remount: Refactor partition filtering into helper functions.
There is a small change of behavior in this patch. If "remount"
specifies a list of arguments, and one of them is invalid, it will now
error rather than try to remount the remaining partitions.
Bug: 241179247
Test: remount
Change-Id: I7a9ef41886f32ae97173796358b41844a1e42ea8
diff --git a/fs_mgr/fs_mgr_remount.cpp b/fs_mgr/fs_mgr_remount.cpp
index 98729ec..ab17c5c 100644
--- a/fs_mgr/fs_mgr_remount.cpp
+++ b/fs_mgr/fs_mgr_remount.cpp
@@ -43,6 +43,8 @@
#include <libgsi/libgsid.h>
using namespace std::literals;
+using android::fs_mgr::Fstab;
+using android::fs_mgr::FstabEntry;
namespace {
@@ -62,22 +64,12 @@
::exit(exit_status);
}
-bool remountable_partition(const android::fs_mgr::FstabEntry& entry) {
- if (entry.fs_mgr_flags.vold_managed) return false;
- if (entry.fs_mgr_flags.recovery_only) return false;
- if (entry.fs_mgr_flags.slot_select_other) return false;
- if (!(entry.flags & MS_RDONLY)) return false;
- if (entry.fs_type == "vfat") return false;
- return true;
-}
-
const std::string system_mount_point(const android::fs_mgr::FstabEntry& entry) {
if (entry.mount_point == "/") return "/system";
return entry.mount_point;
}
-const android::fs_mgr::FstabEntry* is_wrapped(const android::fs_mgr::Fstab& overlayfs_candidates,
- const android::fs_mgr::FstabEntry& entry) {
+const FstabEntry* GetWrappedEntry(const Fstab& overlayfs_candidates, const FstabEntry& entry) {
auto mount_point = system_mount_point(entry);
auto it = std::find_if(overlayfs_candidates.begin(), overlayfs_candidates.end(),
[&mount_point](const auto& entry) {
@@ -188,6 +180,87 @@
return REMOUNT_SUCCESS;
}
+static bool IsRemountable(Fstab& candidates, const FstabEntry& entry) {
+ if (entry.fs_mgr_flags.vold_managed || entry.fs_mgr_flags.recovery_only ||
+ entry.fs_mgr_flags.slot_select_other) {
+ return false;
+ }
+ if (!(entry.flags & MS_RDONLY)) {
+ return false;
+ }
+ if (entry.fs_type == "vfat") {
+ return false;
+ }
+ if (GetEntryForMountPoint(&candidates, entry.mount_point)) {
+ return true;
+ }
+ if (GetWrappedEntry(candidates, entry)) {
+ return false;
+ }
+ return true;
+}
+
+static Fstab::const_iterator FindPartition(const Fstab& fstab, const std::string& partition) {
+ for (auto iter = fstab.begin(); iter != fstab.end(); iter++) {
+ const auto mount_point = system_mount_point(*iter);
+ if (partition == mount_point) {
+ return iter;
+ }
+ if (partition == android::base::Basename(mount_point)) {
+ return iter;
+ }
+ }
+ return fstab.end();
+}
+
+static Fstab GetAllRemountablePartitions(Fstab& fstab) {
+ auto candidates = fs_mgr_overlayfs_candidate_list(fstab);
+
+ Fstab partitions;
+ for (const auto& entry : fstab) {
+ if (IsRemountable(candidates, entry)) {
+ partitions.emplace_back(entry);
+ }
+ }
+ return partitions;
+}
+
+static RemountStatus GetRemountList(const Fstab& fstab, const std::vector<std::string>& argv,
+ Fstab* partitions) {
+ auto candidates = fs_mgr_overlayfs_candidate_list(fstab);
+
+ for (const auto& arg : argv) {
+ std::string partition = arg;
+ if (partition == "/") {
+ partition = "/system";
+ }
+
+ auto it = FindPartition(fstab, partition);
+ if (it == fstab.end()) {
+ LOG(ERROR) << "Unknown partition " << arg;
+ return UNKNOWN_PARTITION;
+ }
+
+ const FstabEntry* entry = &*it;
+ if (auto wrap = GetWrappedEntry(candidates, *entry); wrap != nullptr) {
+ LOG(INFO) << "partition " << arg << " covered by overlayfs for " << wrap->mount_point
+ << ", switching";
+ entry = wrap;
+ }
+
+ if (!IsRemountable(candidates, *entry)) {
+ LOG(ERROR) << "Invalid partition " << arg;
+ return INVALID_PARTITION;
+ }
+ if (GetEntryForMountPoint(partitions, entry->mount_point) != nullptr) {
+ continue;
+ }
+ partitions->emplace_back(*entry);
+ }
+
+ return REMOUNT_SUCCESS;
+}
+
static int do_remount(int argc, char* argv[]) {
RemountStatus retval = REMOUNT_SUCCESS;
@@ -201,6 +274,7 @@
const char* fstab_file = nullptr;
auto can_reboot = false;
+ std::vector<std::string> partition_args;
struct option longopts[] = {
{"fstab", required_argument, nullptr, 'T'},
@@ -237,6 +311,10 @@
}
}
+ for (; argc > optind; ++optind) {
+ partition_args.emplace_back(argv[optind]);
+ }
+
// Make sure we are root.
