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Systemd/src/device.c

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd 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.
systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <sys/epoll.h>
#include <libudev.h>
#include "unit.h"
#include "device.h"
#include "strv.h"
#include "log.h"
#include "unit-name.h"
#include "dbus-device.h"
static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = {
[DEVICE_DEAD] = UNIT_INACTIVE,
[DEVICE_PLUGGED] = UNIT_ACTIVE
};
static void device_unset_sysfs(Device *d) {
Device *first;
assert(d);
if (!d->sysfs)
return;
/* Remove this unit from the chain of devices which share the
* same sysfs path. */
first = hashmap_get(d->meta.manager->devices_by_sysfs, d->sysfs);
LIST_REMOVE(Device, same_sysfs, first, d);
if (first)
hashmap_remove_and_replace(d->meta.manager->devices_by_sysfs, d->sysfs, first->sysfs, first);
else
hashmap_remove(d->meta.manager->devices_by_sysfs, d->sysfs);
free(d->sysfs);
d->sysfs = NULL;
}
static void device_init(Unit *u) {
Device *d = DEVICE(u);
assert(d);
assert(d->meta.load_state == UNIT_STUB);
/* In contrast to all other unit types we timeout jobs waiting
* for devices by default. This is because they otherwise wait
* indefinetely for plugged in devices, something which cannot
* happen for the other units since their operations time out
* anyway. */
d->meta.job_timeout = DEFAULT_TIMEOUT_USEC;
}
static void device_done(Unit *u) {
Device *d = DEVICE(u);
assert(d);
device_unset_sysfs(d);
}
static void device_set_state(Device *d, DeviceState state) {
DeviceState old_state;
assert(d);
old_state = d->state;
d->state = state;
if (state != old_state)
log_debug("%s changed %s -> %s",
d->meta.id,
device_state_to_string(old_state),
device_state_to_string(state));
unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state]);
}
static int device_coldplug(Unit *u) {
Device *d = DEVICE(u);
assert(d);
assert(d->state == DEVICE_DEAD);
if (d->sysfs)
device_set_state(d, DEVICE_PLUGGED);
return 0;
}
static void device_dump(Unit *u, FILE *f, const char *prefix) {
Device *d = DEVICE(u);
assert(d);
fprintf(f,
"%sDevice State: %s\n"
"%sSysfs Path: %s\n",
prefix, device_state_to_string(d->state),
prefix, strna(d->sysfs));
}
static UnitActiveState device_active_state(Unit *u) {
assert(u);
return state_translation_table[DEVICE(u)->state];
}
static const char *device_sub_state_to_string(Unit *u) {
assert(u);
return device_state_to_string(DEVICE(u)->state);
}
static int device_add_escaped_name(Unit *u, const char *dn) {
char *e;
int r;
assert(u);
assert(dn);
assert(dn[0] == '/');
if (!(e = unit_name_from_path(dn, ".device")))
return -ENOMEM;
r = unit_add_name(u, e);
free(e);
if (r < 0 && r != -EEXIST)
return r;
return 0;
}
static int device_find_escape_name(Manager *m, const char *dn, Unit **_u) {
char *e;
Unit *u;
assert(m);
assert(dn);
assert(dn[0] == '/');
assert(_u);
if (!(e = unit_name_from_path(dn, ".device")))
return -ENOMEM;
u = manager_get_unit(m, e);
free(e);
if (u) {
*_u = u;
return 1;
}
return 0;
}
static int device_update_unit(Manager *m, struct udev_device *dev, const char *path, bool main) {
const char *sysfs, *model;
Unit *u = NULL;
int r;
bool delete;
assert(m);
if (!(sysfs = udev_device_get_syspath(dev)))
return -ENOMEM;
if ((r = device_find_escape_name(m, path, &u)) < 0)
return r;
/* If this is a different unit, then let's not merge things */
if (u && DEVICE(u)->sysfs && !path_equal(DEVICE(u)->sysfs, sysfs)) {
log_error("Hmm, something's broken. Asked to create two devices with same name but different sysfs paths. (%s vs %s)",
