blob: 4043fc6a16bd42a61a0f3e42faa41aa8639e9c68 [file] [log] [blame]
/*
* Copyright (C) 2014 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 <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <unistd.h>
#include <algorithm>
#include <array>
#include <utility>
#include <vector>
#include <android-base/file.h>
#include <android-base/parseint.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <libgsi/libgsi.h>
#include "fs_mgr_priv.h"
using android::base::ParseByteCount;
using android::base::ParseInt;
using android::base::Split;
using android::base::StartsWith;
namespace android {
namespace fs_mgr {
namespace {
const std::string kDefaultAndroidDtDir("/proc/device-tree/firmware/android");
struct FlagList {
const char *name;
uint64_t flag;
};
FlagList kMountFlagsList[] = {
{"noatime", MS_NOATIME},
{"noexec", MS_NOEXEC},
{"nosuid", MS_NOSUID},
{"nodev", MS_NODEV},
{"nodiratime", MS_NODIRATIME},
{"ro", MS_RDONLY},
{"rw", 0},
{"remount", MS_REMOUNT},
{"bind", MS_BIND},
{"rec", MS_REC},
{"unbindable", MS_UNBINDABLE},
{"private", MS_PRIVATE},
{"slave", MS_SLAVE},
{"shared", MS_SHARED},
{"defaults", 0},
};
off64_t CalculateZramSize(int percentage) {
off64_t total;
total = sysconf(_SC_PHYS_PAGES);
total *= percentage;
total /= 100;
total *= sysconf(_SC_PAGESIZE);
return total;
}
// Fills 'dt_value' with the underlying device tree value string without the trailing '\0'.
// Returns true if 'dt_value' has a valid string, 'false' otherwise.
bool ReadDtFile(const std::string& file_name, std::string* dt_value) {
if (android::base::ReadFileToString(file_name, dt_value)) {
if (!dt_value->empty()) {
// Trim the trailing '\0' out, otherwise the comparison will produce false-negatives.
dt_value->resize(dt_value->size() - 1);
return true;
}
}
return false;
}
const std::array<const char*, 3> kFileContentsEncryptionMode = {
"aes-256-xts",
"adiantum",
"ice",
};
const std::array<const char*, 3> kFileNamesEncryptionMode = {
"aes-256-cts",
"aes-256-heh",
"adiantum",
};
void ParseFileEncryption(const std::string& arg, FstabEntry* entry) {
// The fileencryption flag is followed by an = and the mode of contents encryption, then
// optionally a and the mode of filenames encryption (defaults to aes-256-cts). Get it and
// return it.
entry->fs_mgr_flags.file_encryption = true;
auto parts = Split(arg, ":");
if (parts.empty() || parts.size() > 2) {
LWARNING << "Warning: fileencryption= flag malformed: " << arg;
return;
}
// Alias for backwards compatibility.
if (parts[0] == "software") {
parts[0] = "aes-256-xts";
}
if (std::find(kFileContentsEncryptionMode.begin(), kFileContentsEncryptionMode.end(),
parts[0]) == kFileContentsEncryptionMode.end()) {
LWARNING << "fileencryption= flag malformed, file contents encryption mode not found: "
<< arg;
return;
}
entry->file_contents_mode = parts[0];
if (parts.size() == 2) {
if (std::find(kFileNamesEncryptionMode.begin(), kFileNamesEncryptionMode.end(), parts[1]) ==
kFileNamesEncryptionMode.end()) {
LWARNING << "fileencryption= flag malformed, file names encryption mode not found: "
<< arg;
return;
}
entry->file_names_mode = parts[1];
} else if (entry->file_contents_mode == "adiantum") {
entry->file_names_mode = "adiantum";
} else {
entry->file_names_mode = "aes-256-cts";
}
}
bool SetMountFlag(const std::string& flag, FstabEntry* entry) {
for (const auto& [name, value] : kMountFlagsList) {
if (flag == name) {
entry->flags |= value;
return true;
}
}
return false;
}
void ParseMountFlags(const std::string& flags, FstabEntry* entry) {
std::string fs_options;
for (const auto& flag : Split(flags, ",")) {
if (!SetMountFlag(flag, entry)) {
// Unknown flag, so it must be a filesystem specific option.
if (!fs_options.empty()) {
fs_options.append(","); // appends a comma if not the first
}
fs_options.append(flag);
}
}
entry->fs_options = std::move(fs_options);
}
void ParseFsMgrFlags(const std::string& flags, FstabEntry* entry) {
for (const auto& flag : Split(flags, ",")) {
if (flag.empty() || flag == "defaults") continue;
std::string arg;
if (auto equal_sign = flag.find('='); equal_sign != std::string::npos) {
arg = flag.substr(equal_sign + 1);
}
// First handle flags that simply set a boolean.
