udev/udev-builtin-path_id.c - pub/scm/linux/hotplug/udev - Git at Google

 /*
  * compose persistent device path
  *
  * Copyright (C) 2009-2011 Kay Sievers <kay.sievers@vrfy.org>
  *
  * Logic based on Hannes Reinecke's shell script.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
 #include <unistd.h>
 #include <string.h>
 #include <ctype.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <dirent.h>
 #include <getopt.h>

 #include "udev.h"

 static int path_prepend(char **path, const char *fmt, ...)
 {
 	va_list va;
 	char *pre;
 	int err = 0;

 	va_start(va, fmt);
 	err = vasprintf(&pre, fmt, va);
 	va_end(va);
 	if (err < 0)
 		goto out;

 	if (*path != NULL) {
 		char *new;

 		err = asprintf(&new, "%s-%s", pre, *path);
 		free(pre);
 		if (err < 0)
 			goto out;
 		free(*path);
 		*path = new;
 	} else {
 		*path = pre;
 	}
 out:
 	return err;
 }

 /*
 ** Linux only supports 32 bit luns.
 ** See drivers/scsi/scsi_scan.c::scsilun_to_int() for more details.
 */
 static int format_lun_number(struct udev_device *dev, char **path)
 {
 	unsigned long lun = strtoul(udev_device_get_sysnum(dev), NULL, 10);

 	/* address method 0, peripheral device addressing with bus id of zero */
 	if (lun < 256)
 		return path_prepend(path, "lun-%d", lun);
 	/* handle all other lun addressing methods by using a variant of the original lun format */
 	return path_prepend(path, "lun-0x%04x%04x00000000", (lun & 0xffff), (lun >> 16) & 0xffff);
 }

 static struct udev_device *skip_subsystem(struct udev_device *dev, const char *subsys)
 {
 	struct udev_device *parent = dev;

 	while (parent != NULL) {
 		const char *subsystem;

 		subsystem = udev_device_get_subsystem(parent);
 		if (subsystem == NULL || strcmp(subsystem, subsys) != 0)
 			break;
 		dev = parent;
 		parent = udev_device_get_parent(parent);
 	}
 	return dev;
 }

 static struct udev_device *handle_scsi_fibre_channel(struct udev_device *parent, char **path)
 {
 	struct udev *udev  = udev_device_get_udev(parent);
 	struct udev_device *targetdev;
 	struct udev_device *fcdev = NULL;
 	const char *port;
 	char *lun = NULL;;

 	targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 	if (targetdev == NULL)
 		return NULL;

 	fcdev = udev_device_new_from_subsystem_sysname(udev, "fc_transport", udev_device_get_sysname(targetdev));
 	if (fcdev == NULL)
 		return NULL;
 	port = udev_device_get_sysattr_value(fcdev, "port_name");
 	if (port == NULL) {
 		parent = NULL;
 		goto out;
 	}

 	format_lun_number(parent, &lun);
 	path_prepend(path, "fc-%s-%s", port, lun);
 	if (lun)
 		free(lun);
 out:
 	udev_device_unref(fcdev);
 	return parent;
 }

 static struct udev_device *handle_scsi_sas(struct udev_device *parent, char **path)
 {
 	struct udev *udev  = udev_device_get_udev(parent);
 	struct udev_device *targetdev;
 	struct udev_device *target_parent;
 	struct udev_device *sasdev;
 	const char *sas_address;
 	char *lun = NULL;

 	targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
 	if (targetdev == NULL)
 		return NULL;

 	target_parent = udev_device_get_parent(targetdev);
 	if (target_parent == NULL)
 		return NULL;

 	sasdev = udev_device_new_from_subsystem_sysname(udev, "sas_device",
 				udev_device_get_sysname(target_parent));
 	if (sasdev == NULL)
 		return NULL;

 	sas_address = udev_device_get_sysattr_value(sasdev, "sas_address");
 	if (sas_address == NULL) {
 		parent = NULL;
 		goto out;
 	}

 	format_lun_number(parent, &lun);
 	path_prepend(path, "sas-%s-%s", sas_address, lun);
 	if (lun)
 		free(lun);
 out:
 	udev_device_unref(sasdev);
 	return parent;
 }

 static struct udev_device *handle_scsi_iscsi(struct udev_device *parent, char **path)
 {
 	struct udev *udev  = udev_device_get_udev(parent);
 	struct udev_device *transportdev;
 	struct udev_device *sessiondev = NULL;
 	const char *target;
 	char *connname;
 	struct udev_device *conndev = NULL;
 	const char *addr;
 	const char *port;
 	char *lun = NULL;

