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mirror of https://github.com/systemd/systemd-stable.git synced 2024-12-23 17:34:00 +03:00

udev-util: introduce udev_available() helper function

This commit is contained in:
Yu Watanabe 2022-02-17 18:47:26 +09:00
parent bfae960e53
commit f92c5bb18c
2 changed files with 17 additions and 0 deletions

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@ -20,6 +20,7 @@
#include "path-util.h"
#include "signal-util.h"
#include "socket-util.h"
#include "stat-util.h"
#include "string-table.h"
#include "string-util.h"
#include "strxcpyx.h"
@ -723,3 +724,17 @@ int on_ac_power(void) {
return found_online || !found_offline;
}
bool udev_available(void) {
static int cache = -1;
/* The service systemd-udevd is started only when /sys is read write.
* See systemd-udevd.service: ConditionPathIsReadWrite=/sys
* Also, our container interface (http://systemd.io/CONTAINER_INTERFACE/) states that /sys must
* be mounted in read-only mode in containers. */
if (cache >= 0)
return cache;
return (cache = path_is_read_only_fs("/sys/") <= 0);
}

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@ -55,6 +55,8 @@ int udev_queue_init(void);
int on_ac_power(void);
bool udev_available(void);
#if HAVE_SYS_SDT_H
/* Each trace point can have different number of additional arguments. Note that when the macro is used only