/* vi: set sw=4 ts=4: */ /* * Mini cmp implementation for busybox * * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ /* 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 <stdio.h> #include <stdlib.h> #include <unistd.h> #include "busybox.h" static FILE *cmp_xfopen_input(const char *filename) { FILE *fp; if ((fp = bb_wfopen_input(filename)) != NULL) { return fp; } exit(bb_default_error_retval); /* We already output an error message. */ } static const char fmt_eof[] = "cmp: EOF on %s\n"; static const char fmt_differ[] = "%s %s differ: char %d, line %d\n"; // This fmt_l_opt uses gnu-isms. SUSv3 would be "%.0s%.0s%d %o %o\n" static const char fmt_l_opt[] = "%.0s%.0s%d %3o %3o\n"; static const char opt_chars[] = "sl"; enum { OPT_s = 1, OPT_l = 2 }; int cmp_main(int argc, char **argv) { FILE *fp1, *fp2, *outfile = stdout; const char *filename1, *filename2; const char *fmt; int c1, c2, char_pos, line_pos; int opt_flags; int exit_val = 0; bb_default_error_retval = 2; /* 1 is returned if files are different. */ opt_flags = bb_getopt_ulflags(argc, argv, opt_chars); if ((opt_flags == 3) || (((unsigned int)(--argc - optind)) > 1)) { bb_show_usage(); } fp1 = cmp_xfopen_input(filename1 = *(argv += optind)); filename2 = "-"; if (*++argv) { filename2 = *argv; } fp2 = cmp_xfopen_input(filename2); if (fp1 == fp2) { /* Paranioa 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; } fmt = fmt_differ; if (opt_flags == OPT_l) { fmt = fmt_l_opt; } char_pos = 0; line_pos = 1; do { c1 = getc(fp1); c2 = getc(fp2); ++char_pos; if (c1 != c2) { /* Remember -- a read error may have occurred. */ exit_val = 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) { bb_xferror(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. */ bb_xfflush_stdout(); } if (opt_flags != OPT_s) { if (opt_flags == OPT_l) { line_pos = c1; /* line_pos is unused in the -l case. */ } bb_fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2); if (opt_flags) { /* This must be -l since not -s. */ /* If we encountered and EOF, the while check will catch it. */ continue; } } break; } if (c1 == '\n') { ++line_pos; } } while (c1 != EOF); bb_xferror(fp1, filename1); bb_xferror(fp2, filename2); bb_fflush_stdout_and_exit(exit_val); }