From db25f083c2ec0e2912aecaed4ae2826865305320 Mon Sep 17 00:00:00 2001
From: Craig Tiller <ctiller@google.com>
Date: Fri, 2 Dec 2016 12:45:24 -0800
Subject: [PATCH] Make TCP error messages more descriptive

---
 src/core/lib/iomgr/tcp_posix.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/core/lib/iomgr/tcp_posix.c b/src/core/lib/iomgr/tcp_posix.c
index 12a4797e6f4..fd807795199 100644
--- a/src/core/lib/iomgr/tcp_posix.c
+++ b/src/core/lib/iomgr/tcp_posix.c
@@ -107,6 +107,12 @@ typedef struct {
   grpc_resource_user_slice_allocator slice_allocator;
 } grpc_tcp;
 
+static grpc_error *tcp_annotate_error(grpc_error *src_error, grpc_tcp *tcp) {
+  return grpc_error_set_str(
+      grpc_error_set_int(src_error, GRPC_ERROR_INT_FD, tcp->fd),
+      GRPC_ERROR_STR_TARGET_ADDRESS, tcp->peer_string);
+}
+
 static void tcp_handle_read(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
                             grpc_error *error);
 static void tcp_handle_write(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
@@ -230,13 +236,15 @@ static void tcp_do_read(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
       grpc_fd_notify_on_read(exec_ctx, tcp->em_fd, &tcp->read_closure);
     } else {
       grpc_slice_buffer_reset_and_unref(tcp->incoming_buffer);
-      call_read_cb(exec_ctx, tcp, GRPC_OS_ERROR(errno, "recvmsg"));
+      call_read_cb(exec_ctx, tcp,
+                   tcp_annotate_error(GRPC_OS_ERROR(errno, "recvmsg"), tcp));
       TCP_UNREF(exec_ctx, tcp, "read");
     }
   } else if (read_bytes == 0) {
     /* 0 read size ==> end of stream */
     grpc_slice_buffer_reset_and_unref(tcp->incoming_buffer);
-    call_read_cb(exec_ctx, tcp, GRPC_ERROR_CREATE("Socket closed"));
+    call_read_cb(exec_ctx, tcp,
+                 tcp_annotate_error(GRPC_ERROR_CREATE("Socket closed"), tcp));
     TCP_UNREF(exec_ctx, tcp, "read");
   } else {
     GPR_ASSERT((size_t)read_bytes <= tcp->incoming_buffer->length);
@@ -366,7 +374,7 @@ static bool tcp_flush(grpc_tcp *tcp, grpc_error **error) {
         tcp->outgoing_byte_idx = unwind_byte_idx;
         return false;
       } else {
-        *error = GRPC_OS_ERROR(errno, "sendmsg");
+        *error = tcp_annotate_error(GRPC_OS_ERROR(errno, "sendmsg"), tcp);
         return true;
       }
     }
@@ -447,9 +455,10 @@ static void tcp_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
 
   if (buf->length == 0) {
     GPR_TIMER_END("tcp_write", 0);
-    grpc_exec_ctx_sched(exec_ctx, cb, grpc_fd_is_shutdown(tcp->em_fd)
-                                          ? GRPC_ERROR_CREATE("EOF")
-                                          : GRPC_ERROR_NONE,
+    grpc_exec_ctx_sched(exec_ctx, cb,
+                        grpc_fd_is_shutdown(tcp->em_fd)
+                            ? tcp_annotate_error(GRPC_ERROR_CREATE("EOF"), tcp)
+                            : GRPC_ERROR_NONE,
                         NULL);
     return;
   }