| /* 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 "busybox.h" |
| |
| static FILE *cmp_xfopen_input(const char * const filename) |
| { |
| FILE *fp; |
| |
| if ((fp = bb_wfopen_input(filename)) != NULL) { |
| return fp; |
| } |
| |
| exit(xfunc_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"; |
| #define CMP_OPT_s (1<<0) |
| #define CMP_OPT_l (1<<1) |
| |
| int cmp_main(int argc, char **argv) |
| { |
| FILE *fp1, *fp2, *outfile = stdout; |
| const char *filename1, *filename2 = "-"; |
| const char *fmt; |
| int c1, c2, char_pos = 0, line_pos = 1; |
| unsigned opt; |
| int retval = 0; |
| |
| xfunc_error_retval = 2; /* 1 is returned if files are different. */ |
| |
| opt = bb_getopt_ulflags(argc, argv, opt_chars); |
| |
| if (((opt & (CMP_OPT_s|CMP_OPT_l)) == (CMP_OPT_s|CMP_OPT_l)) |
| || (((unsigned int)(--argc - optind)) > 1)) |
| bb_show_usage(); |
| |
| fp1 = cmp_xfopen_input(filename1 = *(argv += optind)); |
| |
| 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; |
| } |
| |
| if (opt & CMP_OPT_l) |
| fmt = fmt_l_opt; |
| else |
| fmt = fmt_differ; |
| |
| 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) { |
| 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. */ |
| xfflush_stdout(); |
| } |
| if (!(opt & CMP_OPT_s)) { |
| if (opt & CMP_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) { /* 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); |
| |
| xferror(fp1, filename1); |
| xferror(fp2, filename2); |
| |
| bb_fflush_stdout_and_exit(retval); |
| } |