Fix race in zygote_host_linux where socket was being read from and written to on different threads.

Made ZygoteHost methods all run on PROCESS_LAUNCHER thread. PostTask in linux from UI thread to PROCESS_LAUNCHER thread for DidProcessCrash. Changed DidProcessCrash to answer via a callback, which occurs asynchronously on linux. Rework cases in nacl_host, browser_render_process_host, and child_process_host where this method was being called to fit the callback model.

BUG=31737
TEST=none

Review URL: http://codereview.chromium.org/1695026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@46384 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 3 deletions

diff --git a/chrome/browser/zygote_host_linux.h b/chrome/browser/zygote_host_linux.h
index 53485e0..21118d5 100644
--- a/chrome/browser/zygote_host_linux.h
+++ b/chrome/browser/zygote_host_linux.h
@@ -26,15 +26,19 @@ class ZygoteHost {
  public:
   void Init(const std::string& sandbox_cmd);
 
-  // Tries to start a renderer process.  Returns its pid on success, otherwise
-  // base::kNullProcessHandle;
+  // Tries to start a renderer process. Returns its pid on success, otherwise
+  // base::kNullProcessHandle. Must be called on the PROCESS_LAUNCHER
+  // thread.
   pid_t ForkRenderer(const std::vector<std::string>& command_line,
                      const base::GlobalDescriptors::Mapping& mapping);
+
+  // Must be called on the PROCESS_LAUNCHER thread.
   void EnsureProcessTerminated(pid_t process);
 
   // Get the termination status (exit code) of the process and return true if
   // the status indicates the process crashed. |child_exited| is set to true
   // iff the child process has terminated. (|child_exited| may be NULL.)
+  // Must be called on the PROCESS_LAUNCHER thread.
   bool DidProcessCrash(base::ProcessHandle handle, bool* child_exited);
 
   // These are the command codes used on the wire between the browser and the
@@ -52,7 +56,10 @@ class ZygoteHost {
   ZygoteHost();
   ~ZygoteHost();
 
-  int control_fd_;  // the socket to the zygote
+  // The socket to the zygote, which should only be accessed on the
+  // PROCESS_LAUNCHER thread.
+  int control_fd_;
+
   pid_t pid_;
   bool init_;
   bool using_suid_sandbox_;