1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
5 #include <sys/inotify.h>
8 #include "alloc-util.h"
9 #include "device-nodes.h"
10 #include "device-private.h"
11 #include "device-util.h"
13 #include "errno-util.h"
16 #include "id128-util.h"
19 #include "parse-util.h"
20 #include "path-util.h"
21 #include "signal-util.h"
22 #include "socket-util.h"
23 #include "stat-util.h"
24 #include "string-table.h"
25 #include "string-util.h"
27 #include "udev-util.h"
30 static const char* const resolve_name_timing_table
[_RESOLVE_NAME_TIMING_MAX
] = {
31 [RESOLVE_NAME_NEVER
] = "never",
32 [RESOLVE_NAME_LATE
] = "late",
33 [RESOLVE_NAME_EARLY
] = "early",
36 DEFINE_STRING_TABLE_LOOKUP(resolve_name_timing
, ResolveNameTiming
);
38 int udev_parse_config_full(
39 unsigned *ret_children_max
,
40 usec_t
*ret_exec_delay_usec
,
41 usec_t
*ret_event_timeout_usec
,
42 ResolveNameTiming
*ret_resolve_name_timing
,
43 int *ret_timeout_signal
) {
45 _cleanup_free_
char *log_val
= NULL
, *children_max
= NULL
, *exec_delay
= NULL
, *event_timeout
= NULL
, *resolve_names
= NULL
, *timeout_signal
= NULL
;
48 r
= parse_env_file(NULL
, "/etc/udev/udev.conf",
50 "children_max", &children_max
,
51 "exec_delay", &exec_delay
,
52 "event_timeout", &event_timeout
,
53 "resolve_names", &resolve_names
,
54 "timeout_signal", &timeout_signal
);
67 ((log_val
[0] == '"' && log_val
[n
-1] == '"') ||
68 (log_val
[0] == '\'' && log_val
[n
-1] == '\''))) {
69 log_val
[n
- 1] = '\0';
74 /* we set the udev log level here explicitly, this is supposed
75 * to regulate the code in libudev/ and udev/. */
76 r
= log_set_max_level_from_string(log
);
78 log_syntax(NULL
, LOG_WARNING
, "/etc/udev/udev.conf", 0, r
,
79 "failed to set udev log level '%s', ignoring: %m", log
);
82 if (ret_children_max
&& children_max
) {
83 r
= safe_atou(children_max
, ret_children_max
);
85 log_syntax(NULL
, LOG_WARNING
, "/etc/udev/udev.conf", 0, r
,
86 "failed to parse children_max=%s, ignoring: %m", children_max
);
89 if (ret_exec_delay_usec
&& exec_delay
) {
90 r
= parse_sec(exec_delay
, ret_exec_delay_usec
);
92 log_syntax(NULL
, LOG_WARNING
, "/etc/udev/udev.conf", 0, r
,
93 "failed to parse exec_delay=%s, ignoring: %m", exec_delay
);
96 if (ret_event_timeout_usec
&& event_timeout
) {
97 r
= parse_sec(event_timeout
, ret_event_timeout_usec
);
99 log_syntax(NULL
, LOG_WARNING
, "/etc/udev/udev.conf", 0, r
,
100 "failed to parse event_timeout=%s, ignoring: %m", event_timeout
);
103 if (ret_resolve_name_timing
&& resolve_names
) {
106 t
= resolve_name_timing_from_string(resolve_names
);
108 log_syntax(NULL
, LOG_WARNING
, "/etc/udev/udev.conf", 0, r
,
109 "failed to parse resolve_names=%s, ignoring.", resolve_names
);
111 *ret_resolve_name_timing
= t
;
114 if (ret_timeout_signal
&& timeout_signal
) {
115 r
= signal_from_string(timeout_signal
);
117 log_syntax(NULL
, LOG_WARNING
, "/etc/udev/udev.conf", 0, r
,
118 "failed to parse timeout_signal=%s, ignoring: %m", timeout_signal
);
120 *ret_timeout_signal
= r
;
126 struct DeviceMonitorData
{
132 static void device_monitor_data_free(struct DeviceMonitorData
*d
) {
135 sd_device_unref(d
->device
);
138 static int device_monitor_handler(sd_device_monitor
*monitor
, sd_device
*device
, void *userdata
) {
139 struct DeviceMonitorData
*data
= ASSERT_PTR(userdata
);
143 assert(data
->sysname
|| data
->devlink
);
144 assert(!data
->device
);
146 /* Ignore REMOVE events here. We are waiting for initialization after all, not de-initialization. We
147 * might see a REMOVE event from an earlier use of the device (devices by the same name are recycled
148 * by the kernel after all), which we should not get confused by. After all we cannot distinguish use
149 * cycles of the devices, as the udev queue is entirely asynchronous.