if (::getuid() != 0) {
LOG(ERROR) << "Not running as root. Try \"adb root\" first.";
@@ -244,7 +322,7 @@
}
// Read the selected fstab.
- android::fs_mgr::Fstab fstab;
+ Fstab fstab;
if (!ReadFstab(fstab_file, &fstab) || fstab.empty()) {
PLOG(ERROR) << "Failed to read fstab";
return NO_FSTAB;
@@ -254,62 +332,15 @@
return rv;
}
- // Generate the list of supported overlayfs mount points.
- auto overlayfs_candidates = fs_mgr_overlayfs_candidate_list(fstab);
-
- // Generate the all remountable partitions sub-list
- android::fs_mgr::Fstab all;
- for (auto const& entry : fstab) {
- if (!remountable_partition(entry)) continue;
- if (overlayfs_candidates.empty() ||
- GetEntryForMountPoint(&overlayfs_candidates, entry.mount_point) ||
- (is_wrapped(overlayfs_candidates, entry) == nullptr)) {
- all.emplace_back(entry);
+ Fstab partitions;
+ if (partition_args.empty()) {
+ partitions = GetAllRemountablePartitions(fstab);
+ } else {
+ if (auto rv = GetRemountList(fstab, partition_args, &partitions); rv != REMOUNT_SUCCESS) {
+ return rv;
}
}
- // Parse the unique list of valid partition arguments.
- android::fs_mgr::Fstab partitions;
- for (; argc > optind; ++optind) {
- auto partition = std::string(argv[optind]);
- if (partition.empty()) continue;
- if (partition == "/") partition = "/system";
- auto find_part = [&partition](const auto& entry) {
- const auto mount_point = system_mount_point(entry);
- if (partition == mount_point) return true;
- if (partition == android::base::Basename(mount_point)) return true;
- return false;
- };
- // Do we know about the partition?
- auto it = std::find_if(fstab.begin(), fstab.end(), find_part);
- if (it == fstab.end()) {
- LOG(ERROR) << "Unknown partition " << argv[optind] << ", skipping";
- retval = UNKNOWN_PARTITION;
- continue;
- }
- // Is that one covered by an existing overlayfs?
- auto wrap = is_wrapped(overlayfs_candidates, *it);
- if (wrap) {
- LOG(INFO) << "partition " << argv[optind] << " covered by overlayfs for "
- << wrap->mount_point << ", switching";
- partition = system_mount_point(*wrap);
- }
- // Is it a remountable partition?
- it = std::find_if(all.begin(), all.end(), find_part);
- if (it == all.end()) {
- LOG(ERROR) << "Invalid partition " << argv[optind] << ", skipping";
- retval = INVALID_PARTITION;
- continue;
- }
- if (GetEntryForMountPoint(&partitions, it->mount_point) == nullptr) {
- partitions.emplace_back(*it);
- }
- }
-
- if (partitions.empty() && !retval) {
- partitions = all;
- }
-
// Check verity and optionally setup overlayfs backing.
auto reboot_later = false;
auto user_please_reboot_later = false;