 	/* find iscsi session */
 	transportdev = parent;
 	for (;;) {
 		transportdev = udev_device_get_parent(transportdev);
 		if (transportdev == NULL)
 			return NULL;
 		if (strncmp(udev_device_get_sysname(transportdev), "session", 7) == 0)
 			break;
 	}

 	/* find iscsi session device */
 	sessiondev = udev_device_new_from_subsystem_sysname(udev, "iscsi_session", udev_device_get_sysname(transportdev));
 	if (sessiondev == NULL)
 		return NULL;
 	target = udev_device_get_sysattr_value(sessiondev, "targetname");
 	if (target == NULL) {
 		parent = NULL;
 		goto out;
 	}

 	if (asprintf(&connname, "connection%s:0", udev_device_get_sysnum(transportdev)) < 0) {
 		parent = NULL;
 		goto out;
 	}
 	conndev = udev_device_new_from_subsystem_sysname(udev, "iscsi_connection", connname);
 	free(connname);
 	if (conndev == NULL) {
 		parent = NULL;
 		goto out;
 	}
 	addr = udev_device_get_sysattr_value(conndev, "persistent_address");
 	port = udev_device_get_sysattr_value(conndev, "persistent_port");
 	if (addr == NULL || port == NULL) {
 		parent = NULL;
 		goto out;
 	}

 	format_lun_number(parent, &lun);
 	path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
 	if (lun)
 		free(lun);
 out:
 	udev_device_unref(sessiondev);
 	udev_device_unref(conndev);
 	return parent;
 }

 static struct udev_device *handle_scsi_default(struct udev_device *parent, char **path)
 {
 	struct udev_device *hostdev;
 	int host, bus, target, lun;
 	const char *name;
 	char *base;
 	char *pos;
 	DIR *dir;
 	struct dirent *dent;
 	int basenum;

 	hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
 	if (hostdev == NULL)
 		return NULL;

 	name = udev_device_get_sysname(parent);
 	if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
 		return NULL;

 	/* rebase host offset to get the local relative number */
 	basenum = -1;
 	base = strdup(udev_device_get_syspath(hostdev));
 	if (base == NULL)
 		return NULL;
 	pos = strrchr(base, '/');
 	if (pos == NULL) {
 		parent = NULL;
 		goto out;
 	}
 	pos[0] = '\0';
 	dir = opendir(base);
 	if (dir == NULL) {
 		parent = NULL;
 		goto out;
 	}
 	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 		char *rest;
 		int i;

 		if (dent->d_name[0] == '.')
 			continue;
 		if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
 			continue;
 		if (strncmp(dent->d_name, "host", 4) != 0)
 			continue;
 		i = strtoul(&dent->d_name[4], &rest, 10);
 		if (rest[0] != '\0')
 			continue;
 		if (basenum == -1 || i < basenum)
 			basenum = i;
 	}
 	closedir(dir);
 	if (basenum == -1) {
 		parent = NULL;
 		goto out;
 	}
 	host -= basenum;

 	path_prepend(path, "scsi-%u:%u:%u:%u", host, bus, target, lun);
 out:
 	free(base);
 	return hostdev;
 }

 static struct udev_device *handle_scsi(struct udev_device *parent, char **path)
 {
 	const char *devtype;
 	const char *name;
 	const char *id;

 	devtype = udev_device_get_devtype(parent);
 	if (devtype == NULL || strcmp(devtype, "scsi_device") != 0)
 		return parent;

 	/* firewire */
 	id = udev_device_get_sysattr_value(parent, "ieee1394_id");
 	if (id != NULL) {
 		parent = skip_subsystem(parent, "scsi");
 		path_prepend(path, "ieee1394-0x%s", id);
 		goto out;
 	}

