mirror of
https://git.busybox.net/busybox.git
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97 lines
2.1 KiB
C
97 lines
2.1 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini head implementation for busybox
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*
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*
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* Copyright (C) 1999,2000 by Lineo, inc.
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* Written by John Beppu <beppu@lineo.com>
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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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#include "busybox.h"
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#include <errno.h>
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#include <stdio.h>
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int head(int len, FILE *fp)
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{
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int i;
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char *input;
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for (i = 0; i < len; i++) {
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if ((input = get_line_from_file(fp)) == NULL)
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break;
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fputs(input, stdout);
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free(input);
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}
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return 0;
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}
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/* BusyBoxed head(1) */
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int head_main(int argc, char **argv)
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{
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FILE *fp;
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int need_headers, opt, len = 10, status = EXIT_SUCCESS;
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/* parse argv[] */
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while ((opt = getopt(argc, argv, "n:")) > 0) {
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switch (opt) {
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case 'n':
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len = atoi(optarg);
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if (len >= 1)
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break;
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/* fallthrough */
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default:
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usage(head_usage);
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}
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}
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/* get rest of argv[] or stdin if nothing's left */
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if (argv[optind] == NULL) {
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head(len, stdin);
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return status;
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}
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need_headers = optind != (argc - 1);
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while (argv[optind]) {
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if (strcmp(argv[optind], "-") == 0) {
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fp = stdin;
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argv[optind] = "standard input";
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} else {
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if ((fp = wfopen(argv[optind], "r")) == NULL)
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status = EXIT_FAILURE;
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}
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if (fp) {
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if (need_headers) {
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printf("==> %s <==\n", argv[optind]);
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}
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head(len, fp);
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if (errno) {
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perror_msg("%s", argv[optind]);
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status = EXIT_FAILURE;
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errno = 0;
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}
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if (optind < argc - 1)
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putchar('\n');
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if (fp != stdin)
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fclose(fp);
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}
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optind++;
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}
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return status;
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}
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