1:45 p.m.
We were producing invalid JSON for a server advertising zero exports
(we left a dangling trailing comma after the "TLS" line), or for
multiple exports (we omitted commas between array elements of
"exports"). We were also failing to check for failure in
nbd_get_nr_list_exports (which was fixed a couple patches ago, but
previously possible when querying with a URI matching an export known
by the server which resulted in a handle in Connected state).
Tested by using qemu-kvm in a second terminal (although the setup is
involved enough that I did not add it to the testsuite; instead, I
will add things when nbdkit is also taught to expose list size != 1):
t1$ touch a b
t1$ qemu-kvm -nodefaults -nographic -qmp stdio
{'execute':'qmp_capabilities'}
{'execute':'nbd-server-start','arguments':{'addr':{'type':'inet',
'data':{'host':'localhost','port':'10809'}}}}
{'execute':'blockdev-add','arguments':{'driver':'file','node-name':'a',
'filename':'a'}}
{'execute':'blockdev-add','arguments':{'driver':'file','node-name':'b',
'filename':'b'}}
# now qemu is advertising zero exports
t2$ nbdinfo --list --json nbd://localhost:10809 | jq .
# back to t1
{'execute':'nbd-server-add','arguments':{'device':'a'}}
{'execute':'nbd-server-add','arguments':{'device':'b'}}
# now qemu is advertising two exports
t2$ nbdinfo --list --json nbd://localhost:10809 | jq .
# back to t1
{'execute':'quit'}
---
info/nbdinfo.c | 30 ++++++++++++++++++++++--------
1 file changed, 22 insertions(+), 8 deletions(-)
diff --git a/info/nbdinfo.c b/info/nbdinfo.c
index b18cebc..f37ffea 100644
--- a/info/nbdinfo.c
+++ b/info/nbdinfo.c
@@ -37,7 +37,8 @@ static bool probe_content, content_flag, no_content_flag;
static bool json_output = false;
static bool size_only = false;
-static void list_one_export (struct nbd_handle *nbd, const char *desc);
+static void list_one_export (struct nbd_handle *nbd, const char *desc,
+ bool first, bool last);
static void list_all_exports (struct nbd_handle *nbd1, const char *uri);
static void print_json_string (const char *);
static char *get_content (struct nbd_handle *, int64_t size);
@@ -250,7 +251,7 @@ main (int argc, char *argv[])
if (!list_all)
/* XXX We would need libnbd to request NBD_INFO_DESCRIPTION */
- list_one_export (nbd, NULL);
+ list_one_export (nbd, NULL, true, true);
else
list_all_exports (nbd, argv[optind]);
@@ -263,7 +264,8 @@ main (int argc, char *argv[])
}
static void
-list_one_export (struct nbd_handle *nbd, const char *desc)
+list_one_export (struct nbd_handle *nbd, const char *desc,
+ bool first, bool last)
{
int64_t size;
char *export_name = NULL;
@@ -338,7 +340,8 @@ list_one_export (struct nbd_handle *nbd, const char *desc)
printf ("\t%s: %" PRId64 "\n", "block_size_maximum",
block_maximum);
}
else {
- printf ("\"exports\": [\n");
+ if (first)
+ printf ("\"exports\": [\n");
printf ("\t{\n");
printf ("\t\"export-name\": ");
@@ -399,8 +402,10 @@ list_one_export (struct nbd_handle *nbd, const char *desc)
/* Put this one at the end because of the stupid comma thing in JSON. */
printf ("\t\"export-size\": %" PRIi64 "\n", size);
- printf ("\t}\n");
- printf ("]\n");
+ if (last)
+ printf ("\t} ]\n");
+ else
+ printf ("\t},\n");
}
free (content);
@@ -415,8 +420,17 @@ list_all_exports (struct nbd_handle *nbd1, const char *uri)
{
int i;
xmlURIPtr xmluri = NULL;
+ int count = nbd_get_nr_list_exports (nbd1);
- for (i = 0; i < nbd_get_nr_list_exports (nbd1); ++i) {
+ if (count == -1) {
+ fprintf (stderr, "unable to obtain list of exports: %s\n",
+ nbd_get_error ());
+ exit (EXIT_FAILURE);
+ }
+ if (count == 0 && json_output)
+ printf ("\t\"exports\": []\n");
+
+ for (i = 0; i < count; ++i) {
char *name, *desc, *new_path, *new_uri;
struct nbd_handle *nbd2;
@@ -453,7 +467,7 @@ list_all_exports (struct nbd_handle *nbd1, const char *uri)
/* List the metadata of this export. */
desc = nbd_get_list_export_description (nbd1, i);
- list_one_export (nbd2, desc);
+ list_one_export (nbd2, desc, i == 0, i + 1 == count);
nbd_close (nbd2);
free (new_uri);
--
2.28.0