151 * If we see a REMOVE event here for the use cycle we actually care about then we won't notice of
152 * course, but that should be OK, given the timeout logic used on the wait loop: this will be noticed
153 * by means of -ETIMEDOUT. Thus we won't notice immediately, but eventually, and that should be
154 * sufficient for an error path that should regularly not happen.
156 * (And yes, we only need to special case REMOVE. It's the only "negative" event type, where a device
157 * ceases to exist. All other event types are "positive": the device exists and is registered in the
158 * udev database, thus whenever we see the event, we can consider it initialized.) */
159 if (device_for_action(device
, SD_DEVICE_REMOVE
))
162 if (data
->sysname
&& sd_device_get_sysname(device
, &sysname
) >= 0 && streq(sysname
, data
->sysname
))
168 FOREACH_DEVICE_DEVLINK(device
, link
)
169 if (path_equal(link
, data
->devlink
))
172 if (sd_device_get_devname(device
, &devlink
) >= 0 && path_equal(devlink
, data
->devlink
))
179 data
->device
= sd_device_ref(device
);
180 return sd_event_exit(sd_device_monitor_get_event(monitor
), 0);
183 static int device_wait_for_initialization_internal(
186 const char *subsystem
,
190 _cleanup_(sd_device_monitor_unrefp
) sd_device_monitor
*monitor
= NULL
;
191 _cleanup_(sd_event_unrefp
) sd_event
*event
= NULL
;
192 /* Ensure that if !_device && devlink, device gets unrefd on errors since it will be new */
193 _cleanup_(sd_device_unrefp
) sd_device
*device
= sd_device_ref(_device
);
194 _cleanup_(device_monitor_data_free
) struct DeviceMonitorData data
= {
199 assert(device
|| (subsystem
&& devlink
));
201 /* Devlink might already exist, if it does get the device to use the sysname filtering */
202 if (!device
&& devlink
) {
203 r
= sd_device_new_from_devname(&device
, devlink
);
204 if (r
< 0 && !ERRNO_IS_DEVICE_ABSENT(r
))
205 return log_error_errno(r
, "Failed to create sd-device object from %s: %m", devlink
);
209 if (sd_device_get_is_initialized(device
) > 0) {
211 *ret
= sd_device_ref(device
);
214 /* We need either the sysname or the devlink for filtering */
215 assert_se(sd_device_get_sysname(device
, &data
.sysname
) >= 0 || devlink
);
218 /* Wait until the device is initialized, so that we can get access to the ID_PATH property */
220 r
= sd_event_new(&event
);
222 return log_error_errno(r
, "Failed to get default event: %m");
224 r
= sd_device_monitor_new(&monitor
);
226 return log_error_errno(r
, "Failed to acquire monitor: %m");
228 if (device
&& !subsystem
) {
229 r
= sd_device_get_subsystem(device
, &subsystem
);
230 if (r
< 0 && r
!= -ENOENT
)
231 return log_device_error_errno(device
, r
, "Failed to get subsystem: %m");
235 r
= sd_device_monitor_filter_add_match_subsystem_devtype(monitor
, subsystem
, NULL
);
237 return log_error_errno(r
, "Failed to add %s subsystem match to monitor: %m", subsystem
);
240 _cleanup_free_
char *desc
= NULL
;
241 const char *sysname
= NULL
;
243 (void) sd_device_get_sysname(device
, &sysname
);
245 desc
= strjoin(sysname
?: subsystem
, devlink
? ":" : ":initialization", devlink
);
247 (void) sd_device_monitor_set_description(monitor
, desc
);
249 r
= sd_device_monitor_attach_event(monitor
, event
);
251 return log_error_errno(r
, "Failed to attach event to device monitor: %m");
253 r
= sd_device_monitor_start(monitor
, device_monitor_handler
, &data
);
255 return log_error_errno(r