 	/* lousy scsi sysfs does not have a "subsystem" for the transport */
 	name = udev_device_get_syspath(parent);

 	if (strstr(name, "/rport-") != NULL) {
 		parent = handle_scsi_fibre_channel(parent, path);
 		goto out;
 	}

 	if (strstr(name, "/end_device-") != NULL) {
 		parent = handle_scsi_sas(parent, path);
 		goto out;
 	}

 	if (strstr(name, "/session") != NULL) {
 		parent = handle_scsi_iscsi(parent, path);
 		goto out;
 	}

 	parent = handle_scsi_default(parent, path);
 out:
 	return parent;
 }

 static void handle_scsi_tape(struct udev_device *dev, char **path)
 {
 	const char *name;

 	/* must be the last device in the syspath */
 	if (*path != NULL)
 		return;

 	name = udev_device_get_sysname(dev);
 	if (strncmp(name, "nst", 3) == 0 && strchr("lma", name[3]) != NULL)
 		path_prepend(path, "nst%c", name[3]);
 	else if (strncmp(name, "st", 2) == 0 && strchr("lma", name[2]) != NULL)
 		path_prepend(path, "st%c", name[2]);
 }

 static struct udev_device *handle_usb(struct udev_device *parent, char **path)
 {
 	const char *devtype;
 	const char *str;
 	const char *port;

 	devtype = udev_device_get_devtype(parent);
 	if (devtype == NULL)
 		return parent;
 	if (strcmp(devtype, "usb_interface") != 0 && strcmp(devtype, "usb_device") != 0)
 		return parent;

 	str = udev_device_get_sysname(parent);
 	port = strchr(str, '-');
 	if (port == NULL)
 		return parent;
 	port++;

 	parent = skip_subsystem(parent, "usb");
 	path_prepend(path, "usb-0:%s", port);
 	return parent;
 }

 static struct udev_device *handle_cciss(struct udev_device *parent, char **path)
 {
 	return NULL;
 }

 static struct udev_device *handle_ccw(struct udev_device *parent, struct udev_device *dev, char **path)
 {
 	struct udev_device *scsi_dev;

 	scsi_dev = udev_device_get_parent_with_subsystem_devtype(dev, "scsi", "scsi_device");
 	if (scsi_dev != NULL) {
 		const char *wwpn;
 		const char *lun;
 		const char *hba_id;

 		hba_id = udev_device_get_sysattr_value(scsi_dev, "hba_id");
 		wwpn = udev_device_get_sysattr_value(scsi_dev, "wwpn");
 		lun = udev_device_get_sysattr_value(scsi_dev, "fcp_lun");
 		if (hba_id != NULL && lun != NULL && wwpn != NULL) {
 			path_prepend(path, "ccw-%s-zfcp-%s:%s", hba_id, wwpn, lun);
 			goto out;
 		}
 	}

 	path_prepend(path, "ccw-%s", udev_device_get_sysname(parent));
 out:
 	parent = skip_subsystem(parent, "ccw");
 	return parent;
 }

 static int builtin_path_id(struct udev_device *dev, bool test)
 {
 	struct udev_device *parent;
 	char *path = NULL;

 	/* S390 ccw bus */
 	parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
 	if (parent != NULL) {
 		handle_ccw(parent, dev, &path);
 		goto out;
 	}

 	/* walk up the chain of devices and compose path */
 	parent = dev;
 	while (parent != NULL) {
 		const char *subsys;

