libfstools/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 "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 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 int
 160 jffs2_switch(int argc, char **argv)
 161 {
 162         struct volume *v;
 163         char *mp;
 164         int ret = -1;
 165
 166         if (find_mount_overlay("overlayfs:/tmp/root"))
 167                 return -1;
 168
 169         if (find_filesystem("overlay")) {
 170                 fprintf(stderr, "overlayfs not found\n");
 171                 return ret;
 172         }
 173
 174         v = volume_find("rootfs_data");
 175         mp = find_mount_point(v->blk, NULL);
 176         if (mp) {
 177                 fprintf(stderr, "rootfs_data:%s is already mounted as %s\n", v->blk, mp);
 178                 return -1;
 179         }
 180
 181         switch (volume_identify(v)) {
 182         case FS_NONE:
 183                 fprintf(stderr, "no jffs2 marker found\n");
 184                 /* fall through */
 185
 186         case FS_DEADCODE:
 187                 ret = switch2jffs();
 188                 if (!ret) {
 189                         fprintf(stderr, "doing fo cleanup\n");
 190                         umount2("/tmp/root", MNT_DETACH);
 191                         foreachdir("/overlay/", handle_whiteout);
 192                 }
 193                 break;
 194
 195         case FS_JFFS2:
 196                 ret = jffs2_mount();
 197                 if (ret)
 198                         break;
 199                 if (mount_move("/tmp", "", "/overlay") || fopivot("/overlay", "/rom")) {
 200                         fprintf(stderr, "switching to jffs2 failed\n");
 201                         ret = -1;
 202                 }
 203                 break;
 204         }
 205
 206         return ret;
 207 }
 208
 209 static int mount_overlay_fs(void)
 210 {
 211         struct volume *v;
 212
 213         if (mkdir("/tmp/overlay", 0755)) {
 214                 fprintf(stderr, "failed to mkdir /tmp/overlay: %s\n", strerror(errno));
 215                 return -1;
 216         }
 217
 218         v = volume_find("rootfs_data");
 219         if (!v) {
 220                 fprintf(stderr, "rootfs_data does not exist\n");
 221                 return -1;
 222         }
 223
 224         if (mount(v->blk, "/tmp/overlay", "jffs2", MS_NOATIME, NULL)) {
 225                 fprintf(stderr, "failed to mount -t jffs2 %s /tmp/overlay: %s\n",
 226                                 v->blk, strerror(errno));
 227                 return -1;
 228         }
 229
 230         volume_init(v);
 231
 232         return -1;
 233 }
 234
 235 int mount_overlay(void)
 236 {
 237         struct volume *v = volume_find("rootfs_data");;
 238         char *mp;
 239
 240         if (!v)
 241                 return -1;
 242
 243         mp = find_mount_point(v->blk, NULL);
 244         if (mp) {
 245                 fprintf(stderr, "rootfs_data:%s is already mounted as %s\n", v->blk, mp);
 246                 return -1;
 247         }
 248
 249         mount_overlay_fs();
 250
 251         extroot_prefix = "/tmp/overlay";
 252         if (!mount_extroot()) {
 253                 fprintf(stderr, "fs-state: switched to extroot\n");
 254                 return 0;
 255         }
 256
 257         fprintf(stderr, "switching to jffs2\n");
 258         if (mount_move("/tmp", "", "/overlay") || fopivot("/overlay", "/rom")) {
 259                 fprintf(stderr, "switching to jffs2 failed - fallback to ramoverlay\n");
 260                 return ramoverlay();
 261         }
 262
 263         return -1;
 264 }