1 /* $NetBSD: fwcfg.c,v 1.7 2022/01/22 07:53:06 pho Exp $ */
2
3 /*-
4 * Copyright (c) 2017 Jared McNeill <jmcneill@invisible.ca>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __RCSID("$NetBSD: fwcfg.c,v 1.7 2022/01/22 07:53:06 pho Exp $");
31
32 #define FUSE_USE_VERSION FUSE_MAKE_VERSION(2, 6)
33
34 #include <sys/ioctl.h>
35 #include <sys/param.h>
36
37 #include <err.h>
38 #include <errno.h>
39 #include <fcntl.h>
40 #include <fuse.h>
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <unistd.h>
45
46 #include <dev/ic/qemufwcfgio.h>
47
48 #include "virtdir.h"
49
50 #define _PATH_FWCFG "/dev/qemufwcfg"
51
52 struct fwcfg_file {
53 uint32_t size;
54 uint16_t select;
55 uint16_t reserved;
56 char name[56];
57 };
58
59 static int fwcfg_fd;
60 static mode_t fwcfg_dir_mask = 0555;
61 static mode_t fwcfg_file_mask = 0444;
62 static uid_t fwcfg_uid;
63 static gid_t fwcfg_gid;
64
65 static virtdir_t fwcfg_virtdir;
66
67 static void
set_index(uint16_t index)68 set_index(uint16_t index)
69 {
70 if (ioctl(fwcfg_fd, FWCFGIO_SET_INDEX, &index) != 0)
71 err(EXIT_FAILURE, "failed to set index 0x%04x", index);
72 }
73
74 static void
read_data(void * buf,size_t buflen)75 read_data(void *buf, size_t buflen)
76 {
77 if (read(fwcfg_fd, buf, buflen) != (ssize_t)buflen)
78 err(EXIT_FAILURE, "failed to read data");
79 }
80
81 static int
fwcfg_getattr(const char * path,struct stat * st)82 fwcfg_getattr(const char *path, struct stat *st)
83 {
84 virt_dirent_t *ep;
85
86 if (strcmp(path, "/") == 0) {
87 memset(st, 0, sizeof(*st));
88 st->st_mode = S_IFDIR | fwcfg_dir_mask;
89 st->st_nlink = 2;
90 return 0;
91 }
92
93 if ((ep = virtdir_find(&fwcfg_virtdir, path, strlen(path))) == NULL)
94 return -ENOENT;
95
96 switch (ep->type) {
97 case 'f':
98 memcpy(st, &fwcfg_virtdir.file, sizeof(*st));
99 st->st_size = (off_t)ep->tgtlen;
100 st->st_mode = S_IFREG | fwcfg_file_mask;
101 break;
102 case 'd':
103 memcpy(st, &fwcfg_virtdir.dir, sizeof(*st));
104 st->st_mode = S_IFDIR | fwcfg_dir_mask;
105 break;
106 }
107 st->st_ino = (ino_t)virtdir_offset(&fwcfg_virtdir, ep) + 10;
108
109 return 0;
110 }
111
112 static int
fwcfg_readdir(const char * path,void * buf,fuse_fill_dir_t filler,off_t offset,struct fuse_file_info * fi)113 fwcfg_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
114 off_t offset, struct fuse_file_info *fi)
115 {
116 static VIRTDIR *dirp;
117 virt_dirent_t *dp;
118
119 if (offset == 0) {
120 if ((dirp = openvirtdir(&fwcfg_virtdir, path)) == NULL)
121 return 0;
122 filler(buf, ".", NULL, 0);
123 filler(buf, "..", NULL, 0);
124 }
125 while ((dp = readvirtdir(dirp)) != NULL) {
126 if (filler(buf, dp->d_name, NULL, 0) != 0)
127 return 0;
128 }
129 closevirtdir(dirp);
130 dirp = NULL;
131
132 return 0;
133 }
134
135 static int
fwcfg_open(const char * path,struct fuse_file_info * fi)136 fwcfg_open(const char *path, struct fuse_file_info *fi)
137 {
138 return 0;
139 }
140
141 static int
fwcfg_read(const char * path,char * buf,size_t size,off_t offset,struct fuse_file_info * fi)142 fwcfg_read(const char *path, char *buf, size_t size, off_t offset,
