first stage mount: support mount points like /vendor/abc
Current syntax of the fstab in device tree (fstab_dt) assumes the
node name is the mount point, which doesn't allow subdir:
vendor { <== using "vendor/abc" leads to syntax error in device tree
compatible = "android,vendor";
dev = "/dev/block/platform/soc.0/f9824900.sdhci/by-name/vendor";
type = "ext4";
mnt_flags = "ro,barrier=1,inode_readahead_blks=8";
fsmgr_flags = "wait";
};
This CL adds a new field "mnt_point" in the fstab_dt configuration:
vendor_abc {
compatible = "android,vendor_abc";
dev = "/dev/block/platform/soc.0/f9824900.sdhci/by-name/abc";
type = "ext4";
mnt_flags = "ro,barrier=1,inode_readahead_blks=8";
mnt_point = "/vendor/abc"; <== new field
fsmgr_flags = "wait";
};
The new field is optional and will fallback to using node name as mount
point if it is absent.
Note that this CL also sorts fstab_dt by mount point, because
/vendor needs to be mounted first, which contains a directory
/vendor/abc, before /vendor/abc can be mounted.
Bug: 69955336
Test: first stage mount /vendor/abc on a device
Change-Id: Ie2e519f9801f211a7a221622f32c82bedd00353f
diff --git a/fs_mgr/Android.bp b/fs_mgr/Android.bp
index ed165ed..f23150d 100644
--- a/fs_mgr/Android.bp
+++ b/fs_mgr/Android.bp
@@ -25,6 +25,9 @@
"-Werror",
"-Wno-unused-variable",
],
+ cppflags: [
+ "-std=gnu++1z",
+ ],
}
cc_library_static {
diff --git a/fs_mgr/fs_mgr_fstab.cpp b/fs_mgr/fs_mgr_fstab.cpp
index 2c18a6d..34afed1 100644
--- a/fs_mgr/fs_mgr_fstab.cpp
+++ b/fs_mgr/fs_mgr_fstab.cpp
@@ -23,6 +23,10 @@
#include <sys/mount.h>
#include <unistd.h>
+#include <algorithm>
+#include <utility>
+#include <vector>
+
#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
@@ -397,16 +401,17 @@
}
static std::string read_fstab_from_dt() {
- std::string fstab;
if (!is_dt_compatible() || !is_dt_fstab_compatible()) {
- return fstab;
+ 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 fstab;
+ 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;
@@ -427,41 +432,54 @@
file_name = android::base::StringPrintf("%s/%s/dev", fstabdir_name.c_str(), dp->d_name);
if (!read_dt_file(file_name, &value)) {
LERROR << "dt_fstab: Failed to find device for partition " << dp->d_name;
- fstab.clear();
- break;
+ return {};
}
fstab_entry.push_back(value);
- fstab_entry.push_back(android::base::StringPrintf("/%s", dp->d_name));
+
+ std::string mount_point;
+ file_name =
+ android::base::StringPrintf("%s/%s/mnt_point", fstabdir_name.c_str(), dp->d_name);
+ if (read_dt_file(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 (!read_dt_file(file_name, &value)) {
LERROR << "dt_fstab: Failed to find type for partition " << dp->d_name;
- fstab.clear();
- break;
+ return {};
}
fstab_entry.push_back(value);
file_name = android::base::StringPrintf("%s/%s/mnt_flags", fstabdir_name.c_str(), dp->d_name);
if (!read_dt_file(file_name, &value)) {
LERROR << "dt_fstab: Failed to find type for partition " << dp->d_name;
- fstab.clear();
- break;
+ return {};
}
fstab_entry.push_back(value);
file_name = android::base::StringPrintf("%s/%s/fsmgr_flags", fstabdir_name.c_str(), dp->d_name);
if (!read_dt_file(file_name, &value)) {
LERROR << "dt_fstab: Failed to find type for partition " << dp->d_name;
- fstab.clear();
- break;
+ return {};
}
fstab_entry.push_back(value);
-
- fstab += android::base::Join(fstab_entry, " ");
- fstab += '\n';
+ // 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, " "));
}
- return fstab;
+ // 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;
}
bool is_dt_compatible() {