On Wed, May 28, 2025 at 10:44:42PM +0200, Michal Luczaj wrote:
Return a bitmap of registered vsock transports. As guesstimated by grepping
/proc/kallsyms (CONFIG_KALLSYMS=y) for known symbols of type `struct
virtio_transport`.
Suggested-by: Stefano Garzarella <sgarz...@redhat.com>
Signed-off-by: Michal Luczaj <m...@rbox.co>
---
tools/testing/vsock/util.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++
tools/testing/vsock/util.h | 12 ++++++++++
2 files changed, 72 insertions(+)
diff --git a/tools/testing/vsock/util.c b/tools/testing/vsock/util.c
index
b7b3fb2221c1682ecde58cf12e2f0b0ded1cff39..74fb52f566148b16436251216dd9d9275f0ec95b
100644
--- a/tools/testing/vsock/util.c
+++ b/tools/testing/vsock/util.c
@@ -7,6 +7,7 @@
* Author: Stefan Hajnoczi <stefa...@redhat.com>
*/
+#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdint.h>
@@ -17,6 +18,7 @@
#include <assert.h>
#include <sys/epoll.h>
#include <sys/mman.h>
+#include <linux/kernel.h>
#include <linux/sockios.h>
#include "timeout.h"
@@ -854,3 +856,61 @@ void enable_so_linger(int fd, int timeout)
exit(EXIT_FAILURE);
}
}
+
+static int __get_transports(void)
+{
+ /* Order must match transports defined in util.h.
+ * man nm: "d" The symbol is in the initialized data section.
+ */
+ const char * const syms[] = {
+ "d loopback_transport",
+ "d virtio_transport",
+ "d vhost_transport",
+ "d vmci_transport",
+ "d hvs_transport",
+ };
I would move this array (or a macro that define it), near the transport
defined in util.h, so they are near and we can easily update/review
changes.
BTW what about adding static asserts to check we are aligned?
+ char buf[KALLSYMS_LINE_LEN];
+ int ret = 0;
+ FILE *f;
+
+ f = fopen(KALLSYMS_PATH, "r");
+ if (!f) {
+ perror("Can't open " KALLSYMS_PATH);
+ exit(EXIT_FAILURE);
+ }
+
+ while (fgets(buf, sizeof(buf), f)) {
+ char *match;
+ int i;
+
+ assert(buf[strlen(buf) - 1] == '\n');
+
+ for (i = 0; i < ARRAY_SIZE(syms); ++i) {
+ match = strstr(buf, syms[i]);
+
+ /* Match should be followed by '\t' or '\n'.
+ * See kallsyms.c:s_show().
+ */
+ if (match && isspace(match[strlen(syms[i])])) {
+ ret |= _BITUL(i);
+ break;
+ }
+ }
+ }
+
+ fclose(f);
+ return ret;
+}
+
+/* Return integer with TRANSPORT_* bit set for every (known) registered vsock
+ * transport.
+ */
+int get_transports(void)
+{
+ static int tr = -1;
+
+ if (tr == -1)
+ tr = __get_transports();
+
+ return tr;
+}
diff --git a/tools/testing/vsock/util.h b/tools/testing/vsock/util.h
index
0afe7cbae12e5194172c639ccfbeb8b81f7c25ac..63953e32c3e18e1aa5c2addcf6f09f433660fa84
100644
--- a/tools/testing/vsock/util.h
+++ b/tools/testing/vsock/util.h
@@ -3,8 +3,19 @@
#define UTIL_H
#include <sys/socket.h>
+#include <linux/bitops.h>
#include <linux/vm_sockets.h>
+#define KALLSYMS_PATH "/proc/kallsyms"
+#define KALLSYMS_LINE_LEN 512
We don't need to expose them in util.h IMO, we can keep in util.c
+
+/* All known transports */
+#define TRANSPORT_LOOPBACK _BITUL(0)
+#define TRANSPORT_VIRTIO _BITUL(1)
+#define TRANSPORT_VHOST _BITUL(2)
+#define TRANSPORT_VMCI _BITUL(3)
+#define TRANSPORT_HYPERV _BITUL(4)
+
/* Tests can either run as the client or the server */
enum test_mode {
TEST_MODE_UNSET,
@@ -82,4 +93,5 @@ void setsockopt_timeval_check(int fd, int level, int optname,
struct timeval val, char const *errmsg);
void enable_so_zerocopy_check(int fd);
void enable_so_linger(int fd, int timeout);
+int get_transports(void);
#endif /* UTIL_H */
--
2.49.0
