blob: a4af6f4809cdb8dfa996032cde97b5d6dfa88725
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Mini cmp implementation for busybox |
4 | * |
5 | * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu> |
6 | * |
7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
8 | */ |
9 | |
10 | /* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */ |
11 | /* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */ |
12 | |
13 | //config:config CMP |
14 | //config: bool "cmp" |
15 | //config: default y |
16 | //config: help |
17 | //config: cmp is used to compare two files and returns the result |
18 | //config: to standard output. |
19 | |
20 | //kbuild:lib-$(CONFIG_CMP) += cmp.o |
21 | |
22 | //applet:IF_CMP(APPLET(cmp, BB_DIR_USR_BIN, BB_SUID_DROP)) |
23 | |
24 | //usage:#define cmp_trivial_usage |
25 | //usage: "[-l] [-s] FILE1 [FILE2" IF_DESKTOP(" [SKIP1 [SKIP2]]") "]" |
26 | //usage:#define cmp_full_usage "\n\n" |
27 | //usage: "Compare FILE1 with FILE2 (or stdin)\n" |
28 | //usage: "\n -l Write the byte numbers (decimal) and values (octal)" |
29 | //usage: "\n for all differing bytes" |
30 | //usage: "\n -s Quiet" |
31 | |
32 | #include "libbb.h" |
33 | |
34 | static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n"; |
35 | static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"u, line %u\n"; |
36 | // This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n" |
37 | static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n"; |
38 | |
39 | static const char opt_chars[] ALIGN1 = "sl"; |
40 | #define CMP_OPT_s (1<<0) |
41 | #define CMP_OPT_l (1<<1) |
42 | |
43 | int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
44 | int cmp_main(int argc UNUSED_PARAM, char **argv) |
45 | { |
46 | FILE *fp1, *fp2, *outfile = stdout; |
47 | const char *filename1, *filename2 = "-"; |
48 | off_t skip1 = 0, skip2 = 0, char_pos = 0; |
49 | int line_pos = 1; /* Hopefully won't overflow... */ |
50 | const char *fmt; |
51 | int c1, c2; |
52 | unsigned opt; |
53 | int retval = 0; |
54 | |
55 | opt_complementary = "-1" |
56 | IF_DESKTOP(":?4") |
57 | IF_NOT_DESKTOP(":?2") |
58 | ":l--s:s--l"; |
59 | opt = getopt32(argv, opt_chars); |
60 | argv += optind; |
61 | |
62 | filename1 = *argv; |
63 | if (*++argv) { |
64 | filename2 = *argv; |
65 | if (ENABLE_DESKTOP && *++argv) { |
66 | skip1 = XATOOFF(*argv); |
67 | if (*++argv) { |
68 | skip2 = XATOOFF(*argv); |
69 | } |
70 | } |
71 | } |
72 | |
73 | xfunc_error_retval = 2; /* missing file results in exitcode 2 */ |
74 | if (opt & CMP_OPT_s) |
75 | logmode = 0; /* -s suppresses open error messages */ |
76 | fp1 = xfopen_stdin(filename1); |
77 | fp2 = xfopen_stdin(filename2); |
78 | if (fp1 == fp2) { /* Paranoia check... stdin == stdin? */ |
79 | /* Note that we don't bother reading stdin. Neither does gnu wc. |
80 | * But perhaps we should, so that other apps down the chain don't |
81 | * get the input. Consider 'echo hello | (cmp - - && cat -)'. |
82 | */ |
83 | return 0; |
84 | } |
85 | logmode = LOGMODE_STDIO; |
86 | |
87 | if (opt & CMP_OPT_l) |
88 | fmt = fmt_l_opt; |
89 | else |
90 | fmt = fmt_differ; |
91 | |
92 | if (ENABLE_DESKTOP) { |
93 | while (skip1) { getc(fp1); skip1--; } |
94 | while (skip2) { getc(fp2); skip2--; } |
95 | } |
96 | do { |
97 | c1 = getc(fp1); |
98 | c2 = getc(fp2); |
99 | ++char_pos; |
100 | if (c1 != c2) { /* Remember: a read error may have occurred. */ |
101 | retval = 1; /* But assume the files are different for now. */ |
102 | if (c2 == EOF) { |
103 | /* We know that fp1 isn't at EOF or in an error state. But to |
104 | * save space below, things are setup to expect an EOF in fp1 |
105 | * if an EOF occurred. So, swap things around. |
106 | */ |
107 | fp1 = fp2; |
108 | filename1 = filename2; |
109 | c1 = c2; |
110 | } |
111 | if (c1 == EOF) { |
112 | die_if_ferror(fp1, filename1); |
113 | fmt = fmt_eof; /* Well, no error, so it must really be EOF. */ |
114 | outfile = stderr; |
115 | /* There may have been output to stdout (option -l), so |
116 | * make sure we fflush before writing to stderr. */ |
117 | fflush_all(); |
118 | } |
119 | if (!(opt & CMP_OPT_s)) { |
120 | if (opt & CMP_OPT_l) { |
121 | line_pos = c1; /* line_pos is unused in the -l case. */ |
122 | } |
123 | fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2); |
124 | if (opt) { /* This must be -l since not -s. */ |
125 | /* If we encountered an EOF, |
126 | * the while check will catch it. */ |
127 | continue; |
128 | } |
129 | } |
130 | break; |
131 | } |
132 | if (c1 == '\n') { |
133 | ++line_pos; |
134 | } |
135 | } while (c1 != EOF); |
136 | |
137 | die_if_ferror(fp1, filename1); |
138 | die_if_ferror(fp2, filename2); |
139 | |
140 | fflush_stdout_and_exit(retval); |
141 | } |
142 |