_param(arg); arg[0] = first_ch; *p = SPECIAL_VAR_SYMBOL; if (val) { len += strlen(val) + 1; if (!(first_ch & 0x80)) count += count_ifs(val); } } arg = ++p; } len += strlen(arg) + 1; count++; *lenp = len; *countp = count; } /* Store given string, finalizing the word and starting new one whenever * we encounter ifs char(s). This is used for expanding variable values. * End-of-string does NOT finalize word: think about 'echo -$VAR-' */ static int expand_on_ifs(char **list, int n, char **posp, const char *str) { char *pos = *posp; while (1) { int word_len = strcspn(str, ifs); if (word_len) { memcpy(pos, str, word_len); /* store non-ifs chars */ pos += word_len; str += word_len; } if (!*str) /* EOL - do not finalize word */ break; *pos++ = '\0'; if (n) debug_printf_expand("expand_on_ifs finalized list[%d]=%p '%s' " "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1], strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos); list[n++] = pos; str += strspn(str, ifs); /* skip ifs chars */ } *posp = pos; return n; } /* Expand all variable references in given string, adding words to list[] * at n, n+1,... positions. Return updated n (so that list[n] is next one * to be filled). This routine is extremely tricky: has to deal with * variables/parameters with whitespace, $* and $@, and constructs like * 'echo -$*-'. If you play here, you must run testsuite afterwards! */ /* NB: another bug is that we cannot detect empty strings yet: * "" or $empty"" expands to zero words, has to expand to empty word */ static int expand_vars_to_list(char **list, int n, char **posp, char *arg, char or_mask) { /* or_mask is either 0 (normal case) or 0x80 * (expansion of right-hand side of assignment == 1-element expand) */ char first_ch, ored_ch; int i; const char *val; char *p; char *pos = *posp; ored_ch = 0; if (n) debug_printf_expand("expand_vars_to_list finalized list[%d]=%p '%s' " "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1], strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos); list[n++] = pos; while ((p = strchr(arg, SPECIAL_VAR_SYMBOL))) { memcpy(pos, arg, p - arg); pos += (p - arg); arg = ++p; p = strchr(p, SPECIAL_VAR_SYMBOL); first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */ ored_ch |= first_ch; val = NULL; switch (first_ch & 0x7f) { /* Highest bit in first_ch indicates that var is double-quoted */ case '$': /* pid */ /* FIXME: (echo $$) should still print pid of main shell */ val = utoa(getpid()); /* rootpid? */ break; case '!': /* bg pid */ val = last_bg_pid ? utoa(last_bg_pid) : (char*)""; break; case '?': /* exitcode */ val = utoa(last_return_code); break; case '#': /* argc */ val = utoa(global_argc ? global_argc-1 : 0); break; case '*': case '@': i = 1; if (!global_argv[i]) break; if (!(first_ch & 0x80)) { /* unquoted $* or $@ */ while (global_argv[i]) { n = expand_on_ifs(list, n, &pos, global_argv[i]); debug_printf_expand("expand_vars_to_list: argv %d (last %d)\n", i, global_argc-1); if (global_argv[i++][0] && global_argv[i]) { /* this argv[] is not empty and not last: * put terminating NUL, start new word */ *pos++ = '\0'; if (n) debug_printf_expand("expand_vars_to_list 2 finalized list[%d]=%p '%s' " "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1], strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos); list[n++] = pos; } } } else /* If or_mask is nonzero, we handle assignment 'a=....$@.....' * and in this case should treat it like '$*' - see 'else...' below */ if (first_ch == ('@'|0x80) && !or_mask) { /* quoted $@ */ while (1) { strcpy(pos, global_argv[i]); pos += strlen(global_argv[i]); if (++i >= global_argc) break; *pos++ = '\0'; if (n) debug_printf_expand("expand_vars_to_list 3 finalized list[%d]=%p '%s' " "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1], strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos); list[n++] = pos; } } else { /* quoted $*: add as one word */ while (1) { strcpy(pos, global_argv[i]); pos += strlen(global_argv[i]); if (!global_argv[++i]) break; if (ifs[0]) *pos++ = ifs[0]; } } break; default: *p = '\0'; arg[0] = first_ch & 0x7f; if (isdigit(arg[0])) { i = xatoi_u(arg); val = NULL; if (i < global_argc) val = global_argv[i]; } else val = lookup_param(arg); arg[0] = first_ch; *p = SPECIAL_VAR_SYMBOL; if (!(first_ch & 0x80)) { /* unquoted $VAR */ if (val) { n = expand_on_ifs(list, n, &pos, val); val = NULL; } } /* else: quoted $VAR, val will be appended at pos */ } if (val) { strcpy(pos, val); pos += strlen(val); } arg = ++p; } debug_printf_expand("expand_vars_to_list adding tail '%s' at %p\n", arg, pos); strcpy(pos, arg); pos += strlen(arg) + 1; if (pos == list[n-1] + 1) { /* expansion is empty */ if (!