/* vi: set sw=4 ts=4: */ /* * Utility routines. * * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> * * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. */ #include "libbb.h" /* In Linux we have three ways to determine "process name": 1. /proc/PID/stat has "...(name)...", among other things. It's so-called "comm" field. 2. /proc/PID/cmdline's first NUL-terminated string. It's argv[0] from exec syscall. 3. /proc/PID/exe symlink. Points to the running executable file. kernel threads: comm: thread name cmdline: empty exe: <readlink fails> executable comm: first 15 chars of base name (if executable is a symlink, then first 15 chars of symlink name are used) cmdline: argv[0] from exec syscall exe: points to executable (resolves symlink, unlike comm) script (an executable with #!/path/to/interpreter): comm: first 15 chars of script's base name (symlinks are not resolved) cmdline: /path/to/interpreter (symlinks are not resolved) (script name is in argv[1], args are pushed into argv[2] etc) exe: points to interpreter's executable (symlinks are resolved) If FEATURE_PREFER_APPLETS=y (and more so if FEATURE_SH_STANDALONE=y), some commands started from busybox shell, xargs or find are started by execXXX("/proc/self/exe", applet_name, params....) and therefore comm field contains "exe". */ static int comm_match(procps_status_t *p, const char *procName) { int argv1idx; /* comm does not match */ if (strncmp(p->comm, procName, 15) != 0) return 0; /* in Linux, if comm is 15 chars, it may be a truncated */ if (p->comm[14] == '\0') /* comm is not truncated - match */ return 1; /* comm is truncated, but first 15 chars match. * This can be crazily_long_script_name.sh! * The telltale sign is basename(argv[1]) == procName. */ if (!p->argv0) return 0; argv1idx = strlen(p->argv0) + 1; if (argv1idx >= p->argv_len) return 0; if (strcmp(bb_basename(p->argv0 + argv1idx), procName) != 0) return 0; return 1; } /* This finds the pid of the specified process. * Currently, it's implemented by rummaging through * the proc filesystem. * * Returns a list of all matching PIDs * It is the caller's duty to free the returned pidlist. * * Modified by Vladimir Oleynik for use with libbb/procps.c */ pid_t* FAST_FUNC find_pid_by_name(const char *procName) { pid_t* pidList; int i = 0; procps_status_t* p = NULL; pidList = xzalloc(sizeof(*pidList)); while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGVN))) { if (comm_match(p, procName) /* or we require argv0 to match (essential for matching reexeced /proc/self/exe)*/ || (p->argv0 && strcmp(bb_basename(p->argv0), procName) == 0) /* TODO: we can also try /proc/NUM/exe link, do we want that? */ ) { pidList = xrealloc_vector(pidList, 2, i); pidList[i++] = p->pid; } } pidList[i] = 0; return pidList; } pid_t* FAST_FUNC pidlist_reverse(pid_t *pidList) { int i = 0; while (pidList[i]) i++; if (--i >= 0) { pid_t k; int j; for (j = 0; i > j; i--, j++) { k = pidList[i]; pidList[i] = pidList[j]; pidList[j] = k; } } return pidList; }