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Systemd/src/rfkill/rfkill.c
Lennart Poettering d35c1bb1f4 rfkill: rework and make it listen on /dev/rfkill 
With this rework we introduce systemd-rfkill.service as singleton that
is activated via systemd-rfkill.socket that listens on /dev/rfkill. That
way, we get notified each time a new rfkill device shows up or changes
state, in which case we restore and save its current setting to disk.

This is nicer than the previous logic, as this means we save/restore
state even of rfkill devices that are around only intermittently, and
save/restore the state even if the system is shutdown abruptly instead
of cleanly.

This implements what I suggested in #1019 and obsoletes it.
2015-10-01 16:21:09 +02:00

421 lines
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <linux/rfkill.h>
#include <poll.h>
#include "libudev.h"
#include "sd-daemon.h"
#include "fileio.h"
#include "mkdir.h"
#include "udev-util.h"
#include "util.h"
#define EXIT_USEC (5 * USEC_PER_SEC)
static const char* const rfkill_type_table[NUM_RFKILL_TYPES] = {
[RFKILL_TYPE_ALL] = "all",
[RFKILL_TYPE_WLAN] = "wlan",
[RFKILL_TYPE_BLUETOOTH] = "bluetooth",
[RFKILL_TYPE_UWB] = "uwb",
[RFKILL_TYPE_WIMAX] = "wimax",
[RFKILL_TYPE_WWAN] = "wwan",
[RFKILL_TYPE_GPS] = "gps",
[RFKILL_TYPE_FM] "fm",
[RFKILL_TYPE_NFC] "nfc",
};
DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(rfkill_type, int);
static int find_device(
struct udev *udev,
const struct rfkill_event *event,
struct udev_device **ret) {
_cleanup_free_ char *sysname = NULL;
struct udev_device *device;
const char *name;
assert(udev);
assert(event);
assert(ret);
if (asprintf(&sysname, "rfkill%i", event->idx) < 0)
return log_oom();
device = udev_device_new_from_subsystem_sysname(udev, "rfkill", sysname);
if (!device)
return log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR, errno, "Failed to open device: %m");
name = udev_device_get_sysattr_value(device, "name");
if (!name) {
log_debug("Device has no name, ignoring.");
udev_device_unref(device);
return -ENOENT;
}
log_debug("Operating on rfkill device '%s'.", name);
*ret = device;
return 0;
}
static int wait_for_initialized(
struct udev *udev,
struct udev_device *device,
struct udev_device **ret) {
_cleanup_udev_monitor_unref_ struct udev_monitor *monitor = NULL;
struct udev_device *d;
const char *sysname;
int watch_fd, r;
assert(udev);
assert(device);
assert(ret);
if (udev_device_get_is_initialized(device) != 0) {
*ret = udev_device_ref(device);
return 0;
}
assert_se(sysname = udev_device_get_sysname(device));
/* Wait until the device is initialized, so that we can get
* access to the ID_PATH property */
monitor = udev_monitor_new_from_netlink(udev, "udev");
if (!monitor)
return log_error_errno(errno, "Failed to acquire monitor: %m");
r = udev_monitor_filter_add_match_subsystem_devtype(monitor, "rfkill", NULL);
if (r < 0)
return log_error_errno(r, "Failed to add rfkill udev match to monitor: %m");
r = udev_monitor_enable_receiving(monitor);
if (r < 0)
return log_error_errno(r, "Failed to enable udev receiving: %m");
watch_fd = udev_monitor_get_fd(monitor);
if (watch_fd < 0)
return log_error_errno(watch_fd, "Failed to get watch fd: %m");
/* Check again, maybe things changed */
d = udev_device_new_from_subsystem_sysname(udev, "rfkill", sysname);
if (!d)
return log_full_errno(errno == ENOENT ? LOG_DEBUG : LOG_ERR, errno, "Failed to open device: %m");
if (udev_device_get_is_initialized(d) != 0) {
*ret = d;
return 0;
}
for (;;) {
_cleanup_udev_device_unref_ struct udev_device *t = NULL;
r = fd_wait_for_event(watch_fd, POLLIN, USEC_INFINITY);
if (r == -EINTR)
continue;
if (r < 0)
return log_error_errno(r, "Failed to watch udev monitor: %m");
t = udev_monitor_receive_device(monitor);
if (!t)
continue;
if (streq_ptr(udev_device_get_sysname(device), sysname)) {
*ret = udev_device_ref(t);
return 0;
}
}
}
static int determine_state_file(
struct udev *udev,
const struct rfkill_event *event,
struct udev_device *d,
char **ret) {
_cleanup_udev_device_unref_ struct udev_device *device = NULL;
const char *path_id, *type;
char *state_file;
int r;
assert(event);
assert(d);
assert(ret);
r = wait_for_initialized(udev, d, &device);
if (r < 0)
return r;
assert_se(type = rfkill_type_to_string(event->type));
path_id = udev_device_get_property_value(device, "ID_PATH");
if (path_id) {
_cleanup_free_ char *escaped_path_id = NULL;
escaped_path_id = cescape(path_id);
if (!escaped_path_id)
return log_oom();
state_file = strjoin("/var/lib/systemd/rfkill/", escaped_path_id, ":", type, NULL);
} else
state_file = strjoin("/var/lib/systemd/rfkill/", type, NULL);
if (!state_file)
return log_oom();
*ret = state_file;
return 0;
}
static int load_state(
int rfkill_fd,
struct udev *udev,
const struct rfkill_event *event) {
_cleanup_udev_device_unref_ struct udev_device *device = NULL;
_cleanup_free_ char *state_file = NULL, *value = NULL;
