qga: Support enum names in guest-file-seek

Magic constants are a pain to use, especially when we run the
risk that our choice of '1' for QGA_SEEK_CUR might differ from
the host or guest's choice of SEEK_CUR.  Better is to use an
enum value, via a qapi alternate type for back-compatibility.

With this,
 {"command":"guest-file-seek", "arguments":{"handle":1,
  "offset":0, "whence":"cur"}}
becomes a synonym for the older
 {"command":"guest-file-seek", "arguments":{"handle":1,
  "offset":0, "whence":1}}

Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

1 files changed, 6 insertions, 13 deletions

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index 9589b2d..9f51fae 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -550,31 +550,24 @@ GuestFileWrite *qmp_guest_file_write(int64_t handle, const char *buf_b64,
 }
 
 struct GuestFileSeek *qmp_guest_file_seek(int64_t handle, int64_t offset,
-                                          int64_t whence_code, Error **errp)
+                                          GuestFileWhence *whence_code,
+                                          Error **errp)
 {
     GuestFileHandle *gfh = guest_file_handle_find(handle, errp);
     GuestFileSeek *seek_data = NULL;
     FILE *fh;
     int ret;
     int whence;
+    Error *err = NULL;
 
     if (!gfh) {
         return NULL;
     }
 
     /* We stupidly exposed 'whence':'int' in our qapi */
-    switch (whence_code) {
-    case QGA_SEEK_SET:
-        whence = SEEK_SET;
-        break;
-    case QGA_SEEK_CUR:
-        whence = SEEK_CUR;
-        break;
-    case QGA_SEEK_END:
-        whence = SEEK_END;
-        break;
-    default:
-        error_setg(errp, "invalid whence code %"PRId64, whence_code);
+    whence = ga_parse_whence(whence_code, &err);
+    if (err) {
+        error_propagate(errp, err);
         return NULL;
     }