1 /*
2 * Copyright (c) 2019, Linaro Ltd.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice,
12 * this list of conditions and the following disclaimer in the documentation
13 * and/or other materials provided with the distribution.
14 *
15 * 3. Neither the name of the copyright holder nor the names of its contributors
16 * may be used to endorse or promote products derived from this software without
17 * specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
23 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31 #include <sys/stat.h>
32 #include <sys/types.h>
33 #include <dirent.h>
34 #include <err.h>
35 #include <errno.h>
36 #include <fcntl.h>
37 #include <libgen.h>
38 #include <limits.h>
39 #include <stdio.h>
40 #include <string.h>
41 #include <unistd.h>
42
43 #include "translate.h"
44
45 #define READONLY_PATH "/readonly/firmware/image/"
46 #define READWRITE_PATH "/readwrite/"
47
48 #ifndef ANDROID
49 #define FIRMWARE_BASE "/lib/firmware/"
50 #define TQFTPSERV_TMP "/tmp/tqftpserv"
51 #else
52 #define FIRMWARE_BASE "/vendor/firmware/"
53 #define TQFTPSERV_TMP "/data/vendor/tmp/tqftpserv"
54 #endif
55
56 /**
57 * translate_readonly() - open "file" residing with remoteproc firmware
58 * @file: file requested, stripped of "/readonly/image/" prefix
59 *
60 * It is assumed that the readonly files requested by the client resides under
61 * /lib/firmware in the same place as its associated remoteproc firmware. This
62 * function scans through all entries under /sys/class/remoteproc and read the
63 * dirname of each "firmware" file in an attempt to find, and open(2), the
64 * requested file.
65 *
66 * As these files are readonly, it's not possible to pass flags to open(2).
67 *
68 * Return: opened fd on success, -1 otherwise
69 */
translate_readonly(const char * file)70 static int translate_readonly(const char *file)
71 {
72 char firmware_value[PATH_MAX];
73 char firmware_attr[32];
74 char path[PATH_MAX];
75 struct dirent *de;
76 int firmware_fd;
77 DIR *class_dir;
78 int class_fd;
79 ssize_t n;
80 int fd = -1;
81
82 class_fd = open("/sys/class/remoteproc", O_RDONLY | O_DIRECTORY);
83 if (class_fd < 0) {
84 warn("failed to open remoteproc class");
85 return -1;
86 }
87
88 class_dir = fdopendir(class_fd);
89 if (!class_dir) {
90 warn("failed to opendir");
91 goto close_class;
92 }
93
94 while ((de = readdir(class_dir)) != NULL) {
95 if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
96 continue;
97
98 if (strlen(de->d_name) + sizeof("/firmware") > sizeof(firmware_attr))
99 continue;
100 strcpy(firmware_attr, de->d_name);
101 strcat(firmware_attr, "/firmware");
102
103 firmware_fd = openat(class_fd, firmware_attr, O_RDONLY);
104 if (firmware_fd < 0)
105 continue;
106
107 n = read(firmware_fd, firmware_value, sizeof(firmware_value));
108 close(firmware_fd);
109 if (n < 0) {
110 continue;
111 }
112 firmware_value[n] = '\0';
113
114 if (strlen(FIRMWARE_BASE) + strlen(firmware_value) + 1 +
115 strlen(file) + 1 > sizeof(path))
116 continue;
117
118 strcpy(path, FIRMWARE_BASE);
119 strcat(path, dirname(firmware_value));
120 strcat(path, "/");
121 strcat(path, file);
122
123 fd = open(path, O_RDONLY);
124 if (fd >= 0)
125 break;
126
127 if (errno != ENOENT)
128 warn("failed to open %s", path);
129 }
130
131 closedir(class_dir);
132
133 close_class:
134 close(class_fd);
135
136 return fd;
137 }
138
139 /**
140 * translate_readwrite() - open "file" from a temporary directory
141 * @file: relative path of the requested file, with /readwrite/ stripped
142 * @flags: flags to be passed to open(2)
143 *
144 * Return: opened fd on success, -1 otherwise
145 */
translate_readwrite(const char * file,int flags)146 static int translate_readwrite(const char *file, int flags)
147 {
148 int base;
149 int ret;
150 int fd;
151
152 ret = mkdir(TQFTPSERV_TMP, 0700);
153 if (ret < 0 && errno != EEXIST) {
154 warn("failed to create temporary tqftpserv directory");
155 return -1;
156 }
157
158 base = open(TQFTPSERV_TMP, O_RDONLY | O_DIRECTORY);
159 if (base < 0) {
160 warn("failed top open temporary tqftpserv directory");
161 return -1;
162 }
163
164 fd = openat(base, file, flags, 0600);
165 close(base);
166 if (fd < 0)
167 warn("failed to open %s", file);
168
169 return fd;
170 }
171
172 /**
173 * translate_open() - open file after translating path
174 *
175
176 * Strips /readonly/firmware/image and search among remoteproc firmware.
177 * Replaces /readwrite with a temporary directory.
178
179 */
translate_open(const char * path,int flags)180 int translate_open(const char *path, int flags)
181 {
182 if (!strncmp(path, READONLY_PATH, strlen(READONLY_PATH)))
183 return translate_readonly(path + strlen(READONLY_PATH));
184 else if (!strncmp(path, READWRITE_PATH, strlen(READWRITE_PATH)))
185 return translate_readwrite(path + strlen(READWRITE_PATH), flags);
186
187 fprintf(stderr, "invalid path %s, rejecting\n", path);
188 errno = ENOENT;
189 return -1;
190 }
191