filter-mpath: get wwids from sysfs vpd_pg83

to compare with wwids in /etc/multipath/wwids when
excluding multipath components.  The wwid printed
from the sysfs wwid file may not be the wwid used
in multipath wwids.  Save the wwids found for each
device on dev->wwids to avoid repeating reading
and parsing the sysfs files.

lib/device/dev-mpath.c

@@ -200,11 +200,12 @@ static void _read_wwid_exclusions(void)
 		log_debug("multipath config ignored %d wwids", rem_count);
 }
 
-static void _read_wwid_file(const char *config_wwids_file)
+static void _read_wwid_file(const char *config_wwids_file, int *entries)
 {
 	FILE *fp;
 	char line[MAX_WWID_LINE];
 	char *wwid, *p;
+	char typestr[2] = { 0 };
 	int count = 0;
 
 	if (config_wwids_file[0] != '/') {
@@ -226,8 +227,17 @@ static void _read_wwid_file(const char *config_wwids_file)
 		if (line[0] == '/')
 			wwid++;
 
-		/* skip the initial '3' */
-		wwid++;
+
+		/*
+		 * the initial character is the id type,
+		 * 1 is t10, 2 is eui, 3 is naa, 8 is scsi name.
+		 * wwids are stored in the hash table without the type charater.
+		 * It seems that sometimes multipath does not include
+		 * the type charater (seen with t10 scsi_debug devs).
+		 */
+		typestr[0] = *wwid;
+		if (typestr[0] == '1' || typestr[0] == '2' || typestr[0] == '3')
+			wwid++;
 
 		if ((p = strchr(wwid, '/')))
 			*p = '\0';
@@ -240,6 +250,7 @@ static void _read_wwid_file(const char *config_wwids_file)
 		stack;
 
 	log_debug("multipath wwids read %d from %s", count, config_wwids_file);
+	*entries = count;
 }
 
 int dev_mpath_init(const char *config_wwids_file)
@@ -247,6 +258,7 @@ int dev_mpath_init(const char *config_wwids_file)
 	struct dm_pool *mem;
 	struct dm_hash_table *minor_tab;
 	struct dm_hash_table *wwid_tab;
+	int entries = 0;
 
 	dm_list_init(&_ignored);
 	dm_list_init(&_ignored_exceptions);
@@ -283,10 +295,16 @@ int dev_mpath_init(const char *config_wwids_file)
 	_wwid_hash_tab = wwid_tab;
 
 	if (config_wwids_file) {
-		_read_wwid_file(config_wwids_file);
+		_read_wwid_file(config_wwids_file, &entries);
 		_read_wwid_exclusions();
 	}
 
+	if (!entries) {
+		/* reading dev wwids is skipped with null wwid_hash_tab */
+		dm_hash_destroy(_wwid_hash_tab);
+		_wwid_hash_tab = NULL;
+	}
+
 	return 1;
 }
 
@@ -432,10 +450,10 @@ static int _dev_is_mpath_component_udev(struct device *dev)
 }
 #endif
 
-static int _dev_is_mpath_component_sysfs(struct cmd_context *cmd, struct device *dev)
+static int _dev_is_mpath_component_sysfs(struct cmd_context *cmd, struct device *dev,
+					 int primary_result, dev_t primary_dev)
 {
 	struct dev_types *dt = cmd->dev_types;
-	const char *part_name;
 	const char *name;               /* e.g. "sda" for "/dev/sda" */
 	char link_path[PATH_MAX];       /* some obscure, unpredictable sysfs path */
 	char holders_path[PATH_MAX];    /* e.g. "/sys/block/sda/holders/" */
@@ -449,25 +467,15 @@ static int _dev_is_mpath_component_sysfs(struct cmd_context *cmd, struct device
 	int dm_dev_major;
 	int dm_dev_minor;
 	struct stat info;
-	dev_t primary_dev;
 	int is_mpath_component = 0;
 
-	/* multipathing is only known to exist for SCSI or NVME devices */
-	if (!major_is_scsi_device(dt, dev_major) && !dev_is_nvme(dt, dev))
-		return 0;
-
-	switch (dev_get_primary_dev(dt, dev, &primary_dev)) {
+	switch (primary_result) {
 
 	case 2: /* The dev is partition. */
-		part_name = dev_name(dev); /* name of original dev for log_debug msg */
 
