Increase maximum file descriptors per IPC message on POSIX from 5 to 7.

On POSIX, the maximum number of file descriptors passable in an IPC message is controlled by a constant 'kMaxDescriptorsPerMessage'. It's currently set at 5. This patch makes it 7.

The Picasa album table reader utility process (https://codereview.chromium.org/18986012/) needs to pass 7 files to the utility process. This works on Windows, but fails on POSIX (Mac), due to the aforementioned limit. This CL increases this limit to 7, as well as adds some DLOG messages to give better info to developers who hit this limit.

ipc_channel_posix.cc seems to indicate adding extra file descriptors just makes the messages longer by an 'int' per file descriptor. Making the maximum even larger would be okay with me too.

BUG=

Review URL: https://chromiumcodereview.appspot.com/23534018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@220371 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 6 insertions, 2 deletions

diff --git a/ipc/file_descriptor_set_posix.cc b/ipc/file_descriptor_set_posix.cc
index 3cb5880..584efec 100644
--- a/ipc/file_descriptor_set_posix.cc
+++ b/ipc/file_descriptor_set_posix.cc
@@ -37,8 +37,10 @@ FileDescriptorSet::~FileDescriptorSet() {
 }
 
 bool FileDescriptorSet::Add(int fd) {
-  if (descriptors_.size() == kMaxDescriptorsPerMessage)
+  if (descriptors_.size() == kMaxDescriptorsPerMessage) {
+    DLOG(WARNING) << "Cannot add file descriptor. FileDescriptorSet full.";
     return false;
+  }
 
   struct base::FileDescriptor sd;
   sd.fd = fd;
@@ -48,8 +50,10 @@ bool FileDescriptorSet::Add(int fd) {
 }
 
 bool FileDescriptorSet::AddAndAutoClose(int fd) {
-  if (descriptors_.size() == kMaxDescriptorsPerMessage)
+  if (descriptors_.size() == kMaxDescriptorsPerMessage) {
+    DLOG(WARNING) << "Cannot add file descriptor. FileDescriptorSet full.";
     return false;
+  }
 
   struct base::FileDescriptor sd;
   sd.fd = fd;