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Message-ID: <20240329181651.319326-1-kuba@kernel.org>
Date: Fri, 29 Mar 2024 11:16:51 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org,
edumazet@...gle.com,
pabeni@...hat.com,
Jakub Kicinski <kuba@...nel.org>,
nicolas.dichtel@...nd.com,
sdf@...gle.com
Subject: [PATCH net-next] tools: ynl: add ynl_dump_empty() helper
Checking if dump is empty requires a couple of casts.
Add a convenient wrapper.
Add an example use in the netdev sample, loopback is always
present so an empty dump is an error.
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
CC: nicolas.dichtel@...nd.com
CC: sdf@...gle.com
---
tools/net/ynl/lib/ynl.h | 12 ++++++++++++
tools/net/ynl/samples/netdev.c | 2 ++
2 files changed, 14 insertions(+)
diff --git a/tools/net/ynl/lib/ynl.h b/tools/net/ynl/lib/ynl.h
index 9842e85a8c57..eef7c6324ed4 100644
--- a/tools/net/ynl/lib/ynl.h
+++ b/tools/net/ynl/lib/ynl.h
@@ -91,6 +91,18 @@ void ynl_sock_destroy(struct ynl_sock *ys);
!ynl_dump_obj_is_last(iter); \
iter = ynl_dump_obj_next(iter))
+/**
+ * ynl_dump_empty() - does the dump have no entries
+ * @dump: pointer to the dump list, as returned by a dump call
+ *
+ * Check if the dump is empty, i.e. contains no objects.
+ * Dump calls return NULL on error, and terminator element if empty.
+ */
+static inline bool ynl_dump_empty(void *dump)
+{
+ return dump == (void *)YNL_LIST_END;
+}
+
int ynl_subscribe(struct ynl_sock *ys, const char *grp_name);
int ynl_socket_get_fd(struct ynl_sock *ys);
int ynl_ntf_check(struct ynl_sock *ys);
diff --git a/tools/net/ynl/samples/netdev.c b/tools/net/ynl/samples/netdev.c
index 591b90e21890..3e7b29bd55d5 100644
--- a/tools/net/ynl/samples/netdev.c
+++ b/tools/net/ynl/samples/netdev.c
@@ -100,6 +100,8 @@ int main(int argc, char **argv)
if (!devs)
goto err_close;
+ if (ynl_dump_empty(devs))
+ fprintf(stderr, "Error: no devices reported\n");
ynl_dump_foreach(devs, d)
netdev_print_device(d, 0);
netdev_dev_get_list_free(devs);
--
2.44.0
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