More solid detection of browser process in chrome_process_util_linux.cc:

- use GetAppOutput instead of popen
- make unexpected conditions fatal (otherwise the tests using this code
  would mistakenly assume that there is no running browser process)

Also add a constant for SingletonSocket.

Make necessary adjustments to GetAppOutput - ignore stderr (because fuser
prints the file name to stderr and having stderr in |output| would
require more parsing).

Review URL: http://codereview.chromium.org/77031

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@14091 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 12 insertions, 5 deletions

diff --git a/base/process_util.h b/base/process_util.h
index 367c772..20cdd5e 100644
--- a/base/process_util.h
+++ b/base/process_util.h
@@ -126,9 +126,10 @@ bool LaunchApp(const CommandLine& cl,
 
 #if defined(OS_POSIX)
 // Execute the application specified by |cl| and wait for it to exit. Store
-// the output (stdout and stderr) in |output|. Returns true on success
-// (application launched and exited cleanly, with exit code indicating success).
-// |output| is modified only when the function finished successfully.
+// the output (stdout) in |output|. Redirects stderr to /dev/null. Returns true
+// on success (application launched and exited cleanly, with exit code
+// indicating success). |output| is modified only when the function finished
+// successfully.
 bool GetAppOutput(const CommandLine& cl, std::string* output);
 #endif  // defined(OS_POSIX)
 
diff --git a/base/process_util_posix.cc b/base/process_util_posix.cc
index 75c9b96..3570a16 100644
--- a/base/process_util_posix.cc
+++ b/base/process_util_posix.cc
@@ -326,17 +326,23 @@ bool GetAppOutput(const CommandLine& cl, std::string* output) {
       return false;
     case 0:  // child
       {
+        int dev_null = open("/dev/null", O_WRONLY);
+        if (dev_null < 0)
+          exit(127);
+
         int rv;
         do {
           rv = dup2(pipe_fd[1], STDOUT_FILENO);
         } while (rv == -1 && errno == EINTR);
         do {
-          rv = dup2(pipe_fd[1], STDERR_FILENO);
+          rv = dup2(dev_null, STDERR_FILENO);
         } while (rv == -1 && errno == EINTR);
         if (pipe_fd[0] != STDOUT_FILENO && pipe_fd[0] != STDERR_FILENO)
           close(pipe_fd[0]);
         if (pipe_fd[1] != STDOUT_FILENO && pipe_fd[1] != STDERR_FILENO)
           close(pipe_fd[1]);
+        if (dev_null != STDOUT_FILENO && dev_null != STDERR_FILENO)
+          close(dev_null);
 
         const std::vector<std::string> argv = cl.argv();
         char* argv_cstr[argv.size() + 1];
@@ -373,7 +379,7 @@ bool GetAppOutput(const CommandLine& cl, std::string* output) {
           if (bytes_read > 0)
             buf_output.append(buffer, bytes_read);
         }
-        output->assign(buf_output);
+        output->swap(buf_output);
         close(pipe_fd[0]);
         return true;
       }