POSIX: don't leak FDs when launching child Processes.

base/process_util_posix.cc

Index: base/process_util_posix.cc
diff --git a/base/process_util_posix.cc b/base/process_util_posix.cc
index 3153a59aa0fce1c877cceb3754b680523a8aa79e..2cfa6f9a4c2ca000cd5839abfbda8d285694d650 100644
--- a/base/process_util_posix.cc
+++ b/base/process_util_posix.cc
@@ -9,6 +9,7 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
+#include <limits>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
@@ -31,6 +32,23 @@ int GetProcId(ProcessHandle process) {
   return process;
 }
 
+int GetMaxFilesOpenInProcess() {
+  struct rlimit rlimit;
+  if (getrlimit(RLIMIT_NOFILE, &rlimit) != 0) {
+    return 0;
+  }
+
+  // rlim_t is a uint64 - clip to maxint.
+  // We do this since we use the value of this function to close FD #s in a loop
+  // if we didn't clamp the value, doing this would be too time consuming.
+  rlim_t max_int = static_cast<rlim_t>(std::numeric_limits<int32>::max());
+  if (rlimit.rlim_cur > max_int) {
+    return max_int;
+  }
+
+  return rlimit.rlim_cur;
+}
+
 ProcessMetrics::ProcessMetrics(ProcessHandle process) : process_(process),
                                                         last_time_(0),
                                                         last_system_time_(0) {