#define CheckFlag(flag_name, value) \
if (flag == flag_name) { \
entry->fs_mgr_flags.value = true; \
continue; \
}
CheckFlag("wait", wait);
CheckFlag("check", check);
CheckFlag("nonremovable", nonremovable);
CheckFlag("recoveryonly", recovery_only);
CheckFlag("noemulatedsd", no_emulated_sd);
CheckFlag("notrim", no_trim);
CheckFlag("verify", verify);
CheckFlag("formattable", formattable);
CheckFlag("slotselect", slot_select);
CheckFlag("latemount", late_mount);
CheckFlag("nofail", no_fail);
CheckFlag("verifyatboot", verify_at_boot);
CheckFlag("quota", quota);
CheckFlag("avb", avb);
CheckFlag("logical", logical);
CheckFlag("checkpoint=block", checkpoint_blk);
CheckFlag("checkpoint=fs", checkpoint_fs);
CheckFlag("first_stage_mount", first_stage_mount);
CheckFlag("slotselect_other", slot_select_other);
CheckFlag("fsverity", fs_verity);
#undef CheckFlag
// Then handle flags that take an argument.
if (StartsWith(flag, "encryptable=")) {
// The encryptable flag is followed by an = and the location of the keys.
entry->fs_mgr_flags.crypt = true;
entry->key_loc = arg;
} else if (StartsWith(flag, "voldmanaged=")) {
// The voldmanaged flag is followed by an = and the label, a colon and the partition
// number or the word "auto", e.g. voldmanaged=sdcard:3
entry->fs_mgr_flags.vold_managed = true;
auto parts = Split(arg, ":");
if (parts.size() != 2) {
LWARNING << "Warning: voldmanaged= flag malformed: " << arg;
continue;
}
entry->label = std::move(parts[0]);
if (parts[1] == "auto") {
entry->partnum = -1;
} else {
if (!ParseInt(parts[1], &entry->partnum)) {
entry->partnum = -1;
LWARNING << "Warning: voldmanaged= flag malformed: " << arg;
continue;
}
}
} else if (StartsWith(flag, "length=")) {
// The length flag is followed by an = and the size of the partition.
if (!ParseInt(arg, &entry->length)) {
LWARNING << "Warning: length= flag malformed: " << arg;
}
} else if (StartsWith(flag, "swapprio=")) {
if (!ParseInt(arg, &entry->swap_prio)) {
LWARNING << "Warning: length= flag malformed: " << arg;
}
} else if (StartsWith(flag, "zramsize=")) {
if (!arg.empty() && arg.back() == '%') {
arg.pop_back();
int val;
if (ParseInt(arg, &val, 0, 100)) {
entry->zram_size = CalculateZramSize(val);
} else {
LWARNING << "Warning: zramsize= flag malformed: " << arg;
}
} else {
if (!ParseInt(arg, &entry->zram_size)) {
LWARNING << "Warning: zramsize= flag malformed: " << arg;
}
}
} else if (StartsWith(flag, "verify=")) {
// If the verify flag is followed by an = and the location for the verity state.
entry->fs_mgr_flags.verify = true;
entry->verity_loc = arg;
} else if (StartsWith(flag, "forceencrypt=")) {
// The forceencrypt flag is followed by an = and the location of the keys.
entry->fs_mgr_flags.force_crypt = true;
entry->key_loc = arg;
} else if (StartsWith(flag, "fileencryption=")) {
ParseFileEncryption(arg, entry);
} else if (StartsWith(flag, "forcefdeorfbe=")) {
// The forcefdeorfbe flag is followed by an = and the location of the keys. Get it and
// return it.
entry->fs_mgr_flags.force_fde_or_fbe = true;
entry->key_loc = arg;
entry->file_contents_mode = "aes-256-xts";
entry->file_names_mode = "aes-256-cts";
} else if (StartsWith(flag, "max_comp_streams=")) {
if (!ParseInt(arg, &entry->max_comp_streams)) {
LWARNING << "Warning: max_comp_streams= flag malformed: " << arg;
}
} else if (StartsWith(flag, "reservedsize=")) {
// The reserved flag is followed by an = and the reserved size of the partition.
