xref: /freebsd/usr.bin/cmp/special.c (revision 7937bfbc0ca53fe7cdd0d54414f9296e273a518e)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1991, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/types.h>
33 
34 #include <capsicum_helpers.h>
35 #include <err.h>
36 #include <stdbool.h>
37 #include <stdlib.h>
38 #include <stdio.h>
39 
40 #include "extern.h"
41 
42 int
43 c_special(int fd1, const char *file1, off_t skip1,
44     int fd2, const char *file2, off_t skip2, off_t limit)
45 {
46 	int ch1, ch2;
47 	off_t byte, line;
48 	FILE *fp1, *fp2;
49 	int dfound;
50 
51 	if (caph_limit_stream(fd1, CAPH_READ) < 0)
52 		err(ERR_EXIT, "caph_limit_stream(%s)", file1);
53 	if (caph_limit_stream(fd2, CAPH_READ) < 0)
54 		err(ERR_EXIT, "caph_limit_stream(%s)", file2);
55 	if (caph_enter() < 0)
56 		err(ERR_EXIT, "unable to enter capability mode");
57 
58 	if ((fp1 = fdopen(fd1, "r")) == NULL)
59 		err(ERR_EXIT, "%s", file1);
60 	(void)setvbuf(fp1, NULL, _IOFBF, 65536);
61 	if ((fp2 = fdopen(fd2, "r")) == NULL)
62 		err(ERR_EXIT, "%s", file2);
63 	(void)setvbuf(fp2, NULL, _IOFBF, 65536);
64 
65 	dfound = 0;
66 	while (skip1--)
67 		if (getc(fp1) == EOF)
68 			goto eof;
69 	while (skip2--)
70 		if (getc(fp2) == EOF)
71 			goto eof;
72 
73 	for (byte = line = 1; limit == 0 || byte <= limit; ++byte) {
74 #ifdef SIGINFO
75 		if (info) {
76 			(void)fprintf(stderr, "%s %s char %zu line %zu\n",
77 			    file1, file2, (size_t)byte, (size_t)line);
78 			info = 0;
79 		}
80 #endif
81 		ch1 = getc(fp1);
82 		ch2 = getc(fp2);
83 		if (ch1 == EOF || ch2 == EOF)
84 			break;
85 		if (ch1 != ch2) {
86 			if (xflag) {
87 				dfound = 1;
88 				(void)printf("%08llx %02x %02x\n",
89 				    (long long)byte - 1, ch1, ch2);
90 			} else if (lflag) {
91 				dfound = 1;
92 				if (bflag)
93 					(void)printf("%6lld %3o %c %3o %c\n",
94 					    (long long)byte, ch1, ch1, ch2,
95 					    ch2);
96 				else
97 					(void)printf("%6lld %3o %3o\n",
98 					    (long long)byte, ch1, ch2);
99 			} else {
100 				diffmsg(file1, file2, byte, line, ch1, ch2);
101 				return (DIFF_EXIT);
102 			}
103 		}
104 		if (ch1 == '\n')
105 			++line;
106 	}
107 
108 eof:	if (ferror(fp1))
109 		err(ERR_EXIT, "%s", file1);
110 	if (ferror(fp2))
111 		err(ERR_EXIT, "%s", file2);
112 	if (feof(fp1)) {
113 		if (!feof(fp2)) {
114 			eofmsg(file1);
115 			return (DIFF_EXIT);
116 		}
117 	} else {
118 		if (feof(fp2)) {
119 			eofmsg(file2);
120 			return (DIFF_EXIT);
121 		}
122 	}
123 	fclose(fp2);
124 	fclose(fp1);
125 	return (dfound ? DIFF_EXIT : 0);
126 }
127