 		subsys = udev_device_get_subsystem(parent);
 		if (subsys == NULL) {
 			;
 		} else if (strcmp(subsys, "scsi_tape") == 0) {
 			handle_scsi_tape(parent, &path);
 		} else if (strcmp(subsys, "scsi") == 0) {
 			parent = handle_scsi(parent, &path);
 		} else if (strcmp(subsys, "cciss") == 0) {
 			handle_cciss(parent, &path);
 		} else if (strcmp(subsys, "usb") == 0) {
 			parent = handle_usb(parent, &path);
 		} else if (strcmp(subsys, "serio") == 0) {
 			path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
 			parent = skip_subsystem(parent, "serio");
 		} else if (strcmp(subsys, "pci") == 0) {
 			path_prepend(&path, "pci-%s", udev_device_get_sysname(parent));
 			parent = skip_subsystem(parent, "pci");
 		} else if (strcmp(subsys, "platform") == 0) {
 			path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
 			parent = skip_subsystem(parent, "platform");
 		} else if (strcmp(subsys, "acpi") == 0) {
 			path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
 			parent = skip_subsystem(parent, "acpi");
 		} else if (strcmp(subsys, "xen") == 0) {
 			path_prepend(&path, "xen-%s", udev_device_get_sysname(parent));
 			parent = skip_subsystem(parent, "xen");
 		} else if (strcmp(subsys, "virtio") == 0) {
 			path_prepend(&path, "virtio-pci-%s", udev_device_get_sysname(parent));
 			parent = skip_subsystem(parent, "virtio");
 		}

 		parent = udev_device_get_parent(parent);
 	}
 out:
 	if (path != NULL) {
 		char tag[UTIL_NAME_SIZE];
 		size_t i;
 		const char *p;

 		/* compose valid udev tag name */
 		for (p = path, i = 0; *p; p++) {
 			if ((*p >= '0' && *p <= '9') ||
 			    (*p >= 'A' && *p <= 'Z') ||
 			    (*p >= 'a' && *p <= 'z') ||
 			    *p == '-') {
 				tag[i++] = *p;
 				continue;
 			}

 			/* skip all leading '_' */
 			if (i == 0)
 				continue;

 			/* avoid second '_' */
 			if (tag[i-1] == '_')
 				continue;

 			tag[i++] = '_';
 		}
 		/* strip trailing '_' */
 		while (i > 0 && tag[i-1] == '_')
 			i--;
 		tag[i] = '\0';

 		udev_builtin_add_property(dev, test, "ID_PATH", path);
 		udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
 		free(path);
 		return EXIT_SUCCESS;
 	}
 	return EXIT_FAILURE;
 }

 const struct udev_builtin udev_builtin_path_id = {
 	.name = "path_id",
 	.cmd = builtin_path_id,
 	.help = "compose persistent device path",
 };
	/*
	* compose persistent device path
	*
	* Copyright (C) 2009-2011 Kay Sievers <kay.sievers@vrfy.org>
	*
	* Logic based on Hannes Reinecke's shell script.
	*
	* This program is free software: you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation, either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <stdarg.h>
	#include <unistd.h>
	#include <string.h>
	#include <ctype.h>
	#include <fcntl.h>
	#include <errno.h>
	#include <dirent.h>
	#include <getopt.h>

	#include "udev.h"

	static int path_prepend(char *path, const char fmt, ...)
	{
	va_list va;
	char *pre;
	int err = 0;

	va_start(va, fmt);
	err = vasprintf(&pre, fmt, va);
	va_end(va);
	if (err < 0)
	goto out;

	if (*path != NULL) {
	char *new;

	err = asprintf(&new, "%s-%s", pre, *path);
	free(pre);
	if (err < 0)
	goto out;
	free(*path);
	*path = new;
	} else {
	*path = pre;
	}
	out:
	return err;
	}

	/*
	** Linux only supports 32 bit luns.
	** See drivers/scsi/scsi_scan.c::scsilun_to_int() for more details.
	*/
	static int format_lun_number(struct udev_device dev, char *path)
	{
	unsigned long lun = strtoul(udev_device_get_sysnum(dev), NULL, 10);

