From: Kay Sievers Date: Sun, 5 Jun 2005 02:38:10 +0000 (+0200) Subject: udevd: listen for netlink events X-Git-Tag: 059~13^2~23 X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=88f4b6485e2a551de55fd9d39aeef89debf3121c udevd: listen for netlink events After the first valid netlink-event all event with a serial number received on the udevsend socket will be ignored. Signed-off-by: Kay Sievers --- diff --git a/udev.c b/udev.c index ce9b42f30..2be4c3574 100644 --- a/udev.c +++ b/udev.c @@ -54,8 +54,10 @@ void log_message(int priority, const char *format, ...) } #endif -/* decide if we should manage the whole hotplug event - * for now look if the kernel calls udevsend instead of /sbin/hotplug +/* Decide if we should manage the whole uevent, including multiplexing + * of the hotplug directories. + * For now look if the kernel calls udevsend instead of /sbin/hotplug, + * or the uevent-helper in /proc/sys/kernel/hotplug is empty. */ static int manage_hotplug_event(void) { char helper[256]; @@ -70,13 +72,15 @@ static int manage_hotplug_event(void) { if (fd < 0) return 0; - len = read(fd, helper, 256); + len = read(fd, helper, sizeof(helper)-1); close(fd); if (len < 0) return 0; helper[len] = '\0'; + if (helper[0] == '\0' || helper[0] == '\n') + return 1; if (strstr(helper, "udevsend")) return 1; diff --git a/udevd.c b/udevd.c index 91033b068..68e3a75f3 100644 --- a/udevd.c +++ b/udevd.c @@ -38,6 +38,7 @@ #include #include #include +#include #include "list.h" #include "udev_libc_wrapper.h" @@ -49,6 +50,7 @@ /* global variables*/ static int udevsendsock; +static int ueventsock; static pid_t sid; static int pipefds[2]; @@ -126,7 +128,8 @@ static void msg_queue_insert(struct hotplug_msg *msg) break; if (loop_msg->seqnum == msg->seqnum) { - info("ignoring duplicate message seq %llu", msg->seqnum); + dbg("ignoring duplicate message seq %llu", msg->seqnum); + free(msg); return; } } @@ -154,6 +157,8 @@ static void execute_udev(struct hotplug_msg *msg) switch (pid) { case 0: /* child */ + if (ueventsock != -1) + close(ueventsock); close(udevsendsock); logging_close(); @@ -416,13 +421,60 @@ recheck: } } +static struct hotplug_msg *get_msg_from_envbuf(const char *buf, int buf_size) +{ + int bufpos; + int i; + struct hotplug_msg *msg; + + msg = malloc(sizeof(struct hotplug_msg) + buf_size); + if (msg == NULL) + return NULL; + memset(msg, 0x00, sizeof(struct hotplug_msg) + buf_size); + + /* copy environment buffer and reconstruct envp */ + memcpy(msg->envbuf, buf, buf_size); + bufpos = 0; + for (i = 0; (bufpos < buf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) { + int keylen; + char *key; + + key = &msg->envbuf[bufpos]; + keylen = strlen(key); + msg->envp[i] = key; + bufpos += keylen + 1; + dbg("add '%s' to msg.envp[%i]", msg->envp[i], i); + + /* remember some keys for further processing */ + if (strncmp(key, "ACTION=", 7) == 0) + msg->action = &key[7]; + + if (strncmp(key, "DEVPATH=", 8) == 0) + msg->devpath = &key[8]; + + if (strncmp(key, "SUBSYSTEM=", 10) == 0) + msg->subsystem = &key[10]; + + if (strncmp(key, "SEQNUM=", 7) == 0) + msg->seqnum = strtoull(&key[7], NULL, 10); + + if (strncmp(key, "PHYSDEVPATH=", 12) == 0) + msg->physdevpath = &key[12]; + + if (strncmp(key, "TIMEOUT=", 8) == 0) + msg->timeout = strtoull(&key[8], NULL, 10); + } + msg->envp[i++] = "UDEVD_EVENT=1"; + msg->envp[i] = NULL; + + return msg; +} + /* receive the udevsend message and do some sanity checks */ static struct hotplug_msg *get_udevsend_msg(void) { static struct udevsend_msg usend_msg; struct hotplug_msg *msg; - int bufpos; - int i; ssize_t size; struct msghdr smsg; struct cmsghdr *cmsg; @@ -467,46 +519,60 @@ static struct hotplug_msg *get_udevsend_msg(void) envbuf_size = size - offsetof(struct udevsend_msg, envbuf); dbg("envbuf_size=%i", envbuf_size); - msg = malloc(sizeof(struct hotplug_msg) + envbuf_size); + msg = get_msg_from_envbuf(usend_msg.envbuf, envbuf_size); if (msg == NULL) return NULL; - memset(msg, 