e3f475901
Jan Klötzke
2020-11-22
Subject
mdev: move daemon setup to dedicated function
Binary
No binary (build failed)
Architecture & Compiler Flags
—
Build Log
(log yok)
Commit Diff GitHub →
util-linux/mdev.c+27 -17
| @@ -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. |
| - | */ |
| - | 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. |
| + | * 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. |
| */ | |
| - | initial_scan(temp); |
| + | int fd = daemon_init(temp); |
| if (!(opt & MDEV_OPT_FOREGROUND)) | |
| bb_daemonize_or_rexec(0, argv); | |