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 
11 /*
12  * Write all of the supplied buffer out to a file.
13  * This does multiple writes as necessary.
14  * Returns the amount written, or -1 if error was seen
15  * on the very first write.
16  */
full_write(int fd,const void * buf,size_t len)17 ssize_t FAST_FUNC full_write(int fd, const void *buf, size_t len)
18 {
19 	ssize_t cc;
20 	ssize_t total;
21 
22 	total = 0;
23 
24 	while (len) {
25 		cc = safe_write(fd, buf, len);
26 
27 		if (cc < 0) {
28 			if (total) {
29 				/* we already wrote some! */
30 				/* user can do another write to know the error code */
31 				return total;
32 			}
33 			return cc;  /* write() returns -1 on failure. */
34 		}
35 
36 		total += cc;
37 		buf = ((const char *)buf) + cc;
38 		len -= cc;
39 	}
40 
41 	return total;
42 }
43