/* vi: set sw=4 ts=4: */ /* * head implementation for busybox * * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org> * * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. */ /* 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:" #if ENABLE_FEATURE_FANCY_HEAD "c:qv" #endif ; #if ENABLE_FEATURE_FANCY_HEAD static const struct suffix_mult head_suffixes[] = { { "b", 512 }, { "k", 1024 }, { "m", 1024*1024 }, { NULL, 0 } }; #endif static const char header_fmt_str[] = "\n==> %s <==\n"; int head_main(int argc, char **argv) { unsigned long count = 10; unsigned long i; #if ENABLE_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 !ENABLE_DEBUG_YANK_SUSv2 || ENABLE_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) { #if ENABLE_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; #if !ENABLE_DEBUG_YANK_SUSv2 || ENABLE_FEATURE_FANCY_HEAD GET_COUNT: #endif #if !ENABLE_FEATURE_FANCY_HEAD count = bb_xgetularg10(p); #else count = bb_xgetularg_bnd_sfx(p, 10, 0, ULONG_MAX, head_suffixes); #endif break; default: bb_show_usage(); } } argv += optind; if (!*argv) { *--argv = "-"; } fmt = header_fmt_str + 1; #if ENABLE_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); }