blob: 2b923c845e2d976c64e65c1045082959765a25d5 [file] [log] [blame]
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
Eric Andersencbe31da2001-02-20 06:14:08 +000024#include "busybox.h"
Mark Whitley872138d2000-10-09 18:56:47 +000025
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000026static FILE *cmp_xfopen_input(const char * const filename)
Manuel Novoa III cad53642003-03-19 09:13:01 +000027{
28 FILE *fp;
29
30 if ((fp = bb_wfopen_input(filename)) != NULL) {
31 return fp;
32 }
33
Denis Vlasenko40920822006-10-03 20:28:06 +000034 exit(xfunc_error_retval); /* We already output an error message. */
Manuel Novoa III cad53642003-03-19 09:13:01 +000035}
36
37static const char fmt_eof[] = "cmp: EOF on %s\n";
38static const char fmt_differ[] = "%s %s differ: char %d, line %d\n";
Rob Landleyc370ea82006-03-27 17:00:11 +000039// This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%d %o %o\n"
40static const char fmt_l_opt[] = "%.0s%.0s%d %3o %3o\n";
Manuel Novoa III cad53642003-03-19 09:13:01 +000041
42static const char opt_chars[] = "sl";
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000043#define CMP_OPT_s (1<<0)
44#define CMP_OPT_l (1<<1)
Manuel Novoa III cad53642003-03-19 09:13:01 +000045
Mark Whitley872138d2000-10-09 18:56:47 +000046int cmp_main(int argc, char **argv)
47{
Manuel Novoa III cad53642003-03-19 09:13:01 +000048 FILE *fp1, *fp2, *outfile = stdout;
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000049 const char *filename1, *filename2 = "-";
Manuel Novoa III cad53642003-03-19 09:13:01 +000050 const char *fmt;
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000051 int c1, c2, char_pos = 0, line_pos = 1;
52 unsigned opt;
53 int retval = 0;
Mark Whitley872138d2000-10-09 18:56:47 +000054
Denis Vlasenko40920822006-10-03 20:28:06 +000055 xfunc_error_retval = 2; /* 1 is returned if files are different. */
Manuel Novoa III cad53642003-03-19 09:13:01 +000056
Denis Vlasenko67b23e62006-10-03 21:00:06 +000057 opt = getopt32(argc, argv, opt_chars);
Manuel Novoa III cad53642003-03-19 09:13:01 +000058
Bernhard Reutner-Fischera6585772006-09-20 15:29:13 +000059 if (((opt & (CMP_OPT_s|CMP_OPT_l)) == (CMP_OPT_s|CMP_OPT_l))
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000060 || (((unsigned int)(--argc - optind)) > 1))
Manuel Novoa III cad53642003-03-19 09:13:01 +000061 bb_show_usage();
Mark Whitley872138d2000-10-09 18:56:47 +000062
Manuel Novoa III cad53642003-03-19 09:13:01 +000063 fp1 = cmp_xfopen_input(filename1 = *(argv += optind));
64
Manuel Novoa III cad53642003-03-19 09:13:01 +000065 if (*++argv) {
66 filename2 = *argv;
67 }
68 fp2 = cmp_xfopen_input(filename2);
69
70 if (fp1 == fp2) { /* Paranioa check... stdin == stdin? */
71 /* 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
Mark Whitley872138d2000-10-09 18:56:47 +000083 do {
Manuel Novoa III cad53642003-03-19 09:13:01 +000084 c1 = getc(fp1);
85 c2 = getc(fp2);
86 ++char_pos;
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +000087 if (c1 != c2) { /* Remember: a read error may have occurred. */
88 retval = 1; /* But assume the files are different for now. */
Manuel Novoa III cad53642003-03-19 09:13:01 +000089 if (c2 == EOF) {
90 /* We know that fp1 isn't at EOF or in an error state. But to
91 * save space below, things are setup to expect an EOF in fp1
92 * if an EOF occurred. So, swap things around.
93 */
94 fp1 = fp2;
95 filename1 = filename2;
96 c1 = c2;
97 }
98 if (c1 == EOF) {
Denis Vlasenkof0ed3762006-10-26 23:21:47 +000099 die_if_ferror(fp1, filename1);
Manuel Novoa III cad53642003-03-19 09:13:01 +0000100 fmt = fmt_eof; /* Well, no error, so it must really be EOF. */
101 outfile = stderr;
102 /* There may have been output to stdout (option -l), so
103 * make sure we fflush before writing to stderr. */
Rob Landleyd921b2e2006-08-03 15:41:12 +0000104 xfflush_stdout();
Manuel Novoa III cad53642003-03-19 09:13:01 +0000105 }
Bernhard Reutner-Fischera6585772006-09-20 15:29:13 +0000106 if (!(opt & CMP_OPT_s)) {
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +0000107 if (opt & CMP_OPT_l) {
Manuel Novoa III cad53642003-03-19 09:13:01 +0000108 line_pos = c1; /* line_pos is unused in the -l case. */
109 }
Denis Vlasenkof0ed3762006-10-26 23:21:47 +0000110 fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
Bernhard Reutner-Fischer73561cc2006-08-28 23:31:54 +0000111 if (opt) { /* This must be -l since not -s. */
112 /* If we encountered an EOF,
113 * the while check will catch it. */
Manuel Novoa III cad53642003-03-19 09:13:01 +0000114 continue;
115 }
116 }
117 break;
Mark Whitley872138d2000-10-09 18:56:47 +0000118 }
Manuel Novoa III cad53642003-03-19 09:13:01 +0000119 if (c1 == '\n') {
120 ++line_pos;
121 }
Mark Whitley872138d2000-10-09 18:56:47 +0000122 } while (c1 != EOF);
123
Denis Vlasenkof0ed3762006-10-26 23:21:47 +0000124 die_if_ferror(fp1, filename1);
125 die_if_ferror(fp2, filename2);
Manuel Novoa III cad53642003-03-19 09:13:01 +0000126
Denis Vlasenkof0ed3762006-10-26 23:21:47 +0000127 fflush_stdout_and_exit(retval);
Mark Whitley872138d2000-10-09 18:56:47 +0000128}