 		/* gets "foo" for "/dev/foo" where "/dev/foo" comes from major:minor */
 		if (!(name = _get_sysfs_name_by_devt(sysfs_dir, primary_dev, link_path, sizeof(link_path))))
 			return_0;
-
-		log_debug_devs("%s: Device is a partition, using primary "
-			       "device %s for mpath component detection",
-			       part_name, name);
 		break;
 
 	case 1: /* The dev is already a primary dev. Just continue with the dev. */
@@ -589,47 +597,189 @@ static int _dev_is_mpath_component_sysfs(struct cmd_context *cmd, struct device
 	return is_mpath_component;
 }
 
-static int _dev_in_wwid_file(struct cmd_context *cmd, struct device *dev)
+static int _read_sys_wwid(struct cmd_context *cmd, struct device *dev,
+			  char *idbuf, int idbufsize)
 {
-	char sysbuf[PATH_MAX] = { 0 };
+	char idtmp[DEV_WWID_SIZE];
+
+	if (!read_sys_block(cmd, dev, "device/wwid", idbuf, idbufsize)) {
+		/* the wwid file is not under device for nvme devs */
+		if (!read_sys_block(cmd, dev, "wwid", idbuf, idbufsize))
+			return 0;
+	}
+	if (!idbuf[0])
+		return 0;
+
+	/* in t10 id, replace series of spaces with one _ like multipath */
+	if (!strncmp(idbuf, "t10.", 4) && strchr(idbuf, ' ')) {
+		if (idbufsize < DEV_WWID_SIZE)
+			return 0;
+		memcpy(idtmp, idbuf, DEV_WWID_SIZE);
+		memset(idbuf, 0, idbufsize);
+		format_t10_id((const unsigned char *)idtmp, DEV_WWID_SIZE, (unsigned char *)idbuf, idbufsize);
+	}
+	return 1;
+}
+
+#define VPD_SIZE 4096
+
+static int _read_sys_vpd_wwids(struct cmd_context *cmd, struct device *dev,
+			       struct dm_list *ids)
+{
+	unsigned char vpd_data[VPD_SIZE] = { 0 };
+	int vpd_datalen = 0;
+
+	if (!read_sys_block_binary(cmd, dev, "device/vpd_pg83", (char *)vpd_data, VPD_SIZE, &vpd_datalen))
+		return 0;
+	if (!vpd_datalen)
+		return 0;
+
+	/* adds dev_wwid entry to dev->wwids for each id in vpd data */
+	parse_vpd_ids(vpd_data, vpd_datalen, ids);
+	return 1;
+}
+
+void free_wwids(struct dm_list *ids)
+{
+	struct dev_wwid *dw, *safe;
+
+	dm_list_iterate_items_safe(dw, safe, ids) {
+		dm_list_del(&dw->list);
+		free(dw);
+	}
+}
+
+static int _wwid_type_num(char *id)
+{
+	if (!strncmp(id, "naa.", 4))
+		return 3;
+	else if (!strncmp(id, "eui.", 4))
+		return 2;
+	else if (!strncmp(id, "t10.", 4))
+		return 1;
+	else
+		return -1;
+}
+
+/*
+ * TODO: if each of the different wwid types (naa/eui/t10) were
+ * represented by different DEV_ID_TYPE_FOO values, and used
+ * as device_id types, then we could drop struct dev_wwid and
+ * drop dev->wwids, and just use dev->ids for each of the
+ * different wwids found in vpd_pg83.  This would also require
+ * the ability to handle both the original method of replacing
+ * every space in the id string with _ and the new/multipath
+ * format_t10_id replacing series of spaces with one _.
+ */
+struct dev_wwid *add_wwid(char *id, int id_type, struct dm_list *ids)
+{
+	struct dev_wwid *dw;
+	int len;
+
+	if (!id_type) {
+		id_type = _wwid_type_num(id);
+		if (id_type == -1)
+			log_debug("unknown wwid type %s", id);
+	}
+
+	if (!(dw = zalloc(sizeof(struct dev_wwid))))
+		return NULL;
+	len = strlen(id);
+	if (len >= DEV_WWID_SIZE)
+		len = DEV_WWID_SIZE - 1;
+	memcpy(dw->id, id, len);
+	dw->type = id_type;
+	dm_list_add(ids, &dw->list);
+	return dw;
+}
+
+/*
+ * we save ids with format: naa.<value>, eui.<value>, t10.<value>.
+ * multipath wwids file uses format: 3<value>, 2<value>, 1<value>.
+ * The values are saved in wwid_hash_tab without the type prefix.
+ */
+
+static int _dev_in_wwid_file(struct cmd_context *cmd, struct device *dev,
+			     int primary_result, dev_t primary_dev)
+{
+	char idbuf[DEV_WWID_SIZE] = { 0 };
+	struct dev_wwid *dw;
 	char *wwid;
-	long look;
 
 	if (!_wwid_hash_tab)
 		return 0;
 
