android_mt6572_jiabo/bootable/recovery/roots.cpp
2025-09-05 16:56:03 +08:00

585 lines
17 KiB
C++

/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <errno.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <ctype.h>
#include <fcntl.h>
#include <dirent.h>
#include <fs_mgr.h>
#include "mtdutils/mtdutils.h"
#include "mtdutils/mounts.h"
#include "roots.h"
#include "common.h"
#include "make_ext4fs.h"
#include "wipe.h"
#include "cryptfs.h"
#include "voldclient.h"
#include <blkid/blkid.h>
static struct fstab *fstab = NULL;
extern struct selabel_handle *sehandle;
static int mkdir_p(const char* path, mode_t mode)
{
char dir[PATH_MAX];
char* p;
strcpy(dir, path);
for (p = strchr(&dir[1], '/'); p != NULL; p = strchr(p+1, '/')) {
*p = '\0';
if (mkdir(dir, mode) != 0 && errno != EEXIST) {
return -1;
}
*p = '/';
}
if (mkdir(dir, mode) != 0 && errno != EEXIST) {
return -1;
}
return 0;
}
static void write_fstab_entry(Volume *v, FILE *file)
{
if (NULL != v && strcmp(v->fs_type, "mtd") != 0 && strcmp(v->fs_type, "emmc") != 0
&& strcmp(v->fs_type, "bml") != 0 && !fs_mgr_is_voldmanaged(v)
&& strncmp(v->blk_device, "/", 1) == 0
&& strncmp(v->mount_point, "/", 1) == 0) {
fprintf(file, "%s ", v->blk_device);
fprintf(file, "%s ", v->mount_point);
fprintf(file, "%s ", v->fs_type);
fprintf(file, "%s 0 0\n", v->fs_options == NULL ? "defaults" : v->fs_options);
}
}
int get_num_volumes() {
return fstab->num_entries;
}
Volume* get_device_volumes() {
return fstab->recs;
}
void load_volume_table()
{
int i;
int ret;
fstab = fs_mgr_read_fstab("/etc/recovery.fstab");
if (!fstab) {
LOGE("failed to read /etc/recovery.fstab\n");
return;
}
ret = fs_mgr_add_entry(fstab, "/tmp", "ramdisk", "ramdisk");
if (ret < 0 ) {
LOGE("failed to add /tmp entry to fstab\n");
fs_mgr_free_fstab(fstab);
fstab = NULL;
return;
}
// Create a boring /etc/fstab so tools like Busybox work
FILE *file = fopen("/etc/fstab", "w");
if (file == NULL) {
LOGW("Unable to create /etc/fstab!\n");
return;
}
printf("recovery filesystem table\n");
printf("=========================\n");
for (i = 0; i < fstab->num_entries; ++i) {
Volume* v = &fstab->recs[i];
printf(" %d %s %s %s %lld\n", i, v->mount_point, v->fs_type,
v->blk_device, v->length);
write_fstab_entry(v, file);
}
fclose(file);
printf("\n");
}
bool volume_is_mountable(Volume *v)
{
return (fs_mgr_is_voldmanaged(v) ||
!strcmp(v->fs_type, "yaffs2") ||
!strcmp(v->fs_type, "ext4") ||
!strcmp(v->fs_type, "f2fs") ||
!strcmp(v->fs_type, "vfat"));
}
bool volume_is_readonly(Volume *v)
{
return (v->flags & MS_RDONLY);
}
bool volume_is_verity(Volume *v)
{
return fs_mgr_is_verified(v);
}
Volume* volume_for_path(const char* path) {
Volume *rec = fs_mgr_get_entry_for_mount_point(fstab, path);
if (rec == NULL)
return rec;
if (strcmp(rec->fs_type, "ext4") == 0 || strcmp(rec->fs_type, "f2fs") == 0 ||
strcmp(rec->fs_type, "vfat") == 0) {
char *detected_fs_type = blkid_get_tag_value(NULL, "TYPE", rec->blk_device);
if (detected_fs_type == NULL)
return rec;
Volume *fetched_rec = rec;
while (rec != NULL && strcmp(rec->fs_type, detected_fs_type) != 0)
rec = fs_mgr_get_entry_for_mount_point_after(rec, fstab, path);
if (rec == NULL)
return fetched_rec;
}
return rec;
}
Volume* volume_for_label(const char* label) {
int i;
for (i = 0; i < get_num_volumes(); i++) {
Volume* v = get_device_volumes() + i;
if (v->label && !strcmp(v->label, label)) {
return v;
}
}
return NULL;
}
// Mount the volume specified by path at the given mount_point.
