2 * SPDX-License-Identifier: BSD-3-Clause
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32 #include <sys/param.h>
36 #include <capsicum_helpers.h>
46 static u_char *remmap(u_char *, int, off_t);
47 static void segv_handler(int);
48 #define MMAP_CHUNK (8*1024*1024)
50 #define ROUNDPAGE(i) ((i) & ~pagemask)
53 c_regular(int fd1, const char *file1, off_t skip1, off_t len1,
54 int fd2, const char *file2, off_t skip2, off_t len2, off_t limit)
56 struct sigaction act, oact;
58 u_char ch, *p1, *p2, *m1, *m2, *e1, *e2;
59 off_t byte, length, line;
60 off_t pagemask, off1, off2;
71 if (sflag && len1 != len2)
74 pagesize = getpagesize();
75 pagemask = (off_t)pagesize - 1;
76 off1 = ROUNDPAGE(skip1);
77 off2 = ROUNDPAGE(skip2);
79 length = MIN(len1, len2);
81 length = MIN(length, limit);
83 if ((m1 = remmap(NULL, fd1, off1)) == NULL) {
84 c_special(fd1, file1, skip1, fd2, file2, skip2, limit);
88 if ((m2 = remmap(NULL, fd2, off2)) == NULL) {
89 munmap(m1, MMAP_CHUNK);
90 c_special(fd1, file1, skip1, fd2, file2, skip2, limit);
94 if (caph_rights_limit(fd1, cap_rights_init(&rights, CAP_MMAP_R)) < 0)
95 err(1, "unable to limit rights for %s", file1);
96 if (caph_rights_limit(fd2, cap_rights_init(&rights, CAP_MMAP_R)) < 0)
97 err(1, "unable to limit rights for %s", file2);
99 err(ERR_EXIT, "unable to enter capability mode");
101 sigemptyset(&act.sa_mask);
102 act.sa_flags = SA_NODEFER;
103 act.sa_handler = segv_handler;
104 if (sigaction(SIGSEGV, &act, &oact))
105 err(ERR_EXIT, "sigaction()");
108 e1 = m1 + MMAP_CHUNK;
109 e2 = m2 + MMAP_CHUNK;
110 p1 = m1 + (skip1 - off1);
111 p2 = m2 + (skip2 - off2);
113 for (byte = line = 1; length--; ++byte) {
116 (void)fprintf(stderr, "%s %s char %zu line %zu\n",
117 file1, file2, (size_t)byte, (size_t)line);
121 if ((ch = *p1) != *p2) {
124 (void)printf("%08llx %02x %02x\n",
125 (long long)byte - 1, ch, *p2);
129 (void)printf("%6lld %3o %c %3o %c\n",
130 (long long)byte, ch, ch, *p2, *p2);
132 (void)printf("%6lld %3o %3o\n",
133 (long long)byte, ch, *p2);
135 diffmsg(file1, file2, byte, line, ch, *p2);
142 if ((p1 = m1 = remmap(m1, fd1, off1)) == NULL) {
143 munmap(m2, MMAP_CHUNK);
144 err(ERR_EXIT, "remmap %s", file1);
146 e1 = m1 + MMAP_CHUNK;
150 if ((p2 = m2 = remmap(m2, fd2, off2)) == NULL) {
151 munmap(m1, MMAP_CHUNK);
152 err(ERR_EXIT, "remmap %s", file2);
154 e2 = m2 + MMAP_CHUNK;
157 munmap(m1, MMAP_CHUNK);
158 munmap(m2, MMAP_CHUNK);
160 if (sigaction(SIGSEGV, &oact, NULL))
161 err(ERR_EXIT, "sigaction()");
164 eofmsg (len1 > len2 ? file2 : file1);
170 remmap(u_char *mem, int fd, off_t offset)
173 munmap(mem, MMAP_CHUNK);
174 mem = mmap(NULL, MMAP_CHUNK, PROT_READ, MAP_SHARED, fd, offset);
175 if (mem == MAP_FAILED)
177 madvise(mem, MMAP_CHUNK, MADV_SEQUENTIAL);
182 segv_handler(int sig __unused) {
183 static const char msg[] = "cmp: Input/output error (caught SIGSEGV)\n";
185 write(STDERR_FILENO, msg, sizeof(msg));