(ored_ch & 0x80)) { /* all vars were not quoted... */ debug_printf_expand("expand_vars_to_list list[%d] empty, going back\n", n); pos--; n--; } } *posp = pos; return n; } static char **expand_variables(char **argv, char or_mask) { int n; int count = 1; int len = 0; char *pos, **v, **list; v = argv; if (!*v) debug_printf_expand("count_var_expansion_space: " "argv[0]=NULL count=%d len=%d alloc_space=%d\n", count, len, sizeof(char*) * count + len); while (*v) { count_var_expansion_space(&count, &len, *v); debug_printf_expand("count_var_expansion_space: " "'%s' count=%d len=%d alloc_space=%d\n", *v, count, len, sizeof(char*) * count + len); v++; } len += sizeof(char*) * count; /* total to alloc */ list = xmalloc(len); pos = (char*)(list + count); debug_printf_expand("list=%p, list[0] should be %p\n", list, pos); n = 0; v = argv; while (*v) n = expand_vars_to_list(list, n, &pos, *v++, or_mask); if (n) debug_printf_expand("finalized list[%d]=%p '%s' " "strlen=%d next=%p pos=%p\n", n-1, list[n-1], list[n-1], strlen(list[n-1]), list[n-1] + strlen(list[n-1]) + 1, pos); list[n] = NULL; #ifdef DEBUG_EXPAND { int m = 0; while (m <= n) { debug_printf_expand("list[%d]=%p '%s'\n", m, list[m], list[m]); m++; } debug_printf_expand("used_space=%d\n", pos - (char*)list); } #endif if (ENABLE_HUSH_DEBUG) if (pos - (char*)list > len) bb_error_msg_and_die("BUG in varexp"); return list; } static char **expand_strvec_to_strvec(char **argv) { return expand_variables(argv, 0); } static char *expand_string_to_string(const char *str) { char *argv[2], **list; argv[0] = (char*)str; argv[1] = NULL; list = expand_variables(argv, 0x80); /* 0x80: make one-element expansion */ if (ENABLE_HUSH_DEBUG) if (!list[0] || list[1]) bb_error_msg_and_die("BUG in varexp2"); /* actually, just move string 2*sizeof(char*) bytes back */ strcpy((char*)list, list[0]); debug_printf_expand("string_to_string='%s'\n", (char*)list); return (char*)list; } static char* expand_strvec_to_string(char **argv) { char **list; list = expand_variables(argv, 0x80); /* Convert all NULs to spaces */ if (list[0]) { int n = 1; while (list[n]) { if (ENABLE_HUSH_DEBUG) if (list[n-1] + strlen(list[n-1]) + 1 != list[n]) bb_error_msg_and_die("BUG in varexp3"); list[n][-1] = ' '; /* TODO: or to ifs[0]? */ n++; } } strcpy((char*)list, list[0]); debug_printf_expand("strvec_to_string='%s'\n", (char*)list); return (char*)list; } /* This is used to get/check local shell variables */ static struct variable *get_local_var(const char *name) { struct variable *cur; int len; if (!name) return NULL; len = strlen(name); for (cur = top_var; cur; cur = cur->next) { if (strncmp(cur->varstr, name, len) == 0 && cur->varstr[len] == '=') return cur; } return NULL; } /* str holds "NAME=VAL" and is expected to be malloced. * We take ownership of it. */ static int set_local_var(char *str, int flg_export) { struct variable *cur; char *value; int name_len; value = strchr(str, '='); if (!value) { /* not expected to ever happen? */ free(str); return -1; } name_len = value - str + 1; /* including '=' */ cur = top_var; /* cannot be NULL (we have HUSH_VERSION and it's RO) */ while (1) { if (strncmp(cur->varstr, str, name_len) != 0) { if (!cur->next) { /* Bail out. Note that now cur points * to last var in linked list */ break; } cur = cur->next; continue; } /* We found an existing var with this name */ *value = '\0'; if (cur->flg_read_only) { bb_error_msg("%s: readonly variable", str); free(str); return -1; } unsetenv(str); /* just in case */ *value = '='; if (strcmp(cur->varstr, str) == 0) { free_and_exp: free(str); goto exp; } if (cur->max_len >= strlen(str)) { /* This one is from startup env, reuse space */ strcpy(cur->varstr, str); goto free_and_exp; } /* max_len == 0 signifies "malloced" var, which we can * (and has to) free */ if (!cur->max_len) free(cur->varstr); cur->max_len = 0; goto set_str_and_exp; } /* Not found - create next variable struct */ cur->next = xzalloc(sizeof(*cur)); cur = cur->next; set_str_and_exp: cur->varstr = str; exp: if (flg_export) cur->flg_export = 1; if (cur->flg_export) return putenv(cur->varstr); return 0; } static void unset_local_var(const char *name) { struct variable *cur; struct variable *prev = prev; /* for gcc */ int name_len; if (!name) return; name_len = strlen(name); cur = top_var; while (cur) { if (strncmp(cur->varstr, name, name_len) == 0 && cur->varstr[name_len] == '=') { if (cur->flg_read_only) { bb_error_msg("%s: readonly variable", name); return; } /* prev is ok to use here because 1st variable, HUSH_VERSION, * is ro, and we cannot reach this code on the 1st pass */ prev->next = cur->next; unsetenv(cur->varstr); if (!cur->max_len) free(cur->varstr); free(cur); return; } prev = cur; cur = cur->next; } } static int is_assignment(const char *s) { if (!s || !isalpha(*s)) return 0; s++; while (isalnum(*s) || *s == '_') s++; return *s == '='; } /* the src parameter allows us to peek forward to a possible &n syntax * for file descriptor duplication, e.g., "2>&1". * Return code is 0 normally, 1 if a syntax error is detected in src. * Resource errors (in xmalloc) cause the process to exit */ static int setup_redirect(struct p_context *ctx, int fd, redir_type style, struct in_str *input) { struct child_prog *child = ctx->child; struct redir_struct *redir = child->redirects; struct redir_struct *last_redir = NULL; /* Create a new redir_struct and drop it onto the end of the linked list */ while (redir) { last_redir = redir; redir = redir->next; } redir = xzalloc(sizeof(struct redir_struct)); /* redir->next = NULL; */ /* redir->glob_word = NULL; */ if (last_redir) { last_redir->next = redir; } else { child->redirects = redir; } redir->type = style; redir->fd = (fd == -1) ? redir_table[style].default_fd : fd; debug_printf("Redirect type %d%s\n", redir->fd, redir_table[style].descrip); /* Check for a '2>&1' type redirect */ redir->dup = redirect_dup_num(input); if (redir->dup == -2) return 1; /* syntax error */ if (redir->dup != -1) { /* Erik had a check here that the file descriptor in question * is legit; I postpone that to "run time" * A "-" representation of "close me" shows up as a -3 here */ debug_printf("Duplicating redirect '%d>&%d'\n", redir->fd, redir->dup); } else { /* We do _not_ try to open the file that src points to, * since we need to return and let src be expanded first. * Set ctx->pending_redirect, so we know what to do at the * end of the next parsed word. */ ctx->pending_redirect = redir; } return 0; } static struct pipe *new_pipe(void) { struct pipe *pi; pi = xzalloc(sizeof(struct pipe)); /*pi->num_progs = 0;*/ /*pi->progs = NULL;*/ /*pi->next = NULL;*/ /*pi->followup = 0; invalid */ if (RES_NONE) pi->res_word = RES_NONE; return pi; } static void initialize_context(struct p_context *ctx) { ctx->child = NULL; ctx->pipe = ctx->list_head = new_pipe(); ctx->pending_redirect = NULL; ctx->res_w = RES_NONE; //only ctx->parse_type is not touched... is this intentional? ctx->old_flag = 0; ctx->stack = NULL; done_command(ctx); /* creates the memory for working child */ } /* normal return is 0 * if a reserved word is found, and processed, return 1 * should handle if, then, elif, else, fi, for, while, until, do, done. * case, function, and select are obnoxious, save those for later. */ #if ENABLE_HUSH_IF || ENABLE_HUSH_LOOPS static int reserved_word(o_string *dest, struct p_context *ctx) { struct reserved_combo { char literal[7]; unsigned char code; int flag; }; /* Mostly a list of accepted follow-up reserved words. * FLAG_END means we are done with the sequence, and are ready * to turn the compound list into a command. * FLAG_START means the word must start a new compound list. */ static const struct reserved_combo reserved_list[] = { #if ENABLE_HUSH_IF { "if", RES_IF, FLAG_THEN | FLAG_START }, { "then", RES_THEN, FLAG_ELIF | FLAG_ELSE | FLAG_FI }, { "elif", RES_ELIF, FLAG_THEN }, { "else", RES_ELSE, FLAG_FI }, { "fi", RES_FI, FLAG_END }, #endif #if ENABLE_HUSH_LOOPS { "for", RES_FOR, FLAG_IN | FLAG_START }, { "while", RES_WHILE, FLAG_DO | FLAG_START }, { "until", RES_UNTIL, FLAG_DO | FLAG_START }, { "in", RES_IN, FLAG_DO }, { "do", RES_DO, FLAG_DONE }, { "done", RES_DONE, FLAG_END } #endif }; const struct reserved_combo *r; for (r = reserved_list; r < reserved_list + ARRAY_SIZE(reserved_list); r++) { if (strcmp(dest->data, r->literal) != 0) continue; debug_printf("found reserved word %s, code %d\n", r->literal, r->code); if (r->flag & FLAG_START) { struct p_context *new; debug_printf("push stack\n"); #if ENABLE_HUSH_LOOPS if (ctx->res_w == RES_IN || ctx->res_w == RES_FOR) { syntax("malformed for"); /* example: 'for if' */ ctx->res_w = RES_SNTX; b_reset(dest); return 1; } #endif new = xmalloc(sizeof(*new)); *new = *ctx; /* physical copy */ initialize_context(ctx); ctx->stack = new; } else if (ctx->res_w == RES_NONE || !(ctx->old_flag & (1 << r->code))) { syntax(NULL); ctx->res_w = RES_SNTX; b_reset(dest); return 1; } ctx->res_w = r->code; ctx->old_flag = r->flag; if (ctx->old_flag & FLAG_END) { struct p_context *old; debug_printf("pop stack\n"); done_pipe(ctx, PIPE_SEQ); old = ctx->stack; old->child->group = ctx->list_head; old->child->subshell = 0; *ctx = *old; /* physical copy */ free(old); } b_reset(dest); return 1; } return 0; } #else #define reserved_word(dest, ctx) ((int)0) #endif /* Normal return is 0. * Syntax or xglob errors return 1. */ static int done_word(o_string *dest, struct p_context *ctx) { struct child_prog *child = ctx->child; char ***glob_target; int gr; debug_printf_parse("done_word entered: '%s' %p\n", dest->data, child); if (dest->length == 0 && !dest->nonnull) { debug_printf_parse("done_word return 0: true null, ignored\n"); return 0; } if (ctx->pending_redirect) { glob_target = &ctx->pending_redirect->glob_word; } else { if (child->group) { syntax(NULL); debug_printf_parse("done_word return 1: syntax error, groups and arglists don't mix\n"); return 1; } if (!child->argv && (ctx->parse_type & PARSEFLAG_SEMICOLON)) { debug_printf_parse(": checking '%s' for reserved-ness\n", dest->data); if (reserved_word(dest, ctx)) { debug_printf_parse("done_word return %d\n", (ctx->res_w == RES_SNTX)); return (ctx->res_w == RES_SNTX); } } glob_target = &child->argv; } gr = xglob(dest, glob_target); if (gr != 0) { debug_printf_parse("done_word return 1: xglob returned %d\n", gr); return 1; } b_reset(dest); if (ctx->pending_redirect) { /* NB: don't free_strings(ctx->pending_redirect->glob_word) here */ if (ctx->pending_redirect->glob_word && ctx->pending_redirect->glob_word[0] && ctx->pending_redirect->glob_word[1] ) { /* more than one word resulted from globbing redir */ ctx->pending_redirect = NULL; bb_error_msg("ambiguous redirect"); debug_printf_parse("done_word return 1: ambiguous redirect\n"); return 1; } ctx->pending_redirect = NULL; } #if ENABLE_HUSH_LOOPS if (ctx->res_w == RES_FOR) { done_word(dest, ctx); done_pipe(ctx, PIPE_SEQ); } #endif debug_printf_parse("done_word return 0\n"); return 0; } /* The only possible error here is out of memory, in which case * xmalloc exits. */ static int done_command(struct p_context *ctx) { /* The child is really already in the pipe structure, so * advance the pipe counter and make a new, null child. */ struct pipe *pi = ctx->pipe; struct child_prog *child = ctx->child; if (child) { if (child->group == NULL && child->argv == NULL && child->redirects == NULL ) { debug_printf_parse("done_command: skipping null cmd, num_progs=%d\n", pi->num_progs); return pi->num_progs; } pi->num_progs++; debug_printf_parse("done_command: ++num_progs=%d\n", pi->num_progs); } else { debug_printf_parse("done_command: initializing, num_progs=%d\n", pi->num_progs); } /* Only real trickiness here is that the uncommitted * child structure is not counted in pi->num_progs. */ pi->progs = xrealloc(pi->progs, sizeof(*pi->progs) * (pi->num_progs+1)); child = &pi->progs[pi->num_progs]; memset(child, 0, sizeof(*child)); /*child->redirects = NULL;*/ /*child->argv = NULL;*/ /*child->is_stopped = 0;*/ /*child->group = NULL;*/ child->family = pi; //sp: /*child->sp = 0;*/ //pt: child->parse_type = ctx->parse_type; ctx->child = child; /* but ctx->pipe and ctx->list_head remain unchanged */ return pi->num_progs; /* used only for 0/nonzero check */ } static int done_pipe(struct p_context *ctx, pipe_style type) { struct pipe *new_p; int not_null; debug_printf_parse("done_pipe entered, followup %d\n", type); not_null = done_command(ctx); /* implicit closure of previous command */ ctx->pipe->followup = type; ctx->pipe->res_word = ctx->res_w; /* Without this check, even just <enter> on command line generates * tree of three NOPs (!). Which is harmless but annoying. * IOW: it is safe to do it unconditionally. */ if (not_null) { new_p = new_pipe(); ctx->pipe->next = new_p; ctx->pipe = new_p; ctx->child = NULL; done_command(ctx); /* set up new pipe to accept commands */ } debug_printf_parse("done_pipe return 0\n"); return 0; } /* peek ahead in the in_str to find out if we have a "&n" construct, * as in "2>&1", that represents duplicating a file descriptor. * returns either -2 (syntax error), -1 (no &), or the number found. */ static int redirect_dup_num(struct in_str *input) { int ch, d = 0, ok = 0; ch = b_peek(input); if (ch != '&') return -1; b_getch(input); /* get the & */ ch = b_peek(input); if (ch == '-') { b_getch(input); return -3; /* "-" represents "close me" */ } while (isdigit(ch)) { d = d*10 + (ch-'0'); ok = 1; b_getch(input); ch = b_peek(input); } if (ok) return d; bb_error_msg("ambiguous redirect"); return -2; } /* If a redirect is immediately preceded by a number, that number is * supposed to tell which file descriptor to redirect. This routine * looks for such preceding numbers. In an ideal world this routine * needs to handle all the following classes of redirects... * echo 2>foo # redirects fd 2 to file "foo", nothing passed to echo * echo 49>foo # redirects fd 49 to file "foo", nothing passed to echo * echo -2>foo # redirects fd 1 to file "foo", "-2" passed to echo * echo 49x>foo # redirects fd 1 to file "foo", "49x" passed to echo * A -1 output from this program means no valid number was found, so the * caller should use the appropriate default for this redirection. */ static int redirect_opt_num(o_string *o) { int num; if (o->length == 0) return -1; for (num = 0; num < o->length; num++) { if (!isdigit(*(o->data + num))) { return -1; } } /* reuse num (and save an int) */ num = atoi(o->data); b_reset(o); return num; } #if ENABLE_HUSH_TICK /* NB: currently disabled on NOMMU */ static FILE *generate_stream_from_list(struct pipe *head) { FILE *pf; int pid, channel[2]; xpipe(channel); /* *** NOMMU WARNING *** */ /* By using vfork here, we suspend parent till child exits or execs. * If child will not do it before it fills the pipe, it can block forever * in write(STDOUT_FILENO), and parent (shell) will be also stuck. */ pid = BB_MMU ? fork() : vfork(); if (pid < 0) bb_perror_msg_and_die(BB_MMU ? "fork" : "vfork"); if (pid == 0) { /* child */ if (ENABLE_HUSH_JOB) die_sleep = 0; /* let nofork's xfuncs die */ close(channel[0]); /* NB: close _first_, then move fd! */ xmove_fd(channel[1], 1); /* Prevent it from trying to handle ctrl-z etc */ #if ENABLE_HUSH_JOB run_list_level = 1; #endif /* Process substitution is not considered to be usual * 'command execution'. * SUSv3 says ctrl-Z should be ignored, ctrl-C should not. */ /* Not needed, we are relying on it being disabled * everywhere outside actual command execution. */ /*set_jobctrl_sighandler(SIG_IGN);*/ set_misc_sighandler(SIG_DFL); /* Freeing 'head' here would break NOMMU. */ _exit(run_list(head)); } close(channel[1]); pf = fdopen(channel[0], "r"); return pf; /* 'head' is freed by the caller */ } /* Return code is exit status of the process that is run. */ static int process_command_subs(o_string *dest, /*struct p_context *ctx,*/ struct in_str *input, const char *subst_end) { int retcode, ch, eol_cnt; o_string result = NULL_O_STRING; struct p_context inner; FILE *p; struct in_str pipe_str; initialize_context(&inner); /* recursion to generate command */ retcode = parse_stream(&result, &inner, input, subst_end); if (retcode != 0) return retcode; /* syntax error or EOF */ done_word(&result, &inner); done_pipe(&inner, PIPE_SEQ); b_free(&result); p = generate_stream_from_list(inner.list_head); if (p == NULL) return 1; close_on_exec_on(fileno(p)); setup_file_in_str(&pipe_str, p); /* now send results of command back into original context */ eol_cnt = 0; while ((ch = b_getch(&pipe_str)) != EOF) { if (ch == '\n') { eol_cnt++; continue; } while (eol_cnt) { b_addqchr(dest, '\n', dest->o_quote); eol_cnt--; } b_addqchr(dest, ch, dest->o_quote); } debug_printf("done reading from pipe, pclose()ing\n"); /* This is the step that wait()s for the child. Should be pretty * safe, since we just read an EOF from its stdout. We could try * to do better, by using wait(), and keeping track of background jobs * at the same time. That would be a lot of work, and contrary * to the KISS philosophy of this program. */ retcode = fclose(p); free_pipe_list(inner.list_head, /* indent: */ 0); debug_printf("closed FILE from child, retcode=%d\n", retcode); return retcode; } #endif static int parse_group(o_string *dest, struct p_context *ctx, struct in_str *input, int ch) { int rcode; const char *endch = NULL; struct p_context sub; struct child_prog *child = ctx->child; debug_printf_parse("parse_group entered\n"); if (child->argv) { syntax(NULL); debug_printf_parse("parse_group return 1: syntax error, groups and arglists don't mix\n"); return 1; } initialize_context(&sub); endch = "}"; if (ch == '(') { endch = ")"; child->subshell = 1; } rcode = parse_stream(dest, &sub, input, endch); //vda: err chk? done_word(dest, &sub); /* finish off the final word in the subcontext */ done_pipe(&sub, PIPE_SEQ); /* and the final command there, too */ child->group = sub.list_head; debug_printf_parse("parse_group return %d\n", rcode); return rcode; /* child remains "open", available for possible redirects */ } /* Basically useful version until someone wants to get fancier, * see the bash man page under "Parameter Expansion" */ static const char *lookup_param(const char *src) { struct variable *var = get_local_var(src); if (var) return strchr(var->varstr, '=') + 1; return NULL; } /* return code: 0 for OK, 1 for syntax error */ static int handle_dollar(o_string *dest, /*struct p_context *ctx,*/ struct in_str *input) { int ch = b_peek(input); /* first character after the $ */ unsigned char quote_mask = dest->o_quote ? 