int ensure_path_mounted_at(const char* path, const char* mount_point, bool force_rw) {
Volume* v = volume_for_path(path);
if (v == NULL) {
LOGE("unknown volume for path [%s]\n", path);
return -1;
}
if (strcmp(v->fs_type, "ramdisk") == 0) {
// the ramdisk is always mounted.
return 0;
}
int result;
result = scan_mounted_volumes();
if (result < 0) {
LOGE("failed to scan mounted volumes\n");
return -1;
}
if (!mount_point) {
mount_point = v->mount_point;
}
if (!fs_mgr_is_voldmanaged(v)) {
const MountedVolume* mv =
find_mounted_volume_by_mount_point(mount_point);
if (mv) {
// volume is already mounted
return 0;
}
}
mkdir_p(mount_point, 0755); // in case it doesn't already exist
if (strcmp(v->fs_type, "yaffs2") == 0) {
// mount an MTD partition as a YAFFS2 filesystem.
mtd_scan_partitions();
const MtdPartition* partition;
partition = mtd_find_partition_by_name(v->blk_device);
if (partition == NULL) {
LOGE("failed to find \"%s\" partition to mount at \"%s\"\n",
v->blk_device, mount_point);
return -1;
}
return mtd_mount_partition(partition, mount_point, v->fs_type, 0);
} else if (strcmp(v->fs_type, "ext4") == 0 ||
strcmp(v->fs_type, "f2fs") == 0 ||
strcmp(v->fs_type, "squashfs") == 0 ||
strcmp(v->fs_type, "vfat") == 0) {
unsigned long mntflags = v->flags;
if (!force_rw) {
if ((v->flags & MS_RDONLY) || fs_mgr_is_verified(v)) {
mntflags |= MS_RDONLY;
}
}
result = mount(v->blk_device, mount_point, v->fs_type,
mntflags, v->fs_options);
if (result == 0) return 0;
LOGE("failed to mount %s (%s)\n", mount_point, strerror(errno));
return -1;
}
LOGE("unknown fs_type \"%s\" for %s\n", v->fs_type, mount_point);
return -1;
}
int ensure_volume_mounted(Volume* v, bool force_rw) {
if (v == NULL) {
LOGE("cannot mount unknown volume\n");
return -1;
}
return ensure_path_mounted_at(v->mount_point, nullptr, force_rw);
}
int remount_no_selinux(const char* path) {
int ret;
char *old_fs_options;
char *new_fs_options;
char se_context[] = ",context=u:object_r:app_data_file:s0";
Volume *v;
// Backup original mount options
v = volume_for_path(path);
old_fs_options = v->fs_options;
// Add SELinux mount override
asprintf(&new_fs_options, "%s%s", v->fs_options, se_context);
v->fs_options = new_fs_options;
ensure_path_unmounted(path);
ret = ensure_path_mounted(path);
// Restore original mount options
v->fs_options = old_fs_options;
free(new_fs_options);
return ret;
}
int ensure_path_mounted(const char* path, bool force_rw) {
// Mount at the default mount point.
return ensure_path_mounted_at(path, nullptr, force_rw);
}
int ensure_path_unmounted(const char* path, bool detach /* = false */) {
Volume* v;
if (memcmp(path, "/storage/", 9) == 0) {
char label[PATH_MAX];
const char* p = path+9;
const char* q = strchr(p, '/');
memset(label, 0, sizeof(label));
if (q) {
memcpy(label, p, q-p);
}
else {
strcpy(label, p);
}
v = volume_for_label(label);
}
else {
v = volume_for_path(path);
}
if (v == NULL) {
LOGE("unknown volume for path [%s]\n", path);
return -1;
}
return ensure_volume_unmounted(v, detach);
}
int ensure_volume_unmounted(Volume* v, bool detach /* = false */) {
if (v == NULL) {
LOGE("cannot unmount unknown volume\n");
return -1;
}
if (strcmp(v->fs_type, "ramdisk") == 0) {
// the ramdisk is always mounted; you can't unmount it.
return -1;
}
int result;
result = scan_mounted_volumes();
if (result < 0) {
LOGE("failed to scan mounted volumes\n");
return -1;
}
const MountedVolume* mv =
find_mounted_volume_by_mount_point(v->mount_point);
if (mv == NULL) {
// volume is already unmounted
return 0;
}
if (detach) {
result = unmount_mounted_volume_detach(mv);
}
else {
result = unmount_mounted_volume(mv);
}
return result;
}
static int exec_cmd(const char* path, char* const argv[]) {
int status;
pid_t child;
if ((child = vfork()) == 0) {
execv(path, argv);
_exit(-1);
}
waitpid(child, &status, 0);
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
LOGE("%s failed with status %d\n", path, WEXITSTATUS(status));
}
return WEXITSTATUS(status);
}
static int rmtree_except(const char* path, const char* except)
{
char pathbuf[PATH_MAX];
int rc = 0;
DIR* dp = opendir(path);
if (dp == NULL) {
return -1;
}
struct dirent* de;
while ((de = readdir(dp)) != NULL) {
if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
continue;
if (except && !strcmp(de->d_name, except))
continue;
struct stat st;
snprintf(pathbuf, sizeof(pathbuf), "%s/%s", path, de->d_name);
rc = lstat(pathbuf, &st);
if (rc != 0) {
LOGE("Failed to stat %s\n", pathbuf);
break;
}
if (S_ISDIR(st.st_mode)) {
rc = rmtree_except(pathbuf, NULL);
if (rc != 0)
break;
rc = rmdir(pathbuf);
}
else {
rc = unlink(pathbuf);
}
if (rc != 0) {
LOGI("Failed to remove %s: %s\n", pathbuf, strerror(errno));
break;
}
}
closedir(dp);
return rc;
}
int format_volume(const char* volume, const char* directory, bool force) {
if (strcmp(volume, "media") == 0) {
if (!vdc->isEmulatedStorage()) {
return 0;
}
if (ensure_path_mounted("/data") != 0) {
LOGE("format_volume failed to mount /data\n");
return -1;
}
remount_no_selinux("/data");
int rc = 0;
rc = rmtree_except("/data/media", NULL);
ensure_path_unmounted("/data");
return rc;
}
Volume* v = volume_for_path(volume);
if (v == NULL) {
LOGE("unknown volume \"%s\"\n", volume);
return -1;
}
if (strcmp(v->fs_type, "ramdisk") == 0) {
// you can't format the ramdisk.
LOGE("can't format_volume \"%s\"", volume);
return -1;
}
if (strcmp(v->mount_point, volume) != 0) {
LOGE("can't give path \"%s\" to format_volume\n", volume);
return -1;
}
if (!force && strcmp(volume, "/data") == 0 && vdc->isEmulatedStorage()) {
if (ensure_path_mounted("/data") == 0) {
remount_no_selinux("/data");
// Preserve .layout_version to avoid "nesting bug"
LOGI("Preserving layout version\n");
unsigned char layout_buf[256];
ssize_t layout_buflen = -1;
int fd;
fd = open("/data/.layout_version", O_RDONLY);
if (fd != -1) {
layout_buflen = read(fd, layout_buf, sizeof(layout_buf));
close(fd);
}
int rc = rmtree_except("/data", "media");
// Restore .layout_version
if (layout_buflen > 0) {
LOGI("Restoring layout version\n");
fd = open("/data/.layout_version", O_WRONLY | O_CREAT | O_EXCL, 0600);
if (fd != -1) {
write(fd, layout_buf, layout_buflen);
close(fd);
}
}
ensure_path_unmounted(volume);
return rc;
}
else {
LOGE("format_volume failed to mount /data\n");
return -1;
}
}
if (ensure_path_unmounted(volume) != 0) {
LOGE("format_volume failed to unmount \"%s\"\n", v->mount_point);
return -1;
}
if (fs_mgr_is_voldmanaged(v)) {
LOGE("can't format vold volume \"%s\"", volume);
return -1;
}
if (strcmp(v->fs_type, "yaffs2") == 0 || strcmp(v->fs_type, "mtd") == 0) {
mtd_scan_partitions();
const MtdPartition* partition = mtd_find_partition_by_name(v->blk_device);
if (partition == NULL) {
LOGE("format_volume: no MTD partition \"%s\"\n", v->blk_device);
return -1;
}
MtdWriteContext *write = mtd_write_partition(partition);
if (write == NULL) {
LOGW("format_volume: can't open MTD \"%s\"\n", v->blk_device);
return -1;
} else if (mtd_erase_blocks(write, -1) == (off_t) -1) {
LOGW("format_volume: can't erase MTD \"%s\"\n", v->blk_device);
mtd_write_close(write);
return -1;
} else if (mtd_write_close(write)) {
LOGW("format_volume: can't close MTD \"%s\"\n", v->blk_device);
return -1;
}
return 0;
}
if (strcmp(v->fs_type, "ext4") == 0 || strcmp(v->fs_type, "f2fs") == 0) {
// if there's a key_loc that looks like a path, it should be a
// block device for storing encryption metadata. wipe it too.
