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/* vi: set sw=4 ts=4: */
/*
* tac implementation for busybox
* tac - concatenate and print files in reverse
*
* Copyright (C) 2003 Yang Xiaopeng <yxp at hanwang.com.cn>
* Copyright (C) 2007 Natanael Copa <natanael.copa@gmail.com>
* Copyright (C) 2007 Tito Ragusa <farmatito@tiscali.it>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
/* Based on Yang Xiaopeng's (yxp at hanwang.com.cn) patch
* http://www.uclibc.org/lists/busybox/2003-July/008813.html
*/
//config:config TAC
//config: bool "tac"
//config: default y
//config: help
//config: tac is used to concatenate and print files in reverse.
//applet:IF_TAC(APPLET_NOEXEC(tac, tac, BB_DIR_USR_BIN, BB_SUID_DROP, tac))
//kbuild:lib-$(CONFIG_TAC) += tac.o
//usage:#define tac_trivial_usage
//usage: "[FILE]..."
//usage:#define tac_full_usage "\n\n"
//usage: "Concatenate FILEs and print them in reverse"
#include "libbb.h"
/* This is a NOEXEC applet. Be very careful! */
struct lstring {
int size;
char buf[1];
};
int tac_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tac_main(int argc UNUSED_PARAM, char **argv)
{
char **name;
FILE *f;
struct lstring *line = NULL;
llist_t *list = NULL;
int retval = EXIT_SUCCESS;
#if ENABLE_DESKTOP
/* tac from coreutils 6.9 supports:
-b, --before
attach the separator before instead of after
-r, --regex
interpret the separator as a regular expression
-s, --separator=STRING
use STRING as the separator instead of newline
We support none, but at least we will complain or handle "--":
*/
getopt32(argv, "");
argv += optind;
#else
argv++;
#endif
if (!*argv)
*--argv = (char *)"-";
/* We will read from last file to first */
name = argv;
while (*name)
name++;
do {
int ch, i;
name--;
f = fopen_or_warn_stdin(*name);
if (f == NULL) {
/* error message is printed by fopen_or_warn_stdin */
retval = EXIT_FAILURE;
continue;
}
errno = i = 0;
do {
ch = fgetc(f);
if (ch != EOF) {
if (!(i & 0x7f))
/* Grow on every 128th char */
line = xrealloc(line, i + 0x7f + sizeof(int) + 1);
line->buf[i++] = ch;
}
if (ch == '\n' || (ch == EOF && i != 0)) {
line = xrealloc(line, i + sizeof(int));
line->size = i;
llist_add_to(&list, line);
line = NULL;
i = 0;
}
} while (ch != EOF);
/* fgetc sets errno to ENOENT on EOF, we don't want
* to warn on this non-error! */
if (errno && errno != ENOENT) {
bb_simple_perror_msg(*name);
retval = EXIT_FAILURE;
}
} while (name != argv);
while (list) {
line = (struct lstring *)list->data;
xwrite(STDOUT_FILENO, line->buf, line->size);
if (ENABLE_FEATURE_CLEAN_UP) {
free(llist_pop(&list));
} else {
list = list->link;
}
}
return retval;
}
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