use a single file for storing persistent properties
We have seen that storing persistent properties in separate files
causes increased boot latency compared to if they were stored in a
single contiguous file.
This change creates a simple format for a contiguously stored property
file, and adds the support for arbitrary characters in the names of
persistent properties, which previously had been restricted. It has a
mechanism for converting older devices to the new format as well.
Bug: 64392887
Test: boot bullhead with new properties
Test: boot bullhead and verify old properties are converted to the new
property file
Test: corrupt property file and ensure that it gets recovered from memory
Test: new unit tests
Change-Id: I60d8201d655ce5c97b33faae81d5ca8dbbb21a14
diff --git a/init/property_service.cpp b/init/property_service.cpp
index f0e4d2e..8c592cb 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -17,7 +17,6 @@
#include "property_service.h"
#include <ctype.h>
-#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
@@ -54,17 +53,17 @@
#include <selinux/selinux.h>
#include "init.h"
+#include "persistent_properties.h"
#include "util.h"
using android::base::Timer;
-#define PERSISTENT_PROPERTY_DIR "/data/property"
#define RECOVERY_MOUNT_POINT "/recovery"
namespace android {
namespace init {
-static int persistent_properties_loaded = 0;
+static bool persistent_properties_loaded = false;
static int property_set_fd = -1;
@@ -120,29 +119,6 @@
return check_mac_perms(ctl_name, sctx, cr);
}
-static void write_persistent_property(const char *name, const char *value)
-{
- char tempPath[PATH_MAX];
- char path[PATH_MAX];
- int fd;
-
- snprintf(tempPath, sizeof(tempPath), "%s/.temp.XXXXXX", PERSISTENT_PROPERTY_DIR);
- fd = mkstemp(tempPath);
- if (fd < 0) {
- PLOG(ERROR) << "Unable to write persistent property to temp file " << tempPath;
- return;
- }
- write(fd, value, strlen(value));
- fsync(fd);
- close(fd);
-
- snprintf(path, sizeof(path), "%s/%s", PERSISTENT_PROPERTY_DIR, name);
- if (rename(tempPath, path)) {
- PLOG(ERROR) << "Unable to rename persistent property file " << tempPath << " to " << path;
- unlink(tempPath);
- }
-}
-
bool is_legal_property_name(const std::string& name) {
size_t namelen = name.size();
@@ -204,7 +180,7 @@
// Don't write properties to disk until after we have read all default
// properties to prevent them from being overwritten by default values.
if (persistent_properties_loaded && android::base::StartsWith(name, "persist.")) {
- write_persistent_property(name.c_str(), value.c_str());
+ WritePersistentProperty(name, value);
}
property_changed(name, value);
return PROP_SUCCESS;
@@ -599,61 +575,6 @@
LOG(VERBOSE) << "(Loading properties from " << filename << " took " << t << ".)";
}
-static void load_persistent_properties() {
- persistent_properties_loaded = 1;
-
- std::unique_ptr<DIR, int(*)(DIR*)> dir(opendir(PERSISTENT_PROPERTY_DIR), closedir);
- if (!dir) {
- PLOG(ERROR) << "Unable to open persistent property directory \""
- << PERSISTENT_PROPERTY_DIR << "\"";
- return;
- }
-
- struct dirent* entry;
- while ((entry = readdir(dir.get())) != NULL) {
- if (strncmp("persist.", entry->d_name, strlen("persist."))) {
- continue;
- }
- if (entry->d_type != DT_REG) {
- continue;
- }
-
- // Open the file and read the property value.
- int fd = openat(dirfd(dir.get()), entry->d_name, O_RDONLY | O_NOFOLLOW);
- if (fd == -1) {
- PLOG(ERROR) << "Unable to open persistent property file \"" << entry->d_name << "\"";
- continue;
- }
-
- struct stat sb;
- if (fstat(fd, &sb) == -1) {
- PLOG(ERROR) << "fstat on property file \"" << entry->d_name << "\" failed";
- close(fd);
- continue;
- }
-
- // File must not be accessible to others, be owned by root/root, and
- // not be a hard link to any other file.
- if (((sb.st_mode & (S_IRWXG | S_IRWXO)) != 0) || sb.st_uid != 0 || sb.st_gid != 0 || sb.st_nlink != 1) {
- PLOG(ERROR) << "skipping insecure property file " << entry->d_name
- << " (uid=" << sb.st_uid << " gid=" << sb.st_gid
- << " nlink=" << sb.st_nlink << " mode=" << std::oct << sb.st_mode << ")";
- close(fd);
- continue;
- }
-
- char value[PROP_VALUE_MAX];
- int length = read(fd, value, sizeof(value) - 1);
- if (length >= 0) {
- value[length] = 0;
- property_set(entry->d_name, value);
- } else {
- PLOG(ERROR) << "Unable to read persistent property file " << entry->d_name;
- }
- close(fd);
- }
-}
-
// persist.sys.usb.config values can't be combined on build-time when property
// files are split into each partition.
// So we need to apply the same rule of build/make/tools/post_process_props.py
@@ -703,7 +624,11 @@
load_override_properties();
/* Read persistent properties after all default values have been loaded. */
- load_persistent_properties();
+ auto persistent_properties = LoadPersistentProperties();
+ for (const auto& [name, value] : persistent_properties) {
+ property_set(name, value);
+ }
+ persistent_properties_loaded = true;
property_set("ro.persistent_properties.ready", "true");
}