	/* address method 0, peripheral device addressing with bus id of zero */
	if (lun < 256)
	return path_prepend(path, "lun-%d", lun);
	/* handle all other lun addressing methods by using a variant of the original lun format */
	return path_prepend(path, "lun-0x%04x%04x00000000", (lun & 0xffff), (lun >> 16) & 0xffff);
	}

	static struct udev_device skip_subsystem(struct udev_device dev, const char *subsys)
	{
	struct udev_device *parent = dev;

	while (parent != NULL) {
	const char *subsystem;

	subsystem = udev_device_get_subsystem(parent);
	if (subsystem == NULL \|\| strcmp(subsystem, subsys) != 0)
	break;
	dev = parent;
	parent = udev_device_get_parent(parent);
	}
	return dev;
	}

	static struct udev_device handle_scsi_fibre_channel(struct udev_device parent, char **path)
	{
	struct udev *udev = udev_device_get_udev(parent);
	struct udev_device *targetdev;
	struct udev_device *fcdev = NULL;
	const char *port;
	char *lun = NULL;;

	targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
	if (targetdev == NULL)
	return NULL;

	fcdev = udev_device_new_from_subsystem_sysname(udev, "fc_transport", udev_device_get_sysname(targetdev));
	if (fcdev == NULL)
	return NULL;
	port = udev_device_get_sysattr_value(fcdev, "port_name");
	if (port == NULL) {
	parent = NULL;
	goto out;
	}

	format_lun_number(parent, &lun);
	path_prepend(path, "fc-%s-%s", port, lun);
	if (lun)
	free(lun);
	out:
	udev_device_unref(fcdev);
	return parent;
	}

	static struct udev_device handle_scsi_sas(struct udev_device parent, char **path)
	{
	struct udev *udev = udev_device_get_udev(parent);
	struct udev_device *targetdev;
	struct udev_device *target_parent;
	struct udev_device *sasdev;
	const char *sas_address;
	char *lun = NULL;

	targetdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_target");
	if (targetdev == NULL)
	return NULL;

	target_parent = udev_device_get_parent(targetdev);
	if (target_parent == NULL)
	return NULL;

	sasdev = udev_device_new_from_subsystem_sysname(udev, "sas_device",
	udev_device_get_sysname(target_parent));
	if (sasdev == NULL)
	return NULL;

	sas_address = udev_device_get_sysattr_value(sasdev, "sas_address");
	if (sas_address == NULL) {
	parent = NULL;
	goto out;
	}

	format_lun_number(parent, &lun);
	path_prepend(path, "sas-%s-%s", sas_address, lun);
	if (lun)
	free(lun);
	out:
	udev_device_unref(sasdev);
	return parent;
	}

	static struct udev_device handle_scsi_iscsi(struct udev_device parent, char **path)
	{
	struct udev *udev = udev_device_get_udev(parent);
	struct udev_device *transportdev;
	struct udev_device *sessiondev = NULL;
	const char *target;
	char *connname;
	struct udev_device *conndev = NULL;
	const char *addr;
	const char *port;
	char *lun = NULL;

	/* find iscsi session */
	transportdev = parent;
	for (;;) {
	transportdev = udev_device_get_parent(transportdev);
	if (transportdev == NULL)
	return NULL;
	if (strncmp(udev_device_get_sysname(transportdev), "session", 7) == 0)
	break;
	}

	/* find iscsi session device */
	sessiondev = udev_device_new_from_subsystem_sysname(udev, "iscsi_session", udev_device_get_sysname(transportdev));
	if (sessiondev == NULL)
	return NULL;
	target = udev_device_get_sysattr_value(sessiondev, "targetname");
	if (target == NULL) {
	parent = NULL;
	goto out;
	}

	if (asprintf(&connname, "connection%s:0", udev_device_get_sysnum(transportdev)) < 0) {
	parent = NULL;
	goto out;
	}
	conndev = udev_device_new_from_subsystem_sysname(udev, "iscsi_connection", connname);
	free(connname);
	if (conndev == NULL) {
	parent = NULL;
	goto out;
	}
	addr = udev_device_get_sysattr_value(conndev, "persistent_address");
	port = udev_device_get_sysattr_value(conndev, "persistent_port");
	if (addr == NULL \|\| port == NULL) {
	parent = NULL;
	goto out;
	}

	format_lun_number(parent, &lun);
	path_prepend(path, "ip-%s:%s-iscsi-%s-%s", addr, port, target, lun);
	if (lun)
	free(lun);
	out:
	udev_device_unref(sessiondev);
	udev_device_unref(conndev);
	return parent;
	}

	static struct udev_device handle_scsi_default(struct udev_device parent, char **path)
	{
	struct udev_device *hostdev;
	int host, bus, target, lun;
	const char *name;
	char *base;
	char *pos;
	DIR *dir;
	struct dirent *dent;
	int basenum;

	hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
	if (hostdev == NULL)
	return NULL;

	name = udev_device_get_sysname(parent);
	if (sscanf(name, "%d:%d:%d:%d", &host, &bus, &target, &lun) != 4)
	return NULL;