0x80 : 0; debug_printf_parse("handle_dollar entered: ch='%c'\n", ch); if (isalpha(ch)) { b_addchr(dest, SPECIAL_VAR_SYMBOL); //sp: ctx->child->sp++; while (1) { debug_printf_parse(": '%c'\n", ch); b_getch(input); b_addchr(dest, ch | quote_mask); quote_mask = 0; ch = b_peek(input); if (!isalnum(ch) && ch != '_') break; } b_addchr(dest, SPECIAL_VAR_SYMBOL); } else if (isdigit(ch)) { make_one_char_var: b_addchr(dest, SPECIAL_VAR_SYMBOL); //sp: ctx->child->sp++; debug_printf_parse(": '%c'\n", ch); b_getch(input); b_addchr(dest, ch | quote_mask); b_addchr(dest, SPECIAL_VAR_SYMBOL); } else switch (ch) { case '$': /* pid */ case '!': /* last bg pid */ case '?': /* last exit code */ case '#': /* number of args */ case '*': /* args */ case '@': /* args */ goto make_one_char_var; case '{': b_addchr(dest, SPECIAL_VAR_SYMBOL); //sp: ctx->child->sp++; b_getch(input); /* XXX maybe someone will try to escape the '}' */ while (1) { ch = b_getch(input); if (ch == '}') break; if (!isalnum(ch) && ch != '_') { syntax("unterminated ${name}"); debug_printf_parse("handle_dollar return 1: unterminated ${name}\n"); return 1; } debug_printf_parse(": '%c'\n", ch); b_addchr(dest, ch | quote_mask); quote_mask = 0; } b_addchr(dest, SPECIAL_VAR_SYMBOL); break; #if ENABLE_HUSH_TICK case '(': b_getch(input); process_command_subs(dest, /*ctx,*/ input, ")"); break; #endif case '-': case '_': /* still unhandled, but should be eventually */ bb_error_msg("unhandled syntax: $%c", ch); return 1; break; default: b_addqchr(dest, '$', dest->o_quote); } debug_printf_parse("handle_dollar return 0\n"); return 0; } /* return code is 0 for normal exit, 1 for syntax error */ static int parse_stream(o_string *dest, struct p_context *ctx, struct in_str *input, const char *end_trigger) { int ch, m; int redir_fd; redir_type redir_style; int next; /* Only double-quote state is handled in the state variable dest->o_quote. * A single-quote triggers a bypass of the main loop until its mate is * found. When recursing, quote state is passed in via dest->o_quote. */ debug_printf_parse("parse_stream entered, end_trigger='%s'\n", end_trigger); while (1) { m = CHAR_IFS; next = '\0'; ch = b_getch(input); if (ch != EOF) { m = charmap[ch]; if (ch != '\n') next = b_peek(input); } debug_printf_parse(": ch=%c (%d) m=%d quote=%d\n", ch, ch, m, dest->o_quote); if (m == CHAR_ORDINARY || (m != CHAR_SPECIAL && dest->o_quote) ) { if (ch == EOF) { syntax("unterminated \""); debug_printf_parse("parse_stream return 1: unterminated \"\n"); return 1; } b_addqchr(dest, ch, dest->o_quote); continue; } if (m == CHAR_IFS) { if (done_word(dest, ctx)) { debug_printf_parse("parse_stream return 1: done_word!=0\n"); return 1; } if (ch == EOF) break; /* If we aren't performing a substitution, treat * a newline as a command separator. * [why we don't handle it exactly like ';'? --vda] */ if (end_trigger && ch == '\n') { done_pipe(ctx, PIPE_SEQ); } } if ((end_trigger && strchr(end_trigger, ch)) && !dest->o_quote && ctx->res_w == RES_NONE ) { debug_printf_parse("parse_stream return 0: end_trigger char found\n"); return 0; } if (m == CHAR_IFS) continue; switch (ch) { case '#': if (dest->length == 0 && !dest->o_quote) { while (1) { ch = b_peek(input); if (ch == EOF || ch == '\n') break; b_getch(input); } } else { b_addqchr(dest, ch, dest->o_quote); } break; case '\\': if (next == EOF) { syntax("\\<eof>"); debug_printf_parse("parse_stream return 1: \\<eof>\n"); return 1; } b_addqchr(dest, '\\', dest->o_quote); b_addqchr(dest, b_getch(input), dest->o_quote); break; case '$': if (handle_dollar(dest, /*ctx,*/ input) != 0) { debug_printf_parse("parse_stream return 1: handle_dollar returned non-0\n"); return 1; } break; case '\'': dest->nonnull = 1; while (1) { ch = b_getch(input); if (ch == EOF || ch == '\'') break; b_addchr(dest, ch); } if (ch == EOF) { syntax("unterminated '"); debug_printf_parse("parse_stream return 1: unterminated '\n"); return 1; } break; case '"': dest->nonnull = 1; dest->o_quote ^= 1; /* invert */ break; #if ENABLE_HUSH_TICK case '`': process_command_subs(dest, /*ctx,*/ input, "`"); break; #endif case '>': redir_fd = redirect_opt_num(dest); done_word(dest, ctx); redir_style = REDIRECT_OVERWRITE; if (next == '>') { redir_style = REDIRECT_APPEND; b_getch(input); } #if 0 else if (next == '(') { syntax(">(process) not supported"); debug_printf_parse("parse_stream return 1: >(process) not supported\n"); return 1; } #endif setup_redirect(ctx, redir_fd, redir_style, input); break; case '<': redir_fd = redirect_opt_num(dest); done_word(dest, ctx); redir_style = REDIRECT_INPUT; if (next == '<') { redir_style = REDIRECT_HEREIS; b_getch(input); } else if (next == '>') { redir_style = REDIRECT_IO; b_getch(input); } #if 0 else if (next == '(') { syntax("<(process) not supported"); debug_printf_parse("parse_stream return 1: <(process) not supported\n"); return 1; } #endif setup_redirect(ctx, redir_fd, redir_style, input); break; case ';': done_word(dest, ctx); done_pipe(ctx, PIPE_SEQ); break; case '&': done_word(dest, ctx); if (next == '&') { b_getch(input); done_pipe(ctx, PIPE_AND); } else { done_pipe(ctx, PIPE_BG); } break; case '|': done_word(dest, ctx); if (next == '|') { b_getch(input); done_pipe(ctx, PIPE_OR); } else { /* we could pick up a file descriptor choice here * with redirect_opt_num(), but bash doesn't do it. * "echo foo 2| cat" yields "foo 2". */ done_command(ctx); } break; case '(': case '{': if (parse_group(dest, ctx, input, ch) != 0) { debug_printf_parse("parse_stream return 1: parse_group returned non-0\n"); return 1; } break; case ')': case '}': syntax("unexpected }"); /* Proper use of this character is caught by end_trigger */ debug_printf_parse("parse_stream return 1: unexpected '}'\n"); return 1; default: if (ENABLE_HUSH_DEBUG) bb_error_msg_and_die("BUG: unexpected %c\n", ch); } } /* Complain if quote? No, maybe we just finished a command substitution * that was quoted. Example: * $ echo "`cat foo` plus more" * and we just got the EOF generated by the subshell that ran "cat foo" * The only real complaint is if we got an EOF when end_trigger != NULL, * that is, we were really supposed to get end_trigger, and never got * one before the EOF. Can't use the standard "syntax error" return code, * so that parse_stream_outer can distinguish the EOF and exit smoothly. */ debug_printf_parse("parse_stream return %d\n", -(end_trigger != NULL)); if (end_trigger) return -1; return 0; } static void set_in_charmap(const char *set, int code) { while (*set) charmap[(unsigned char)*set++] = code; } static void update_charmap(void) { /* char *ifs and char charmap[256] are both globals. */ ifs = getenv("IFS"); if (ifs == NULL) ifs = " \t\n"; /* Precompute a list of 'flow through' behavior so it can be treated * quickly up front. Computation is necessary because of IFS. * Special case handling of IFS == " \t\n" is not implemented. * The charmap[] array only really needs two bits each, * and on most machines that would be faster (reduced L1 cache use). */ memset(charmap, CHAR_ORDINARY, sizeof(charmap)); #if ENABLE_HUSH_TICK set_in_charmap("\\$\"`", CHAR_SPECIAL); #else set_in_charmap("\\$\"", CHAR_SPECIAL); #endif set_in_charmap("<>;&|(){}#'", CHAR_ORDINARY_IF_QUOTED); set_in_charmap(ifs, CHAR_IFS); /* are ordinary if quoted */ } /* most recursion does not come through here, the exception is * from builtin_source() and builtin_eval() */ static int parse_and_run_stream(struct in_str *inp, int parse_flag) { struct p_context ctx; o_string temp = NULL_O_STRING; int rcode; do { ctx.parse_type = parse_flag; initialize_context(&ctx); update_charmap(); if (!(parse_flag & PARSEFLAG_SEMICOLON) || (parse_flag & PARSEFLAG_REPARSING)) set_in_charmap(";$&|", CHAR_ORDINARY); #if ENABLE_HUSH_INTERACTIVE inp->promptmode = 0; /* PS1 */ #endif /* We will stop & execute after each ';' or '\n'. * Example: "sleep 9999; echo TEST" + ctrl-C: * TEST should be printed */ rcode = parse_stream(&temp, &ctx, inp, ";\n"); if (rcode != 1 && ctx.old_flag != 0) { syntax(NULL); } if (rcode != 1 && ctx.old_flag == 0) { done_word(&temp, &ctx); done_pipe(&ctx, PIPE_SEQ); debug_print_tree(ctx.list_head, 0); debug_printf_exec("parse_stream_outer: run_and_free_list\n"); run_and_free_list(ctx.list_head); } else { if (ctx.old_flag != 0) { free(ctx.stack); b_reset(&temp); } temp.nonnull = 0; temp.o_quote = 0; inp->p = NULL; free_pipe_list(ctx.list_head, /* indent: */ 0); } b_free(&temp); } while (rcode != -1 && !(parse_flag & PARSEFLAG_EXIT_FROM_LOOP)); /* loop on syntax errors, return on EOF */ return 0; } static int parse_and_run_string(const char *s, int parse_flag) { struct in_str input; setup_string_in_str(&input, s); return parse_and_run_stream(&input, parse_flag); } static int parse_and_run_file(FILE *f) { int rcode; struct in_str input; setup_file_in_str(&input, f); rcode = parse_and_run_stream(&input, PARSEFLAG_SEMICOLON); return rcode; } #if ENABLE_HUSH_JOB /* Make sure we have a controlling tty. If we get started under a job * aware app (like bash for example), make sure we are now in charge so * we don't fight over who gets the foreground */ static void setup_job_control(void) { pid_t shell_pgrp; saved_task_pgrp = shell_pgrp = getpgrp(); debug_printf_jobs("saved_task_pgrp=%d\n", saved_task_pgrp); close_on_exec_on(interactive_fd); /* If we were ran as 'hush &', * sleep until we are in the foreground. */ while (tcgetpgrp(interactive_fd) != shell_pgrp) { /* Send TTIN to ourself (should stop us) */ kill(- shell_pgrp, SIGTTIN); shell_pgrp = getpgrp(); } /* Ignore job-control and misc signals. */ set_jobctrl_sighandler(SIG_IGN); set_misc_sighandler(SIG_IGN); //huh? signal(SIGCHLD, SIG_IGN); /* We _must_ restore tty pgrp on fatal signals */ set_fatal_sighandler(sigexit); /* Put ourselves in our own process group. */ setpgrp(); /* is the same as setpgid(our_pid, our_pid); */ /* Grab control of the terminal. */ tcsetpgrp(interactive_fd, getpid()); } #endif int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int hush_main(int argc, char **argv) { static const char version_str[] ALIGN1 = "HUSH_VERSION="HUSH_VER_STR; static const struct variable