From bfd03b069b21e2c3668b2fd1932484357c6f3bb1 Mon Sep 17 00:00:00 2001
From: Jed Davis <jld@mozilla.com>
Date: Tue, 10 Mar 2015 10:32:00 +0100
Subject: [PATCH] Bug 1140714 - Pass through remote
 NS_OpenAnonymousTemporaryFile failure to caller. r=billm

---
 dom/ipc/ContentParent.cpp             |  7 +++++--
 dom/ipc/ContentParent.h               |  2 +-
 dom/ipc/PContent.ipdl                 |  7 ++++++-
 xpcom/io/nsAnonymousTemporaryFile.cpp | 15 +++++++++------
 4 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/dom/ipc/ContentParent.cpp b/dom/ipc/ContentParent.cpp
index d1b8f0daf78..c27c3fa20bf 100755
--- a/dom/ipc/ContentParent.cpp
+++ b/dom/ipc/ContentParent.cpp
@@ -4459,12 +4459,15 @@ ContentParent::RecvBackUpXResources(const FileDescriptor& aXSocketFd)
 }
 
 bool
-ContentParent::RecvOpenAnonymousTemporaryFile(FileDescriptor *aFD)
+ContentParent::RecvOpenAnonymousTemporaryFile(FileDescOrError *aFD)
 {
     PRFileDesc *prfd;
     nsresult rv = NS_OpenAnonymousTemporaryFile(&prfd);
     if (NS_WARN_IF(NS_FAILED(rv))) {
-        return false;
+        // Returning false will kill the child process; instead
+        // propagate the error and let the child handle it.
+        *aFD = rv;
+        return true;
     }
     *aFD = FileDescriptor(FileDescriptor::PlatformHandleType(PR_FileDesc2NativeHandle(prfd)));
     // The FileDescriptor object owns a duplicate of the file handle; we
diff --git a/dom/ipc/ContentParent.h b/dom/ipc/ContentParent.h
index 1acc1700b7a..8b19b4c0aad 100644
--- a/dom/ipc/ContentParent.h
+++ b/dom/ipc/ContentParent.h
@@ -762,7 +762,7 @@ private:
     RecvBackUpXResources(const FileDescriptor& aXSocketFd) MOZ_OVERRIDE;
 
     virtual bool
-    RecvOpenAnonymousTemporaryFile(FileDescriptor* aFD) MOZ_OVERRIDE;
+    RecvOpenAnonymousTemporaryFile(FileDescOrError* aFD) MOZ_OVERRIDE;
 
     virtual bool
     RecvKeygenProcessValue(const nsString& oldValue, const nsString& challenge,
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index 3b87e808358..8a290781917 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -335,6 +335,11 @@ union MaybeFileDesc {
     void_t;
 };
 
+union FileDescOrError {
+    FileDescriptor;
+    nsresult;
+};
+
 union OptionalContentId
 {
   ContentParentId;
@@ -827,7 +832,7 @@ parent:
      */
     BackUpXResources(FileDescriptor aXSocketFd);
 
-    sync OpenAnonymousTemporaryFile() returns (FileDescriptor aFD);
+    sync OpenAnonymousTemporaryFile() returns (FileDescOrError aFD);
 
     /**
      * Keygen requires us to call it after a <keygen> element is parsed and
diff --git a/xpcom/io/nsAnonymousTemporaryFile.cpp b/xpcom/io/nsAnonymousTemporaryFile.cpp
index e76e1c641b4..102acad2d22 100644
--- a/xpcom/io/nsAnonymousTemporaryFile.cpp
+++ b/xpcom/io/nsAnonymousTemporaryFile.cpp
@@ -90,12 +90,15 @@ NS_OpenAnonymousTemporaryFile(PRFileDesc** aOutFileDesc)
   }
 
   if (dom::ContentChild* child = dom::ContentChild::GetSingleton()) {
-    ipc::FileDescriptor fd;
-    DebugOnly<bool> succeeded = child->SendOpenAnonymousTemporaryFile(&fd);
-    // The child process should already have been terminated if the
-    // IPC had failed.
-    MOZ_ASSERT(succeeded);
-    *aOutFileDesc = PR_ImportFile(PROsfd(fd.PlatformHandle()));
+    dom::FileDescOrError fd;
+    child->SendOpenAnonymousTemporaryFile(&fd);
+    if (fd.type() == dom::FileDescOrError::Tnsresult) {
+      nsresult rv = fd.get_nsresult();
+      MOZ_ASSERT(NS_FAILED(rv));
+      return rv;
+    }
+    *aOutFileDesc =
+      PR_ImportFile(PROsfd(fd.get_FileDescriptor().PlatformHandle()));
     return NS_OK;
   }