, "Failed to start device monitor: %m");
257 if (timeout_usec
!= USEC_INFINITY
) {
258 r
= sd_event_add_time_relative(
260 CLOCK_MONOTONIC
, timeout_usec
, 0,
261 NULL
, INT_TO_PTR(-ETIMEDOUT
));
263 return log_error_errno(r
, "Failed to add timeout event source: %m");
266 /* Check again, maybe things changed. Udev will re-read the db if the device wasn't initialized yet. */
267 if (!device
&& devlink
) {
268 r
= sd_device_new_from_devname(&device
, devlink
);
269 if (r
< 0 && !ERRNO_IS_DEVICE_ABSENT(r
))
270 return log_error_errno(r
, "Failed to create sd-device object from %s: %m", devlink
);
272 if (device
&& sd_device_get_is_initialized(device
) > 0) {
274 *ret
= sd_device_ref(device
);
278 r
= sd_event_loop(event
);
280 return log_error_errno(r
, "Failed to wait for device to be initialized: %m");
283 *ret
= TAKE_PTR(data
.device
);
287 int device_wait_for_initialization(sd_device
*device
, const char *subsystem
, usec_t timeout_usec
, sd_device
**ret
) {
288 return device_wait_for_initialization_internal(device
, NULL
, subsystem
, timeout_usec
, ret
);
291 int device_wait_for_devlink(const char *devlink
, const char *subsystem
, usec_t timeout_usec
, sd_device
**ret
) {
292 return device_wait_for_initialization_internal(NULL
, devlink
, subsystem
, timeout_usec
, ret
);
295 int device_is_renaming(sd_device
*dev
) {
300 r
= sd_device_get_property_value(dev
, "ID_RENAMING", NULL
);
309 bool device_for_action(sd_device
*dev
, sd_device_action_t a
) {
310 sd_device_action_t b
;
317 if (sd_device_get_action(dev
, &b
) < 0)
323 void log_device_uevent(sd_device
*device
, const char *str
) {
324 sd_device_action_t action
= _SD_DEVICE_ACTION_INVALID
;
325 sd_id128_t event_id
= SD_ID128_NULL
;
331 (void) sd_device_get_seqnum(device
, &seqnum
);
332 (void) sd_device_get_action(device
, &action
);
333 (void) sd_device_get_trigger_uuid(device
, &event_id
);
334 log_device_debug(device
, "%s%s(SEQNUM=%"PRIu64
", ACTION=%s%s%s)",
335 strempty(str
), isempty(str
) ? "" : " ",
336 seqnum
, strna(device_action_to_string(action
)),
337 sd_id128_is_null(event_id
) ? "" : ", UUID=",
338 sd_id128_is_null(event_id
) ? "" : SD_ID128_TO_UUID_STRING(event_id
));
341 int udev_rule_parse_value(char *str
, char **ret_value
, char **ret_endpos
) {
345 /* value must be double quotated */
346 is_escaped
= str
[0] == 'e';
352 /* unescape double quotation '\"'->'"' */
353 for (j
= str
, i
= str
+ 1; *i
!= '"'; i
++, j
++) {
356 if (i
[0] == '\\' && i
[1] == '"')
362 * The return value must be terminated by two subsequent NULs
363 * so it could be safely interpreted as nulstr.
367 _cleanup_free_
char *unescaped
= NULL
;
370 /* find the end position of value */
371 for (i
= str
+ 1; *i
!= '"'; i
++) {
379 l
= cunescape_length(str
+ 1, i
- (str
+ 1), 0, &unescaped
);
383 assert(l
<= i
- (str
+ 1));
384 memcpy(str
, unescaped
, l
+ 1);
386 * The return value must be terminated by two subsequent NULs
387 * so it could be safely interpreted as nulstr.
397 size_t udev_replace_whitespace(const char *str
, char *to
, size_t len
) {
398 bool is_space
= false;
404 /* Copy from 'str' to 'to', while removing all leading and trailing whitespace, and replacing
405 * each run of consecutive whitespace with a single underscore. The chars from 'str' are copied
406 * up to the \0 at the end of the string, or at most 'len' chars. This appends \0 to 'to', at
407 * the end of the copied characters.