const_shell_ver = { .next = NULL, .varstr = (char*)version_str, .max_len = 1, /* 0 can provoke free(name) */ .flg_export = 1, .flg_read_only = 1, }; int opt; FILE *input; char **e; struct variable *cur_var; INIT_G(); /* Deal with HUSH_VERSION */ shell_ver = const_shell_ver; /* copying struct here */ top_var = &shell_ver; unsetenv("HUSH_VERSION"); /* in case it exists in initial env */ /* Initialize our shell local variables with the values * currently living in the environment */ cur_var = top_var; e = environ; if (e) while (*e) { char *value = strchr(*e, '='); if (value) { /* paranoia */ cur_var->next = xzalloc(sizeof(*cur_var)); cur_var = cur_var->next; cur_var->varstr = *e; cur_var->max_len = strlen(*e); cur_var->flg_export = 1; } e++; } putenv((char *)version_str); /* reinstate HUSH_VERSION */ #if ENABLE_FEATURE_EDITING line_input_state = new_line_input_t(FOR_SHELL); #endif /* XXX what should these be while sourcing /etc/profile? */ global_argc = argc; global_argv = argv; /* Initialize some more globals to non-zero values */ set_cwd(); #if ENABLE_HUSH_INTERACTIVE #if ENABLE_FEATURE_EDITING cmdedit_set_initial_prompt(); #endif PS2 = "> "; #endif if (EXIT_SUCCESS) /* otherwise is already done */ last_return_code = EXIT_SUCCESS; if (argv[0] && argv[0][0] == '-') { debug_printf("sourcing /etc/profile\n"); input = fopen("/etc/profile", "r"); if (input != NULL) { close_on_exec_on(fileno(input)); parse_and_run_file(input); fclose(input); } } input = stdin; while ((opt = getopt(argc, argv, "c:xif")) > 0) { switch (opt) { case 'c': global_argv = argv + optind; global_argc = argc - optind; opt = parse_and_run_string(optarg, PARSEFLAG_SEMICOLON); goto final_return; case 'i': /* Well, we cannot just declare interactiveness, * we have to have some stuff (ctty, etc) */ /* interactive_fd++; */ break; case 'f': fake_mode = 1; break; default: #ifndef BB_VER fprintf(stderr, "Usage: sh [FILE]...\n" " or: sh -c command [args]...\n\n"); exit(EXIT_FAILURE); #else bb_show_usage(); #endif } } #if ENABLE_HUSH_JOB /* A shell is interactive if the '-i' flag was given, or if all of * the following conditions are met: * no -c command * no arguments remaining or the -s flag given * standard input is a terminal * standard output is a terminal * Refer to Posix.2, the description of the 'sh' utility. */ if (argv[optind] == NULL && input == stdin && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO) ) { saved_tty_pgrp = tcgetpgrp(STDIN_FILENO); debug_printf("saved_tty_pgrp=%d\n", saved_tty_pgrp); if (saved_tty_pgrp >= 0) { /* try to dup to high fd#, >= 255 */ interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255); if (interactive_fd < 0) { /* try to dup to any fd */ interactive_fd = dup(STDIN_FILENO); if (interactive_fd < 0) /* give up */ interactive_fd = 0; } // TODO: track & disallow any attempts of user // to (inadvertently) close/redirect it } } debug_printf("interactive_fd=%d\n", interactive_fd); if (interactive_fd) { fcntl(interactive_fd, F_SETFD, FD_CLOEXEC); /* Looks like they want an interactive shell */ setup_job_control(); /* -1 is special - makes xfuncs longjmp, not exit * (we reset die_sleep = 0 whereever we [v]fork) */ die_sleep = -1; if (setjmp(die_jmp)) { /* xfunc has failed! die die die */ hush_exit(xfunc_error_retval); } #if !ENABLE_FEATURE_SH_EXTRA_QUIET printf("\n\n%s hush - the humble shell v"HUSH_VER_STR"\n", bb_banner); printf("Enter 'help' for a list of built-in commands.\n\n"); #endif } #elif ENABLE_HUSH_INTERACTIVE /* no job control compiled, only prompt/line editing */ if (argv[optind] == NULL && input == stdin && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO) ) { interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255); if (interactive_fd < 0) { /* try to dup to any fd */ interactive_fd = dup(STDIN_FILENO); if (interactive_fd < 0) /* give up */ interactive_fd = 0; } if (interactive_fd) fcntl(interactive_fd, F_SETFD, FD_CLOEXEC); } #endif if (argv[optind] == NULL) { opt = parse_and_run_file(stdin); } else { debug_printf("\nrunning script '%s'\n", argv[optind]); global_argv = argv + optind; global_argc = argc - optind; input = xfopen(argv[optind], "r"); fcntl(fileno(input), F_SETFD, FD_CLOEXEC); opt = parse_and_run_file(input); } final_return: #if ENABLE_FEATURE_CLEAN_UP fclose(input); if (cwd != bb_msg_unknown) free((char*)cwd); cur_var = top_var->next; while (cur_var) { struct variable *tmp = cur_var; if (!cur_var->max_len) free(cur_var->varstr); cur_var = cur_var->next; free(tmp); } #endif hush_exit(opt ? opt : last_return_code); } #if ENABLE_LASH int lash_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int lash_main(int argc, char **argv) { //bb_error_msg("lash is deprecated, please use hush instead"); return hush_main(argc, argv); } #endif