142 lines
4.0 KiB
C
142 lines
4.0 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini cmp implementation for busybox
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*
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* Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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/* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
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/* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
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//config:config CMP
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//config: bool "cmp (5.4 kb)"
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//config: default y
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//config: help
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//config: cmp is used to compare two files and returns the result
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//config: to standard output.
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//kbuild:lib-$(CONFIG_CMP) += cmp.o
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//applet:IF_CMP(APPLET(cmp, BB_DIR_USR_BIN, BB_SUID_DROP))
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//usage:#define cmp_trivial_usage
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//usage: "[-l] [-s] FILE1 [FILE2" IF_DESKTOP(" [SKIP1 [SKIP2]]") "]"
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//usage:#define cmp_full_usage "\n\n"
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//usage: "Compare FILE1 with FILE2 (or stdin)\n"
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//usage: "\n -l Write the byte numbers (decimal) and values (octal)"
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//usage: "\n for all differing bytes"
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//usage: "\n -s Quiet"
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#include "libbb.h"
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static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n";
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static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"u, line %u\n";
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// This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n"
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static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n";
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static const char opt_chars[] ALIGN1 = "sl";
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#define CMP_OPT_s (1<<0)
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#define CMP_OPT_l (1<<1)
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int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int cmp_main(int argc UNUSED_PARAM, char **argv)
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{
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FILE *fp1, *fp2, *outfile = stdout;
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const char *filename1, *filename2 = "-";
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off_t skip1 = 0, skip2 = 0, char_pos = 0;
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int line_pos = 1; /* Hopefully won't overflow... */
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const char *fmt;
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int c1, c2;
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unsigned opt;
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int retval = 0;
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opt_complementary = "-1"
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IF_DESKTOP(":?4")
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IF_NOT_DESKTOP(":?2")
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":l--s:s--l";
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opt = getopt32(argv, opt_chars);
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argv += optind;
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filename1 = *argv;
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if (*++argv) {
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filename2 = *argv;
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if (ENABLE_DESKTOP && *++argv) {
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skip1 = XATOOFF(*argv);
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if (*++argv) {
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skip2 = XATOOFF(*argv);
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}
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}
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}
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xfunc_error_retval = 2; /* missing file results in exitcode 2 */
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if (opt & CMP_OPT_s)
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logmode = 0; /* -s suppresses open error messages */
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fp1 = xfopen_stdin(filename1);
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fp2 = xfopen_stdin(filename2);
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if (fp1 == fp2) { /* Paranoia check... stdin == stdin? */
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/* Note that we don't bother reading stdin. Neither does gnu wc.
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* But perhaps we should, so that other apps down the chain don't
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* get the input. Consider 'echo hello | (cmp - - && cat -)'.
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*/
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return 0;
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}
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logmode = LOGMODE_STDIO;
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if (opt & CMP_OPT_l)
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fmt = fmt_l_opt;
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else
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fmt = fmt_differ;
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if (ENABLE_DESKTOP) {
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while (skip1) { getc(fp1); skip1--; }
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while (skip2) { getc(fp2); skip2--; }
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}
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do {
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c1 = getc(fp1);
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c2 = getc(fp2);
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++char_pos;
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if (c1 != c2) { /* Remember: a read error may have occurred. */
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retval = 1; /* But assume the files are different for now. */
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if (c2 == EOF) {
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/* We know that fp1 isn't at EOF or in an error state. But to
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* save space below, things are setup to expect an EOF in fp1
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* if an EOF occurred. So, swap things around.
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*/
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fp1 = fp2;
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filename1 = filename2;
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c1 = c2;
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}
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if (c1 == EOF) {
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die_if_ferror(fp1, filename1);
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fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
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outfile = stderr;
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/* There may have been output to stdout (option -l), so
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* make sure we fflush before writing to stderr. */
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fflush_all();
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}
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if (!(opt & CMP_OPT_s)) {
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if (opt & CMP_OPT_l) {
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line_pos = c1; /* line_pos is unused in the -l case. */
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}
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fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
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if (opt) { /* This must be -l since not -s. */
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/* If we encountered an EOF,
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* the while check will catch it. */
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continue;
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}
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}
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break;
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}
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if (c1 == '\n') {
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++line_pos;
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}
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} while (c1 != EOF);
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die_if_ferror(fp1, filename1);
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die_if_ferror(fp2, filename2);
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fflush_stdout_and_exit(retval);
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}
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