DEVICE(u)->sysfs, sysfs);
return -EEXIST;
}
if (!u) {
delete = true;
if (!(u = unit_new(m)))
return -ENOMEM;
if ((r = device_add_escaped_name(u, path)) < 0)
goto fail;
unit_add_to_load_queue(u);
} else
delete = false;
/* If this was created via some dependency and has not
* actually been seen yet ->sysfs will not be
* initialized. Hence initialize it if necessary. */
if (!DEVICE(u)->sysfs) {
Device *first;
if (!(DEVICE(u)->sysfs = strdup(sysfs))) {
r = -ENOMEM;
goto fail;
}
if (!m->devices_by_sysfs)
if (!(m->devices_by_sysfs = hashmap_new(string_hash_func, string_compare_func))) {
r = -ENOMEM;
goto fail;
}
first = hashmap_get(m->devices_by_sysfs, sysfs);
LIST_PREPEND(Device, same_sysfs, first, DEVICE(u));
if ((r = hashmap_replace(m->devices_by_sysfs, DEVICE(u)->sysfs, first)) < 0)
goto fail;
}
if ((model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE")) ||
(model = udev_device_get_property_value(dev, "ID_MODEL"))) {
if ((r = unit_set_description(u, model)) < 0)
goto fail;
} else
if ((r = unit_set_description(u, path)) < 0)
goto fail;
if (main) {
/* The additional systemd udev properties we only
* interpret for the main object */
const char *wants, *alias;
if ((alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS"))) {
if (!is_path(alias))
log_warning("SYSTEMD_ALIAS for %s is not a path, ignoring: %s", sysfs, alias);
else {
if ((r = device_add_escaped_name(u, alias)) < 0)
goto fail;
}
}
if ((wants = udev_device_get_property_value(dev, "SYSTEMD_WANTS"))) {
char *state, *w;
size_t l;
FOREACH_WORD_QUOTED(w, l, wants, state) {
char *e;
if (!(e = strndup(w, l))) {
r = -ENOMEM;
goto fail;
}
r = unit_add_dependency_by_name(u, UNIT_WANTS, e, NULL, true);
free(e);
if (r < 0)
goto fail;
}
}
}
unit_add_to_dbus_queue(u);
return 0;
fail:
log_warning("Failed to load device unit: %s", strerror(-r));
if (delete && u)
unit_free(u);
return r;
}
static int device_process_new_device(Manager *m, struct udev_device *dev, bool update_state) {
const char *sysfs, *dn;
struct udev_list_entry *item = NULL, *first = NULL;
assert(m);
if (!(sysfs = udev_device_get_syspath(dev)))
return -ENOMEM;
/* Add the main unit named after the sysfs path */
device_update_unit(m, dev, sysfs, true);
/* Add an additional unit for the device node */
if ((dn = udev_device_get_devnode(dev)))
device_update_unit(m, dev, dn, false);
/* Add additional units for all symlinks */
first = udev_device_get_devlinks_list_entry(dev);
udev_list_entry_foreach(item, first) {
const char *p;
/* Don't bother with the /dev/block links */
p = udev_list_entry_get_name(item);
if (path_startswith(p, "/dev/block/") ||
path_startswith(p, "/dev/char/"))
continue;
device_update_unit(m, dev, p, false);
}
if (update_state) {
Device *d, *l;
manager_dispatch_load_queue(m);
l = hashmap_get(m->devices_by_sysfs, sysfs);
LIST_FOREACH(same_sysfs, d, l)
device_set_state(d, DEVICE_PLUGGED);
}
return 0;
}
static int device_process_path(Manager *m, const char *path, bool update_state) {
int r;
struct udev_device *dev;
assert(m);
assert(path);
if (!(dev = udev_device_new_from_syspath(m->udev, path))) {
log_warning("Failed to get udev device object from udev for path %s.", path);
return -ENOMEM;
}
r = device_process_new_device(m, dev, update_state);
udev_device_unref(dev);
return r;
}
static int device_process_removed_device(Manager *m, struct udev_device *dev) {
const char *sysfs;
Device *d;
assert(m);
assert(dev);
if (!(sysfs = udev_device_get_syspath(dev)))
return -ENOMEM;
/* Remove all units of this sysfs path */
while ((d = hashmap_get(m->devices_by_sysfs, sysfs))) {
device_unset_sysfs(d);
