libfstools: convert to ulog() api
[project/fstools.git] / libfstools / overlay.c
1 /*
2 * Copyright (C) 2014 John Crispin <blogic@openwrt.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU Lesser General Public License version 2.1
6 * as published by the Free Software Foundation
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 */
13
14 #include <sys/stat.h>
15 #include <sys/types.h>
16 #include <sys/mount.h>
17
18 #include <asm/byteorder.h>
19
20 #include <errno.h>
21 #include <string.h>
22 #include <stdio.h>
23 #include <unistd.h>
24 #include <stdlib.h>
25 #include <glob.h>
26 #include <errno.h>
27 #include <dirent.h>
28 #include <fcntl.h>
29
30 #include "libfstools.h"
31 #include "volume.h"
32
33 #define SWITCH_JFFS2 "/tmp/.switch_jffs2"
34
35 void
36 foreachdir(const char *dir, int (*cb)(const char*))
37 {
38 char globdir[256];
39 glob_t gl;
40 int j;
41
42 if (dir[strlen(dir) - 1] == '/')
43 snprintf(globdir, 256, "%s*", dir);
44 else
45 snprintf(globdir, 256, "%s/*", dir); /**/
46
47 if (!glob(globdir, GLOB_NOESCAPE | GLOB_MARK | GLOB_ONLYDIR, NULL, &gl))
48 for (j = 0; j < gl.gl_pathc; j++)
49 foreachdir(gl.gl_pathv[j], cb);
50
51 cb(dir);
52 }
53
54 static int
55 overlay_mount(struct volume *v, char *fs)
56 {
57 if (mkdir("/tmp/overlay", 0755)) {
58 ULOG_ERR("failed to mkdir /tmp/overlay: %s\n", strerror(errno));
59 return -1;
60 }
61
62 if (mount(v->blk, "/tmp/overlay", fs, MS_NOATIME, NULL)) {
63 ULOG_ERR("failed to mount -t %s %s /tmp/overlay: %s\n", fs, v->blk, strerror(errno));
64 return -1;
65 }
66
67 return volume_init(v);
68 }
69
70 static int
71 switch2jffs(struct volume *v)
72 {
73 struct stat s;
74 int ret;
75
76 if (!stat(SWITCH_JFFS2, &s)) {
77 ULOG_ERR("jffs2 switch already running\n");
78 return -1;
79 }
80
81 creat("/tmp/.switch_jffs2", 0600);
82 ret = mount(v->blk, "/rom/overlay", "jffs2", MS_NOATIME, NULL);
83 unlink("/tmp/.switch_jffs2");
84 if (ret) {
85 ULOG_ERR("failed - mount -t jffs2 %s /rom/overlay: %s\n", v->blk, strerror(errno));
86 return -1;
87 }
88
89 if (mount("none", "/", NULL, MS_NOATIME | MS_REMOUNT, 0)) {
90 ULOG_ERR("failed - mount -o remount,ro none: %s\n", strerror(errno));
91 return -1;
92 }
93
94 system("cp -a /tmp/root/* /rom/overlay"); /**/
95
96 if (pivot("/rom", "/mnt")) {
97 ULOG_ERR("failed - pivot /rom /mnt: %s\n", strerror(errno));
98 return -1;
99 }
100
101 if (mount_move("/mnt", "/tmp/root", "")) {
102 ULOG_ERR("failed - mount -o move /mnt /tmp/root %s\n", strerror(errno));
103 return -1;
104 }
105
106 return fopivot("/overlay", "/rom");
107 }
108
109 int
110 handle_whiteout(const char *dir)
111 {
112 struct stat s;
113 char link[256];
114 ssize_t sz;
115 struct dirent **namelist;
116 int n;
117
118 n = scandir(dir, &namelist, NULL, NULL);
119
120 if (n < 1)
121 return -1;
122
123 while (n--) {
124 char file[256];
125
