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multirom: Support mounting booted external EXT4/F2FS #12

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multirom: Support mounting booted external EXT4/F2FS #12

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122 changes: 120 additions & 2 deletions multirom.c
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,9 @@ static char kexec_path[64] = { 0 };
static char ntfs_path[64] = { 0 };
static char exfat_path[64] = { 0 };
static char partition_dir[64] = { 0 };
static char external_mount_fs[5] = { 0 };
static char external_mount_part[256] = { 0 };
static char external_mount_path[256] = { 0 };

static volatile int run_usb_refresh = 0;
static pthread_t usb_refresh_thread;
Expand Down Expand Up @@ -1515,6 +1518,24 @@ int multirom_prep_android_mounts(struct multirom_status *s, struct multirom_rom
struct fstab_part *fw_part = NULL;
int res = -1;

// Detect booting from an unmountable external partition
// * Only external partitions have a partition defined
// * Detect ext4 or f2fs as external unmountable because of vold
external_mount_part[0] = 0;
external_mount_path[0] = 0;
if (rom->partition && (strcmp(rom->partition->fs, "ext4") == 0 ||
strcmp(rom->partition->fs, "f2fs") == 0))
{
snprintf(external_mount_part, sizeof(external_mount_part),
"/dev/block/%s", rom->partition->name);
snprintf(external_mount_path, sizeof(external_mount_path),
"/mnt/mrom/%s", rom->partition->name);
snprintf(external_mount_fs, sizeof(external_mount_fs),
"%4s", rom->partition->fs);
ERROR("Booting from external unmountable partition: '%s', %s\n",
external_mount_part, external_mount_fs);
}

sprintf(path, "%s/firmware.img", rom->base_path);
has_fw = (access(path, R_OK) >= 0);

Expand Down Expand Up @@ -1550,7 +1571,7 @@ int multirom_prep_android_mounts(struct multirom_status *s, struct multirom_rom
}
closedir(d);

if(multirom_process_android_fstab(fstab_name, has_fw, &fw_part) != 0)
if (multirom_process_android_fstab(fstab_name, has_fw, &fw_part, s) != 0)
goto exit;

unlink("/cache");
Expand Down Expand Up @@ -1641,7 +1662,8 @@ int multirom_prep_android_mounts(struct multirom_status *s, struct multirom_rom
return res;
}

int multirom_process_android_fstab(char *fstab_name, int has_fw, struct fstab_part **fw_part)
int multirom_process_android_fstab(char *fstab_name, int has_fw,
struct fstab_part **fw_part, struct multirom_status *s)
{
int res = -1;

Expand Down Expand Up @@ -1734,6 +1756,52 @@ int multirom_process_android_fstab(char *fstab_name, int has_fw, struct fstab_pa
mkdir("/dummy_tmpfs", 0644);
}

// Booting from an unmountable external partition
if (external_mount_path[0] != 0)
{
// Access MultiROM fstab as second mount path reference
struct fstab_part* ext_part = NULL;
for (int i = 0; i < s->fstab->count; ++i)
{
if (strcmp(s->fstab->parts[i]->device, external_mount_part) == 0)
{
ext_part = s->fstab->parts[i];
break;
}
}

// Handle external MicroSD boot for voldmanaged removal
if (strstr(external_mount_part, "mmcblk1p1") != NULL ||
ext_part && strstr(ext_part->path, "external_sd") != NULL)
{
ERROR("Searching for voldmanaged 'sdcard1' flag in fstab\n");
for (int i = 0; i < tab->count; ++i)
{
if (strstr(tab->parts[i]->options2, "voldmanaged=sdcard1") != NULL)
{
ERROR("Removing '%s' from fstab to avoid 'voldmanaged'\n",
tab->parts[i]->device);
tab->parts[i]->disabled = 1;
}
}
}
// Handle external USB boot for voldmanaged removal
else if (strstr(external_mount_part, "usb") != NULL ||
ext_part && strstr(ext_part->path, "usb") != NULL)
{
ERROR("Searching for voldmanaged 'usb' flag in fstab\n");
for (int i = 0; i < tab->count; ++i)
{
if (strstr(tab->parts[i]->options2, "voldmanaged=usb") != NULL)
{
ERROR("Removing '%s' from fstab to avoid 'voldmanaged'\n",
tab->parts[i]->device);
tab->parts[i]->disabled = 1;
}
}
}
}

if(fstab_save(tab, fstab_name) == 0)
res = 0;

Expand Down Expand Up @@ -1821,6 +1889,56 @@ int multirom_create_media_link(struct multirom_status *s)
rcadditions_append_trigger(&s->rc, "post-fs-data", " restorecon " LAYOUT_VERSION "\n");
}

// Booting from an unmountable external partition
if (external_mount_path[0] != 0)
{
// Select internal media path for 'external_multirom'
char path_ext[256];
if (stat("/data/media/0", &info) >= 0)
{
snprintf(path_ext, sizeof(path_ext),
"/data/media/0/external_multirom");
}
else
{
snprintf(path_ext, sizeof(path_ext),
"/data/media/external_multirom");
}

INFO("Preparing to mount '%s' to '%s'\n", external_mount_path,
path_ext);

// Create and set accesses to 'external_multirom' on internal media
mkdir(path_ext, 0770);
chmod(path_ext, 0770);

// Bind external partition to internal media 'external_multirom'
if (mount(external_mount_path, path_ext, external_mount_fs, MS_BIND,
"") < 0)
{
ERROR("Failed to bind '%s' (%s) to '%s': %d (%s)\n",
external_mount_path, external_mount_fs, path_ext, errno,
strerror(errno));
external_mount_part[0] = 0;
external_mount_path[0] = 0;
return 0;
}

// Apply internal media owners for 'external_multirom'
unsigned int media_rw_id = decode_uid("media_rw");
if (media_rw_id != -1U)
{
chown(path_ext, (uid_t)media_rw_id, (gid_t)media_rw_id);
}

// Append init restorecon for 'external_multirom' context
char restorecon_ext[64];
snprintf(restorecon_ext, sizeof(restorecon_ext),
" restorecon %s\n", path_ext);
rcadditions_append_trigger(&s->rc, "post-fs-data",
restorecon_ext);
}

return 0;
}

Expand Down
2 changes: 1 addition & 1 deletion multirom.h
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Original file line number Diff line number Diff line change
Expand Up @@ -142,7 +142,7 @@ void multirom_free_rom(void *rom);
int multirom_init_fb(int rotation);
int multirom_prep_android_mounts(struct multirom_status *s, struct multirom_rom *rom);
int multirom_create_media_link(struct multirom_status *s);
int multirom_process_android_fstab(char *fstab_name, int has_fw, struct fstab_part **fw_part);
int multirom_process_android_fstab(char *fstab_name, int has_fw, struct fstab_part **fw_part, struct multirom_status *s);
int multirom_get_api_level(const char *path);
int multirom_get_rom_type(struct multirom_rom *rom);
int multirom_get_trampoline_ver(void);
Expand Down