xref: /freebsd/lib/libsecureboot/readfile.c (revision 4543ef516683042d46f3bd3bb8a4f3f746e00499)
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 #include <libsecureboot.h>
27 
28 unsigned char *
29 read_fd(int fd, size_t len)
30 {
31 	int m, n, x;
32 	unsigned char *buf;
33 
34 	buf = malloc(len + 1);
35 	if (buf != NULL) {
36 		for (x = 0, m = len; m > 0; ) {
37 			n = read(fd, &buf[x], m);
38 			if (n < 0)
39 				break;
40 			if (n > 0) {
41 				m -= n;
42 				x += n;
43 			}
44 		}
45 		if (m == 0) {
46 			buf[len] = '\0';
47 			return (buf);
48 		}
49 		free(buf);
50 	}
51 	return (NULL);
52 }
53 
54 unsigned char *
55 read_file(const char *path, size_t *len)
56 {
57 	struct stat st;
58 	unsigned char *ucp;
59 	int fd;
60 
61     	if (len)
62 		*len = 0;
63 	if ((fd = open(path, O_RDONLY)) < 0)
64 		return (NULL);
65 	fstat(fd, &st);
66 	ucp = read_fd(fd, st.st_size);
67 	close(fd);
68 	if (ucp != NULL) {
69 		if (len != NULL)
70 			*len = st.st_size;
71 	}
72 #ifdef _STANDALONE
73 	else
74 		printf("%s: out of memory! %lu\n", __func__,
75 		    (unsigned long)len);
76 #endif
77 
78 	return (ucp);
79 }
80 
81