uint64_t size;
if (!ParseByteCount(arg, &size)) {
LWARNING << "Warning: reservedsize= flag malformed: " << arg;
} else {
entry->reserved_size = static_cast<off64_t>(size);
}
} else if (StartsWith(flag, "eraseblk=")) {
// The erase block size flag is followed by an = and the flash erase block size. Get it,
// check that it is a power of 2 and at least 4096, and return it.
off64_t val;
if (!ParseInt(arg, &val) || val < 4096 || (val & (val - 1)) != 0) {
LWARNING << "Warning: eraseblk= flag malformed: " << arg;
} else {
entry->erase_blk_size = val;
}
} else if (StartsWith(flag, "logicalblk=")) {
// The logical block size flag is followed by an = and the flash logical block size. Get
// it, check that it is a power of 2 and at least 4096, and return it.
off64_t val;
if (!ParseInt(arg, &val) || val < 4096 || (val & (val - 1)) != 0) {
LWARNING << "Warning: logicalblk= flag malformed: " << arg;
} else {
entry->logical_blk_size = val;
}
} else if (StartsWith(flag, "avb_keys=")) { // must before the following "avb"
entry->avb_keys = arg;
} else if (StartsWith(flag, "avb")) {
entry->fs_mgr_flags.avb = true;
entry->vbmeta_partition = arg;
} else if (StartsWith(flag, "keydirectory=")) {
// The metadata flag is followed by an = and the directory for the keys.
entry->key_dir = arg;
} else if (StartsWith(flag, "sysfs_path=")) {
// The path to trigger device gc by idle-maint of vold.
entry->sysfs_path = arg;
} else if (StartsWith(flag, "zram_loopback_path=")) {
// The path to use loopback for zram.
entry->zram_loopback_path = arg;
} else if (StartsWith(flag, "zram_loopback_size=")) {
if (!ParseByteCount(arg, &entry->zram_loopback_size)) {
LWARNING << "Warning: zram_loopback_size= flag malformed: " << arg;
}
} else if (StartsWith(flag, "zram_backing_dev_path=")) {
entry->zram_backing_dev_path = arg;
} else {
LWARNING << "Warning: unknown flag: " << flag;
}
}
}
std::string InitAndroidDtDir() {
std::string android_dt_dir;
// The platform may specify a custom Android DT path in kernel cmdline
if (!fs_mgr_get_boot_config_from_kernel_cmdline("android_dt_dir", &android_dt_dir)) {
// Fall back to the standard procfs-based path
android_dt_dir = kDefaultAndroidDtDir;
}
return android_dt_dir;
}
bool IsDtFstabCompatible() {
std::string dt_value;
std::string file_name = get_android_dt_dir() + "/fstab/compatible";
if (ReadDtFile(file_name, &dt_value) && dt_value == "android,fstab") {
// If there's no status property or its set to "ok" or "okay", then we use the DT fstab.
std::string status_value;
std::string status_file_name = get_android_dt_dir() + "/fstab/status";
return !ReadDtFile(status_file_name, &status_value) || status_value == "ok" ||
status_value == "okay";
}
return false;
}
std::string ReadFstabFromDt() {
if (!is_dt_compatible() || !IsDtFstabCompatible()) {
return {};
}
std::string fstabdir_name = get_android_dt_dir() + "/fstab";
std::unique_ptr<DIR, int (*)(DIR*)> fstabdir(opendir(fstabdir_name.c_str()), closedir);
if (!fstabdir) return {};
dirent* dp;
// Each element in fstab_dt_entries is <mount point, the line format in fstab file>.
std::vector<std::pair<std::string, std::string>> fstab_dt_entries;
while ((dp = readdir(fstabdir.get())) != NULL) {
// skip over name, compatible and .
