/* 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 tarball for details. */ /* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */ /* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */ /* Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org) * * Original version majorly reworked for SUSv3 compliance, bug fixes, and * size optimizations. Changes include: * 1) Now correctly distinguishes between errors and actual file differences. * 2) Proper handling of '-' args. * 3) Actual error checking of i/o. * 4) Accept SUSv3 -l option. Note that we use the slightly nicer gnu format * in the '-l' case. */ #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"d, line %d\n"; // This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%"OFF_FMT"d %o %o\n" static const char fmt_l_opt[] ALIGN1 = "%.0s%.0s%"OFF_FMT"d %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 = "-"; IF_DESKTOP(off_t skip1 = 0, skip2 = 0;) off_t char_pos = 0; int line_pos = 1; /* Hopefully won't overflow... */ const char *fmt; int c1, c2; unsigned opt; int retval = 0; xfunc_error_retval = 2; /* 1 is returned if files are different. */ opt_complementary = "-1" IF_DESKTOP(":?4") IF_NOT_DESKTOP(":?2") ":l--s:s--l"; opt = getopt32(argv, opt_chars); argv += optind; filename1 = *argv; fp1 = xfopen_stdin(filename1); if (*++argv) { filename2 = *argv; #if ENABLE_DESKTOP if (*++argv) { skip1 = XATOOFF(*argv); if (*++argv) { skip2 = XATOOFF(*argv); } } #endif } 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; } 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--; } #endif 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. */ xfflush_stdout(); } 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); }