409 * If 'len' chars are copied into 'to', the final \0 is placed at len+1 (i.e. 'to[len] = \0'),
410 * so the 'to' buffer must have at least len+1 chars available.
412 * Note this may be called with 'str' == 'to', i.e. to replace whitespace in-place in a buffer.
413 * This function can handle that situation.
415 * Note that only 'len' characters are read from 'str'. */
417 i
= strspn(str
, WHITESPACE
);
419 for (j
= 0; j
< len
&& i
< len
&& str
[i
] != '\0'; i
++) {
420 if (isspace(str
[i
])) {
439 size_t udev_replace_ifname(char *str
) {
444 /* See ifname_valid_full(). */
446 for (char *p
= str
; *p
!= '\0'; p
++)
447 if (!ifname_valid_char(*p
)) {
455 size_t udev_replace_chars(char *str
, const char *allow
) {
456 size_t i
= 0, replaced
= 0;
460 /* allow chars in allow list, plain ascii, hex-escaping and valid utf8. */
462 while (str
[i
] != '\0') {
465 if (allow_listed_char_for_devnode(str
[i
], allow
)) {
470 /* accept hex encoding */
471 if (str
[i
] == '\\' && str
[i
+1] == 'x') {
476 /* accept valid utf8 */
477 len
= utf8_encoded_valid_unichar(str
+ i
, SIZE_MAX
);
483 /* if space is allowed, replace whitespace with ordinary space */
484 if (isspace(str
[i
]) && allow
&& strchr(allow
, ' ')) {
491 /* everything else is replaced with '_' */
499 int udev_resolve_subsys_kernel(const char *string
, char *result
, size_t maxsize
, bool read_value
) {
500 _cleanup_(sd_device_unrefp
) sd_device
*dev
= NULL
;
501 _cleanup_free_
char *temp
= NULL
;
502 char *subsys
, *sysname
, *attr
;
509 /* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
511 if (string
[0] != '[')
514 temp
= strdup(string
);
520 sysname
= strchr(subsys
, '/');
524 sysname
= &sysname
[1];
526 attr
= strchr(sysname
, ']');
536 if (read_value
&& !attr
)
539 r
= sd_device_new_from_subsystem_sysname(&dev
, subsys
, sysname
);
544 r
= sd_device_get_sysattr_value(dev
, attr
, &val
);
545 if (r
< 0 && !ERRNO_IS_PRIVILEGE(r
) && r
!= -ENOENT
)
548 strscpy(result
, maxsize
, val
);
551 log_debug("value '[%s/%s]%s' is '%s'", subsys
, sysname
, attr
, result
);
553 r
= sd_device_get_syspath(dev
, &val
);
557 strscpyl(result
, maxsize
, val
, attr
? "/" : NULL
, attr
?: NULL
, NULL
);
558 log_debug("path '[%s/%s]%s' is '%s'", subsys
, sysname
, strempty(attr
), result
);
563 bool devpath_conflict(const char *a
, const char *b
) {
564 /* This returns true when two paths are equivalent, or one is a child of another. */
569 for (; *a
!= '\0' && *b
!= '\0'; a
++, b
++)
573 return *a
== '/' || *b
== '/' || *a
== *b
;
576 int udev_queue_is_empty(void) {
577 return access("/run/udev/queue", F_OK
) < 0 ?
578 (errno
== ENOENT
? true : -errno
) : false;
581 int udev_queue_init(void) {
582 _cleanup_close_
int fd
= -EBADF
;
584 fd
= inotify_init1(IN_CLOEXEC
);
588 if (inotify_add_watch(fd
, "/run/udev" , IN_DELETE
) < 0)
594 bool udev_available(void) {
595 static int cache
= -1;
597 /* The service systemd-udevd is started only when /sys is read write.
598 * See systemd-udevd.service: ConditionPathIsReadWrite=/sys
599 * Also, our container interface (http://systemd.io/CONTAINER_INTERFACE/) states that /sys must
600 * be mounted in read-only mode in containers. */
605 return (cache
= (path_is_read_only_fs("/sys/") <= 0));