| /* vi: set sw=4 ts=4: */ |
| /* |
| * Mini cmp implementation for busybox |
| * |
| * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu> |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| */ |
| |
| /* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */ |
| /* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */ |
| |
| //config:config CMP |
| //config: bool "cmp" |
| //config: default y |
| //config: help |
| //config: cmp is used to compare two files and returns the result |
| //config: to standard output. |
| |
| //kbuild:lib-$(CONFIG_CMP) += cmp.o |
| |
| //applet:IF_CMP(APPLET(cmp, BB_DIR_USR_BIN, BB_SUID_DROP)) |
| |
| //usage:#define cmp_trivial_usage |
| //usage: "[-l] [-s] FILE1 [FILE2" IF_DESKTOP(" [SKIP1 [SKIP2]]") "]" |
| //usage:#define cmp_full_usage "\n\n" |
| //usage: "Compare FILE1 with FILE2 (or stdin)\n" |
| //usage: "\n -l Write the byte numbers (decimal) and values (octal)" |
| //usage: "\n for all differing bytes" |
| //usage: "\n -s Quiet" |
| |
| #include "libbb.h" |
| |
| static const char fmt_eof[] ALIGN1 = "cmp: EOF on %s\n"; |
| static const char fmt_differ[] ALIGN1 = "%s %s differ: char %"OFF_FMT"u, line %u\n"; |
| // This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"u %o %o\n" |
| static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"u %3o %3o\n"; |
| |
| static const char opt_chars[] ALIGN1 = "sl"; |
| #define CMP_OPT_s (1<<0) |
| #define CMP_OPT_l (1<<1) |
| |
| int cmp_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int cmp_main(int argc UNUSED_PARAM, char **argv) |
| { |
| FILE *fp1, *fp2, *outfile = stdout; |
| const char *filename1, *filename2 = "-"; |
| off_t skip1 = 0, skip2 = 0, char_pos = 0; |
| int line_pos = 1; /* Hopefully won't overflow... */ |
| const char *fmt; |
| int c1, c2; |
| unsigned opt; |
| int retval = 0; |
| |
| opt_complementary = "-1" |
| IF_DESKTOP(":?4") |
| IF_NOT_DESKTOP(":?2") |
| ":l--s:s--l"; |
| opt = getopt32(argv, opt_chars); |
| argv += optind; |
| |
| filename1 = *argv; |
| if (*++argv) { |
| filename2 = *argv; |
| if (ENABLE_DESKTOP && *++argv) { |
| skip1 = XATOOFF(*argv); |
| if (*++argv) { |
| skip2 = XATOOFF(*argv); |
| } |
| } |
| } |
| |
| xfunc_error_retval = 2; /* missing file results in exitcode 2 */ |
| if (opt & CMP_OPT_s) |
| logmode = 0; /* -s suppresses open error messages */ |
| fp1 = xfopen_stdin(filename1); |
| fp2 = xfopen_stdin(filename2); |
| if (fp1 == fp2) { /* Paranoia check... stdin == stdin? */ |
| /* Note that we don't bother reading stdin. Neither does gnu wc. |
| * But perhaps we should, so that other apps down the chain don't |
| * get the input. Consider 'echo hello | (cmp - - && cat -)'. |
| */ |
| return 0; |
| } |
| logmode = LOGMODE_STDIO; |
| |
| if (opt & CMP_OPT_l) |
| fmt = fmt_l_opt; |
| else |
| fmt = fmt_differ; |
| |
| if (ENABLE_DESKTOP) { |
| while (skip1) { getc(fp1); skip1--; } |
| while (skip2) { getc(fp2); skip2--; } |
| } |
| do { |
| c1 = getc(fp1); |
| c2 = getc(fp2); |
| ++char_pos; |
| if (c1 != c2) { /* Remember: a read error may have occurred. */ |
| retval = 1; /* But assume the files are different for now. */ |
| if (c2 == EOF) { |
| /* We know that fp1 isn't at EOF or in an error state. But to |
| * save space below, things are setup to expect an EOF in fp1 |
| * if an EOF occurred. So, swap things around. |
| */ |
| fp1 = fp2; |
| filename1 = filename2; |
| c1 = c2; |
| } |
| if (c1 == EOF) { |
| die_if_ferror(fp1, filename1); |
| fmt = fmt_eof; /* Well, no error, so it must really be EOF. */ |
| outfile = stderr; |
| /* There may have been output to stdout (option -l), so |
| * make sure we fflush before writing to stderr. */ |
| fflush_all(); |
| } |
| if (!(opt & CMP_OPT_s)) { |
| if (opt & CMP_OPT_l) { |
| line_pos = c1; /* line_pos is unused in the -l case. */ |
| } |
| fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2); |
| if (opt) { /* This must be -l since not -s. */ |
| /* If we encountered an EOF, |
| * the while check will catch it. */ |
| continue; |
| } |
| } |
| break; |
| } |
| if (c1 == '\n') { |
| ++line_pos; |
| } |
| } while (c1 != EOF); |
| |
| die_if_ferror(fp1, filename1); |
| die_if_ferror(fp2, filename2); |
| |
| fflush_stdout_and_exit(retval); |
| } |