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139 lines
3.1 KiB
C
139 lines
3.1 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* head implementation for busybox
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*
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* Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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/* BB_AUDIT SUSv3 compliant */
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/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
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/* http://www.opengroup.org/onlinepubs/007904975/utilities/head.html */
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#include <stdio.h>
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#include <stdlib.h>
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#include <limits.h>
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#include <ctype.h>
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#include <unistd.h>
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#include "busybox.h"
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static const char head_opts[] =
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"n:"
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#ifdef CONFIG_FEATURE_FANCY_HEAD
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"c:qv"
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#endif
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;
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static const char header_fmt_str[] = "\n==> %s <==\n";
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int head_main(int argc, char **argv)
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{
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unsigned long count = 10;
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unsigned long i;
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#ifdef CONFIG_FEATURE_FANCY_HEAD
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int count_bytes = 0;
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int header_threshhold = 1;
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#endif
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FILE *fp;
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const char *fmt;
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char *p;
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int opt;
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int c;
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int retval = EXIT_SUCCESS;
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/* Allow legacy syntax of an initial numeric option without -n. */
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if ((argc > 1) && (argv[1][0] == '-')
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/* && (isdigit)(argv[1][1]) */
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&& (((unsigned int)(argv[1][1] - '0')) <= 9)
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) {
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--argc;
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++argv;
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p = (*argv) + 1;
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goto GET_COUNT;
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}
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while ((opt = getopt(argc, argv, head_opts)) > 0) {
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switch(opt) {
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#ifdef CONFIG_FEATURE_FANCY_HEAD
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case 'q':
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header_threshhold = INT_MAX;
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break;
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case 'v':
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header_threshhold = -1;
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break;
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case 'c':
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count_bytes = 1;
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/* fall through */
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#endif
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case 'n':
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p = optarg;
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GET_COUNT:
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count = bb_xgetularg10(p);
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break;
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default:
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bb_show_usage();
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}
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}
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argv += optind;
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if (!*argv) {
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*--argv = "-";
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}
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fmt = header_fmt_str + 1;
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#ifdef CONFIG_FEATURE_FANCY_HEAD
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if (argc - optind <= header_threshhold) {
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header_threshhold = 0;
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}
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#else
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if (argc <= optind + 1) {
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fmt += 11;
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}
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/* Now define some things here to avoid #ifdefs in the code below.
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* These should optimize out of the if conditions below. */
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#define header_threshhold 1
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#define count_bytes 0
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#endif
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do {
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if ((fp = bb_wfopen_input(*argv)) != NULL) {
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if (fp == stdin) {
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*argv = (char *) bb_msg_standard_input;
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}
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if (header_threshhold) {
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bb_printf(fmt, *argv);
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}
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i = count;
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while (i && ((c = getc(fp)) != EOF)) {
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if (count_bytes || (c == '\n')) {
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--i;
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}
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putchar(c);
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}
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if (bb_fclose_nonstdin(fp)) {
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bb_perror_msg("%s", *argv); /* Avoid multibyte problems. */
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retval = EXIT_FAILURE;
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}
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bb_xferror_stdout();
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}
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fmt = header_fmt_str;
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} while (*++argv);
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bb_fflush_stdout_and_exit(retval);
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}
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