143 struct fuse_file_info *fi)
144 {
145 virt_dirent_t *ep;
146 uint8_t tmp[64];
147
148 if ((ep = virtdir_find(&fwcfg_virtdir, path, strlen(path))) == NULL)
149 return -ENOENT;
150
151 if (ep->select == 0)
152 return -ENOENT;
153
154 set_index(ep->select);
155
156 /* Seek to correct offset */
157 while (offset > 0) {
158 const size_t len = MIN(sizeof(tmp), (size_t)offset);
159 read_data(tmp, len);
160 offset -= (off_t)len;
161 }
162
163 /* Read the data */
164 read_data(buf, size);
165
166 return (int)size;
167 }
168
169 static int
fwcfg_statfs(const char * path,struct statvfs * st)170 fwcfg_statfs(const char *path, struct statvfs *st)
171 {
172 uint32_t count;
173
174 set_index(FW_CFG_FILE_DIR);
175 read_data(&count, sizeof(count));
176
177 memset(st, 0, sizeof(*st));
178 st->f_files = be32toh(count);
179
180 return 0;
181 }
182
183 static struct fuse_operations fwcfg_ops = {
184 .getattr = fwcfg_getattr,
185 .readdir = fwcfg_readdir,
186 .open = fwcfg_open,
187 .read = fwcfg_read,
188 .statfs = fwcfg_statfs,
189 };
190
191 static void
build_tree(virtdir_t * v)192 build_tree(virtdir_t *v)
193 {
194 char path[PATH_MAX];
195 struct fwcfg_file f;
196 uint32_t count, n;
197 struct stat st;
198
199 memset(&st, 0, sizeof(st));
200 st.st_uid = fwcfg_uid;
201 st.st_gid = fwcfg_gid;
202 virtdir_init(v, NULL, &st, &st, &st);
203
204 set_index(FW_CFG_FILE_DIR);
205 read_data(&count, sizeof(count));
206 for (n = 0; n < be32toh(count); n++) {
207 read_data(&f, sizeof(f));
208 snprintf(path, sizeof(path), "/%s", f.name);
209 virtdir_add(v, path, strlen(path), 'f', NULL,
210 be32toh(f.size), be16toh(f.select));
211 }
212 }
213
214 #if 0
215 static __dead void
216 usage(void)
217 {
218 fprintf(stderr, "Usage: %s [-F path] [-g gid] [-M dir-mode] "
219 "[-m file-mode] [-u uid] [fuse-options]", getprogname());
220 exit(EXIT_FAILURE);
221 }
222 #endif
223
224 int
main(int argc,char * argv[])225 main(int argc, char *argv[])
226 {
227 const char *path = _PATH_FWCFG;
228 int ch;
229 long m;
230 char *ep;
231
232 fwcfg_uid = geteuid();
233 fwcfg_gid = getegid();
234
235 while ((ch = getopt(argc, argv, "F:g:m:M:u:")) != -1) {
236 switch (ch) {
237 case 'F':
238 path = optarg;
239 break;
240 case 'g':
241 fwcfg_gid = (gid_t)atoi(optarg);
242 break;
243 case 'm':
244 m = strtol(optarg, &ep, 8);
245 if (optarg == ep || *ep || m < 0)
246 errx(EXIT_FAILURE, "invalid file mode: %s",
247 optarg);
248 fwcfg_file_mask = (mode_t)m;
249 break;
250 case 'M':
251 m = strtol(optarg, &ep, 8);
252 if (optarg == ep || *ep || m < 0)
253 errx(EXIT_FAILURE, "invalid directory mode: %s",
254 optarg);
255 fwcfg_dir_mask = (mode_t)m;
256 break;
257 case 'u':
258 fwcfg_uid = (uid_t)atoi(optarg);
259 break;
260 #ifdef notyet
261 default:
262 usage();
263 #endif
264 }
265 }
266
267 fwcfg_fd = open(path, O_RDWR);
268 if (fwcfg_fd == -1)
269 err(EXIT_FAILURE, "failed to open %s", path);
270
271 build_tree(&fwcfg_virtdir);
272
273 return fuse_main(argc, argv, &fwcfg_ops, NULL);
274 }
275