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

base/process_util_linux.cc

Index: base/process_util_linux.cc
diff --git a/base/process_util_linux.cc b/base/process_util_linux.cc
index 81090327985f0919ab14b210670f50b6801295e1..ba22a409f43259aebb5c7cfcc9508eba18a11534 100644
--- a/base/process_util_linux.cc
+++ b/base/process_util_linux.cc
@@ -6,6 +6,8 @@
 
 #include <ctype.h>
 #include <dirent.h>
+#include <fcntl.h>
+#include <unistd.h>
 #include <string>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -29,6 +31,7 @@ enum ParsingState {
 namespace base {
 
 bool LaunchApp(const std::vector<std::string>& argv,
+               const file_handle_mapping_vector& fds_to_remap,
                bool wait, ProcessHandle* process_handle) {
   bool retval = true;
 
@@ -39,8 +42,33 @@ bool LaunchApp(const std::vector<std::string>& argv,
   }
   argv_copy[argv.size()] = NULL;
 
+  // Make sure we don't leak any FDs to the child process by marking all FDs
+  // as close-on-exec.
+  int max_files = GetMaxFilesOpenInProcess();
+  for (int i = STDERR_FILENO + 1; i < max_files; i++) {
+    int flags = fcntl(i, F_GETFD);
+    if (flags != -1) {
+      fcntl(i, F_SETFD, flags | FD_CLOEXEC);
+    }
+  }
+
   int pid = fork();
   if (pid == 0) {
+    for (file_handle_mapping_vector::const_iterator it = fds_to_remap.begin();
+         it != fds_to_remap.end();
+         ++it) {
+      int src_fd = it->first;
+      int dest_fd = it->second;
+      if (src_fd == dest_fd) {
+        int flags = fcntl(src_fd, F_GETFD);
+        if (flags != -1) {
+          fcntl(src_fd, F_SETFD, flags & ~FD_CLOEXEC);
+        }
+      } else {
+        dup2(src_fd, dest_fd);
+      }
+    }
+
     execvp(argv_copy[0], argv_copy);
   } else if (pid < 0) {
     retval = false;
@@ -60,7 +88,8 @@ bool LaunchApp(const std::vector<std::string>& argv,
 
 bool LaunchApp(const CommandLine& cl,
                bool wait, bool start_hidden, ProcessHandle* process_handle) {
-  return LaunchApp(cl.argv(), wait, process_handle);
+  file_handle_mapping_vector no_files;
+  return LaunchApp(cl.argv(), no_files, wait, process_handle);
 }
 
 // Attempts to kill the process identified by the given process
@@ -108,7 +137,7 @@ bool DidProcessCrash(ProcessHandle handle) {
 }
 
 NamedProcessIterator::NamedProcessIterator(const std::wstring& executable_name,
-                                           const ProcessFilter* filter) 
+                                           const ProcessFilter* filter)
     :
        executable_name_(executable_name),
        filter_(filter) {