Fix memory leak in MacOS process handling.

runtime/bin/process_linux.cc

Index: runtime/bin/process_linux.cc
diff --git a/runtime/bin/process_linux.cc b/runtime/bin/process_linux.cc
index e82d0d685de9aca4fdf9b063111380dbd70dde41..2351de97809dd23ce3403aa2e108adfadb5819e3 100644
--- a/runtime/bin/process_linux.cc
+++ b/runtime/bin/process_linux.cc
@@ -230,13 +230,19 @@ int Process::Start(const char* path,
     close(read_err[0]);
     close(exec_control[0]);
 
-    dup2(write_out[0], STDIN_FILENO);
+    if (dup2(write_out[0], STDIN_FILENO) == -1) {

[Søren Gjesse, 2011/11/29 09:39:25]

As this is in the child process the output of these perror calls will not be
visible anywhere.

We should probably write something to the exec_control[1] file descriptor as
below and exit the child process.

[Mads Ager (google), 2011/11/29 10:10:13]

Yes, refactored the code after execvp into a ReportChildError helper and called
it from each of these.

+      perror("Failed to dup stdin");
+    }
     close(write_out[0]);
 
-    dup2(read_in[1], STDOUT_FILENO);
+    if (dup2(read_in[1], STDOUT_FILENO) == -1) {
+      perror("Failed to dup stdout");
+    }
     close(read_in[1]);
 
-    dup2(read_err[1], STDERR_FILENO);
+    if (dup2(read_err[1], STDERR_FILENO) == -1) {
+      perror("Failed to dup stderr");
+    }
     close(read_err[1]);
 
     execvp(path, const_cast<char* const*>(program_arguments));