	/* rebase host offset to get the local relative number */
	basenum = -1;
	base = strdup(udev_device_get_syspath(hostdev));
	if (base == NULL)
	return NULL;
	pos = strrchr(base, '/');
	if (pos == NULL) {
	parent = NULL;
	goto out;
	}
	pos[0] = '\0';
	dir = opendir(base);
	if (dir == NULL) {
	parent = NULL;
	goto out;
	}
	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
	char *rest;
	int i;

	if (dent->d_name[0] == '.')
	continue;
	if (dent->d_type != DT_DIR && dent->d_type != DT_LNK)
	continue;
	if (strncmp(dent->d_name, "host", 4) != 0)
	continue;
	i = strtoul(&dent->d_name[4], &rest, 10);
	if (rest[0] != '\0')
	continue;
	if (basenum == -1 \|\| i < basenum)
	basenum = i;
	}
	closedir(dir);
	if (basenum == -1) {
	parent = NULL;
	goto out;
	}
	host -= basenum;

	path_prepend(path, "scsi-%u:%u:%u:%u", host, bus, target, lun);
	out:
	free(base);
	return hostdev;
	}

	static struct udev_device handle_scsi(struct udev_device parent, char **path)
	{
	const char *devtype;
	const char *name;
	const char *id;

	devtype = udev_device_get_devtype(parent);
	if (devtype == NULL \|\| strcmp(devtype, "scsi_device") != 0)
	return parent;

	/* firewire */
	id = udev_device_get_sysattr_value(parent, "ieee1394_id");
	if (id != NULL) {
	parent = skip_subsystem(parent, "scsi");
	path_prepend(path, "ieee1394-0x%s", id);
	goto out;
	}

	/* lousy scsi sysfs does not have a "subsystem" for the transport */
	name = udev_device_get_syspath(parent);

	if (strstr(name, "/rport-") != NULL) {
	parent = handle_scsi_fibre_channel(parent, path);
	goto out;
	}

	if (strstr(name, "/end_device-") != NULL) {
	parent = handle_scsi_sas(parent, path);
	goto out;
	}

	if (strstr(name, "/session") != NULL) {
	parent = handle_scsi_iscsi(parent, path);
	goto out;
	}

	parent = handle_scsi_default(parent, path);
	out:
	return parent;
	}

	static void handle_scsi_tape(struct udev_device dev, char *path)
	{
	const char *name;

	/* must be the last device in the syspath */
	if (*path != NULL)
	return;

	name = udev_device_get_sysname(dev);
	if (strncmp(name, "nst", 3) == 0 && strchr("lma", name[3]) != NULL)
	path_prepend(path, "nst%c", name[3]);
	else if (strncmp(name, "st", 2) == 0 && strchr("lma", name[2]) != NULL)
	path_prepend(path, "st%c", name[2]);
	}

	static struct udev_device handle_usb(struct udev_device parent, char **path)
	{
	const char *devtype;
	const char *str;
	const char *port;

	devtype = udev_device_get_devtype(parent);
	if (devtype == NULL)
	return parent;
	if (strcmp(devtype, "usb_interface") != 0 && strcmp(devtype, "usb_device") != 0)
	return parent;

	str = udev_device_get_sysname(parent);
	port = strchr(str, '-');
	if (port == NULL)
	return parent;
	port++;

	parent = skip_subsystem(parent, "usb");
	path_prepend(path, "usb-0:%s", port);
	return parent;
	}

	static struct udev_device handle_cciss(struct udev_device parent, char **path)
	{
	return NULL;
	}

	static struct udev_device handle_ccw(struct udev_device parent, struct udev_device dev, char *path)
	{
	struct udev_device *scsi_dev;