device_set_state(d, DEVICE_DEAD);
}
return 0;
}
static Unit *device_following(Unit *u) {
Device *d = DEVICE(u);
Device *other, *first = NULL;
assert(d);
if (startswith(u->meta.id, "sys-"))
return NULL;
/* Make everybody follow the unit that's named after the sysfs path */
for (other = d->same_sysfs_next; other; other = other->same_sysfs_next)
if (startswith(other->meta.id, "sys-"))
return UNIT(other);
for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev) {
if (startswith(other->meta.id, "sys-"))
return UNIT(other);
first = other;
}
return UNIT(first);
}
static void device_shutdown(Manager *m) {
assert(m);
if (m->udev_monitor) {
udev_monitor_unref(m->udev_monitor);
m->udev_monitor = NULL;
}
if (m->udev) {
udev_unref(m->udev);
m->udev = NULL;
}
hashmap_free(m->devices_by_sysfs);
m->devices_by_sysfs = NULL;
}
static int device_enumerate(Manager *m) {
struct epoll_event ev;
int r;
struct udev_enumerate *e = NULL;
struct udev_list_entry *item = NULL, *first = NULL;
assert(m);
if (!m->udev) {
if (!(m->udev = udev_new()))
return -ENOMEM;
if (!(m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"))) {
r = -ENOMEM;
goto fail;
}
if (udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd") < 0) {
r = -ENOMEM;
goto fail;
}
if (udev_monitor_enable_receiving(m->udev_monitor) < 0) {
r = -EIO;
goto fail;
}
m->udev_watch.type = WATCH_UDEV;
m->udev_watch.fd = udev_monitor_get_fd(m->udev_monitor);
zero(ev);
ev.events = EPOLLIN;
ev.data.ptr = &m->udev_watch;
if (epoll_ctl(m->epoll_fd, EPOLL_CTL_ADD, m->udev_watch.fd, &ev) < 0)
return -errno;
}
if (!(e = udev_enumerate_new(m->udev))) {
r = -ENOMEM;
goto fail;
}
if (udev_enumerate_add_match_tag(e, "systemd") < 0) {
r = -EIO;
goto fail;
}
if (udev_enumerate_scan_devices(e) < 0) {
r = -EIO;
goto fail;
}
first = udev_enumerate_get_list_entry(e);
udev_list_entry_foreach(item, first)
device_process_path(m, udev_list_entry_get_name(item), false);
udev_enumerate_unref(e);
return 0;
fail:
if (e)
udev_enumerate_unref(e);
device_shutdown(m);
return r;
}
void device_fd_event(Manager *m, int events) {
struct udev_device *dev;
int r;
const char *action;
assert(m);
assert(events == EPOLLIN);
if (!(dev = udev_monitor_receive_device(m->udev_monitor))) {
log_error("Failed to receive device.");
return;
}
if (!(action = udev_device_get_action(dev))) {
log_error("Failed to get udev action string.");
goto fail;
}
if (streq(action, "remove")) {
if ((r = device_process_removed_device(m, dev)) < 0) {
log_error("Failed to process udev device event: %s", strerror(-r));
goto fail;
}
} else {
if ((r = device_process_new_device(m, dev, true)) < 0) {
log_error("Failed to process udev device event: %s", strerror(-r));
goto fail;
}
}
fail:
udev_device_unref(dev);
}
static const char* const device_state_table[_DEVICE_STATE_MAX] = {
[DEVICE_DEAD] = "dead",
[DEVICE_PLUGGED] = "plugged"
};
DEFINE_STRING_TABLE_LOOKUP(device_state, DeviceState);
const UnitVTable device_vtable = {
.suffix = ".device",
.no_requires = true,
.no_instances = true,
.no_snapshots = true,
.no_isolate = true,
.no_alias = true,
.init = device_init,
.load = unit_load_fragment_and_dropin_optional,
.done = device_done,
.coldplug = device_coldplug,
.dump = device_dump,
.active_state = device_active_state,
.sub_state_to_string = device_sub_state_to_string,
.bus_interface = "org.freedesktop.systemd1.Device",
.bus_message_handler = bus_device_message_handler,
.bus_invalidating_properties = bus_device_invalidating_properties,
.following = device_following,
.enumerate = device_enumerate,
.shutdown = device_shutdown
};
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