if (dp->d_type != DT_DIR || dp->d_name[0] == '.') continue;
// create <dev> <mnt_point> <type> <mnt_flags> <fsmgr_flags>\n
std::vector<std::string> fstab_entry;
std::string file_name;
std::string value;
// skip a partition entry if the status property is present and not set to ok
file_name = android::base::StringPrintf("%s/%s/status", fstabdir_name.c_str(), dp->d_name);
if (ReadDtFile(file_name, &value)) {
if (value != "okay" && value != "ok") {
LINFO << "dt_fstab: Skip disabled entry for partition " << dp->d_name;
continue;
}
}
file_name = android::base::StringPrintf("%s/%s/dev", fstabdir_name.c_str(), dp->d_name);
if (!ReadDtFile(file_name, &value)) {
LERROR << "dt_fstab: Failed to find device for partition " << dp->d_name;
return {};
}
fstab_entry.push_back(value);
std::string mount_point;
file_name =
android::base::StringPrintf("%s/%s/mnt_point", fstabdir_name.c_str(), dp->d_name);
if (ReadDtFile(file_name, &value)) {
LINFO << "dt_fstab: Using a specified mount point " << value << " for " << dp->d_name;
mount_point = value;
} else {
mount_point = android::base::StringPrintf("/%s", dp->d_name);
}
fstab_entry.push_back(mount_point);
file_name = android::base::StringPrintf("%s/%s/type", fstabdir_name.c_str(), dp->d_name);
if (!ReadDtFile(file_name, &value)) {
LERROR << "dt_fstab: Failed to find type for partition " << dp->d_name;
return {};
}
fstab_entry.push_back(value);
file_name = android::base::StringPrintf("%s/%s/mnt_flags", fstabdir_name.c_str(), dp->d_name);
if (!ReadDtFile(file_name, &value)) {
LERROR << "dt_fstab: Failed to find type for partition " << dp->d_name;
return {};
}
fstab_entry.push_back(value);
file_name = android::base::StringPrintf("%s/%s/fsmgr_flags", fstabdir_name.c_str(), dp->d_name);
if (!ReadDtFile(file_name, &value)) {
LERROR << "dt_fstab: Failed to find type for partition " << dp->d_name;
return {};
}
fstab_entry.push_back(value);
// Adds a fstab_entry to fstab_dt_entries, to be sorted by mount_point later.
fstab_dt_entries.emplace_back(mount_point, android::base::Join(fstab_entry, " "));
}
// Sort fstab_dt entries, to ensure /vendor is mounted before /vendor/abc is attempted.
std::sort(fstab_dt_entries.begin(), fstab_dt_entries.end(),
[](const auto& a, const auto& b) { return a.first < b.first; });
std::string fstab_result;
for (const auto& [_, dt_entry] : fstab_dt_entries) {
fstab_result += dt_entry + "\n";
}
return fstab_result;
}
// Identify path to fstab file. Lookup is based on pattern fstab.<hardware>,
// fstab.<hardware.platform> in folders /odm/etc, vendor/etc, or /.
std::string GetFstabPath() {
for (const char* prop : {"hardware", "hardware.platform"}) {
std::string hw;
if (!fs_mgr_get_boot_config(prop, &hw)) continue;
for (const char* prefix : {"/odm/etc/fstab.", "/vendor/etc/fstab.", "/fstab."}) {
std::string fstab_path = prefix + hw;
if (access(fstab_path.c_str(), F_OK) == 0) {
return fstab_path;
}
}
}
return "";
}
bool ReadFstabFile(FILE* fstab_file, bool proc_mounts, Fstab* fstab_out) {
ssize_t len;
size_t alloc_len = 0;
char *line = NULL;
const char *delim = " \t";
char *save_ptr, *p;
Fstab fstab;
while ((len = getline(&line, &alloc_len, fstab_file)) != -1) {
/* if the last character is a newline, shorten the string by 1 byte */
if (line[len - 1] == '\n') {
line[len - 1] = '\0';
}
/* Skip any leading whitespace */
p = line;
while (isspace(*p)) {
p++;
}
/* ignore comments or empty lines */
if (*p == '#' || *p == '\0')
continue;
FstabEntry entry;
if (!(p = strtok_r(line, delim, &save_ptr))) {
LERROR << "Error parsing mount source";
goto err;
}
entry.blk_device = p;
if (!(p = strtok_r(NULL, delim, &save_ptr))) {
LERROR << "Error parsing mount_point";
goto err;
}
entry.mount_point = p;
if (!(p = strtok_r(NULL, delim, &save_ptr))) {
LERROR << "Error parsing fs_type";
goto err;
}
entry.fs_type = p;
if (!(p = strtok_r(NULL, delim, &save_ptr))) {
LERROR << "Error parsing mount_flags";
goto err;
}
ParseMountFlags(p, &entry);
// For /proc/mounts, ignore everything after mnt_freq and mnt_passno
if (proc_mounts) {
p += strlen(p);
} else if (!(p = strtok_r(NULL, delim, &save_ptr))) {
LERROR << "Error parsing fs_mgr_options";
goto err;
}
ParseFsMgrFlags(p, &entry);
if (entry.fs_mgr_flags.logical) {
entry.logical_partition_name = entry.blk_device;
}
fstab.emplace_back(std::move(entry));
}
if (fstab.empty()) {
LERROR << "No entries found in fstab";
goto err;
}
/* If an A/B partition, modify block device to be the real block device */
if (!fs_mgr_update_for_slotselect(&fstab)) {
LERROR << "Error updating for slotselect";
goto err;
}
free(line);
*fstab_out = std::move(fstab);
return true;
err:
free(line);
return false;
}
/* Extracts <device>s from the by-name symlinks specified in a fstab:
* /dev/block/<type>/<device>/by-name/<partition>
*
* <type> can be: platform, pci or vbd.
