backend/jffs2.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 "../fs-state.h"
  31 #include "../driver/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 jffs2_mount(void)
  56 {
  57         struct volume *v;
  58
  59         if (mkdir("/tmp/overlay", 0755)) {
  60                 fprintf(stderr, "failed to mkdir /tmp/overlay: %s\n", strerror(errno));
  61                 return -1;
  62         }
  63
  64         v = volume_find("rootfs_data");
  65         if (!v) {
  66                 fprintf(stderr, "rootfs_data does not exist\n");
  67                 return -1;
  68         }
  69
  70         if (mount(v->blk, "/tmp/overlay", "jffs2", MS_NOATIME, NULL)) {
  71                 fprintf(stderr, "failed to mount -t jffs2 %s /tmp/overlay: %s\n", v->blk, strerror(errno));
  72                 return -1;
  73         }
  74
  75         return volume_init(v);
  76 }
  77
  78 static int
  79 switch2jffs(void)
  80 {
  81         struct volume *v = volume_find("rootfs_data");
  82         struct stat s;
  83         int ret;
  84
  85         if (!stat(SWITCH_JFFS2, &s)) {
  86                 fprintf(stderr, "jffs2 switch already running\n");
  87                 return -1;
  88         }
  89
  90         if (!v) {
  91                 fprintf(stderr, "no rootfs_data was found\n");
  92                 return -1;
  93         }
  94
  95         creat("/tmp/.switch_jffs2", 0600);
  96         ret = mount(v->blk, "/rom/overlay", "jffs2", MS_NOATIME, NULL);
  97         unlink("/tmp/.switch_jffs2");
  98         if (ret) {
  99                 fprintf(stderr, "failed - mount -t jffs2 %s /rom/overlay: %s\n", v->blk, strerror(errno));
 100                 return -1;
 101         }
 102
 103         if (mount("none", "/", NULL, MS_NOATIME | MS_REMOUNT, 0)) {
 104                 fprintf(stderr, "failed - mount -o remount,ro none: %s\n", strerror(errno));
 105                 return -1;
 106         }
 107
 108         system("cp -a /tmp/root/* /rom/overlay");
 109
 110         if (pivot("/rom", "/mnt")) {
 111                 fprintf(stderr, "failed - pivot /rom /mnt: %s\n", strerror(errno));
 112                 return -1;
 113         }
 114
 115         if (mount_move("/mnt", "/tmp/root", "")) {
 116                 fprintf(stderr, "failed - mount -o move /mnt /tmp/root %s\n", strerror(errno));
 117                 return -1;
 118         }
 119
 120         return fopivot("/overlay", "/rom");
 121 }
 122
 123 int
 124 handle_whiteout(const char *dir)
 125 {
 126         struct stat s;
 127         char link[256];
 128         ssize_t sz;
 129         struct dirent **namelist;
 130         int n;
 131
 132         n = scandir(dir, &namelist, NULL, NULL);
 133
 134         if (n < 1)
 135                 return -1;
 136
 137         while (n--) {
 138                 char file[256];
 139
 140                 snprintf(file, sizeof(file), "%s%s", dir, namelist[n]->d_name);
 141                 if (!lstat(file, &s) && S_ISLNK(s.st_mode)) {
 142                         sz = readlink(file, link, sizeof(link) - 1);
 143                         if (sz > 0) {
 144                                 char *orig;
 145
 146                                 link[sz] = '\0';
 147                                 orig = strstr(&file[1], "/");
 148                                 if (orig && !strcmp(link, "(overlay-whiteout)"))
 149                                         unlink(orig);
 150                         }
 151                 }
 152                 free(namelist[n]);
 153         }
 154         free(namelist);
 155
 156         return 0;
 157 }
 158
 159 static int
 160 ask_user(int argc, char **argv)
 161 {
 162         if ((argc < 2) || strcmp(argv[1], "-y")) {
 163                 fprintf(stderr, "This will erase all settings and remove any installed packages. Are you sure? [N/y]\n");
 164                 if (getchar() != 'y')
 165                         return -1;
 166         }
 167         return 0;
 168
 169 }
 170
 171 static int
 172 handle_rmdir(const char *dir)
 173 {
 174         struct stat s;
 175         struct dirent **namelist;
 176         int n;
 177
 178         n = scandir(dir, &namelist, NULL, NULL);
 179
 180         if (n < 1)
 181                 return -1;
 182
 183         while (n--) {
 184                 char file[256];
 185
 186                 snprintf(file, sizeof(file), "%s%s", dir, namelist[n]->d_name);
 187                 if (!lstat(file, &s) && !S_ISDIR(s.st_mode))
 188                         unlink(file);
 189                 free(namelist[n]);
 190         }
 191         free(namelist);
 192
 193         rmdir(dir);
 194
 195         return 0;
 196 }
 197
 198 static int
 199 jffs2_reset(int argc, char **argv)
 200 {
 201         struct volume *v;
 202         char *mp;
 203
 204         if (ask_user(argc, argv))
 205                 return -1;
 206
 207         if (find_filesystem("overlay")) {
 208                 fprintf(stderr, "overlayfs not found\n");
 209                 return -1;
 210         }
 211
 212         v = volume_find("rootfs_data");
 213         if (!v) {
 214                 fprintf(stderr, "no rootfs_data was found\n");
 215                 return -1;
 216         }
 217
 218         mp = find_mount_point(v->blk, "jffs2");
 219         if (mp) {
