1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or https://opensource.org/licenses/CDDL-1.0.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (c) 2024 by Pawel Jakub Dawidek
24  */
25 
26 #include <sys/mman.h>
27 #include <sys/stat.h>
28 
29 #include <assert.h>
30 #include <errno.h>
31 #include <fcntl.h>
32 #include <stdbool.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <unistd.h>
37 
38 #ifdef __FreeBSD__
39 #define	loff_t	off_t
40 #endif
41 
42 ssize_t
43 copy_file_range(int, loff_t *, int, loff_t *, size_t, unsigned int)
44     __attribute__((weak));
45 
46 static void *
47 mmap_file(int fd, size_t size)
48 {
49 	void *p;
50 
51 	p = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
52 	if (p == MAP_FAILED) {
53 		(void) fprintf(stderr, "mmap failed: %s\n", strerror(errno));
54 		exit(2);
55 	}
56 
57 	return (p);
58 }
59 
60 static void
61 usage(const char *progname)
62 {
63 
64 	/*
65 	 * -i cache input before copy_file_range(2).
66 	 * -o cache input before copy_file_range(2).
67 	 */
68 	(void) fprintf(stderr, "usage: %s [-io] <input> <output>\n", progname);
69 	exit(3);
70 }
71 
72 int
73 main(int argc, char *argv[])
74 {
75 	int dfd, sfd;
76 	size_t dsize, ssize;
77 	void *dmem, *smem, *ptr;
78 	off_t doff, soff;
79 	struct stat sb;
80 	bool cache_input, cache_output;
81 	const char *progname;
82 	int c;
83 
84 	progname = argv[0];
85 	cache_input = cache_output = false;
86 
87 	while ((c = getopt(argc, argv, "io")) != -1) {
88 		switch (c) {
89 		case 'i':
90 			cache_input = true;
91 			break;
92 		case 'o':
93 			cache_output = true;
94 			break;
95 		default:
96 			usage(progname);
97 		}
98 	}
99 	argc -= optind;
100 	argv += optind;
101 
102 	if (argc != 2) {
103 		usage(progname);
104 	}
105 
106 	sfd = open(argv[0], O_RDONLY);
107 	if (fstat(sfd, &sb) == -1) {
108 		(void) fprintf(stderr, "fstat failed: %s\n", strerror(errno));
109 		exit(2);
110 	}
111 	ssize = sb.st_size;
112 	smem = mmap_file(sfd, ssize);
113 
114 	dfd = open(argv[1], O_RDWR);
115 	if (fstat(dfd, &sb) == -1) {
116 		(void) fprintf(stderr, "fstat failed: %s\n", strerror(errno));
117 		exit(2);
118 	}
119 	dsize = sb.st_size;
120 	dmem = mmap_file(dfd, dsize);
121 
122 	/*
123 	 * Hopefully it won't be compiled out.
124 	 */
125 	if (cache_input) {
126 		ptr = malloc(ssize);
127 		assert(ptr != NULL);
128 		memcpy(ptr, smem, ssize);
129 		free(ptr);
130 	}
131 	if (cache_output) {
132 		ptr = malloc(ssize);
133 		assert(ptr != NULL);
134 		memcpy(ptr, dmem, dsize);
135 		free(ptr);
136 	}
137 
138 	soff = doff = 0;
139 	if (copy_file_range(sfd, &soff, dfd, &doff, ssize, 0) < 0) {
140 		(void) fprintf(stderr, "copy_file_range failed: %s\n",
141 		    strerror(errno));
142 		exit(2);
143 	}
144 
145 	exit(memcmp(smem, dmem, ssize) == 0 ? 0 : 1);
146 }
147