blob: e22aaa46887bb0beb67d0a805111ec69ba7dfb59
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * readahead implementation for busybox |
4 | * |
5 | * Preloads the given files in RAM, to reduce access time. |
6 | * Does this by calling the readahead(2) system call. |
7 | * |
8 | * Copyright (C) 2006 Michael Opdenacker <michael@free-electrons.com> |
9 | * |
10 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
11 | */ |
12 | |
13 | //usage:#define readahead_trivial_usage |
14 | //usage: "[FILE]..." |
15 | //usage:#define readahead_full_usage "\n\n" |
16 | //usage: "Preload FILEs to RAM" |
17 | |
18 | #include "libbb.h" |
19 | |
20 | int readahead_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
21 | int readahead_main(int argc UNUSED_PARAM, char **argv) |
22 | { |
23 | int retval = EXIT_SUCCESS; |
24 | |
25 | if (!argv[1]) { |
26 | bb_show_usage(); |
27 | } |
28 | |
29 | while (*++argv) { |
30 | int fd = open_or_warn(*argv, O_RDONLY); |
31 | if (fd >= 0) { |
32 | off_t len; |
33 | int r; |
34 | |
35 | /* fdlength was reported to be unreliable - use seek */ |
36 | len = xlseek(fd, 0, SEEK_END); |
37 | xlseek(fd, 0, SEEK_SET); |
38 | r = readahead(fd, 0, len); |
39 | close(fd); |
40 | if (r >= 0) |
41 | continue; |
42 | } |
43 | retval = EXIT_FAILURE; |
44 | } |
45 | |
46 | return retval; |
47 | } |
48 |