if (v->key_loc != NULL && v->key_loc[0] == '/') {
LOGI("wiping %s\n", v->key_loc);
int fd = open(v->key_loc, O_WRONLY | O_CREAT, 0644);
if (fd < 0) {
LOGE("format_volume: failed to open %s\n", v->key_loc);
return -1;
}
wipe_block_device(fd, get_file_size(fd));
close(fd);
}
ssize_t length = 0;
if (v->length != 0) {
length = v->length;
} else if (v->key_loc != NULL && strcmp(v->key_loc, "footer") == 0) {
length = -CRYPT_FOOTER_OFFSET;
}
int result;
if (strcmp(v->fs_type, "ext4") == 0) {
result = make_ext4fs_directory(v->blk_device, length, volume, sehandle, directory);
} else { /* Has to be f2fs because we checked earlier. */
char bytes_reserved[20], num_sectors[20];
const char* f2fs_argv[6] = {"mkfs.f2fs", "-t1"};
if (length < 0) {
snprintf(bytes_reserved, sizeof(bytes_reserved), "%zd", -length);
f2fs_argv[2] = "-r";
f2fs_argv[3] = bytes_reserved;
f2fs_argv[4] = v->blk_device;
f2fs_argv[5] = NULL;
} else {
/* num_sectors can be zero which mean whole device space */
snprintf(num_sectors, sizeof(num_sectors), "%zd", length / 512);
f2fs_argv[2] = v->blk_device;
f2fs_argv[3] = num_sectors;
f2fs_argv[4] = NULL;
}
const char *f2fs_path = "/sbin/mkfs.f2fs";
result = exec_cmd(f2fs_path, (char* const*)f2fs_argv);
}
if (result != 0) {
LOGE("format_volume: make %s failed on %s with %d(%s)\n", v->fs_type, v->blk_device, result, strerror(errno));
return -1;
}
return 0;
}
LOGE("format_volume: fs_type \"%s\" unsupported\n", v->fs_type);
return -1;
}
int format_volume(const char* volume, bool force) {
return format_volume(volume, NULL, force);
}
int setup_install_mounts() {
if (fstab == NULL) {
LOGE("can't set up install mounts: no fstab loaded\n");
return -1;
}
for (int i = 0; i < fstab->num_entries; ++i) {
Volume* v = fstab->recs + i;
if (strcmp(v->mount_point, "/tmp") == 0 ||
strcmp(v->mount_point, "/cache") == 0) {
if (ensure_path_mounted(v->mount_point) != 0) {
LOGE("failed to mount %s\n", v->mount_point);
return -1;
}
} else {
// datamedia and anything managed by vold must be unmounted
// with the detach flag to ensure that FUSE works.
bool detach = false;
if (vdc->isEmulatedStorage() && strcmp(v->mount_point, "/data") == 0) {
detach = true;
}
if (ensure_volume_unmounted(v, detach) != 0) {
LOGE("failed to unmount %s\n", v->mount_point);
return -1;
}
}
}
return 0;
}