/* 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 "libbb.h" static const char head_opts[] ALIGN1 = "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 }, { "", 0 } }; #endif static const char header_fmt_str[] ALIGN1 = "\n==> %s <==\n"; int head_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 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_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD /* Allow legacy syntax of an initial numeric option without -n. */ if (argv[1] && argv[1][0] == '-' && isdigit(argv[1][1]) ) { --argc; ++argv; p = (*argv) + 1; goto GET_COUNT; } #endif /* No size benefit in converting this to getopt32 */ 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_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD GET_COUNT: #endif #if !ENABLE_FEATURE_FANCY_HEAD count = xatoul(p); #else count = xatoul_sfx(p, head_suffixes); #endif break; default: bb_show_usage(); } } argc -= optind; argv += optind; if (!*argv) *--argv = (char*)"-"; fmt = header_fmt_str + 1; #if ENABLE_FEATURE_FANCY_HEAD if (argc <= header_threshhold) { header_threshhold = 0; } #else if (argc <= 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 { fp = fopen_or_warn_stdin(*argv); if (fp) { if (fp == stdin) { *argv = (char *) bb_msg_standard_input; } if (header_threshhold) { printf(fmt, *argv); } i = count; while (i && ((c = getc(fp)) != EOF)) { if (count_bytes || (c == '\n')) { --i; } putchar(c); } if (fclose_if_not_stdin(fp)) { bb_simple_perror_msg(*argv); retval = EXIT_FAILURE; } die_if_ferror_stdout(); } else { retval = EXIT_FAILURE; } fmt = header_fmt_str; } while (*++argv); fflush_stdout_and_exit(retval); }