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 tarball for details. 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#include "libbb.h" 14 15static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n"; 16static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"u, line %u\n"; 17// This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n" 18static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n"; 19 20static const char opt_chars[] ALIGN1 = "sl"; 21#define CMP_OPT_s (1<<0) 22#define CMP_OPT_l (1<<1) 23 24int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 25int cmp_main(int argc UNUSED_PARAM, char **argv) 26{ 27 FILE *fp1, *fp2, *outfile = stdout; 28 const char *filename1, *filename2 = "-"; 29 off_t skip1 = 0, skip2 = 0, char_pos = 0; 30 int line_pos = 1; /* Hopefully won't overflow... */ 31 const char *fmt; 32 int c1, c2; 33 unsigned opt; 34 int retval = 0; 35 36 xfunc_error_retval = 2; /* 1 is returned if files are different. */ 37 38 opt_complementary = "-1" 39 IF_DESKTOP(":?4") 40 IF_NOT_DESKTOP(":?2") 41 ":l--s:s--l"; 42 opt = getopt32(argv, opt_chars); 43 argv += optind; 44 45 filename1 = *argv; 46 fp1 = xfopen_stdin(filename1); 47 48 if (*++argv) { 49 filename2 = *argv; 50 if (ENABLE_DESKTOP && *++argv) { 51 skip1 = XATOOFF(*argv); 52 if (*++argv) { 53 skip2 = XATOOFF(*argv); 54 } 55 } 56 } 57 58 fp2 = xfopen_stdin(filename2); 59 if (fp1 == fp2) { /* Paranoia check... stdin == stdin? */ 60 /* Note that we don't bother reading stdin. Neither does gnu wc. 61 * But perhaps we should, so that other apps down the chain don't 62 * get the input. Consider 'echo hello | (cmp - - && cat -)'. 63 */ 64 return 0; 65 } 66 67 if (opt & CMP_OPT_l) 68 fmt = fmt_l_opt; 69 else 70 fmt = fmt_differ; 71 72 if (ENABLE_DESKTOP) { 73 while (skip1) { getc(fp1); skip1--; } 74 while (skip2) { getc(fp2); skip2--; } 75 } 76 do { 77 c1 = getc(fp1); 78 c2 = getc(fp2); 79 ++char_pos; 80 if (c1 != c2) { /* Remember: a read error may have occurred. */ 81 retval = 1; /* But assume the files are different for now. */ 82 if (c2 == EOF) { 83 /* We know that fp1 isn't at EOF or in an error state. But to 84 * save space below, things are setup to expect an EOF in fp1 85 * if an EOF occurred. So, swap things around. 86 */ 87 fp1 = fp2; 88 filename1 = filename2; 89 c1 = c2; 90 } 91 if (c1 == EOF) { 92 die_if_ferror(fp1, filename1); 93 fmt = fmt_eof; /* Well, no error, so it must really be EOF. */ 94 outfile = stderr; 95 /* There may have been output to stdout (option -l), so 96 * make sure we fflush before writing to stderr. */ 97 fflush_all(); 98 } 99 if (!(opt & CMP_OPT_s)) { 100 if (opt & CMP_OPT_l) { 101 line_pos = c1; /* line_pos is unused in the -l case. */ 102 } 103 fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2); 104 if (opt) { /* This must be -l since not -s. */ 105 /* If we encountered an EOF, 106 * the while check will catch it. */ 107 continue; 108 } 109 } 110 break; 111 } 112 if (c1 == '\n') { 113 ++line_pos; 114 } 115 } while (c1 != EOF); 116 117 die_if_ferror(fp1, filename1); 118 die_if_ferror(fp2, filename2); 119 120 fflush_stdout_and_exit(retval); 121} 122