-	if (!read_sys_block(cmd, dev, "device/wwid", sysbuf, sizeof(sysbuf)))
-		return 0;
-
-	if (!sysbuf[0])
-		return 0;
+	/*
+	 * Check the primary device, not the partition.
+	 */
+	if (primary_result == 2) {
+		if (!(dev = dev_cache_get_by_devt(cmd, primary_dev))) {
+			log_debug("dev_is_mpath_component %s no primary dev", dev_name(dev));
+			return 0;
+		}
+	}
 
 	/*
-	 * sysfs prints wwid as <typestr>.<value>
-	 * multipath wwid uses '3'<value>
-	 * does "<typestr>." always correspond to "3"?
+	 * This function may be called multiple times for the same device, in
+	 * particular if partitioned for each partition.
 	 */
-	if (!(wwid = strchr(sysbuf, '.')))
-		return 0;
+	if (!dm_list_empty(&dev->wwids))
+		goto lookup;
 
-	/* skip the type and dot, just as '3' was skipped from wwids entry */
-	wwid++;
-	
-	look = (long) dm_hash_lookup_binary(_wwid_hash_tab, wwid, strlen(wwid));
+	/*
+	 * Get all the ids for the device from vpd_pg83 and check if any of
+	 * those are in /etc/multipath/wwids.  These ids should include the
+	 * value printed from the sysfs wwid file.
+	 */
+	_read_sys_vpd_wwids(cmd, dev, &dev->wwids);
+	if (!dm_list_empty(&dev->wwids))
+		goto lookup;
 
-	if (look) {
-		log_debug_devs("dev_is_mpath_component %s multipath wwid %s", dev_name(dev), wwid);
-		return 1;
+	/*
+	 * This will read the sysfs wwid file, nvme devices in particular have
+	 * a wwid file but not a vpd_pg83 file.
+	 */
+	if (_read_sys_wwid(cmd, dev, idbuf, sizeof(idbuf)))
+		add_wwid(idbuf, 0, &dev->wwids);
+
+ lookup:
+	dm_list_iterate_items(dw, &dev->wwids) {
+		if (dw->type == 1 || dw->type == 2 || dw->type == 3)
+			wwid = &dw->id[4];
+		else
+			wwid = dw->id;
+
+		if (dm_hash_lookup_binary(_wwid_hash_tab, wwid, strlen(wwid))) {
+			log_debug_devs("dev_is_mpath_component %s %s in wwids file", dev_name(dev), dw->id);
+			return 1;
+		}
 	}
+
 	return 0;
 }
 
 int dev_is_mpath_component(struct cmd_context *cmd, struct device *dev)
 {
-	if (_dev_is_mpath_component_sysfs(cmd, dev) == 1)
+	struct dev_types *dt = cmd->dev_types;
+	int primary_result;
+	dev_t primary_dev;
+
+	/*
+	 * multipath only uses SCSI or NVME devices
+	 */
+	if (!major_is_scsi_device(dt, MAJOR(dev->dev)) && !dev_is_nvme(dt, dev))
+		return 0;
+
+	/*
+	 * primary_result 2: dev is a partition, primary_dev is the whole device
+	 * primary_result 1: dev is a whole device
+	 */
+	primary_result = dev_get_primary_dev(dt, dev, &primary_dev);
+
+	if (_dev_is_mpath_component_sysfs(cmd, dev, primary_result, primary_dev) == 1)
 		goto found;
 
-	if (_dev_in_wwid_file(cmd, dev))
+	if (_dev_in_wwid_file(cmd, dev, primary_result, primary_dev))
 		goto found;
 
 	if (external_device_info_source() == DEV_EXT_UDEV) {
@@ -637,6 +787,12 @@ int dev_is_mpath_component(struct cmd_context *cmd, struct device *dev)
 			goto found;
 	}
 
+	/*
+	 * TODO: save the result of this function in dev->flags and use those
+	 * flags on repeated calls to avoid repeating the work multiple times
+	 * for the same device when there are partitions on the device.
+	 */
+
 	return 0;
 found:
 	return 1;