net/dump: Improve -net/host_net_add dump error reporting

When -net dump fails, it first reports a specific error, then a
generic one, like this:

    $ qemu-system-x86_64 -net dump,id=foo,file=/eperm
    qemu-system-x86_64: -net dump,id=foo,file=/eperm: -net dump: can't open /eperm
    qemu-system-x86_64: -net dump,id=foo,file=/eperm: Device 'dump' could not be initialized

Convert net_init_tap() to Error.  This suppresses the unwanted second
message.

Improve the error messages to include strerror(errno) where
appropriate.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1431691143-1015-5-git-send-email-armbru@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/net/dump.c b/net/dump.c
index 214e88a76..02c8064be 100644
--- a/net/dump.c
+++ b/net/dump.c
@@ -101,7 +101,8 @@ static NetClientInfo net_dump_info = {
 };
 
 static int net_dump_init(NetClientState *peer, const char *device,
-                         const char *name, const char *filename, int len)
+                         const char *name, const char *filename, int len,
+                         Error **errp)
 {
     struct pcap_file_hdr hdr;
     NetClientState *nc;
@@ -111,7 +112,7 @@ static int net_dump_init(NetClientState *peer, const char *device,
 
     fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY | O_BINARY, 0644);
     if (fd < 0) {
-        error_report("-net dump: can't open %s", filename);
+        error_setg_errno(errp, errno, "-net dump: can't open %s", filename);
         return -1;
     }
 
@@ -124,7 +125,7 @@ static int net_dump_init(NetClientState *peer, const char *device,
     hdr.linktype = 1;
 
     if (write(fd, &hdr, sizeof(hdr)) < sizeof(hdr)) {
-        error_report("-net dump write error: %s", strerror(errno));
+        error_setg_errno(errp, errno, "-net dump write error");
         close(fd);
         return -1;
     }
@@ -148,7 +149,6 @@ static int net_dump_init(NetClientState *peer, const char *device,
 int net_init_dump(const NetClientOptions *opts, const char *name,
                   NetClientState *peer, Error **errp)
 {
-    /* FIXME error_setg(errp, ...) on failure */
     int len;
     const char *file;
     char def_file[128];
@@ -174,7 +174,7 @@ int net_init_dump(const NetClientOptions *opts, const char *name,
 
     if (dump->has_len) {
         if (dump->len > INT_MAX) {
-            error_report("invalid length: %"PRIu64, dump->len);
+            error_setg(errp, "invalid length: %"PRIu64, dump->len);
             return -1;
         }
         len = dump->len;
@@ -182,5 +182,5 @@ int net_init_dump(const NetClientOptions *opts, const char *name,
         len = 65536;
     }
 
-    return net_dump_init(peer, "dump", name, file, len);
+    return net_dump_init(peer, "dump", name, file, len, errp);
 }