It is impossible to formulate sane ABI based on size of ulong because it can be 32-bit or 64-bit. Basically it means that you cannot portably use more that 32 option chars in one call anyway... Make it explicit.
		
			
				
	
	
		
			129 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			129 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* vi: set sw=4 ts=4: */
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/*
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 * Mini cmp implementation for busybox
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 *
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 * Copyright (C) 2000,2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
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 *
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 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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 */
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/* BB_AUDIT SUSv3 (virtually) compliant -- uses nicer GNU format for -l. */
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/* http://www.opengroup.org/onlinepubs/007904975/utilities/cmp.html */
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/* Mar 16, 2003      Manuel Novoa III   (mjn3@codepoet.org)
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 *
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 * Original version majorly reworked for SUSv3 compliance, bug fixes, and
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 * size optimizations.  Changes include:
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 * 1) Now correctly distinguishes between errors and actual file differences.
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 * 2) Proper handling of '-' args.
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 * 3) Actual error checking of i/o.
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 * 4) Accept SUSv3 -l option.  Note that we use the slightly nicer gnu format
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 *    in the '-l' case.
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 */
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#include "busybox.h"
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static FILE *cmp_xfopen_input(const char * const filename)
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{
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	FILE *fp;
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	if ((fp = bb_wfopen_input(filename)) != NULL) {
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		return fp;
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	}
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	exit(xfunc_error_retval);	/* We already output an error message. */
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}
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static const char fmt_eof[] = "cmp: EOF on %s\n";
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static const char fmt_differ[] = "%s %s differ: char %d, line %d\n";
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// This fmt_l_opt uses gnu-isms.  SUSv3 would be "%.0s%.0s%d %o %o\n"
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static const char fmt_l_opt[] = "%.0s%.0s%d %3o %3o\n";
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static const char opt_chars[] = "sl";
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#define CMP_OPT_s (1<<0)
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#define CMP_OPT_l (1<<1)
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int cmp_main(int argc, char **argv)
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{
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	FILE *fp1, *fp2, *outfile = stdout;
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	const char *filename1, *filename2 = "-";
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	const char *fmt;
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	int c1, c2, char_pos = 0, line_pos = 1;
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	unsigned opt;
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	int retval = 0;
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	xfunc_error_retval = 2;	/* 1 is returned if files are different. */
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	opt = getopt32(argc, argv, opt_chars);
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	if (((opt & (CMP_OPT_s|CMP_OPT_l)) == (CMP_OPT_s|CMP_OPT_l))
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			|| (((unsigned int)(--argc - optind)) > 1))
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		bb_show_usage();
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	fp1 = cmp_xfopen_input(filename1 = *(argv += optind));
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	if (*++argv) {
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		filename2 = *argv;
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	}
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	fp2 = cmp_xfopen_input(filename2);
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	if (fp1 == fp2) {			/* Paranioa check... stdin == stdin? */
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		/* Note that we don't bother reading stdin.  Neither does gnu wc.
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		 * But perhaps we should, so that other apps down the chain don't
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		 * get the input.  Consider 'echo hello | (cmp - - && cat -)'.
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		 */
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		return 0;
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	}
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	if (opt & CMP_OPT_l)
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		fmt = fmt_l_opt;
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	else
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		fmt = fmt_differ;
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	do {
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		c1 = getc(fp1);
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		c2 = getc(fp2);
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		++char_pos;
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		if (c1 != c2) {			/* Remember: a read error may have occurred. */
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			retval = 1;		/* But assume the files are different for now. */
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			if (c2 == EOF) {
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				/* We know that fp1 isn't at EOF or in an error state.  But to
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				 * save space below, things are setup to expect an EOF in fp1
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				 * if an EOF occurred.  So, swap things around.
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				 */
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				fp1 = fp2;
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				filename1 = filename2;
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				c1 = c2;
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			}
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			if (c1 == EOF) {
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				xferror(fp1, filename1);
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				fmt = fmt_eof;	/* Well, no error, so it must really be EOF. */
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				outfile = stderr;
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				/* There may have been output to stdout (option -l), so
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				 * make sure we fflush before writing to stderr. */
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				xfflush_stdout();
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			}
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			if (!(opt & CMP_OPT_s)) {
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				if (opt & CMP_OPT_l) {
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					line_pos = c1;	/* line_pos is unused in the -l case. */
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				}
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				bb_fprintf(outfile, fmt, filename1, filename2, char_pos, line_pos, c2);
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				if (opt) {	/* This must be -l since not -s. */
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					/* If we encountered an EOF,
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					 * the while check will catch it. */
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					continue;
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				}
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			}
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			break;
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		}
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		if (c1 == '\n') {
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			++line_pos;
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		}
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	} while (c1 != EOF);
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	xferror(fp1, filename1);
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	xferror(fp2, filename2);
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	bb_fflush_stdout_and_exit(retval);
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}
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