osdep: remove use of socket_error() from all code

Now that QEMU wraps the Win32 sockets methods to automatically
set errno upon failure, there is no reason for callers to use
the socket_error() method. They can rely on accessing errno
even on Win32. Remove all use of socket_error() from general
code, leaving it as a static method in oslib-win32.c only.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

migration/qemu-file-unix.c

@@ -53,18 +53,16 @@ static ssize_t socket_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
         }
 
         if (size > 0) {
-            err = socket_error();
-
-            if (err != EAGAIN && err != EWOULDBLOCK) {
+            if (errno != EAGAIN && errno != EWOULDBLOCK) {
                 error_report("socket_writev_buffer: Got err=%d for (%zu/%zu)",
-                             err, (size_t)size, (size_t)len);
+                             errno, (size_t)size, (size_t)len);
                 /*
                  * If I've already sent some but only just got the error, I
                  * could return the amount validly sent so far and wait for the
                  * next call to report the error, but I'd rather flag the error
                  * immediately.
                  */
-                return -err;
+                return -errno;
             }
 
             /* Emulate blocking */
@@ -99,15 +97,15 @@ static ssize_t socket_get_buffer(void *opaque, uint8_t *buf, int64_t pos,
         if (len != -1) {
             break;
         }
-        if (socket_error() == EAGAIN) {
+        if (errno == EAGAIN) {
             yield_until_fd_readable(s->fd);
-        } else if (socket_error() != EINTR) {
+        } else if (errno != EINTR) {
             break;
         }
     }
 
     if (len == -1) {
-        len = -socket_error();
+        len = -errno;
     }
     return len;
 }

migration/tcp.c

@@ -59,12 +59,11 @@ static void tcp_accept_incoming_migration(void *opaque)
     socklen_t addrlen = sizeof(addr);
     int s = (intptr_t)opaque;
     QEMUFile *f;
-    int c, err;
+    int c;
 
     do {
         c = qemu_accept(s, (struct sockaddr *)&addr, &addrlen);
-        err = socket_error();
-    } while (c < 0 && err == EINTR);
+    } while (c < 0 && errno == EINTR);
     qemu_set_fd_handler(s, NULL, NULL, NULL);
     closesocket(s);
 
@@ -72,7 +71,7 @@ static void tcp_accept_incoming_migration(void *opaque)
 
     if (c < 0) {
         error_report("could not accept migration connection (%s)",
-                     strerror(err));
+                     strerror(errno));
         return;
     }