POSIX: read subprocess output before waiting for termination.

Previously, GetAppOutput was designed only for fuser. However, it
appears that Mac is using it to read the output of ps: which outputs
rather more. In this case, ps can fill up the pipe buffer while we are
waiting for it to exit, leading to deadlock depending on how many other
process are running on the system at the time.

http://codereview.chromium.org/118514


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18068 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 7 insertions, 8 deletions

diff --git a/base/process_util_posix.cc b/base/process_util_posix.cc
index d5d6cb8..840339f 100644
--- a/base/process_util_posix.cc
+++ b/base/process_util_posix.cc
@@ -457,13 +457,6 @@ bool GetAppOutput(const CommandLine& cl, std::string* output) {
         // write to the pipe).
         close(pipe_fd[1]);
 
-        int exit_code = EXIT_FAILURE;
-        bool success = WaitForExitCode(pid, &exit_code);
-        if (!success || exit_code != EXIT_SUCCESS) {
-          close(pipe_fd[0]);
-          return false;
-        }
-
         char buffer[256];
         std::string buf_output;
 
@@ -474,8 +467,14 @@ bool GetAppOutput(const CommandLine& cl, std::string* output) {
             break;
           buf_output.append(buffer, bytes_read);
         }
-        output->swap(buf_output);
         close(pipe_fd[0]);
+
+        int exit_code = EXIT_FAILURE;
+        bool success = WaitForExitCode(pid, &exit_code);
+        if (!success || exit_code != EXIT_SUCCESS)
+          return false;
+
+        output->swap(buf_output);
         return true;
       }
   }