Gave the GetOriginBoundCertificate an asynchronous interface because certificate

net/base/origin_bound_cert_service.cc

 // Copyright (c) 2011 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 "net/base/origin_bound_cert_service.h"
 
 #include <limits>
 
+#include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/message_loop.h"
 #include "base/rand_util.h"
+#include "base/stl_util.h"
+#include "base/threading/worker_pool.h"
 #include "crypto/rsa_private_key.h"
+#include "net/base/net_errors.h"
 #include "net/base/origin_bound_cert_store.h"
 #include "net/base/x509_certificate.h"
 
+#if defined(USE_NSS)
+#include <private/pprthred.h>  // PR_DetachThread
+#endif
+
 namespace net {
 
 namespace {
 
 const int kKeySizeInBits = 1024;
 const int kValidityPeriodInDays = 365;
 
 }  // namespace
 
+// Represents the output and result callback of a request.
+class OriginBoundCertServiceRequest {
+ public:
+  OriginBoundCertServiceRequest(CompletionCallback* callback,
+                                std::string* private_key,
+                                std::string* cert)
+      : callback_(callback),
+        private_key_(private_key),
+        cert_(cert) {
+  }
+
+  // Ensures that the result callback will never be made.
+  void Cancel() {
+    callback_ = NULL;
+    private_key_ = NULL;
+    cert_ = NULL;
+  }
+
+  // Copies the contents of |private_key| and |cert| to the caller's fields
+  // and calls the callback.
+  void Post(int error,
+            const std::string& private_key,
+            const std::string& cert) {
+    if (callback_) {
+      *private_key_ = private_key;
+      *cert_ = cert;
+      callback_->Run(error);
+    }
+    delete this;
+  }
+
+  bool canceled() const { return !callback_; }
+
+ private:
+  CompletionCallback* callback_;
+  std::string* private_key_;
+  std::string* cert_;
+};
+
+// OriginBoundCertServiceWorker runs on a worker thread and takes care of the
+// blocking process of performing key generation. Deletes itself eventually
+// if Start() succeeds.
+class OriginBoundCertServiceWorker {
+ public:
+  OriginBoundCertServiceWorker(
+      const std::string& origin,
+      OriginBoundCertService* origin_bound_cert_service)
+      : origin_(origin),
+        origin_loop_(MessageLoop::current()),
+        origin_bound_cert_service_(origin_bound_cert_service),
+        canceled_(false),
+        error_(ERR_FAILED) {
+  }
+
+  bool Start() {
+    DCHECK_EQ(MessageLoop::current(), origin_loop_);
+
+    return base::WorkerPool::PostTask(
+        FROM_HERE,
+        NewRunnableMethod(this, &OriginBoundCertServiceWorker::Run),
+        true /* task is slow */);
+  }
+
+  // Cancel is called from the origin loop when the OriginBoundCertService is
+  // getting deleted.
+  void Cancel() {
+    DCHECK_EQ(MessageLoop::current(), origin_loop_);
+    base::AutoLock locked(lock_);
+    canceled_ = true;
+  }
+
+ private:
+  void Run() {
+    uint32 serial_number = base::RandInt(0, std::numeric_limits<int>::max());
+    // Runs on a worker thread.
+    error_ = origin_bound_cert_service_->GenerateCert(origin_,
+                                                      serial_number,
+                                                      &private_key_,
+                                                      &cert_);
+#if defined(USE_NSS)
+    // Detach the thread from NSPR.
+    // Calling NSS functions attaches the thread to NSPR, which stores
+    // the NSPR thread ID in thread-specific data.
+    // The threads in our thread pool terminate after we have called
+    // PR_Cleanup.  Unless we detach them from NSPR, net_unittests gets
+    // segfaults on shutdown when the threads' thread-specific data
+    // destructors run.
+    PR_DetachThread();
+#endif
+    Finish();
+  }
+
+  // DoReply runs on the origin thread.
+  void DoReply() {
+    DCHECK_EQ(MessageLoop::current(), origin_loop_);
+    {
+      // We lock here because the worker thread could still be in Finished,
+      // after the PostTask, but before unlocking |lock_|. If we do not lock in
+      // this case, we will end up deleting a locked Lock, which can lead to
+      // memory leaks or worse errors.
+      base::AutoLock locked(lock_);
+      if (!canceled_) {
+        origin_bound_cert_service_->HandleResult(
+            origin_, error_, private_key_, cert_);
+      }
+    }
+    delete this;
+  }
+
+  void Finish() {
+    // Runs on the worker thread.
+    // We assume that the origin loop outlives the OriginBoundCertService. If
+    // the OriginBoundCertService is deleted, it will call Cancel on us. If it
+    // does so before the Acquire, we'll delete ourselves and return. If it's
+    // trying to do so concurrently, then it'll block on the lock and we'll
+    // call PostTask while the OriginBoundCertService (and therefore the
+    // MessageLoop) is still alive. If it does so after this function, we
+    // assume that the MessageLoop will process pending tasks. In which case
+    // we'll notice the |canceled_| flag in DoReply.
+
+    bool canceled;
+    {
+      base::AutoLock locked(lock_);
+      canceled = canceled_;
+      if (!canceled) {
+        origin_loop_->PostTask(
+            FROM_HERE,
+            NewRunnableMethod(this, &OriginBoundCertServiceWorker::DoReply));
+      }
+    }
+    if (canceled)
+      delete this;
+  }
+
+  const std::string origin_;
+  MessageLoop* const origin_loop_;
+  OriginBoundCertService* const origin_bound_cert_service_;
+
+  // lock_ protects canceled_.
+  base::Lock lock_;
+
+  // If canceled_ is true,
+  // * origin_loop_ cannot be accessed by the worker thread,
+  // * origin_bound_cert_service_ cannot be accessed by any thread.
