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mdev: move daemon setup to dedicated function

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Signed-off-by: Jan Klötzke <jan@kloetzke.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Jan Klötzke 2020-11-22 14:17:56 +01:00 committed by Denys Vlasenko
parent a569fd37fe
commit e3f4759019
1 changed files with 27 additions and 17 deletions
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44
util-linux/mdev.c
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@ -1165,6 +1165,29 @@ static void initial_scan(char *temp)
# define KERN_RCVBUF (128 * 1024 * 1024)
# define MAX_ENV 32
static int daemon_init(char *temp)
{
int fd;
/* Subscribe for UEVENT kernel messages */
/* Without a sufficiently big RCVBUF, a ton of simultaneous events
* can trigger ENOBUFS on read, which is unrecoverable.
* Reproducer:
* mdev -d
* find /sys -name uevent -exec sh -c 'echo add >"{}"' ';'
*/
fd = create_and_bind_to_netlink(NETLINK_KOBJECT_UEVENT, 1 << 0, KERN_RCVBUF);
/*
* Make inital scan after the uevent socket is alive and
* _before_ we fork away. Already open mdev.log because we work
* in daemon mode.
*/
initial_scan(temp);
return fd;
}
static void daemon_loop(char *temp, int fd)
{
for (;;) {
@ -1234,24 +1257,11 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
#if ENABLE_FEATURE_MDEV_DAEMON
if (opt & MDEV_OPT_DAEMON) {
/*
* Daemon mode listening on uevent netlink socket.
* Daemon mode listening on uevent netlink socket. Fork away
* after initial scan so that caller can be sure everything
* is up-to-date when mdev process returns.
*/
int fd;
/* Subscribe for UEVENT kernel messages */
/* Without a sufficiently big RCVBUF, a ton of simultaneous events
* can trigger ENOBUFS on read, which is unrecoverable.
* Reproducer:
* mdev -d
* find /sys -name uevent -exec sh -c 'echo add >"{}"' ';'
*/
fd = create_and_bind_to_netlink(NETLINK_KOBJECT_UEVENT, 1 << 0, KERN_RCVBUF);
/*
* Make inital scan after the uevent socket is alive and
* _before_ we fork away.
*/
initial_scan(temp);
int fd = daemon_init(temp);
if (!(opt & MDEV_OPT_FOREGROUND))
bb_daemonize_or_rexec(0, argv);