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Mark Whitley872138d2000-10-09 18:56:47 +00001/* vi: set sw=4 ts=4: */
2/*
3 * Mini cmp implementation for busybox
4 *
Eric Andersenbdfd0d72001-10-24 05:00:29 +00005 * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
Mark Whitley872138d2000-10-09 18:56:47 +00006 *
"Robert P. J. Day"801ab142006-07-12 07:56:04 +00007 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
Mark Whitley872138d2000-10-09 18:56:47 +00008 */
9
Manuel Novoa III cad53642003-03-19 09:13:01 +000010/* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
11/* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
12
13/* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
14 *
15 * Original version majorly reworked for SUSv3 compliance, bug fixes, and
16 * size optimizations. Changes include:
Eric Andersenaff114c2004-04-14 17:51:38 +000017 * 1) Now correctly distinguishes between errors and actual file differences.
Manuel Novoa III cad53642003-03-19 09:13:01 +000018 * 2) Proper handling of '-' args.
19 * 3) Actual error checking of i/o.
20 * 4) Accept SUSv3 -l option. Note that we use the slightly nicer gnu format
21 * in the '-l' case.
22 */
23
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000024#include "libbb.h"
Mark Whitley872138d2000-10-09 18:56:47 +000025
Denis Vlasenko6ca409e2007-08-12 20:58:27 +000026static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n";
Denys Vlasenkoa3aa3e32009-12-11 12:36:10 +010027static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"u, line %u\n";
28// This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n"
29static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n";
Manuel Novoa III cad53642003-03-19 09:13:01 +000030
Denis Vlasenko6ca409e2007-08-12 20:58:27 +000031static const char opt_chars[] ALIGN1 = "sl";
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000032#define CMP_OPT_s (1<<0)
33#define CMP_OPT_l (1<<1)
Manuel Novoa III cad53642003-03-19 09:13:01 +000034
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +000035int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +000036int cmp_main(int argc UNUSED_PARAM, char **argv)
Mark Whitley872138d2000-10-09 18:56:47 +000037{
Manuel Novoa III cad53642003-03-19 09:13:01 +000038 FILE *fp1, *fp2, *outfile = stdout;
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000039 const char *filename1, *filename2 = "-";
Rob Landley0c1ba442010-04-26 14:01:14 +020040 off_t skip1 = 0, skip2 = 0, char_pos = 0;
Denis Vlasenko9a1fa8c2007-03-21 22:30:14 +000041 int line_pos = 1; /* Hopefully won't overflow... */
Manuel Novoa III cad53642003-03-19 09:13:01 +000042 const char *fmt;
Denis Vlasenko9a1fa8c2007-03-21 22:30:14 +000043 int c1, c2;
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000044 unsigned opt;
45 int retval = 0;
Mark Whitley872138d2000-10-09 18:56:47 +000046
Denis Vlasenko40920822006-10-03 20:28:06 +000047 xfunc_error_retval = 2; /* 1 is returned if files are different. */
Manuel Novoa III cad53642003-03-19 09:13:01 +000048
Denis Vlasenko09196572007-07-21 13:27:44 +000049 opt_complementary = "-1"
Denis Vlasenko5e34ff22009-04-21 11:09:40 +000050 IF_DESKTOP(":?4")
51 IF_NOT_DESKTOP(":?2")
Denis Vlasenko9a1fa8c2007-03-21 22:30:14 +000052 ":l--s:s--l";
Denis Vlasenkofe7cd642007-08-18 15:32:12 +000053 opt = getopt32(argv, opt_chars);
Denis Vlasenko9a1fa8c2007-03-21 22:30:14 +000054 argv += optind;
Manuel Novoa III cad53642003-03-19 09:13:01 +000055
Denis Vlasenko9a1fa8c2007-03-21 22:30:14 +000056 filename1 = *argv;
Denis Vlasenko62a90cd2008-03-17 09:07:36 +000057 fp1 = xfopen_stdin(filename1);
Manuel Novoa III cad53642003-03-19 09:13:01 +000058
Manuel Novoa III cad53642003-03-19 09:13:01 +000059 if (*++argv) {
60 filename2 = *argv;
Rob Landley0c1ba442010-04-26 14:01:14 +020061 if (ENABLE_DESKTOP && *++argv) {
Denis Vlasenko9a1fa8c2007-03-21 22:30:14 +000062 skip1 = XATOOFF(*argv);
63 if (*++argv) {
64 skip2 = XATOOFF(*argv);
65 }
66 }
Manuel Novoa III cad53642003-03-19 09:13:01 +000067 }
Manuel Novoa III cad53642003-03-19 09:13:01 +000068
Denis Vlasenko62a90cd2008-03-17 09:07:36 +000069 fp2 = xfopen_stdin(filename2);
Denis Vlasenko9a1fa8c2007-03-21 22:30:14 +000070 if (fp1 == fp2) { /* Paranoia check... stdin == stdin? */
Manuel Novoa III cad53642003-03-19 09:13:01 +000071 /* Note that we don't bother reading stdin. Neither does gnu wc.
