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[project/opkg-lede.git] / libbb / all_read.c
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 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #include <stdio.h>
23 #include <unistd.h>
24 #include <errno.h>
25 #include "libbb.h"
26
27 extern void archive_xread_all(int fd , char *buf, size_t count)
28 {
29 ssize_t size;
30
31 size = full_read(fd, buf, count);
32 if (size != count) {
33 perror_msg_and_die("Short read");
34 }
35 return;
36 }
37
38 /*
39 * Read all of the supplied buffer from a file.
40 * This does multiple reads as necessary.
41 * Returns the amount read, or -1 on an error.
42 * A short read is returned on an end of file.
43 */
44 ssize_t full_read(int fd, char *buf, int len)
45 {
46 ssize_t cc;
47 ssize_t total;
48
49 total = 0;
50
51 while (len > 0) {
52 cc = safe_read(fd, buf, len);
53
54 if (cc < 0)
55 return cc; /* read() returns -1 on failure. */
56
57 if (cc == 0)
58 break;
59
60 buf = ((char *)buf) + cc;
61 total += cc;
62 len -= cc;
63 }
64
65 return total;
66 }
67
68
69 ssize_t safe_read(int fd, void *buf, size_t count)
70 {
71 ssize_t n;
72
73 do {
74 n = read(fd, buf, count);
75 } while (n < 0 && errno == EINTR);
76
77 return n;
78 }
79
80
81
82 /* END CODE */
83