1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <string.h>
4 #include <stdint.h>
5 #include <fcntl.h>
6 #include <sys/ioctl.h>
7 #include <errno.h>
8
cmp_main(int argc,char * argv[])9 int cmp_main(int argc, char *argv[])
10 {
11 int c;
12 int fd1, fd2;
13 char buf1[4096], buf2[4096];
14 int res, res1, res2;
15 int rv = 0;
16 int i;
17 int filepos = 0;
18
19 int show_byte = 0;
20 int show_all = 0;
21 int limit = 0;
22
23 do {
24 c = getopt(argc, argv, "bln:");
25 if (c == EOF)
26 break;
27 switch (c) {
28 case 'b':
29 show_byte = 1;
30 break;
31 case 'l':
32 show_all = 1;
33 break;
34 case 'n':
35 limit = atoi(optarg);
36 break;
37 case '?':
38 fprintf(stderr, "%s: invalid option -%c\n",
39 argv[0], optopt);
40 exit(1);
41 }
42 } while (1);
43
44 if (optind + 2 != argc) {
45 fprintf(stderr, "Usage: %s [-b] [-l] [-n count] file1 file2\n", argv[0]);
46 exit(1);
47 }
48
49 fd1 = open(argv[optind], O_RDONLY);
50 if(fd1 < 0) {
51 fprintf(stderr, "could not open %s, %s\n", argv[optind], strerror(errno));
52 return 1;
53 }
54
55 fd2 = open(argv[optind+1], O_RDONLY);
56 if(fd2 < 0) {
57 fprintf(stderr, "could not open %s, %s\n", argv[optind+1], strerror(errno));
58 return 1;
59 }
60
61 while(1) {
62 res1 = read(fd1, &buf1, sizeof(buf1));
63 res2 = read(fd2, &buf2, sizeof(buf2));
64 res = res1 < res2 ? res1 : res2;
65 if(res1 == 0 && res2 == 0) {
66 return rv;
67 }
68 for(i = 0; i < res; i++) {
69 if(buf1[i] != buf2[i]) {
70 printf("%s %s differ byte %d", argv[optind], argv[optind+1], filepos + i);
71 if(show_byte)
72 printf(" 0x%02x 0x%02x", buf1[i], buf2[i]);
73 printf("\n");
74 if(!show_all)
75 return 1;
76 rv = 1;
77 }
78 if(limit) {
79 limit--;
80 if(limit == 0)
81 return rv;
82 }
83 }
84 if(res1 != res2 || res < 0) {
85 printf("%s on %s\n", res < 0 ? "Read error" : "EOF", res1 < res2 ? argv[optind] : argv[optind+1]);
86 return 1;
87 }
88 filepos += res;
89 }
90 }
91