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 source tree.
8 */
9 #include "libbb.h"
10
safe_read(int fd,void * buf,size_t count)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 */
full_read(int fd,void * buf,size_t len)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
read_close(int fd,void * buf,size_t size)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
open_read_close(const char * filename,void * buf,size_t size)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 }
73