Contents of /tags/mkinitrd-6_4_0/busybox/libbb/read.c
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Fri May 27 18:20:23 2011 UTC (13 years, 4 months ago) by niro
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Fri May 27 18:20:23 2011 UTC (13 years, 4 months ago) by niro
File MIME type: text/plain
File size: 1384 byte(s)
tagged 'mkinitrd-6_4_0'
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Utility routines. |
4 | * |
5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> |
6 | * |
7 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
8 | */ |
9 | #include "libbb.h" |
10 | |
11 | ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count) |
12 | { |
13 | ssize_t n; |
14 | |
15 | do { |
16 | n = read(fd, buf, count); |
17 | } while (n < 0 && errno == EINTR); |
18 | |
19 | return n; |
20 | } |
21 | |
22 | /* |
23 | * Read all of the supplied buffer from a file. |
24 | * This does multiple reads as necessary. |
25 | * Returns the amount read, or -1 on an error. |
26 | * A short read is returned on an end of file. |
27 | */ |
28 | ssize_t FAST_FUNC full_read(int fd, void *buf, size_t len) |
29 | { |
30 | ssize_t cc; |
31 | ssize_t total; |
32 | |
33 | total = 0; |
34 | |
35 | while (len) { |
36 | cc = safe_read(fd, buf, len); |
37 | |
38 | if (cc < 0) { |
39 | if (total) { |
40 | /* we already have some! */ |
41 | /* user can do another read to know the error code */ |
42 | return total; |
43 | } |
44 | return cc; /* read() returns -1 on failure. */ |
45 | } |
46 | if (cc == 0) |
47 | break; |
48 | buf = ((char *)buf) + cc; |
49 | total += cc; |
50 | len -= cc; |
51 | } |
52 | |
53 | return total; |
54 | } |
55 | |
56 | ssize_t FAST_FUNC read_close(int fd, void *buf, size_t size) |
57 | { |
58 | /*int e;*/ |
59 | size = full_read(fd, buf, size); |
60 | /*e = errno;*/ |
61 | close(fd); |
62 | /*errno = e;*/ |
63 | return size; |
64 | } |
65 | |
66 | ssize_t FAST_FUNC open_read_close(const char *filename, void *buf, size_t size) |
67 | { |
68 | int fd = open(filename, O_RDONLY); |
69 | if (fd < 0) |
70 | return fd; |
71 | return read_close(fd, buf, size); |
72 | } |