From 45e3967c20b5020bf720b9497592e231104398f3 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Mon, 3 Jun 2019 14:16:52 +0200 Subject: libbb: move netlink socket binding to the utility function function old new delta create_and_bind_to_netlink - 134 +134 ifplugd_main 1117 1052 -65 uevent_main 399 306 -93 mdev_main 314 215 -99 ------------------------------------------------------------------------------ (add/remove: 1/0 grow/shrink: 0/3 up/down: 134/-257) Total: -123 bytes Signed-off-by: Denys Vlasenko --- util-linux/mdev.c | 28 ++++++++-------------------- util-linux/uevent.c | 37 ++++++++++--------------------------- 2 files changed, 18 insertions(+), 47 deletions(-) (limited to 'util-linux') diff --git a/util-linux/mdev.c b/util-linux/mdev.c index 88c82b6fb..9cb3586f1 100644 --- a/util-linux/mdev.c +++ b/util-linux/mdev.c @@ -1225,28 +1225,16 @@ int mdev_main(int argc UNUSED_PARAM, char **argv) /* * Daemon mode listening on uevent netlink socket. */ - struct sockaddr_nl sa; int fd; -//TODO: reuse same code in uevent - // Subscribe for UEVENT kernel messages - sa.nl_family = AF_NETLINK; - sa.nl_pad = 0; - sa.nl_pid = getpid(); - sa.nl_groups = 1 << 0; - fd = xsocket(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT); - xbind(fd, (struct sockaddr *) &sa, sizeof(sa)); - close_on_exec_on(fd); - - // 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 >"{}"' ';' - // - // SO_RCVBUFFORCE (root only) can go above net.core.rmem_max sysctl - setsockopt_SOL_SOCKET_int(fd, SO_RCVBUF, RCVBUF); - setsockopt_SOL_SOCKET_int(fd, SO_RCVBUFFORCE, RCVBUF); + /* 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, RCVBUF); /* * Make inital scan after the uevent socket is alive and diff --git a/util-linux/uevent.c b/util-linux/uevent.c index 761743f45..2f8990ed9 100644 --- a/util-linux/uevent.c +++ b/util-linux/uevent.c @@ -46,37 +46,19 @@ enum { RCVBUF = 2 * 1024 * 1024 }; int uevent_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int uevent_main(int argc UNUSED_PARAM, char **argv) { - struct sockaddr_nl sa; int fd; INIT_G(); argv++; - // Subscribe for UEVENT kernel messages - sa.nl_family = AF_NETLINK; - sa.nl_pad = 0; - sa.nl_pid = getpid(); - sa.nl_groups = 1 << 0; - fd = xsocket(AF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT); - xbind(fd, (struct sockaddr *) &sa, sizeof(sa)); - close_on_exec_on(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: // uevent mdev & // find /sys -name uevent -exec sh -c 'echo add >"{}"' ';' - // - // SO_RCVBUFFORCE (root only) can go above net.core.rmem_max sysctl - setsockopt_SOL_SOCKET_int(fd, SO_RCVBUF, RCVBUF); - setsockopt_SOL_SOCKET_int(fd, SO_RCVBUFFORCE, RCVBUF); - if (0) { - int z; - socklen_t zl = sizeof(z); - getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &z, &zl); - bb_error_msg("SO_RCVBUF:%d", z); - } + fd = create_and_bind_to_netlink(NETLINK_KOBJECT_UEVENT, /*groups:*/ 1 << 0, RCVBUF); for (;;) { char *netbuf; @@ -118,14 +100,15 @@ int uevent_main(int argc UNUSED_PARAM, char **argv) } env[idx] = NULL; - idx = 0; - while (env[idx]) - putenv(env[idx++]); - if (argv[0]) + if (argv[0]) { + idx = 0; + while (env[idx]) + putenv(env[idx++]); spawn_and_wait(argv); - idx = 0; - while (env[idx]) - bb_unsetenv(env[idx++]); + idx = 0; + while (env[idx]) + bb_unsetenv(env[idx++]); + } munmap(netbuf, BUFFER_SIZE); } -- cgit v1.2.3