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/* vi: set sw=4 ts=4: */
/*
* tac implementation for busybox
*
* 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 tarball for details.
*
*/
/* tac - concatenate and print files in reverse */
/* Based on Yang Xiaopeng's (yxp at hanwang.com.cn) patch
* http://www.uclibc.org/lists/busybox/2003-July/008813.html
*/
#include "libbb.h"
/* This is a NOEXEC applet. Be very careful! */
struct lstring {
int size;
char buf[];
};
int tac_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tac_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
char **name;
FILE *f;
struct lstring *line = NULL;
llist_t *list = NULL;
int retval = EXIT_SUCCESS;
argv++;
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) {
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) {
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, but */
/* fopen_or_warn_stdin would catch this error */
/* so we can filter it out here. */
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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