 220                 fprintf(stderr, "%s is mounted as %s, only erasing files\n", v->blk, mp);
 221                 foreachdir(mp, handle_rmdir);
 222                 mount(mp, "/", NULL, MS_REMOUNT, 0);
 223         } else {
 224                 fprintf(stderr, "%s is not mounted, erasing it\n", v->blk);
 225                 volume_erase_all(v);
 226         }
 227
 228         return 0;
 229 }
 230
 231 static int
 232 jffs2_mark(int argc, char **argv)
 233 {
 234         __u32 deadc0de = __cpu_to_be32(0xdeadc0de);
 235         struct volume *v;
 236         size_t sz;
 237         int fd;
 238
 239         if (ask_user(argc, argv))
 240                 return -1;
 241
 242         v = volume_find("rootfs_data");
 243         if (!v) {
 244                 fprintf(stderr, "no rootfs_data was found\n");
 245                 return -1;
 246         }
 247
 248         fd = open(v->blk, O_WRONLY);
 249         fprintf(stderr, "%s - marking with deadc0de\n", v->blk);
 250         if (!fd) {
 251                 fprintf(stderr, "opening %s failed\n", v->blk);
 252                 return -1;
 253         }
 254
 255         sz = write(fd, &deadc0de, sizeof(deadc0de));
 256         close(fd);
 257
 258         if (sz != 1) {
 259                 fprintf(stderr, "writing %s failed: %s\n", v->blk, strerror(errno));
 260                 return -1;
 261         }
 262
 263         return 0;
 264 }
 265
 266 int
 267 jffs2_switch(int argc, char **argv)
 268 {
 269         struct volume *v;
 270         char *mp;
 271         int ret = -1;
 272
 273         if (find_overlay_mount("overlayfs:/tmp/root"))
 274                 return -1;
 275
 276         if (find_filesystem("overlay")) {
 277                 fprintf(stderr, "overlayfs not found\n");
 278                 return ret;
 279         }
 280
 281         v = volume_find("rootfs_data");
 282         mp = find_mount_point(v->blk, NULL);
 283         if (mp) {
 284                 fprintf(stderr, "rootfs_data:%s is already mounted as %s\n", v->blk, mp);
 285                 return -1;
 286         }
 287
 288         switch (volume_identify(v)) {
 289         case FS_NONE:
 290                 fprintf(stderr, "no jffs2 marker found\n");
 291                 /* fall through */
 292
 293         case FS_DEADCODE:
 294                 ret = switch2jffs();
 295                 if (!ret) {
 296                         fprintf(stderr, "doing fo cleanup\n");
 297                         umount2("/tmp/root", MNT_DETACH);
 298                         foreachdir("/overlay/", handle_whiteout);
 299                 }
 300                 break;
 301
 302         case FS_JFFS2:
 303                 ret = jffs2_mount();
 304                 if (ret)
 305                         break;
 306                 if (mount_move("/tmp", "", "/overlay") || fopivot("/overlay", "/rom")) {
 307                         fprintf(stderr, "switching to jffs2 failed\n");
 308                         ret = -1;
 309                 }
 310                 break;
 311         }
 312
 313         return ret;
 314 }
 315
 316 static int overlay_mount_fs(void)
 317 {
 318         struct volume *v;
 319
 320         if (mkdir("/tmp/overlay", 0755)) {
 321                 fprintf(stderr, "failed to mkdir /tmp/overlay: %s\n", strerror(errno));
 322                 return -1;
 323         }
 324
 325         v = volume_find("rootfs_data");
 326         if (!v) {
 327                 fprintf(stderr, "rootfs_data does not exist\n");
 328                 return -1;
 329         }
 330
 331         if (mount(v->blk, "/tmp/overlay", "jffs2", MS_NOATIME, NULL)) {
 332                 fprintf(stderr, "failed to mount -t jffs2 %s /tmp/overlay: %s\n",
 333                                 v->blk, strerror(errno));
 334                 return -1;
 335         }
 336
 337         volume_init(v);
 338
 339         return -1;
 340 }
 341
 342 static int overlay_mount(void)
 343 {
 344         struct volume *v = volume_find("rootfs_data");;
 345         char *mp;
 346
 347         if (!v)
 348                 return -1;
 349
 350         mp = find_mount_point(v->blk, NULL);
 351         if (mp) {
 352                 fprintf(stderr, "rootfs_data:%s is already mounted as %s\n", v->blk, mp);
 353                 return -1;
 354         }
 355
 356         overlay_mount_fs();
 357
 358         extroot_prefix = "/tmp/overlay";
 359         if (!backend_mount("extroot")) {
 360                 fprintf(stderr, "fs-state: switched to extroot\n");
 361                 return 0;
 362         }
 363
 364         fprintf(stderr, "switching to jffs2\n");
 365         if (mount_move("/tmp", "", "/overlay") || fopivot("/overlay", "/rom")) {
 366                 fprintf(stderr, "switching to jffs2 failed - fallback to ramoverlay\n");
 367                 return ramoverlay();
 368         }
 369
 370         return -1;
 371 }
 372
 373 static struct backend_handler jffs2_handlers[] = {
 374 {
 375         .name = "jffs2reset",
 376         .cli = jffs2_reset,
 377 }, {
 378         .name = "jffs2mark",
 379         .cli = jffs2_mark,
 380 }};
 381
 382 static struct backend overlay_backend = {
 383         .name = "overlay",
 384         .num_handlers = ARRAY_SIZE(jffs2_handlers),
 385         .handlers = jffs2_handlers,
 386         .mount = overlay_mount,
 387 };
 388 BACKEND(overlay_backend);