1 /* vi: set sw=4 ts=4: */
3 * Mini cmp implementation for busybox
5 * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 /* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
24 /* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
26 /* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
28 * Original version majorly reworked for SUSv3 compliance, bug fixes, and
29 * size optimizations. Changes include:
30 * 1) Now correctly distinguishes between errors and actual file differences.
31 * 2) Proper handling of '-' args.
32 * 3) Actual error checking of i/o.
33 * 4) Accept SUSv3 -l option. Note that we use the slightly nicer gnu format
42 static FILE *cmp_xfopen_input(const char *filename)
46 if ((fp = bb_wfopen_input(filename)) != NULL) {
50 exit(bb_default_error_retval); /* We already output an error message. */
53 static const char fmt_eof[] = "cmp: EOF on %s\n";
54 static const char fmt_differ[] = "%s %s differ: char %d, line %d\n";
55 // This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%d %o %o\n"
56 static const char fmt_l_opt[] = "%.0s%.0s%d %3o %3o\n";
58 static const char opt_chars[] = "sl";
65 int cmp_main(int argc, char **argv)
67 FILE *fp1, *fp2, *outfile = stdout;
68 const char *filename1, *filename2;
70 int c1, c2, char_pos, line_pos;
74 bb_default_error_retval = 2; /* 1 is returned if files are different. */
76 opt_flags = bb_getopt_ulflags(argc, argv, opt_chars);
78 if ((opt_flags == 3) || (((unsigned int)(--argc - optind)) > 1)) {
82 fp1 = cmp_xfopen_input(filename1 = *(argv += optind));
88 fp2 = cmp_xfopen_input(filename2);
90 if (fp1 == fp2) { /* Paranioa check... stdin == stdin? */
91 /* Note that we don't bother reading stdin. Neither does gnu wc.
92 * But perhaps we should, so that other apps down the chain don't
93 * get the input. Consider 'echo hello | (cmp - - && cat -)'.
99 if (opt_flags == OPT_l) {
109 if (c1 != c2) { /* Remember -- a read error may have occurred. */
110 exit_val = 1; /* But assume the files are different for now. */
112 /* We know that fp1 isn't at EOF or in an error state. But to
113 * save space below, things are setup to expect an EOF in fp1
114 * if an EOF occurred. So, swap things around.
117 filename1 = filename2;
121 bb_xferror(fp1, filename1);
122 fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
124 /* There may have been output to stdout (option -l), so
125 * make sure we fflush before writing to stderr. */
128 if (opt_flags != OPT_s) {
129 if (opt_flags == OPT_l) {
130 line_pos = c1; /* line_pos is unused in the -l case. */
132 bb_fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
133 if (opt_flags) { /* This must be -l since not -s. */
134 /* If we encountered and EOF, the while check will catch it. */
145 bb_xferror(fp1, filename1);
146 bb_xferror(fp2, filename2);
148 bb_fflush_stdout_and_exit(exit_val);