Adding crash utilities to chromecast/crash.

chromecast/crash/linux/synchronized_minidump_manager.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chromecast/crash/linux/synchronized_minidump_manager.h"
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <string.h>
+#include <sys/file.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <fstream>
+
+#include "base/logging.h"
+#include "chromecast/base/path_utils.h"
+#include "chromecast/crash/linux/dump_info.h"
+
+namespace chromecast {
+
+namespace {
+
+const mode_t kDirMode = 0770;
+const mode_t kFileMode = 0660;
+const char kLockfileName[] = "lockfile";
+const char kMinidumpsDir[] = "minidumps";
+
+}  // namespace
+
+SynchronizedMinidumpManager::SynchronizedMinidumpManager()
+    : non_blocking_(false), lockfile_fd_(-1) {
+  dump_path_ = GetHomePathASCII(kMinidumpsDir);
+  lockfile_path_ = dump_path_.Append(kLockfileName).value();
+}
+
+SynchronizedMinidumpManager::~SynchronizedMinidumpManager() {
+  // Release the lock if held.
+  ReleaseLockFile();
+}
+
+// TODO(slan): Move some of this pruning logic to ReleaseLockFile?
+int SynchronizedMinidumpManager::GetNumDumps(bool delete_all_dumps) {
+  DIR* dirp;
+  struct dirent* dptr;
+  int num_dumps = 0;
+
+  // folder does not exist
+  dirp = opendir(dump_path_.value().c_str());
+  if (dirp == NULL) {
+    LOG(ERROR) << "Unable to open directory " << dump_path_.value();
+    return 0;
+  }
+
+  while ((dptr = readdir(dirp)) != NULL) {
+    struct stat buf;
+    const std::string file_fullname = dump_path_.value() + "/" + dptr->d_name;
+    if (lstat(file_fullname.c_str(), &buf) == -1 || !S_ISREG(buf.st_mode)) {
+      // if we cannot lstat this file, it is probably bad, so skip
+      // if the file is not regular, skip
+      continue;
+    }
+    // 'lockfile' is not counted
+    if (lockfile_path_ != file_fullname) {
+      ++num_dumps;
+      if (delete_all_dumps) {
+        LOG(INFO) << "Removing " << dptr->d_name
+                  << "which was not in the lockfile";
+        if (remove(file_fullname.c_str()) < 0) {
+          LOG(INFO) << "remove failed. error " << strerror(errno);
+        }
+      }
+    }
+  }
+
+  closedir(dirp);
+  return num_dumps;
+}
+
+int SynchronizedMinidumpManager::AcquireLockAndDoWork() {
+  int success = -1;
+  if (AcquireLockFile() >= 0) {
+    success = DoWork();
+    ReleaseLockFile();
+  }
+  return success;
+}
+
+const ScopedVector<DumpInfo>& SynchronizedMinidumpManager::GetDumpMetadata() {
+  DCHECK_GE(lockfile_fd_, 0);
+  if (!dump_metadata_)
+    ParseLockFile();
+  return *dump_metadata_;
+}
+
+int SynchronizedMinidumpManager::AcquireLockFile() {
+  DCHECK_LT(lockfile_fd_, 0);
+  // Make the directory for the minidumps if it does not exist.
+  if (mkdir(dump_path_.value().c_str(), kDirMode) < 0 && errno != EEXIST) {
+    LOG(ERROR) << "mkdir for " << dump_path_.value().c_str()
+               << " failed. error = " << strerror(errno);
+    return -1;
+  }
+
+  // Open the lockfile. Create it if it does not exist.
+  lockfile_fd_ = open(lockfile_path_.c_str(), O_RDWR | O_CREAT, kFileMode);
+
+  // If opening or creating the lockfile failed, we don't want to proceed
+  // with dump writing for fear of exhausting up system resources.
+  if (lockfile_fd_ < 0) {
+    LOG(ERROR) << "open lockfile failed " << lockfile_path_;
+    return -1;
+  }
+
+  // Acquire the lock on the file. Whether or not we are in non-blocking mode,
+  // flock failure means that we did not acquire it and this method should fail.
+  int operation_mode = non_blocking_ ? (LOCK_EX | LOCK_NB) : LOCK_EX;
+  if (flock(lockfile_fd_, operation_mode) < 0) {
+    ReleaseLockFile();
+    LOG(INFO) << "flock lockfile failed, error = " << strerror(errno);
+    return -1;
+  }
+
+  // The lockfile is open and locked. Parse it to provide subclasses with a
+  // record of all the current dumps.
+  if (ParseLockFile() < 0) {
+    LOG(ERROR) << "Lockfile did not parse correctly. ";
+    return -1;
+  }
+
+  // We successfully have acquired the lock.
+  return 0;
+}
+
+int SynchronizedMinidumpManager::ParseLockFile() {
+  DCHECK_GE(lockfile_fd_, 0);
+  DCHECK(!dump_metadata_);
+
+  scoped_ptr<ScopedVector<DumpInfo> > dumps(new ScopedVector<DumpInfo>());
+  std::string entry;
+
+  // Instead of using |lockfile_fd_|, use <fstream> for readability.
+  std::ifstream in(lockfile_path_);
+  if (!in.is_open()) {
+    NOTREACHED();
+    LOG(ERROR) << lockfile_path_ << " could not be opened.";
+    return -1;
+  }
+
+  // Grab each entry.
+  while (std::getline(in, entry)) {
+    scoped_ptr<DumpInfo> info(new DumpInfo(entry));
+    if (info->valid() && info->crashed_process_dump().size() > 0) {
+      dumps->push_back(info.Pass());
+    } else {
+      LOG(WARNING) << "Entry is not valid: " << entry;
+      return -1;
+    }
+  }
+
+  dump_metadata_ = dumps.Pass();
+  return 0;
+}
+
+int SynchronizedMinidumpManager::AddEntryToLockFile(const DumpInfo& dump_info) {
+  DCHECK_LE(0, lockfile_fd_);
+
+  // Make sure dump_info is valid.
+  if (!dump_info.valid()) {
+    LOG(ERROR) << "Entry to be added is invalid";
+    return -1;
+  }
+
+  // Open the file.
+  std::ofstream out(lockfile_path_, std::ios::app);
+  if (!out.is_open()) {
+    NOTREACHED() << "Lockfile would not open.";
+    return -1;
+  }
+
+  // Write the string and close the file.
+  out << dump_info.entry();
+  out.close();
+  return 0;
+}
+
+int SynchronizedMinidumpManager::RemoveEntryFromLockFile(int index) {
+  const auto& entries = GetDumpMetadata();
+  if (index < 0 || static_cast<size_t>(index) >= entries.size())
+    return -1;
+
+  // Remove the entry and write all remaining entries to file.
+  dump_metadata_->erase(dump_metadata_->begin() + index);
+  std::ofstream out(lockfile_path_);
+  for (auto info : *dump_metadata_) {
+    out << info->entry();
+  }
+  out.close();
+  return 0;
+}
+
+void SynchronizedMinidumpManager::ReleaseLockFile() {
+  // flock is associated with the fd entry in the open fd table, so closing
+  // all fd's will release the lock. To be safe, we explicitly unlock.
+  if (lockfile_fd_ >= 0) {
+    flock(lockfile_fd_, LOCK_UN);
+    close(lockfile_fd_);
+
+    // We may use this object again, so we should reset this.
+    lockfile_fd_ = -1;
+  }
+
+  dump_metadata_.reset();
+}
+
+}  // namespace chromecast