From: Hannes Reinecke <hare@suse.de>
Date: Wed, 24 Mar 2021 07:22:28 +0000 (+0100)
Subject: Read system UUID from DMI and merge hostnqn generation functions
X-Git-Tag: v1.14~32
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=3e0520ecad13b768519ca6b402d8be86e2a48c6b;p=users%2Fsagi%2Fnvme-cli.git

Read system UUID from DMI and merge hostnqn generation functions

Both fabrics.c and the 'gen-hostnqn' command contain functions
to generate a default host NQN. Needless to say, both are different.
_And_ we have the script 'nvme-gen-hostnqn' to read the host nqn
from the system UUID, implement yet another way.

This patch merges all of these functions, and implements a hierarchy
in generating host NQNs:
- Try reading system UUID from /sys/firmware/dmi/entries
- Try reading systemd-generated UUID
- Generate a random UUID

Signed-off-by: Hannes Reinecke <hare@suse.de>
---

diff --git a/fabrics.c b/fabrics.c
index 1615901e..ea8380a4 100644
--- a/fabrics.c
+++ b/fabrics.c
@@ -818,6 +818,18 @@ static char *hostnqn_generate_systemd(void)
 #endif
 }
 
+static char *hostnqn_read_dmi(void)
+{
+	char uuid[16];
+	char *ret = NULL;
+
+	if (uuid_from_dmi(uuid) < 0)
+		return NULL;
+	if (asprintf(&ret, "nqn.2014-08.org.nvmexpress:uuid:%s", uuid) == -1)
+		return NULL;
+	return ret;
+}
+
 /* returns an allocated string or NULL */
 char *hostnqn_read(void)
 {
@@ -827,6 +839,10 @@ char *hostnqn_read(void)
 	if (ret)
 		return ret;
 
+	ret = hostnqn_read_dmi();
+	if (ret)
+		return ret;
+
 	ret = hostnqn_generate_systemd();
 	if (ret)
 		return ret;
diff --git a/nvme-topology.c b/nvme-topology.c
index 63e433d7..db0714f7 100644
--- a/nvme-topology.c
+++ b/nvme-topology.c
@@ -696,3 +696,76 @@ void *mmap_registers(const char *dev)
 	return membase;
 }
 
+#define PATH_DMI_ENTRIES	"/sys/firmware/dmi/entries"
+
+int uuid_from_dmi(char *system_uuid)
+{
+	int f;
+	DIR *d;
+	struct dirent *de;
+	char buf[512];
+
+	system_uuid[0] = '\0';
+	d = opendir(PATH_DMI_ENTRIES);
+	if (!d)
+		return -ENXIO;
+	while ((de = readdir(d))) {
+		char filename[PATH_MAX];
+		int len, type;
+
+		if (de->d_name[0] == '.')
+			continue;
+		sprintf(filename, "%s/%s/type", PATH_DMI_ENTRIES, de->d_name);
+		f = open(filename, O_RDONLY);
+		if (f < 0)
+			continue;
+		len = read(f, buf, 512);
+		close(f);
+		if (len < 0)
+			continue;
+		if (sscanf(buf, "%d", &type) != 1)
+			continue;
+		if (type != 1)
+			continue;
+		sprintf(filename, "%s/%s/raw", PATH_DMI_ENTRIES, de->d_name);
+		f = open(filename, O_RDONLY);
+		if (f < 0)
+			continue;
+		len = read(f, buf, 512);
+		close(f);
+		if (len < 0)
+			continue;
+		/* Sigh. https://en.wikipedia.org/wiki/Overengineering */
+		/* DMTF SMBIOS 3.0 Section 7.2.1 System UUID */
+		sprintf(system_uuid,
+			"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-"
+			"%02x%02x%02x%02x%02x%02x",
+			(uint8_t)buf[8 + 3], (uint8_t)buf[8 + 2],
+			(uint8_t)buf[8 + 1], (uint8_t)buf[8 + 0],
+			(uint8_t)buf[8 + 5], (uint8_t)buf[8 + 4],
+			(uint8_t)buf[8 + 7], (uint8_t)buf[8 + 6],
+			(uint8_t)buf[8 + 8], (uint8_t)buf[8 + 9],
+			(uint8_t)buf[8 + 10], (uint8_t)buf[8 + 11],
+			(uint8_t)buf[8 + 12], (uint8_t)buf[8 + 13],
+			(uint8_t)buf[8 + 14], (uint8_t)buf[8 + 15]);
+		break;
+	}
+	closedir(d);
+	return strlen(system_uuid) ? 0 : -ENXIO;
+}
+
+int uuid_from_systemd(char *systemd_uuid)
+{
+#ifdef HAVE_SYSTEMD
+	sd_id128_t id;
+	char *ret;
+
+	if (sd_id128_get_machine_app_specific(NVME_HOSTNQN_ID, &id) < 0)
+		return -ENXIO;
+
+	sprintf(systemd_uuid, SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(id));
+	return 0;
+#else
+	return -ENOTSUP;
+#endif
+}
diff --git a/nvme.c b/nvme.c
index 8751ffd4..5e77e3f6 100644
--- a/nvme.c
+++ b/nvme.c
@@ -5581,25 +5581,32 @@ static int admin_passthru(int argc, char **argv, struct command *cmd, struct plu
 	return passthru(argc, argv, NVME_IOCTL_ADMIN_CMD, 1, desc, cmd);
 }
 
-#ifdef LIBUUID
 static int gen_hostnqn_cmd(int argc, char **argv, struct command *command, struct plugin *plugin)
 {
-	uuid_t uuid;
+	int ret;
 	char uuid_str[37]; /* e.g. 1b4e28ba-2fa1-11d2-883f-0016d3cca427 + \0 */
+#ifdef LIBUUID
+	uuid_t uuid;
+#endif
 
-	uuid_generate_random(uuid);
-	uuid_unparse_lower(uuid, uuid_str);
+	ret = uuid_from_dmi(uuid_str);
+	if (ret < 0)
+		ret = uuid_from_systemd(uuid_str);
+#ifdef LIBUUID
+	if (ret < 0) {
+		uuid_generate_random(uuid);
+		uuid_unparse_lower(uuid, uuid_str);
+		ret = 0;
+	}
+#endif
+	if (ret < 0) {
+		fprintf(stderr, "\"%s\" not supported. Install lib uuid and rebuild.\n",
+			command->name);
+		return -ENOTSUP;
+	}
 	printf("nqn.2014-08.org.nvmexpress:uuid:%s\n", uuid_str);
 	return 0;
 }
-#else
-static int gen_hostnqn_cmd(int argc, char **argv, struct command *command, struct plugin *plugin)
-{
-	fprintf(stderr, "\"%s\" not supported. Install lib uuid and rebuild.\n",
-		command->name);
-	return -ENOTSUP;
-}
-#endif
 
 static int show_hostnqn_cmd(int argc, char **argv, struct command *command, struct plugin *plugin)
 {
diff --git a/nvme.h b/nvme.h
index 1ffbb1f6..9d772857 100644
--- a/nvme.h
+++ b/nvme.h
@@ -139,6 +139,9 @@ char *nvme_get_ctrl_attr(char *path, const char *attr);
 void *nvme_alloc(size_t len, bool *huge);
 void nvme_free(void *p, bool huge);
 
+int uuid_from_dmi(char *uuid);
+int uuid_from_systemd(char *uuid);
+
 unsigned long long elapsed_utime(struct timeval start_time,
 					struct timeval end_time);
 #endif /* _NVME_H */