*
* For example, given the following entries in the input fstab:
* /dev/block/platform/soc/1da4000.ufshc/by-name/system
* /dev/block/pci/soc.0/f9824900.sdhci/by-name/vendor
* it returns a set { "soc/1da4000.ufshc", "soc.0/f9824900.sdhci" }.
*/
std::set<std::string> ExtraBootDevices(const Fstab& fstab) {
std::set<std::string> boot_devices;
for (const auto& entry : fstab) {
std::string blk_device = entry.blk_device;
// Skips blk_device that doesn't conform to the format.
if (!android::base::StartsWith(blk_device, "/dev/block") ||
android::base::StartsWith(blk_device, "/dev/block/by-name") ||
android::base::StartsWith(blk_device, "/dev/block/bootdevice/by-name")) {
continue;
}
// Skips non-by_name blk_device.
// /dev/block/<type>/<device>/by-name/<partition>
// ^ slash_by_name
auto slash_by_name = blk_device.find("/by-name");
if (slash_by_name == std::string::npos) continue;
blk_device.erase(slash_by_name); // erases /by-name/<partition>
// Erases /dev/block/, now we have <type>/<device>
blk_device.erase(0, std::string("/dev/block/").size());
// <type>/<device>
// ^ first_slash
auto first_slash = blk_device.find('/');
if (first_slash == std::string::npos) continue;
auto boot_device = blk_device.substr(first_slash + 1);
if (!boot_device.empty()) boot_devices.insert(std::move(boot_device));
}
return boot_devices;
}
FstabEntry BuildGsiUserdataFstabEntry() {
constexpr uint32_t kFlags = MS_NOATIME | MS_NOSUID | MS_NODEV;
FstabEntry userdata = {
.blk_device = "userdata_gsi",
.mount_point = "/data",
.fs_type = "ext4",
.flags = kFlags,
.reserved_size = 128 * 1024 * 1024,
};
userdata.fs_mgr_flags.wait = true;
userdata.fs_mgr_flags.check = true;
userdata.fs_mgr_flags.logical = true;
userdata.fs_mgr_flags.quota = true;
userdata.fs_mgr_flags.late_mount = true;
userdata.fs_mgr_flags.formattable = true;
return userdata;
}
bool EraseFstabEntry(Fstab* fstab, const std::string& mount_point) {
auto iter = std::remove_if(fstab->begin(), fstab->end(),
[&](const auto& entry) { return entry.mount_point == mount_point; });
if (iter != fstab->end()) {
fstab->erase(iter, fstab->end());
return true;
}
return false;
}
void TransformFstabForGsi(Fstab* fstab) {
// Inherit fstab properties for userdata.
FstabEntry userdata;
if (FstabEntry* entry = GetEntryForMountPoint(fstab, "/data")) {
userdata = *entry;
userdata.blk_device = "userdata_gsi";
userdata.fs_mgr_flags.logical = true;
userdata.fs_mgr_flags.formattable = true;
if (!userdata.key_dir.empty()) {
userdata.key_dir += "/gsi";
}
} else {
userdata = BuildGsiUserdataFstabEntry();
}
if (EraseFstabEntry(fstab, "/system")) {
fstab->emplace_back(BuildGsiSystemFstabEntry());
}
if (EraseFstabEntry(fstab, "/data")) {
fstab->emplace_back(userdata);
}
}
} // namespace
bool ReadFstabFromFile(const std::string& path, Fstab* fstab) {
auto fstab_file = std::unique_ptr<FILE, decltype(&fclose)>{fopen(path.c_str(), "re"), fclose};
if (!fstab_file) {
PERROR << __FUNCTION__ << "(): cannot open file: '" << path << "'";
return false;
}
bool is_proc_mounts = path == "/proc/mounts";
if (!ReadFstabFile(fstab_file.get(), is_proc_mounts, fstab)) {
LERROR << __FUNCTION__ << "(): failed to load fstab from : '" << path << "'";
return false;
}
if (!is_proc_mounts && !access(android::gsi::kGsiBootedIndicatorFile, F_OK)) {
TransformFstabForGsi(fstab);
}
return true;
}
// Returns fstab entries parsed from the device tree if they exist
bool ReadFstabFromDt(Fstab* fstab, bool log) {
std::string fstab_buf = ReadFstabFromDt();
if (fstab_buf.empty()) {
if (log) LINFO << __FUNCTION__ << "(): failed to read fstab from dt";
return false;
}
std::unique_ptr<FILE, decltype(&fclose)> fstab_file(
fmemopen(static_cast<void*>(const_cast<char*>(fstab_buf.c_str())),
fstab_buf.length(), "r"), fclose);
if (!fstab_file) {
if (log) PERROR << __FUNCTION__ << "(): failed to create a file stream for fstab dt";
return false;
}
if (!ReadFstabFile(fstab_file.get(), false, fstab)) {
if (log) {
LERROR << __FUNCTION__ << "(): failed to load fstab from kernel:" << std::endl
<< fstab_buf;
}
return false;
}
return true;
}
// Loads the fstab file and combines with fstab entries passed in from device tree.