+  bool canceled_;
+
+  int error_;
+  std::string private_key_;
+  std::string cert_;
+
+  DISALLOW_COPY_AND_ASSIGN(OriginBoundCertServiceWorker);
+};
+
+// An OriginBoundCertServiceJob is a one-to-one counterpart of an
+// OriginBoundCertServiceWorker. It lives only on the OriginBoundCertService's
+// origin message loop.
+class OriginBoundCertServiceJob {
+ public:
+  explicit OriginBoundCertServiceJob(OriginBoundCertServiceWorker* worker)
+      : worker_(worker) {
+  }
+
+  ~OriginBoundCertServiceJob() {
+    if (worker_) {
+      worker_->Cancel();
+      DeleteAllCanceled();
+    }
+  }
+
+  void AddRequest(OriginBoundCertServiceRequest* request) {
+    requests_.push_back(request);
+  }
+
+  void HandleResult(int error,
+                    const std::string& private_key,
+                    const std::string& cert) {
+    worker_ = NULL;
+    PostAll(error, private_key, cert);
+  }
+
+ private:
+  void PostAll(int error,
+               const std::string& private_key,
+               const std::string& cert) {
+    std::vector<OriginBoundCertServiceRequest*> requests;
+    requests_.swap(requests);
+
+    for (std::vector<OriginBoundCertServiceRequest*>::iterator
+         i = requests.begin(); i != requests.end(); i++) {
+      (*i)->Post(error, private_key, cert);
+      // Post() causes the OriginBoundCertServiceRequest to delete itself.
+    }
+  }
+
+  void DeleteAllCanceled() {
+    for (std::vector<OriginBoundCertServiceRequest*>::iterator
+         i = requests_.begin(); i != requests_.end(); i++) {
+      if ((*i)->canceled()) {
+        delete *i;
+      } else {
+        LOG(DFATAL) << "OriginBoundCertServiceRequest leaked!";
+      }
+    }
+  }
+
+  std::vector<OriginBoundCertServiceRequest*> requests_;
+  OriginBoundCertServiceWorker* worker_;
+};
+
 OriginBoundCertService::OriginBoundCertService(
     OriginBoundCertStore* origin_bound_cert_store)
-    : origin_bound_cert_store_(origin_bound_cert_store) {}
-
-OriginBoundCertService::~OriginBoundCertService() {}
-
-bool OriginBoundCertService::GetOriginBoundCert(const std::string& origin,
-                                                std::string* private_key_result,
-                                                std::string* cert_result) {
-  // Check if origin bound cert already exists for this origin.
+    : origin_bound_cert_store_(origin_bound_cert_store),
+      requests_(0),
+      cache_hits_(0),
+      inflight_joins_(0) {}
+
+OriginBoundCertService::~OriginBoundCertService() {
+  STLDeleteValues(&inflight_);
+}
+
+int OriginBoundCertService::GetOriginBoundCert(const std::string& origin,
+                                               std::string* private_key,
+                                               std::string* cert,
+                                               CompletionCallback* callback,
+                                               RequestHandle* out_req) {
+
+  DCHECK(CalledOnValidThread());
+
+  if (!callback || !private_key || !cert || origin.empty()) {
+    *out_req = NULL;
+    return ERR_INVALID_ARGUMENT;
+  }
+
+  requests_++;
+
+  // Check if an origin bound cert already exists for this origin.
   if (origin_bound_cert_store_->GetOriginBoundCert(origin,
-                                                   private_key_result,
-                                                   cert_result))
-    return true;
-
-  // No origin bound cert exists, we have to create one.
+                                                   private_key,
+                                                   cert)) {
+    cache_hits_++;
+    *out_req = NULL;
+    return OK;
+  }
+
+  // No cache hit. See if an identical request is currently in flight.
+  OriginBoundCertServiceJob* job;
+  std::map<std::string, OriginBoundCertServiceJob*>::const_iterator j;
+  j = inflight_.find(origin);
+  if (j != inflight_.end()) {
+    // An identical request is in flight already. We'll just attach our
+    // callback.
+    inflight_joins_++;
+    job = j->second;
+  } else {
+    // Need to make a new request.
+    OriginBoundCertServiceWorker* worker =
+      new OriginBoundCertServiceWorker(origin, this);
+    job = new OriginBoundCertServiceJob(worker);
+    if (!worker->Start()) {
+      delete job;
+      delete worker;
+      *out_req = NULL;
+      // TODO(rkn): Log to the NetLog.
+      LOG(ERROR) << "OriginBoundCertServiceWorker couldn't be started.";
+      return ERR_INSUFFICIENT_RESOURCES;  // Just a guess.
+    }
+    inflight_[origin] = job;
+  }
+
+  OriginBoundCertServiceRequest* request =
+      new OriginBoundCertServiceRequest(callback, private_key, cert);
+  job->AddRequest(request);
+  *out_req = request;
+  return ERR_IO_PENDING;
+}
+
+int OriginBoundCertService::GenerateCert(const std::string& origin,
+                                         uint32 serial_number,
+                                         std::string* private_key,
+                                         std::string* cert) {
   std::string subject = "CN=OBC";
   scoped_ptr<crypto::RSAPrivateKey> key(
       crypto::RSAPrivateKey::Create(kKeySizeInBits));
   if (!key.get()) {
     LOG(WARNING) << "Unable to create key pair for client";
-    return false;
-  }
+    return ERR_FAILED;
+  }
+
   scoped_refptr<X509Certificate> x509_cert = X509Certificate::CreateSelfSigned(
       key.get(),
       subject,
-      base::RandInt(0, std::numeric_limits<int>::max()),
+      serial_number,
       base::TimeDelta::FromDays(kValidityPeriodInDays));
   if (!x509_cert) {
     LOG(WARNING) << "Unable to create x509 cert for client";
-    return false;
+    return ERR_FAILED;
   }
 
