Improve error propagation in tree scan code and handle ENOENT and EACCES gracefully

libnvme/examples/discover-loop.c

@@ -50,7 +50,7 @@ static void print_discover_log(struct nvmf_discovery_log *log)
 
 int main()
 {
-	struct nvmf_discovery_log *log = NULL;
+	struct nvmf_discovery_log *log;
 	struct nvme_global_ctx *ctx;
 	nvme_host_t h;
 	nvme_ctrl_t c;
@@ -59,24 +59,30 @@ int main()
 
 	nvmf_default_config(&cfg);
 
-	ret = nvme_scan(NULL, &ctx);
-	if (ret)
-		return ret;
+	ctx = nvme_create_global_ctx(stdout, DEFAULT_LOGLEVEL);
+	if (!ctx)
+		return 1;
+
+	ret = nvme_scan_topology(ctx, NULL, NULL);
+	if (ret) {
+		nvme_free_global_ctx(ctx);
+		return 1;
+	}
 	ret = nvme_host_get(ctx, NULL, NULL, &h);
 	if (ret) {
 		fprintf(stderr, "Failed to allocated memory\n");
-		return ret;
+		return 1;
 	}
 	ret = nvme_create_ctrl(ctx, NVME_DISC_SUBSYS_NAME, "loop",
 			       NULL, NULL, NULL, NULL, &c);
 	if (ret) {
 		fprintf(stderr, "Failed to allocate memory\n");
-		return ENOMEM;
+		return 1;
 	}
 	ret = nvmf_add_ctrl(h, c, &cfg);
 	if (ret) {
 		fprintf(stderr, "no controller found\n");
-		return ret;
+		return 1;
 	}
 
 	ret = nvmf_get_discovery_log(c, &log, 4);

libnvme/examples/display-columnar.c

@@ -23,9 +23,17 @@ int main()
 	nvme_ctrl_t c;
 	nvme_path_t p;
 	nvme_ns_t n;
+	int err;
 
-	if (nvme_scan(NULL, &ctx))
-		return -1;
+	ctx = nvme_create_global_ctx(stdout, DEFAULT_LOGLEVEL);
+	if (!ctx)
+		return 1;
+
+	err = nvme_scan_topology(ctx, NULL, NULL);
+	if (err) {
+		nvme_free_global_ctx(ctx);
+		return 1;
+	}
 
 	printf("%-16s %-96s %-.16s\n", "Subsystem", "Subsystem-NQN", "Controllers");
 	printf("%-.16s %-.96s %-.16s\n", dash, dash, dash);

libnvme/examples/display-tree.c

@@ -22,9 +22,17 @@ int main()
 	nvme_ctrl_t c, _c;
 	nvme_path_t p, _p;
 	nvme_ns_t n, _n;
+	int err;
 
-	if (nvme_scan(NULL, &ctx))
-		return -1;
+	ctx = nvme_create_global_ctx(stdout, DEFAULT_LOGLEVEL);
+	if (!ctx)
+		return 1;
+
+	err = nvme_scan_topology(ctx, NULL, NULL);
+	if (err) {
+		nvme_free_global_ctx(ctx);
+		return 1;
+	}
 
 	printf(".\n");
 	nvme_for_each_host(ctx, h) {

libnvme/examples/telemetry-listen.c

@@ -135,8 +135,14 @@ int main()
 	nvme_ctrl_t c;
 	nvme_host_t h;
 
-	if (nvme_scan(NULL, &ctx))
+	ctx = nvme_create_global_ctx(stdout, DEFAULT_LOGLEVEL);
+	if (!ctx)
+		return 1;
+
+	if (nvme_scan_topology(ctx, NULL, NULL)) {
+		nvme_free_global_ctx(ctx);
 		return EXIT_FAILURE;
+	}
 
 	nvme_for_each_host(ctx, h)
 		nvme_for_each_subsystem(h, s)

libnvme/libnvme/nvme.i

@@ -487,8 +487,14 @@ struct nvme_ns {
 %extend nvme_global_ctx {
 	nvme_global_ctx(const char *config_file = NULL) {
 		struct nvme_global_ctx *ctx;
-		if (nvme_scan(config_file, &ctx))
+
+		ctx = nvme_create_global_ctx(stdout, DEFAULT_LOGLEVEL);
+		if (!ctx)
 			return NULL;
+
+		nvme_scan_topology(ctx, NULL, NULL);
+		nvme_read_config(ctx, config_file);
+
 		return ctx;
 	}
 	~nvme_global_ctx() {

libnvme/src/libnvme.ld

@@ -208,7 +208,6 @@ LIBNVME_2_0 {
 		nvme_release_fds;
 		nvme_rescan_ctrl;
 		nvme_revoke_tls_key;
-		nvme_scan;
 		nvme_scan_ctrl;
 		nvme_scan_ctrl_namespace_paths;
 		nvme_scan_ctrl_namespaces;

libnvme/src/nvme/filters.c

@@ -78,37 +78,71 @@ int nvme_subsys_filter(const struct dirent *d)
 int nvme_scan_subsystems(struct dirent ***subsys)
 {
 	const char *dir = nvme_subsys_sysfs_dir();
+	int ret;
 
