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Commit | Line | Data |
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8680b4e6 TT |
1 | /* |
2 | * make-sparse.c --- make a sparse file from stdin | |
3 | * | |
4 | * Copyright 2004 by Theodore Ts'o. | |
5 | * | |
6 | * %Begin-Header% | |
7 | * This file may be redistributed under the terms of the GNU Public | |
8 | * License. | |
9 | * %End-Header% | |
10 | */ | |
11 | ||
12 | #define _LARGEFILE_SOURCE | |
13 | #define _LARGEFILE64_SOURCE | |
14 | ||
15 | #include <stdio.h> | |
16 | #include <unistd.h> | |
17 | #include <stdlib.h> | |
18 | #include <sys/types.h> | |
19 | #include <sys/stat.h> | |
20 | #include <fcntl.h> | |
21 | #include <errno.h> | |
22 | ||
23 | int full_read(int fd, char *buf, size_t count) | |
24 | { | |
25 | int got, total = 0; | |
26 | int pass = 0; | |
27 | ||
28 | while (count > 0) { | |
29 | got = read(fd, buf, count); | |
30 | if (got == -1) { | |
31 | if ((errno == EINTR) || (errno == EAGAIN)) | |
32 | continue; | |
33 | return total ? total : -1; | |
34 | } | |
35 | if (got == 0) { | |
36 | if (pass++ >= 3) | |
37 | return total; | |
38 | continue; | |
39 | } | |
40 | pass = 0; | |
41 | buf += got; | |
42 | total += got; | |
43 | count -= got; | |
44 | } | |
45 | return total; | |
46 | } | |
47 | ||
48 | int main(int argc, char **argv) | |
49 | { | |
50 | int fd, got, i; | |
4087bbd6 | 51 | int zflag = 0; |
8680b4e6 TT |
52 | char buf[1024]; |
53 | ||
54 | if (argc != 2) { | |
55 | fprintf(stderr, "Usage: make-sparse out-file\n"); | |
56 | exit(1); | |
57 | } | |
58 | fd = open(argv[1], O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0777); | |
59 | if (fd < 0) { | |
60 | perror(argv[1]); | |
61 | exit(1); | |
62 | } | |
63 | while (1) { | |
64 | got = full_read(0, buf, sizeof(buf)); | |
65 | if (got == 0) | |
66 | break; | |
67 | if (got == sizeof(buf)) { | |
68 | for (i=0; i < sizeof(buf); i++) | |
69 | if (buf[i]) | |
70 | break; | |
71 | if (i == sizeof(buf)) { | |
72 | lseek(fd, sizeof(buf), SEEK_CUR); | |
4087bbd6 | 73 | zflag = 1; |
8680b4e6 TT |
74 | continue; |
75 | } | |
76 | } | |
4087bbd6 | 77 | zflag = 0; |
8680b4e6 TT |
78 | write(fd, buf, got); |
79 | } | |
4087bbd6 TT |
80 | if (zflag) { |
81 | lseek(fd, -1, SEEK_CUR); | |
82 | buf[0] = 0; | |
83 | write(fd, buf, 1); | |
84 | } | |
8680b4e6 TT |
85 | return 0; |
86 | } | |
87 |