xref: /freebsd/lib/libsecureboot/readfile.c (revision 349cc55c9796c4596a5b9904cd3281af295f878f)
1 /*-
2  * Copyright (c) 2017-2018, Juniper Networks, Inc.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
14  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
15  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
16  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
17  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
18  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
19  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 #include <sys/cdefs.h>
26 __FBSDID("$FreeBSD$");
27 
28 #include <libsecureboot.h>
29 
30 unsigned char *
31 read_fd(int fd, size_t len)
32 {
33 	int m, n, x;
34 	unsigned char *buf;
35 
36 	buf = malloc(len + 1);
37 	if (buf != NULL) {
38 		for (x = 0, m = len; m > 0; ) {
39 			n = read(fd, &buf[x], m);
40 			if (n < 0)
41 				break;
42 			if (n > 0) {
43 				m -= n;
44 				x += n;
45 			}
46 		}
47 		if (m == 0) {
48 			buf[len] = '\0';
49 			return (buf);
50 		}
51 		free(buf);
52 	}
53 	return (NULL);
54 }
55 
56 unsigned char *
57 read_file(const char *path, size_t *len)
58 {
59 	struct stat st;
60 	unsigned char *ucp;
61 	int fd;
62 
63     	if (len)
64 		*len = 0;
65 	if ((fd = open(path, O_RDONLY)) < 0)
66 		return (NULL);
67 	fstat(fd, &st);
68 	ucp = read_fd(fd, st.st_size);
69 	close(fd);
70 	if (ucp != NULL) {
71 		if (len != NULL)
72 			*len = st.st_size;
73 	}
74 #ifdef _STANDALONE
75 	else
76 		printf("%s: out of memory! %lu\n", __func__,
77 		    (unsigned long)len);
78 #endif
79 
80 	return (ucp);
81 }
82 
83