72 * But perhaps we should, so that other apps down the chain don't
73 * get the input. Consider 'echo hello | (cmp - - && cat -)'.
74 */
75 return 0;
Mark Whitley872138d2000-10-09 18:56:47 +000076 }
77
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000078 if (opt & CMP_OPT_l)
Manuel Novoa III cad53642003-03-19 09:13:01 +000079 fmt = fmt_l_opt;
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000080 else
81 fmt = fmt_differ;
Manuel Novoa III cad53642003-03-19 09:13:01 +000082
Rob Landley0c1ba442010-04-26 14:01:14 +020083 if (ENABLE_DESKTOP) {
84 while (skip1) { getc(fp1); skip1--; }
85 while (skip2) { getc(fp2); skip2--; }
86 }
Mark Whitley872138d2000-10-09 18:56:47 +000087 do {
Manuel Novoa III cad53642003-03-19 09:13:01 +000088 c1 = getc(fp1);
89 c2 = getc(fp2);
90 ++char_pos;
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000091 if (c1 != c2) { /* Remember: a read error may have occurred. */
92 retval = 1; /* But assume the files are different for now. */
Manuel Novoa III cad53642003-03-19 09:13:01 +000093 if (c2 == EOF) {
94 /* We know that fp1 isn't at EOF or in an error state. But to
95 * save space below, things are setup to expect an EOF in fp1
96 * if an EOF occurred. So, swap things around.
97 */
98 fp1 = fp2;
99 filename1 = filename2;
100 c1 = c2;
101 }
102 if (c1 == EOF) {
Denis Vlasenkof0ed3762006-10-26 23:21:47 +0000103 die_if_ferror(fp1, filename1);
Manuel Novoa III cad53642003-03-19 09:13:01 +0000104 fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
105 outfile = stderr;
106 /* There may have been output to stdout (option -l), so
107 * make sure we fflush before writing to stderr. */
Denys Vlasenko8131eea2009-11-02 14:19:51 +0100108 fflush_all();
Manuel Novoa III cad53642003-03-19 09:13:01 +0000109 }
Bernhard Reutner-Fischera6585772006-09-20 15:29:13 +0000110 if (!(opt & CMP_OPT_s)) {
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +0000111 if (opt & CMP_OPT_l) {
Manuel Novoa III cad53642003-03-19 09:13:01 +0000112 line_pos = c1; /* line_pos is unused in the -l case. */
113 }
Denis Vlasenkof0ed3762006-10-26 23:21:47 +0000114 fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +0000115 if (opt) { /* This must be -l since not -s. */
116 /* If we encountered an EOF,
117 * the while check will catch it. */
Manuel Novoa III cad53642003-03-19 09:13:01 +0000118 continue;
119 }
120 }
121 break;
Mark Whitley872138d2000-10-09 18:56:47 +0000122 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000123 if (c1 == '\n') {
124 ++line_pos;
125 }
Mark Whitley872138d2000-10-09 18:56:47 +0000126 } while (c1 != EOF);
127
Denis Vlasenkof0ed3762006-10-26 23:21:47 +0000128 die_if_ferror(fp1, filename1);
129 die_if_ferror(fp2, filename2);
Manuel Novoa III cad53642003-03-19 09:13:01 +0000130
Denis Vlasenkof0ed3762006-10-26 23:21:47 +0000131 fflush_stdout_and_exit(retval);
Mark Whitley872138d2000-10-09 18:56:47 +0000132}