Make the Linux CrashGenerationClient an interface.

Also allow it to be set on the ExceptionHandler. This will allow Chromium's
implementation to be properly treated as an out-of-process handler.

BUG=https://code.google.com/p/chromium/issues/detail?id=349600
R=mark@chromium.org

Review URL: https://breakpad.appspot.com/2664002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1324 4c0a9323-5329-0410-9bdc-e9ce6186880e

src/client/linux/crash_generation/crash_generation_client.cc

@@ -27,37 +27,41 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+#include "client/linux/crash_generation/crash_generation_client.h"
+
 #include <stdio.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 
 #include <algorithm>
 
-#include "client/linux/crash_generation/crash_generation_client.h"
 #include "common/linux/eintr_wrapper.h"
 #include "common/linux/ignore_ret.h"
-#include "common/linux/linux_libc_support.h"
 #include "third_party/lss/linux_syscall_support.h"
 
 namespace google_breakpad {
 
-bool
-CrashGenerationClient::RequestDump(const void* blob, size_t blob_size)
-{
+namespace {
+
+class CrashGenerationClientImpl : public CrashGenerationClient {
+ public:
+  explicit CrashGenerationClientImpl(int server_fd) : server_fd_(server_fd) {}
+  virtual ~CrashGenerationClientImpl() {}
+
+  virtual bool RequestDump(const void* blob, size_t blob_size) {
     int fds[2];
-  sys_socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
+    if (sys_socketpair(AF_UNIX, SOCK_STREAM, 0, fds) < 0)
+      return false;
     static const unsigned kControlMsgSize = CMSG_SPACE(sizeof(int));
 
-  struct kernel_msghdr msg;
-  my_memset(&msg, 0, sizeof(struct kernel_msghdr));
-  struct kernel_iovec iov[1];
-  iov[0].iov_base = const_cast<void*>(blob);
-  iov[0].iov_len = blob_size;
+    struct kernel_iovec iov;
+    iov.iov_base = const_cast<void*>(blob);
+    iov.iov_len = blob_size;
 
-  msg.msg_iov = iov;
-  msg.msg_iovlen = sizeof(iov) / sizeof(iov[0]);
-  char cmsg[kControlMsgSize];
-  my_memset(cmsg, 0, kControlMsgSize);
+    struct kernel_msghdr msg = { 0 };
+    msg.msg_iov = &iov;
+    msg.msg_iovlen = 1;
+    char cmsg[kControlMsgSize] = "";
     msg.msg_control = cmsg;
     msg.msg_controllen = sizeof(cmsg);
 
@@ -70,23 +74,30 @@ CrashGenerationClient::RequestDump(const void* blob, size_t blob_size)
 
     ssize_t ret = HANDLE_EINTR(sys_sendmsg(server_fd_, &msg, 0));
     sys_close(fds[1]);
-  if (ret <= 0)
+    if (ret < 0)
       return false;
 
-  // wait for an ACK from the server
+    // Wait for an ACK from the server.
     char b;
     IGNORE_RET(HANDLE_EINTR(sys_read(fds[0], &b, 1)));
+    sys_close(fds[0]);
 
     return true;
-}
+  }
 
-//static
-CrashGenerationClient*
-CrashGenerationClient::TryCreate(int server_fd)
-{
-  if (0 > server_fd)
+ private:
+  int server_fd_;
+
+  DISALLOW_COPY_AND_ASSIGN(CrashGenerationClientImpl);
+};
+
+}  // namespace
+
+// static
+CrashGenerationClient* CrashGenerationClient::TryCreate(int server_fd) {
+  if (server_fd < 0)
     return NULL;
-  return new CrashGenerationClient(server_fd);
+  return new CrashGenerationClientImpl(server_fd);
 }
 
-}
+}  // namespace google_breakpad

src/client/linux/crash_generation/crash_generation_client.h

@@ -30,38 +30,34 @@
 #ifndef CLIENT_LINUX_CRASH_GENERATION_CRASH_GENERATION_CLIENT_H_
 #define CLIENT_LINUX_CRASH_GENERATION_CRASH_GENERATION_CLIENT_H_
 
+#include "common/basictypes.h"
+
 #include <stddef.h>
 
 namespace google_breakpad {
 
+// CrashGenerationClient is an interface for implementing out-of-process crash
+// dumping.  The default implementation, accessed via the TryCreate() factory,
+// works in conjunction with the CrashGenerationServer to generate a minidump
+// via a remote process.
 class CrashGenerationClient {
-public:
-  ~CrashGenerationClient()
-  {
-  }
+ public:
+  CrashGenerationClient() {}
+  virtual ~CrashGenerationClient() {}
 
-  // Request the crash server to generate a dump.  |blob| is a hack,
-  // see exception_handler.h and minidump_writer.h
-  //
-  // Return true if the dump was successful; false otherwise.
-  bool RequestDump(const void* blob, size_t blob_size);
+  // Request the crash server to generate a dump.  |blob| is an opaque
+  // CrashContext pointer from exception_handler.h.
+  // Returns true if the dump was successful; false otherwise.
+  virtual bool RequestDump(const void* blob, size_t blob_size) = 0;
 
-  // Return a new CrashGenerationClient if |server_fd| is valid and
+  // Returns a new CrashGenerationClient if |server_fd| is valid and
   // connects to a CrashGenerationServer.  Otherwise, return NULL.
   // The returned CrashGenerationClient* is owned by the caller of
   // this function.
   static CrashGenerationClient* TryCreate(int server_fd);
 
-private:
-  CrashGenerationClient(int server_fd) : server_fd_(server_fd)
-  {
-  }
-
-  int server_fd_;
-
-  // prevent copy construction and assignment
-  CrashGenerationClient(const CrashGenerationClient&);
-  CrashGenerationClient& operator=(const CrashGenerationClient&);
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CrashGenerationClient);
 };
 
 }  // namespace google_breakpad

src/client/linux/handler/exception_handler.h

@@ -146,6 +146,10 @@ class ExceptionHandler {
     crash_handler_ = callback;
   }
 
+  void set_crash_generation_client(CrashGenerationClient* client) {
+    crash_generation_client_.reset(client);
+  }
+
   // Writes a minidump immediately.  This can be used to capture the execution
   // state independently of a crash.
   // Returns true on success.