Merge "ueventd: populate /dev/block/mapper link"
am: 5c811fd01a
Change-Id: I3f080cd0cfba9456dc5f1cff478dd47845cb6b19
diff --git a/init/devices.cpp b/init/devices.cpp
index 1a77ba1..159c75e 100644
--- a/init/devices.cpp
+++ b/init/devices.cpp
@@ -21,8 +21,14 @@
#include <sys/sysmacros.h>
#include <unistd.h>
+#include <chrono>
+#include <map>
#include <memory>
+#include <string>
+#include <thread>
+#include <android-base/chrono_utils.h>
+#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
@@ -37,12 +43,16 @@
#error "Do not include init.h in files used by ueventd; it will expose init's globals"
#endif
+using namespace std::chrono_literals;
+
using android::base::Basename;
using android::base::Dirname;
+using android::base::ReadFileToString;
using android::base::Readlink;
using android::base::Realpath;
using android::base::StartsWith;
using android::base::StringPrintf;
+using android::base::Trim;
namespace android {
namespace init {
@@ -101,6 +111,31 @@
return true;
}
+// Given a path that may start with a virtual dm block device, populate
+// the supplied buffer with the dm module's instantiated name.
+// If it doesn't start with a virtual block device, or there is some
+// error, return false.
+static bool FindDmDevicePartition(const std::string& path, std::string* result) {
+ result->clear();
+ if (!StartsWith(path, "/devices/virtual/block/dm-")) return false;
+ if (getpid() == 1) return false; // first_stage_init has no sepolicy needs
+
+ static std::map<std::string, std::string> cache;
+ // wait_for_file will not work, the content is also delayed ...
+ for (android::base::Timer t; t.duration() < 200ms; std::this_thread::sleep_for(10ms)) {
+ if (ReadFileToString("/sys" + path + "/dm/name", result) && !result->empty()) {
+ // Got it, set cache with result, when node arrives
+ cache[path] = *result = Trim(*result);
+ return true;
+ }
+ }
+ auto it = cache.find(path);
+ if ((it == cache.end()) || (it->second.empty())) return false;
+ // Return cached results, when node goes away
+ *result = it->second;
+ return true;
+}
+
Permissions::Permissions(const std::string& name, mode_t perm, uid_t uid, gid_t gid)
: name_(name), perm_(perm), uid_(uid), gid_(gid), prefix_(false), wildcard_(false) {
// Set 'prefix_' or 'wildcard_' based on the below cases:
@@ -293,6 +328,7 @@
std::vector<std::string> DeviceHandler::GetBlockDeviceSymlinks(const Uevent& uevent) const {
std::string device;
std::string type;
+ std::string partition;
if (FindPlatformDevice(uevent.path, &device)) {
// Skip /devices/platform or /devices/ if present
@@ -310,6 +346,8 @@
type = "pci";
} else if (FindVbdDevicePrefix(uevent.path, &device)) {
type = "vbd";
+ } else if (FindDmDevicePartition(uevent.path, &partition)) {
+ return {"/dev/block/mapper/" + partition};
} else {
return {};
}