socket: uevent: use SO_RCVBUF instead of SO_RCVBUFFORCE

The SO_RCVBUFFORCE option requires the caller of uevent_create_socket()
to have net_admin capabilities.

Set platform default rcv/snd buffer sizes to 256kb that will always be
overridden by the device/target. However, it will allow
ueventd / healthd to use the uevent_create_socket() API w/o requiring
the net_admin capability.

Note: All devices override the buffer sizes according to the technology
maximum to at least ~8MB. So, the init.rc change here is to make sure
platform code can work w/o any overrides.

Test: no SELinux failures for healthd with 'net_admin' removed.

Bug: https://b/32733887

Change-Id: Ida346468cd550ad07901bf3a78ad508939849906
Signed-off-by: Sandeep Patil <sspatil@google.com>
diff --git a/libcutils/uevent.c b/libcutils/uevent.c
index de5d227..f548dca 100644
--- a/libcutils/uevent.c
+++ b/libcutils/uevent.c
@@ -116,7 +116,12 @@
     if(s < 0)
         return -1;
 
-    setsockopt(s, SOL_SOCKET, SO_RCVBUFFORCE, &buf_sz, sizeof(buf_sz));
+    /* buf_sz should be less than net.core.rmem_max for this to succeed */
+    if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, &buf_sz, sizeof(buf_sz)) < 0) {
+        close(s);
+        return -1;
+    }
+
     setsockopt(s, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 
     if(bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {