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
11ssize_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 */
28ssize_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
56ssize_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
66ssize_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