tree: handle error when trying to get transport handle

nvme_ns_get_transport_handle is creating a handle on demand, which can
fail. Thus we need to propagate this error case and not blindly access
the handle later and cause a NULL pointer access.

Signed-off-by: Daniel Wagner <[email protected]>

Author: igaw

libnvme/src/nvme/private.h

@@ -739,6 +739,7 @@ static inline __u16 nvmf_exat_size(size_t val_len)
 /**
  * nvme_ns_get_transport_handle() - Get associated transport handle
  * @n:	Namespace instance
+ * @hdl: Transport handle
  *
  * libnvme will open() the file (if not already opened) and keep
  * an internal copy of the link handle. Following calls to
@@ -747,9 +748,10 @@ static inline __u16 nvmf_exat_size(size_t val_len)
  * remain cached until the ns object is deleted or
  * nvme_ns_release_transport_handle() is called.
  *
- * Return: Link handle with @n or NULL
+ * Return: On success 0, else error code.
  */
-struct nvme_transport_handle *nvme_ns_get_transport_handle(nvme_ns_t n);
+int nvme_ns_get_transport_handle(nvme_ns_t n,
+		struct nvme_transport_handle **hdl);
 
 /**
  * nvme_ns_release_transport_handle() - Free transport handle from ns object

libnvme/src/nvme/tree.c

@@ -2299,19 +2299,24 @@ static int nvme_bytes_to_lba(nvme_ns_t n, off_t offset, size_t count,
 	return 0;
 }
 
-struct nvme_transport_handle *nvme_ns_get_transport_handle(nvme_ns_t n)
+int nvme_ns_get_transport_handle(nvme_ns_t n,
+		struct nvme_transport_handle **hdl)
 {
-	if (!n->hdl) {
-		int err;
+	int err;
 
-		err = nvme_open(n->ctx, n->name, &n->hdl);
-		if (err)
-			nvme_msg(n->ctx, LOG_ERR,
-				 "Failed to open ns %s, error %d\n",
-				 n->name, err);
+	if (n->hdl)
+		goto valid;
+
+	err = nvme_open(n->ctx, n->name, &n->hdl);
+	if (err) {
+		nvme_msg(n->ctx, LOG_ERR, "Failed to open ns %s, error %d\n",
+			n->name, err);
+		return err;
 	}
 
-	return n->hdl;
+valid:
+	*hdl = n->hdl;
+	return 0;
 }
 
 void nvme_ns_release_transport_handle(nvme_ns_t n)
@@ -2415,28 +2420,43 @@ void nvme_ns_get_uuid(nvme_ns_t n, unsigned char out[NVME_UUID_LEN])
 
 int nvme_ns_identify(nvme_ns_t n, struct nvme_id_ns *ns)
 {
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return err;
 
 	nvme_init_identify_ns(&cmd, nvme_ns_get_nsid(n), ns);
 	return nvme_submit_admin_passthru(hdl, &cmd);
 }
 
 int nvme_ns_identify_descs(nvme_ns_t n, struct nvme_ns_id_desc *descs)
 {
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return err;
 
 	nvme_init_identify_ns_descs_list(&cmd, nvme_ns_get_nsid(n), descs);
 	return nvme_submit_admin_passthru(hdl, &cmd);
 }
 
 int nvme_ns_verify(nvme_ns_t n, off_t offset, size_t count)
 {
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
 	__u64 slba;
 	__u16 nlb;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return err;
 
 	if (nvme_bytes_to_lba(n, offset, count, &slba, &nlb))
 		return -1;
@@ -2449,10 +2469,15 @@ int nvme_ns_verify(nvme_ns_t n, off_t offset, size_t count)
 
 int nvme_ns_write_uncorrectable(nvme_ns_t n, off_t offset, size_t count)
 {
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
 	__u64 slba;
 	__u16 nlb;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return err;
 
 	if (nvme_bytes_to_lba(n, offset, count, &slba, &nlb))
 		return -1;
@@ -2465,10 +2490,15 @@ int nvme_ns_write_uncorrectable(nvme_ns_t n, off_t offset, size_t count)
 
 int nvme_ns_write_zeros(nvme_ns_t n, off_t offset, size_t count)
 {
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
 	__u64 slba;
 	__u16 nlb;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return err;
 
 	if (nvme_bytes_to_lba(n, offset, count, &slba, &nlb))
 		return -1;
@@ -2480,10 +2510,15 @@ int nvme_ns_write_zeros(nvme_ns_t n, off_t offset, size_t count)
 
 int nvme_ns_write(nvme_ns_t n, void *buf, off_t offset, size_t count)
 {
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
 	__u64 slba;
 	__u16 nlb;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return err;
 
 	if (nvme_bytes_to_lba(n, offset, count, &slba, &nlb))
 		return -1;
@@ -2496,10 +2531,15 @@ int nvme_ns_write(nvme_ns_t n, void *buf, off_t offset, size_t count)
 
 int nvme_ns_read(nvme_ns_t n, void *buf, off_t offset, size_t count)
 {
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
 	__u64 slba;
 	__u16 nlb;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return err;
 
 	if (nvme_bytes_to_lba(n, offset, count, &slba, &nlb))
 		return -1;
@@ -2512,10 +2552,15 @@ int nvme_ns_read(nvme_ns_t n, void *buf, off_t offset, size_t count)
 
 int nvme_ns_compare(nvme_ns_t n, void *buf, off_t offset, size_t count)
 {
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
 	__u64 slba;
 	__u16 nlb;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return err;
 
 	if (nvme_bytes_to_lba(n, offset, count, &slba, &nlb))
 		return -1;
@@ -2528,8 +2573,14 @@ int nvme_ns_compare(nvme_ns_t n, void *buf, off_t offset, size_t count)
 
 int nvme_ns_flush(nvme_ns_t n)
 {
-	return nvme_flush(nvme_ns_get_transport_handle(n),
-			  nvme_ns_get_nsid(n));
+	struct nvme_transport_handle *hdl;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return err;
+
+	return nvme_flush(hdl, nvme_ns_get_nsid(n));
 }
 
 static int nvme_strtou64(const char *str, void *res)

libnvme/test/test.c

@@ -324,13 +324,17 @@ static int test_ctrl(nvme_ctrl_t c)
 static int test_namespace(nvme_ns_t n)
 {
 	int ret, nsid = nvme_ns_get_nsid(n);
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
 	struct nvme_id_ns ns = { 0 }, allocated = { 0 };
 	struct nvme_ns_id_desc *descs;
 	__u64 result = 0;
 	__u8 flbas;
 
+	ret = nvme_ns_get_transport_handle(n, &hdl);
+	if (ret)
+		return ret;
+
 	ret = nvme_ns_identify(n, &ns);
 	if (ret)
 		return ret;

libnvme/test/zns.c

@@ -24,11 +24,16 @@
 
 static void show_zns_properties(nvme_ns_t n)
 {
-	struct nvme_transport_handle *hdl = nvme_ns_get_transport_handle(n);
+	struct nvme_transport_handle *hdl;
 	struct nvme_passthru_cmd cmd;
 	struct nvme_zns_id_ns zns_ns;
 	struct nvme_zns_id_ctrl zns_ctrl;
 	struct nvme_zone_report *zr;
+	int err;
+
+	err = nvme_ns_get_transport_handle(n, &hdl);
+	if (err)
+		return;
 
 	zr = calloc(1, 0x1000);
 	if (!zr)