	scsi_dev = udev_device_get_parent_with_subsystem_devtype(dev, "scsi", "scsi_device");
	if (scsi_dev != NULL) {
	const char *wwpn;
	const char *lun;
	const char *hba_id;

	hba_id = udev_device_get_sysattr_value(scsi_dev, "hba_id");
	wwpn = udev_device_get_sysattr_value(scsi_dev, "wwpn");
	lun = udev_device_get_sysattr_value(scsi_dev, "fcp_lun");
	if (hba_id != NULL && lun != NULL && wwpn != NULL) {
	path_prepend(path, "ccw-%s-zfcp-%s:%s", hba_id, wwpn, lun);
	goto out;
	}
	}

	path_prepend(path, "ccw-%s", udev_device_get_sysname(parent));
	out:
	parent = skip_subsystem(parent, "ccw");
	return parent;
	}

	static int builtin_path_id(struct udev_device *dev, bool test)
	{
	struct udev_device *parent;
	char *path = NULL;

	/* S390 ccw bus */
	parent = udev_device_get_parent_with_subsystem_devtype(dev, "ccw", NULL);
	if (parent != NULL) {
	handle_ccw(parent, dev, &path);
	goto out;
	}

	/* walk up the chain of devices and compose path */
	parent = dev;
	while (parent != NULL) {
	const char *subsys;

	subsys = udev_device_get_subsystem(parent);
	if (subsys == NULL) {
	;
	} else if (strcmp(subsys, "scsi_tape") == 0) {
	handle_scsi_tape(parent, &path);
	} else if (strcmp(subsys, "scsi") == 0) {
	parent = handle_scsi(parent, &path);
	} else if (strcmp(subsys, "cciss") == 0) {
	handle_cciss(parent, &path);
	} else if (strcmp(subsys, "usb") == 0) {
	parent = handle_usb(parent, &path);
	} else if (strcmp(subsys, "serio") == 0) {
	path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
	parent = skip_subsystem(parent, "serio");
	} else if (strcmp(subsys, "pci") == 0) {
	path_prepend(&path, "pci-%s", udev_device_get_sysname(parent));
	parent = skip_subsystem(parent, "pci");
	} else if (strcmp(subsys, "platform") == 0) {
	path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
	parent = skip_subsystem(parent, "platform");
	} else if (strcmp(subsys, "acpi") == 0) {
	path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
	parent = skip_subsystem(parent, "acpi");
	} else if (strcmp(subsys, "xen") == 0) {
	path_prepend(&path, "xen-%s", udev_device_get_sysname(parent));
	parent = skip_subsystem(parent, "xen");
	} else if (strcmp(subsys, "virtio") == 0) {
	path_prepend(&path, "virtio-pci-%s", udev_device_get_sysname(parent));
	parent = skip_subsystem(parent, "virtio");
	}

	parent = udev_device_get_parent(parent);
	}
	out:
	if (path != NULL) {
	char tag[UTIL_NAME_SIZE];
	size_t i;
	const char *p;

	/* compose valid udev tag name */
	for (p = path, i = 0; *p; p++) {
	if ((p >= '0' && p <= '9') \|\|
	(p >= 'A' && p <= 'Z') \|\|
	(p >= 'a' && p <= 'z') \|\|
	*p == '-') {
	tag[i++] = *p;
	continue;
	}

	/* skip all leading '_' */
	if (i == 0)
	continue;

	/* avoid second '_' */
	if (tag[i-1] == '_')
	continue;

	tag[i++] = '_';
	}
	/* strip trailing '_' */
	while (i > 0 && tag[i-1] == '_')
	i--;
	tag[i] = '\0';

	udev_builtin_add_property(dev, test, "ID_PATH", path);
	udev_builtin_add_property(dev, test, "ID_PATH_TAG", tag);
	free(path);
	return EXIT_SUCCESS;
	}
	return EXIT_FAILURE;
	}

	const struct udev_builtin udev_builtin_path_id = {
	.name = "path_id",
	.cmd = builtin_path_id,
	.help = "compose persistent device path",
	};