bool ReadDefaultFstab(Fstab* fstab) {
Fstab dt_fstab;
ReadFstabFromDt(&dt_fstab, false);
*fstab = std::move(dt_fstab);
std::string default_fstab_path;
// Use different fstab paths for normal boot and recovery boot, respectively
if (access("/system/bin/recovery", F_OK) == 0) {
default_fstab_path = "/etc/recovery.fstab";
} else { // normal boot
default_fstab_path = GetFstabPath();
}
Fstab default_fstab;
if (!default_fstab_path.empty()) {
ReadFstabFromFile(default_fstab_path, &default_fstab);
} else {
LINFO << __FUNCTION__ << "(): failed to find device default fstab";
}
for (auto&& entry : default_fstab) {
fstab->emplace_back(std::move(entry));
}
return !fstab->empty();
}
FstabEntry* GetEntryForMountPoint(Fstab* fstab, const std::string& path) {
if (fstab == nullptr) {
return nullptr;
}
for (auto& entry : *fstab) {
if (entry.mount_point == path) {
return &entry;
}
}
return nullptr;
}
std::set<std::string> GetBootDevices() {
// First check the kernel commandline, then try the device tree otherwise
std::string dt_file_name = get_android_dt_dir() + "/boot_devices";
std::string value;
if (fs_mgr_get_boot_config_from_kernel_cmdline("boot_devices", &value) ||
ReadDtFile(dt_file_name, &value)) {
auto boot_devices = Split(value, ",");
return std::set<std::string>(boot_devices.begin(), boot_devices.end());
}
// Fallback to extract boot devices from fstab.
Fstab fstab;
if (!ReadDefaultFstab(&fstab)) {
return {};
}
return ExtraBootDevices(fstab);
}
FstabEntry BuildGsiSystemFstabEntry() {
// .logical_partition_name is required to look up AVB Hashtree descriptors.
FstabEntry system = {
.blk_device = "system_gsi",
.mount_point = "/system",
.fs_type = "ext4",
.flags = MS_RDONLY,
.fs_options = "barrier=1",
// could add more keys separated by ':'.
.avb_keys = "/avb/q-gsi.avbpubkey:/avb/r-gsi.avbpubkey:/avb/s-gsi.avbpubkey",
.logical_partition_name = "system"};
system.fs_mgr_flags.wait = true;
system.fs_mgr_flags.logical = true;
system.fs_mgr_flags.first_stage_mount = true;
return system;
}
std::string GetVerityDeviceName(const FstabEntry& entry) {
std::string base_device;
if (entry.mount_point == "/") {
// In AVB, the dm device name is vroot instead of system.
base_device = entry.fs_mgr_flags.avb ? "vroot" : "system";
} else {
base_device = android::base::Basename(entry.mount_point);
}
return base_device + "-verity";
}
} // namespace fs_mgr
} // namespace android
// FIXME: The same logic is duplicated in system/core/init/
const std::string& get_android_dt_dir() {
// Set once and saves time for subsequent calls to this function
static const std::string kAndroidDtDir = android::fs_mgr::InitAndroidDtDir();
return kAndroidDtDir;
}
bool is_dt_compatible() {
std::string file_name = get_android_dt_dir() + "/compatible";
std::string dt_value;
if (android::fs_mgr::ReadDtFile(file_name, &dt_value)) {
if (dt_value == "android,firmware") {
return true;
}
}
return false;
}