Add locking around boot image generation.
If zygote aborts due to an error, it will restart and
spawn another dex2oat process while the old one is still
running. If this happens fast enough, the system will
eventually need a kernel reboot since neither the zygote
nor dex2oat are killable.
This brings boot image generation in line with dex2oat
generation, which uses a similar pattern of advisory
locking.
bug: 15415316
Change-Id: Iaccd274d3d96ab002b04e246ec4b3ef9a422ff7c
diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 330b110..28164cd 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -27,6 +27,7 @@
#include "base/casts.h"
#include "base/logging.h"
+#include "base/scoped_flock.h"
#include "base/stl_util.h"
#include "base/unix_file/fd_file.h"
#include "class_linker-inl.h"
@@ -701,60 +702,6 @@
return dex_file;
}
-class ScopedFlock {
- public:
- ScopedFlock() {}
-
- bool Init(const char* filename, std::string* error_msg) {
- while (true) {
- file_.reset(OS::OpenFileWithFlags(filename, O_CREAT | O_RDWR));
- if (file_.get() == NULL) {
- *error_msg = StringPrintf("Failed to open file '%s': %s", filename, strerror(errno));
- return false;
- }
- int flock_result = TEMP_FAILURE_RETRY(flock(file_->Fd(), LOCK_EX));
- if (flock_result != 0) {
- *error_msg = StringPrintf("Failed to lock file '%s': %s", filename, strerror(errno));
- return false;
- }
- struct stat fstat_stat;
- int fstat_result = TEMP_FAILURE_RETRY(fstat(file_->Fd(), &fstat_stat));
- if (fstat_result != 0) {
- *error_msg = StringPrintf("Failed to fstat file '%s': %s", filename, strerror(errno));
- return false;
- }
- struct stat stat_stat;
- int stat_result = TEMP_FAILURE_RETRY(stat(filename, &stat_stat));
- if (stat_result != 0) {
- PLOG(WARNING) << "Failed to stat, will retry: " << filename;
- // ENOENT can happen if someone racing with us unlinks the file we created so just retry.
- continue;
- }
- if (fstat_stat.st_dev != stat_stat.st_dev || fstat_stat.st_ino != stat_stat.st_ino) {
- LOG(WARNING) << "File changed while locking, will retry: " << filename;
- continue;
- }
- return true;
- }
- }
-
- File& GetFile() {
- return *file_;
- }
-
- ~ScopedFlock() {
- if (file_.get() != NULL) {
- int flock_result = TEMP_FAILURE_RETRY(flock(file_->Fd(), LOCK_UN));
- CHECK_EQ(0, flock_result);
- }
- }
-
- private:
- std::unique_ptr<File> file_;
-
- DISALLOW_COPY_AND_ASSIGN(ScopedFlock);
-};
-
const DexFile* ClassLinker::FindOrCreateOatFileForDexLocation(
const char* dex_location,
uint32_t dex_location_checksum,
@@ -785,7 +732,7 @@
// Generate the output oat file for the dex file
VLOG(class_linker) << "Generating oat file " << oat_location << " for " << dex_location;
- if (!GenerateOatFile(dex_location, scoped_flock.GetFile().Fd(), oat_location, &error_msg)) {
+ if (!GenerateOatFile(dex_location, scoped_flock.GetFile()->Fd(), oat_location, &error_msg)) {
CHECK(!error_msg.empty());
error_msgs->push_back(error_msg);
return nullptr;