Coverity: Fix failure path for qemu_accept in migration

Coverity defects 1005733 & 1005734 complain about passing a negative
value to closesocket in the error paths on incoming migration.

Stash the error value and print it in the message (previously we gave
no indication of the reason for the failure)

Use error_report

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

migration-tcp.c

@@ -13,7 +13,10 @@
  * GNU GPL, version 2 or (at your option) any later version.
  */
 
+#include <string.h>
+
 #include "qemu-common.h"
+#include "qemu/error-report.h"
 #include "qemu/sockets.h"
 #include "migration/migration.h"
 #include "migration/qemu-file.h"
@@ -56,24 +59,26 @@ static void tcp_accept_incoming_migration(void *opaque)
     socklen_t addrlen = sizeof(addr);
     int s = (intptr_t)opaque;
     QEMUFile *f;
-    int c;
+    int c, err;
 
     do {
         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
-    } while (c == -1 && socket_error() == EINTR);
+        err = socket_error();
+    } while (c < 0 && err == EINTR);
     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
     closesocket(s);
 
     DPRINTF("accepted migration\n");
 
-    if (c == -1) {
-        fprintf(stderr, "could not accept migration connection\n");
-        goto out;
+    if (c < 0) {
+        error_report("could not accept migration connection (%s)",
+                     strerror(err));
+        return;
     }
 
     f = qemu_fopen_socket(c, "rb");
     if (f == NULL) {
-        fprintf(stderr, "could not qemu_fopen socket\n");
+        error_report("could not qemu_fopen socket");
         goto out;
     }
 

migration-unix.c

@@ -13,7 +13,10 @@
  * GNU GPL, version 2 or (at your option) any later version.
  */
 
+#include <string.h>
+
 #include "qemu-common.h"
+#include "qemu/error-report.h"
 #include "qemu/sockets.h"
 #include "qemu/main-loop.h"
 #include "migration/migration.h"
@@ -56,24 +59,26 @@ static void unix_accept_incoming_migration(void *opaque)
     socklen_t addrlen = sizeof(addr);
     int s = (intptr_t)opaque;
     QEMUFile *f;
-    int c;
+    int c, err;
 
     do {
         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
-    } while (c == -1 && errno == EINTR);
+        err = errno;
+    } while (c < 0 && err == EINTR);
     qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
     close(s);
 
     DPRINTF("accepted migration\n");
 
-    if (c == -1) {
-        fprintf(stderr, "could not accept migration connection\n");
-        goto out;
+    if (c < 0) {
+        error_report("could not accept migration connection (%s)",
+                     strerror(err));
+        return;
     }
 
     f = qemu_fopen_socket(c, "rb");
     if (f == NULL) {
-        fprintf(stderr, "could not qemu_fopen socket\n");
+        error_report("could not qemu_fopen socket");
         goto out;
     }