struct rfkill_event we;
ssize_t l;
int b, r;
assert(rfkill_fd >= 0);
assert(udev);
assert(event);
if (!shall_restore_state())
return 0;
r = find_device(udev, event, &device);
if (r < 0)
return r;
r = determine_state_file(udev, event, device, &state_file);
if (r < 0)
return r;
r = read_one_line_file(state_file, &value);
if (r == -ENOENT) {
/* No state file? Then save the current state */
r = write_string_file(state_file, one_zero(event->soft), WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC);
if (r < 0)
return log_error_errno(r, "Failed to write state file %s: %m", state_file);
log_debug("Saved state '%s' to %s.", one_zero(event->soft), state_file);
return 0;
}
if (r < 0)
return log_error_errno(r, "Failed to read state file %s: %m", state_file);
b = parse_boolean(value);
if (b < 0)
return log_error_errno(b, "Failed to parse state file %s: %m", state_file);
we = (struct rfkill_event) {
.op = RFKILL_OP_CHANGE,
.idx = event->idx,
.soft = b,
};
l = write(rfkill_fd, &we, sizeof(we));
if (l < 0)
return log_error_errno(errno, "Failed to restore rfkill state for %i: %m", event->idx);
if (l != sizeof(we)) {
log_error("Couldn't write rfkill event structure, too short.");
return -EIO;
}
log_debug("Loaded state '%s' from %s.", one_zero(b), state_file);
return 0;
}
static int save_state(
int rfkill_fd,
struct udev *udev,
const struct rfkill_event *event) {
_cleanup_udev_device_unref_ struct udev_device *device = NULL;
_cleanup_free_ char *state_file = NULL;
int r;
assert(rfkill_fd >= 0);
assert(udev);
assert(event);
r = find_device(udev, event, &device);
if (r < 0)
return r;
r = determine_state_file(udev, event, device, &state_file);
if (r < 0)
return r;
r = write_string_file(state_file, one_zero(event->soft), WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_ATOMIC);
if (r < 0)
return log_error_errno(r, "Failed to write state file %s: %m", state_file);
log_debug("Saved state '%s' to %s.", one_zero(event->soft), state_file);
return 0;
}
int main(int argc, char *argv[]) {
_cleanup_udev_unref_ struct udev *udev = NULL;
_cleanup_close_ int rfkill_fd = -1;
bool ready = false;
int r, n;
if (argc > 1) {
log_error("This program requires no arguments.");
return EXIT_FAILURE;
}
log_set_target(LOG_TARGET_AUTO);
log_parse_environment();
log_open();
umask(0022);
udev = udev_new();
if (!udev) {
r = log_oom();
goto finish;
}
r = mkdir_p("/var/lib/systemd/rfkill", 0755);
if (r < 0) {
log_error_errno(r, "Failed to create rfkill directory: %m");
goto finish;
}
n = sd_listen_fds(false);
if (n < 0) {
r = log_error_errno(n, "Failed to determine whether we got any file descriptors passed: %m");
goto finish;
}
if (n > 1) {
log_error("Got too many file descriptors.");
r = -EINVAL;
goto finish;
}
if (n == 0) {
rfkill_fd = open("/dev/rfkill", O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
if (rfkill_fd < 0) {
if (errno == ENOENT) {
log_debug_errno(errno, "Missing rfkill subsystem, or no device present, exiting.");
r = 0;
goto finish;
}
r = log_error_errno(errno, "Failed to open /dev/rfkill: %m");
goto finish;
}
} else {
rfkill_fd = SD_LISTEN_FDS_START;
r = fd_nonblock(rfkill_fd, 1);
if (r < 0) {
log_error_errno(r, "Failed to make /dev/rfkill socket non-blocking: %m");
goto finish;
}
}
for (;;) {
struct rfkill_event event;
const char *type;
ssize_t l;
l = read(rfkill_fd, &event, sizeof(event));
if (l < 0) {
if (errno == EAGAIN) {
if (!ready) {
/* Notify manager that we are
* now finished with
* processing whatever was
* queued */
(void) sd_notify(false, "READY=1");
ready = true;
}
/* Hang around for a bit, maybe there's more coming */
r = fd_wait_for_event(rfkill_fd, POLLIN, EXIT_USEC);
if (r == -EINTR)
continue;
if (r < 0) {
log_error_errno(r, "Failed to poll() on device: %m");
goto finish;
}
if (r > 0)
continue;
log_debug("All events read and idle, exiting.");
break;
}
log_error_errno(errno, "Failed to read from /dev/rfkill: %m");
}
if (l != RFKILL_EVENT_SIZE_V1) {
log_error("Read event structure of invalid size.");
r = -EIO;
goto finish;
}
type = rfkill_type_to_string(event.type);
if (!type) {
log_debug("An rfkill device of unknown type %i discovered, ignoring.", event.type);
continue;
}
switch (event.op) {
case RFKILL_OP_ADD:
log_debug("A new rfkill device has been added with index %i and type %s.", event.idx, type);
(void) load_state(rfkill_fd, udev, &event);
break;
case RFKILL_OP_DEL:
log_debug("An rfkill device has been removed with index %i and type %s", event.idx, type);
break;
case RFKILL_OP_CHANGE:
log_debug("An rfkill device has changed state with index %i and type %s", event.idx, type);
(void) save_state(rfkill_fd, udev, &event);
break;
default:
log_debug("Unknown event %i from /dev/rfkill for index %i and type %s, ignoring.", event.op, event.idx, type);
break;
}
}
r = 0;
finish:
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}
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