Kernel: Inherit shared buffers when forking

We need to create a reference for the new PID for each shared buffer
that the process had a reference to. If the process subsequently
get replaced through exec, those references will be dropped again.
But if exec for some reason fails then other code, such as global
destructors could still expect having access to them.

Fixes #4076

1 files changed, 16 insertions, 0 deletions

diff --git a/Kernel/SharedBuffer.cpp b/Kernel/SharedBuffer.cpp
index 29223bcda7..39cd8681aa 100644
--- a/Kernel/SharedBuffer.cpp
+++ b/Kernel/SharedBuffer.cpp
@@ -121,6 +121,22 @@ void SharedBuffer::share_with(ProcessID peer_pid)
     sanity_check("share_with (new ref)");
 }
 
+void SharedBuffer::share_all_shared_buffers(Process& from_process, Process& with_process)
+{
+    LOCKER(shared_buffers().lock());
+    for (auto& shbuf : shared_buffers().resource()) {
+        auto& shared_buffer = *shbuf.value;
+        if (shared_buffer.m_global)
+            continue;
+        for (auto& ref : shared_buffer.m_refs) {
+            if (ref.pid == from_process.pid()) {
+                shared_buffer.share_with(with_process.pid());
+                break;
+            }
+        }
+    }
+}
+
 void SharedBuffer::deref_for_process(Process& process)
 {
     LOCKER(shared_buffers().lock());