-	return scandir(dir, subsys, nvme_subsys_filter, alphasort);
+	ret = scandir(dir, subsys, nvme_subsys_filter, alphasort);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
 }
 
 int nvme_scan_subsystem_namespaces(nvme_subsystem_t s, struct dirent ***ns)
 {
-	return scandir(nvme_subsystem_get_sysfs_dir(s), ns,
+	int ret;
+
+	ret = scandir(nvme_subsystem_get_sysfs_dir(s), ns,
 		       nvme_namespace_filter, alphasort);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
 }
 
 int nvme_scan_ctrls(struct dirent ***ctrls)
 {
 	const char *dir = nvme_ctrl_sysfs_dir();
+	int ret;
 
-	return scandir(dir, ctrls, nvme_ctrls_filter, alphasort);
+	ret = scandir(dir, ctrls, nvme_ctrls_filter, alphasort);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
 }
 
 int nvme_scan_ctrl_namespace_paths(nvme_ctrl_t c, struct dirent ***paths)
 {
-	return scandir(nvme_ctrl_get_sysfs_dir(c), paths,
+	int ret;
+
+	ret = scandir(nvme_ctrl_get_sysfs_dir(c), paths,
 		       nvme_paths_filter, alphasort);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
 }
 
 int nvme_scan_ctrl_namespaces(nvme_ctrl_t c, struct dirent ***ns)
 {
-	return scandir(nvme_ctrl_get_sysfs_dir(c), ns,
+	int ret;
+
+	ret = scandir(nvme_ctrl_get_sysfs_dir(c), ns,
 		       nvme_namespace_filter, alphasort);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
 }
 
 int nvme_scan_ns_head_paths(nvme_ns_head_t head, struct dirent ***paths)
 {
-	return scandir(nvme_ns_head_get_sysfs_dir(head), paths,
+	int ret;
+
+	ret = scandir(nvme_ns_head_get_sysfs_dir(head), paths,
 		       nvme_paths_filter, alphasort);
+	if (ret < 0)
+		return -errno;
+
+	return ret;
 }

libnvme/src/nvme/filters.h

@@ -55,7 +55,7 @@ int nvme_subsys_filter(const struct dirent *d);
  * nvme_scan_subsystems() - Scan for subsystems
  * @subsys: Pointer to array of dirents
  *
- * Return: number of entries in @subsys
+ * Return: number of entries in @subsys or a negative error code
  */
 int nvme_scan_subsystems(struct dirent ***subsys);
 
@@ -64,15 +64,15 @@ int nvme_scan_subsystems(struct dirent ***subsys);
  * @s: Subsystem to scan
  * @ns: Pointer to array of dirents
  *
- * Return: number of entries in @ns
+ * Return: number of entries in @ns or a negative error code
  */
 int nvme_scan_subsystem_namespaces(nvme_subsystem_t s, struct dirent ***ns);
 
 /**
  * nvme_scan_ctrls() - Scan for controllers
  * @ctrls: Pointer to array of dirents
  *
- * Return: number of entries in @ctrls
+ * Return: number of entries in @ctrls or a negative error code
  */
 int nvme_scan_ctrls(struct dirent ***ctrls);
 
@@ -81,7 +81,7 @@ int nvme_scan_ctrls(struct dirent ***ctrls);
  * @c: Controller to scan
  * @paths: Pointer to array of dirents
  *
- * Return: number of entries in @paths
+ * Return: number of entries in @paths or a negative error code
  */
 int nvme_scan_ctrl_namespace_paths(nvme_ctrl_t c, struct dirent ***paths);
 
@@ -90,7 +90,7 @@ int nvme_scan_ctrl_namespace_paths(nvme_ctrl_t c, struct dirent ***paths);
  * @c: Controller to scan
  * @ns: Pointer to array of dirents
  *
- * Return: number of entries in @ns
+ * Return: number of entries in @ns or a negative error code
  */
 int nvme_scan_ctrl_namespaces(nvme_ctrl_t c, struct dirent ***ns);
 
@@ -99,7 +99,7 @@ int nvme_scan_ctrl_namespaces(nvme_ctrl_t c, struct dirent ***ns);
  * @head: Namespace head node to scan
  * @paths : Pointer to array of dirents
  *
- * Return: number of entries in @ents
+ * Return: number of entries in @ents or a negative error code
  */
 int nvme_scan_ns_head_paths(nvme_ns_head_t head, struct dirent ***paths);
 

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