| /* vi: set sw=4 ts=4: */ |
| /* |
| * head implementation for busybox |
| * |
| * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| */ |
| |
| /* BB_AUDIT SUSv3 compliant */ |
| /* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */ |
| /* http://www.opengroup.org/onlinepubs/007904975/utilities/head.html */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <limits.h> |
| #include <ctype.h> |
| #include <unistd.h> |
| #include "busybox.h" |
| |
| static const char head_opts[] = |
| "n:" |
| #ifdef CONFIG_FEATURE_FANCY_HEAD |
| "c:qv" |
| #endif |
| ; |
| |
| static const char header_fmt_str[] = "\n==> %s <==\n"; |
| |
| int head_main(int argc, char **argv) |
| { |
| unsigned long count = 10; |
| unsigned long i; |
| #ifdef CONFIG_FEATURE_FANCY_HEAD |
| int count_bytes = 0; |
| int header_threshhold = 1; |
| #endif |
| |
| FILE *fp; |
| const char *fmt; |
| char *p; |
| int opt; |
| int c; |
| int retval = EXIT_SUCCESS; |
| |
| #if defined CONFIG_FEATURE_SUSv2 || defined CONFIG_FEATURE_FANCY_HEAD |
| /* Allow legacy syntax of an initial numeric option without -n. */ |
| if ((argc > 1) && (argv[1][0] == '-') |
| /* && (isdigit)(argv[1][1]) */ |
| && (((unsigned int)(argv[1][1] - '0')) <= 9) |
| ) { |
| --argc; |
| ++argv; |
| p = (*argv) + 1; |
| goto GET_COUNT; |
| } |
| #endif |
| |
| /* No size benefit in converting this to bb_getopt_ulflags */ |
| while ((opt = getopt(argc, argv, head_opts)) > 0) { |
| switch(opt) { |
| #ifdef CONFIG_FEATURE_FANCY_HEAD |
| case 'q': |
| header_threshhold = INT_MAX; |
| break; |
| case 'v': |
| header_threshhold = -1; |
| break; |
| case 'c': |
| count_bytes = 1; |
| /* fall through */ |
| #endif |
| case 'n': |
| p = optarg; |
| GET_COUNT: |
| count = bb_xgetularg10(p); |
| break; |
| default: |
| bb_show_usage(); |
| } |
| } |
| |
| argv += optind; |
| if (!*argv) { |
| *--argv = "-"; |
| } |
| |
| fmt = header_fmt_str + 1; |
| #ifdef CONFIG_FEATURE_FANCY_HEAD |
| if (argc - optind <= header_threshhold) { |
| header_threshhold = 0; |
| } |
| #else |
| if (argc <= optind + 1) { |
| fmt += 11; |
| } |
| /* Now define some things here to avoid #ifdefs in the code below. |
| * These should optimize out of the if conditions below. */ |
| #define header_threshhold 1 |
| #define count_bytes 0 |
| #endif |
| |
| do { |
| if ((fp = bb_wfopen_input(*argv)) != NULL) { |
| if (fp == stdin) { |
| *argv = (char *) bb_msg_standard_input; |
| } |
| if (header_threshhold) { |
| bb_printf(fmt, *argv); |
| } |
| i = count; |
| while (i && ((c = getc(fp)) != EOF)) { |
| if (count_bytes || (c == '\n')) { |
| --i; |
| } |
| putchar(c); |
| } |
| if (bb_fclose_nonstdin(fp)) { |
| bb_perror_msg("%s", *argv); /* Avoid multibyte problems. */ |
| retval = EXIT_FAILURE; |
| } |
| bb_xferror_stdout(); |
| } |
| fmt = header_fmt_str; |
| } while (*++argv); |
| |
| bb_fflush_stdout_and_exit(retval); |
| } |