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