126 snprintf(file, sizeof(file), "%s%s", dir, namelist[n]->d_name);
127 if (!lstat(file, &s) && S_ISLNK(s.st_mode)) {
128 sz = readlink(file, link, sizeof(link) - 1);
129 if (sz > 0) {
130 char *orig;
131
132 link[sz] = '\0';
133 orig = strstr(&file[1], "/");
134 if (orig && !strcmp(link, "(overlay-whiteout)"))
135 unlink(orig);
136 }
137 }
138 free(namelist[n]);
139 }
140 free(namelist);
141
142 return 0;
143 }
144
145 int
146 jffs2_switch(struct volume *v)
147 {
148 char *mp;
149 int ret = -1;
150
151 if (find_overlay_mount("overlayfs:/tmp/root"))
152 return -1;
153
154 if (find_filesystem("overlay")) {
155 ULOG_ERR("overlayfs not supported by kernel\n");
156 return ret;
157 }
158
159 mp = find_mount_point(v->blk, 0);
160 if (mp) {
161 ULOG_ERR("rootfs_data:%s is already mounted as %s\n", v->blk, mp);
162 return -1;
163 }
164
165 switch (volume_identify(v)) {
166 case FS_NONE:
167 ULOG_ERR("no jffs2 marker found\n");
168 /* fall through */
169
170 case FS_DEADCODE:
171 ret = switch2jffs(v);
172 if (!ret) {
173 ULOG_INFO("performing overlay whiteout\n");
174 umount2("/tmp/root", MNT_DETACH);
175 foreachdir("/overlay/", handle_whiteout);
176 }
177 break;
178
179 case FS_JFFS2:
180 ret = overlay_mount(v, "jffs2");
181 if (ret)
182 break;
183 if (mount_move("/tmp", "", "/overlay") || fopivot("/overlay", "/rom")) {
184 ULOG_ERR("switching to jffs2 failed\n");
185 ret = -1;
186 }
187 break;
188
189 case FS_UBIFS:
190 ret = overlay_mount(v, "ubifs");
191 if (ret)
192 break;
193 if (mount_move("/tmp", "", "/overlay") || fopivot("/overlay", "/rom")) {
194 ULOG_ERR("switching to ubifs failed\n");
195 ret = -1;
196 }
197 break;
198 }
199 return ret;
200 }
201
202 static int overlay_mount_fs(struct volume *v)
203 {
204 char *fstype;
205
206 if (mkdir("/tmp/overlay", 0755)) {
207 ULOG_ERR("failed to mkdir /tmp/overlay: %s\n", strerror(errno));
208 return -1;
209 }
210
211 fstype = "jffs2";
212
213 switch (volume_identify(v)) {
214 case FS_UBIFS:
215 fstype = "ubifs";
216 break;
217 }
218
219 if (mount(v->blk, "/tmp/overlay", fstype, MS_NOATIME, NULL)) {
220 ULOG_ERR("failed to mount -t %s %s /tmp/overlay: %s\n",
221 fstype, v->blk, strerror(errno));
222 return -1;
223 }
224
225 volume_init(v);
226
227 return -1;
228 }
229
230 int mount_overlay(struct volume *v)
231 {
232 char *mp;
233
234 if (!v)
235 return -1;
236
237 mp = find_mount_point(v->blk, 0);
238 if (mp) {
239 ULOG_ERR("rootfs_data:%s is already mounted as %s\n", v->blk, mp);
240 return -1;
241 }
242
243 overlay_mount_fs(v);
244
245 extroot_prefix = "/tmp/overlay";
246 if (!mount_extroot()) {
247 ULOG_INFO("switched to extroot\n");
248 return 0;
249 }
250
251 ULOG_INFO("switching to overlay\n");
252 if (mount_move("/tmp", "", "/overlay") || fopivot("/overlay", "/rom")) {
253 ULOG_ERR("switching to jffs2 failed - fallback to ramoverlay\n");
254 return ramoverlay();
255 }
256
257 return -1;
258 }