nbd: consistently return negative errno values

In the next patch we need to look at the return code of nbd_wr_sync.
To avoid percolating the socket_error() ugliness all around, let's
handle errors by returning negative errno values.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 8 insertions, 7 deletions

diff --git a/qemu-nbd.c b/qemu-nbd.c
index 19cfb04..6c3f9b5 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -126,8 +126,7 @@ static int find_partition(BlockDriverState *bs, int partition,
     }
 
     if (data[510] != 0x55 || data[511] != 0xaa) {
-        errno = -EINVAL;
-        return -1;
+        return -EINVAL;
     }
 
     for (i = 0; i < 4; i++) {
@@ -165,8 +164,7 @@ static int find_partition(BlockDriverState *bs, int partition,
         }
     }
 
-    errno = -ENOENT;
-    return -1;
+    return -ENOENT;
 }
 
 static void termsig_handler(int signum)
@@ -491,9 +489,12 @@ int main(int argc, char **argv)
 
     fd_size = bs->total_sectors * 512;
 
-    if (partition != -1 &&
-        find_partition(bs, partition, &dev_offset, &fd_size)) {
-        err(EXIT_FAILURE, "Could not find partition %d", partition);
+    if (partition != -1) {
+        ret = find_partition(bs, partition, &dev_offset, &fd_size);
+        if (ret < 0) {
+            errno = -ret;
+            err(EXIT_FAILURE, "Could not find partition %d", partition);
+        }
     }
 
     exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags);