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systemd/src/udev/udev-builtin-path_id.c

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/*
* compose persistent device path
*
* Copyright (C) 2009-2011 Kay Sievers <kay@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"
_printf_(2,3)
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-%lu", lun);
/* handle all other lun addressing methods by using a variant of the original lun format */
return path_prepend(path, "lun-0x%04lx%04lx00000000", 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 || !streq(subsystem, subsys))
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 (startswith(udev_device_get_sysname(transportdev), "session"))
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
*
* Note: This is by definition racy, unreliable and too simple.
* Please do not copy this model anywhere. It's just a left-over
* from the time we had no idea how things should look like in
* the end.
*
* Making assumptions about a global in-kernel counter and use
* that to calculate a local offset is a very broken concept. It
* can only work as long as things are in strict order.
*
* The kernel needs to export the instance/port number of a
* controller directly, without the need for rebase magic like
* this. Manual driver unbind/bind, parallel hotplug/unplug will
* get into the way of this "I hope it works" logic.
*/
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 (!startswith(dent->d_name, "host"))
continue;
i = strtoul(&dent->d_name[4], &rest, 10);
if (rest[0] != '\0')
continue;
/*
* find the smallest number; the host really needs to export its
* own instance number per parent device; relying on the global host
* enumeration and plainly rebasing the numbers sounds unreliable
*/
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_hyperv(struct udev_device *parent, char **path) {
struct udev_device *hostdev;
struct udev_device *vmbusdev;
const char *guid_str;
char *lun = NULL;
char guid[38];
size_t i, k;
hostdev = udev_device_get_parent_with_subsystem_devtype(parent, "scsi", "scsi_host");
if (!hostdev)
return NULL;
vmbusdev = udev_device_get_parent(hostdev);
if (!vmbusdev)
return NULL;
guid_str = udev_device_get_sysattr_value(vmbusdev, "device_id");
if (!guid_str)
return NULL;
if (strlen(guid_str) < 37 || guid_str[0] != '{' || guid_str[36] != '}')
return NULL;
for (i = 1, k = 0; i < 36; i++) {
if (guid_str[i] == '-')
continue;
guid[k++] = guid_str[i];
}
guid[k] = '\0';
format_lun_number(parent, &lun);
path_prepend(path, "vmbus-%s-%s", guid, lun);
free(lun);
return parent;
}
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 || !streq(devtype, "scsi_device"))
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;
}
/* 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;
}
/*
* We do not support the ATA transport class, it uses global counters
* to name the ata devices which numbers spread across multiple
* controllers.
*
* The real link numbers are not exported. Also, possible chains of ports
* behind port multipliers cannot be composed that way.
*
* Until all that is solved at the kernel level, there are no by-path/
* links for ATA devices.
*/
if (strstr(name, "/ata") != NULL) {
parent = NULL;
goto out;
}
if (strstr(name, "/vmbus_") != NULL) {
parent = handle_scsi_hyperv(parent, path);
goto out;
}
parent = handle_scsi_default(parent, path);
out:
return parent;
}
static struct udev_device *handle_cciss(struct udev_device *parent, char **path) {
const char *str;
unsigned int controller, disk;
str = udev_device_get_sysname(parent);
if (sscanf(str, "c%ud%u%*s", &controller, &disk) != 2)
return NULL;
path_prepend(path, "cciss-disk%u", disk);
parent = skip_subsystem(parent, "cciss");
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 (startswith(name, "nst") && strchr("lma", name[3]) != NULL)
path_prepend(path, "nst%c", name[3]);
else if (startswith(name, "st") && 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 (!streq(devtype, "usb_interface") && !streq(devtype, "usb_device"))
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_bcma(struct udev_device *parent, char **path) {
const char *sysname;
unsigned int core;
sysname = udev_device_get_sysname(parent);
if (sscanf(sysname, "bcma%*u:%u", &core) != 1)
return NULL;
path_prepend(path, "bcma-%u", core);
return parent;
}
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, int argc, char *argv[], bool test) {
struct udev_device *parent;
char *path = NULL;
bool supported_transport = false;
bool supported_parent = false;
/* 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 (streq(subsys, "scsi_tape")) {
handle_scsi_tape(parent, &path);
} else if (streq(subsys, "scsi")) {
parent = handle_scsi(parent, &path);
supported_transport = true;
} else if (streq(subsys, "cciss")) {
parent = handle_cciss(parent, &path);
supported_transport = true;
} else if (streq(subsys, "usb")) {
parent = handle_usb(parent, &path);
supported_transport = true;
} else if (streq(subsys, "bcma")) {
parent = handle_bcma(parent, &path);
supported_transport = true;
} else if (streq(subsys, "serio")) {
path_prepend(&path, "serio-%s", udev_device_get_sysnum(parent));
parent = skip_subsystem(parent, "serio");
} else if (streq(subsys, "pci")) {
path_prepend(&path, "pci-%s", udev_device_get_sysname(parent));
parent = skip_subsystem(parent, "pci");
supported_parent = true;
} else if (streq(subsys, "platform")) {
path_prepend(&path, "platform-%s", udev_device_get_sysname(parent));
parent = skip_subsystem(parent, "platform");
supported_transport = true;
supported_parent = true;
} else if (streq(subsys, "acpi")) {
path_prepend(&path, "acpi-%s", udev_device_get_sysname(parent));
parent = skip_subsystem(parent, "acpi");
supported_parent = true;
} else if (streq(subsys, "xen")) {
path_prepend(&path, "xen-%s", udev_device_get_sysname(parent));
parent = skip_subsystem(parent, "xen");
supported_parent = true;
} else if (streq(subsys, "scm")) {
path_prepend(&path, "scm-%s", udev_device_get_sysname(parent));
parent = skip_subsystem(parent, "scm");
supported_transport = true;
supported_parent = true;
}
parent = udev_device_get_parent(parent);
}
/*
* Do return devices with have an unknown type of parent device, they
* might produce conflicting IDs below multiple independent parent
* devices.
*/
if (!supported_parent) {
free(path);
path = NULL;
}
/*
* Do not return a have-only a single-parent block devices, some
* have entire hidden buses behind it, and not create predictable
* IDs that way.
*/
if (streq(udev_device_get_subsystem(dev), "block") && !supported_transport) {
free(path);
path = NULL;
}
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",
.run_once = true,
};
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