   std::vector<uint8> private_key_info;
   if (!key->ExportPrivateKey(&private_key_info)) {
     LOG(WARNING) << "Unable to export private key";
-    return false;
+    return ERR_FAILED;
   }
   // TODO(rkn): Perhaps ExportPrivateKey should be changed to output a
   // std::string* to prevent this copying.
   std::string key_out(private_key_info.begin(), private_key_info.end());
 
   std::string der_cert;
   if (!x509_cert->GetDEREncoded(&der_cert)) {
     LOG(WARNING) << "Unable to get DER-enconded cert";
-    return false;
+    return ERR_FAILED;
   }
 
-  if (!origin_bound_cert_store_->SetOriginBoundCert(origin,
-                                                    key_out,
-                                                    der_cert)) {
-    LOG(WARNING) << "Unable to set origin bound certificate";
-    return false;
+  private_key->swap(key_out);
+  cert->swap(der_cert);
+  return OK;
+}
+
+void OriginBoundCertService::CancelRequest(RequestHandle req) {
+  DCHECK(CalledOnValidThread());
+  OriginBoundCertServiceRequest* request =
+      reinterpret_cast<OriginBoundCertServiceRequest*>(req);
+  request->Cancel();
+}
+
+// HandleResult is called by OriginBoundCertServiceWorker on the origin message
+// loop. It deletes OriginBoundCertServiceJob.
+void OriginBoundCertService::HandleResult(const std::string& origin,
+                                         int error,
+                                         const std::string& private_key,
+                                         const std::string& cert) {
+  DCHECK(CalledOnValidThread());
+
+  origin_bound_cert_store_->SetOriginBoundCert(origin, private_key, cert);
+
+  std::map<std::string, OriginBoundCertServiceJob*>::iterator j;
+  j = inflight_.find(origin);
+  if (j == inflight_.end()) {
+    NOTREACHED();
+    return;
   }
+  OriginBoundCertServiceJob* job = j->second;
+  inflight_.erase(j);
 
-  private_key_result->swap(key_out);
-  cert_result->swap(der_cert);
-  return true;
+  job->HandleResult(error, private_key, cert);
+  delete job;
 }
 
 int OriginBoundCertService::GetCertCount() {
   return origin_bound_cert_store_->GetCertCount();
 }
 
 }  // namespace net
+
+DISABLE_RUNNABLE_METHOD_REFCOUNT(net::OriginBoundCertServiceWorker);