0x00, sizeof(struct hotplug_msg) + envbuf_size); - - /* copy environment buffer and reconstruct envp */ - memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size); - bufpos = 0; - for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) { - int keylen; - char *key; + return msg; +} - key = &msg->envbuf[bufpos]; - keylen = strlen(key); - msg->envp[i] = key; - bufpos += keylen + 1; - dbg("add '%s' to msg.envp[%i]", msg->envp[i], i); +/* receive the kernel user event message and do some sanity checks */ +static struct hotplug_msg *get_uevent_msg(void) +{ + struct hotplug_msg *msg; + int bufpos; + ssize_t size; + static char buffer[HOTPLUG_BUFFER_SIZE + 512]; + char *pos; - /* remember some keys for further processing */ - if (strncmp(key, "ACTION=", 7) == 0) - msg->action = &key[7]; + size = recv(ueventsock, &buffer, sizeof(buffer), 0); + if (size < 0) { + if (errno != EINTR) + dbg("unable to receive udevsend message"); + return NULL; + } - if (strncmp(key, "DEVPATH=", 8) == 0) - msg->devpath = &key[8]; + if ((size_t)size > sizeof(buffer)-1) + size = sizeof(buffer)-1; + buffer[size] = '\0'; + dbg("uevent_size=%i", size); - if (strncmp(key, "SUBSYSTEM=", 10) == 0) - msg->subsystem = &key[10]; + /* start of event payload */ + bufpos = strlen(buffer)+1; + msg = get_msg_from_envbuf(&buffer[bufpos], size-bufpos); + if (msg == NULL) + return NULL; - if (strncmp(key, "SEQNUM=", 7) == 0) - msg->seqnum = strtoull(&key[7], NULL, 10); + /* validate message */ + pos = strchr(buffer, '@'); + if (pos == NULL) { + dbg("invalid uevent '%s'", buffer); + free(msg); + return NULL; + } + pos[0] = '\0'; - if (strncmp(key, "PHYSDEVPATH=", 12) == 0) - msg->physdevpath = &key[12]; + if (msg->action == NULL) { + dbg("no ACTION in payload found, skip event '%s'", buffer); + free(msg); + return NULL; + } - if (strncmp(key, "TIMEOUT=", 8) == 0) - msg->timeout = strtoull(&key[8], NULL, 10); + if (strcmp(msg->action, buffer) != 0) { + dbg("ACTION in payload does not match uevent, skip event '%s'", buffer); + free(msg); + return NULL; } - msg->envp[i++] = "UDEVD_EVENT=1"; - msg->envp[i] = NULL; return msg; } @@ -622,6 +688,34 @@ static int init_udevsend_socket(void) return 0; } +static int init_uevent_socket(void) +{ + struct sockaddr_nl snl; + int retval; + + memset(&snl, 0x00, sizeof(struct sockaddr_nl)); + snl.nl_family = AF_NETLINK; + snl.nl_pid = getpid(); + snl.nl_groups = 0xffffffff; + + ueventsock = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT); + if (ueventsock == -1) { + dbg("error getting socket, %s", strerror(errno)); + return -1; + } + + retval = bind(ueventsock, (struct sockaddr *) &snl, + sizeof(struct sockaddr_nl)); + if (retval < 0) { + dbg("bind failed, %s", strerror(errno)); + close(ueventsock); + ueventsock = -1; + return -1; + } + + return 0; +} + int main(int argc, char *argv[], char *envp[]) { struct sysinfo info; @@ -631,6 +725,7 @@ int main(int argc, char *argv[], char *envp[]) struct sigaction act; fd_set readfds; const char *udevd_expected_seqnum; + int uevent_active = 0; logging_init("udevd"); udev_init_config(); @@ -716,6 +811,10 @@ int main(int argc, char *argv[], char *envp[]) sigaction(SIGALRM, &act, NULL); sigaction(SIGCHLD, &act, NULL); + if (init_uevent_socket() < 0) { + dbg("uevent socket not available"); + } + if (init_udevsend_socket() < 0) { if (errno == EADDRINUSE) dbg("another udevd running, exit"); @@ -745,6 +844,8 @@ int main(int argc, char *argv[], char *envp[]) FD_ZERO(&readfds); FD_SET(udevsendsock, &readfds); + if (ueventsock != -1) + FD_SET(ueventsock, &readfds); FD_SET(pipefds[0], &readfds); maxsockplus = udevsendsock+1; while (1) { @@ -761,8 +862,27 @@ int main(int argc, char *argv[], char *envp[]) if (FD_ISSET(udevsendsock, &workreadfds)) { msg = get_udevsend_msg(); - if (msg) + if (msg) { + /* discard kernel messages if netlink is active */ + if (uevent_active && msg->seqnum != 0) { + dbg("skip kernel udevsend message, netlink is active"); + free(msg); + continue; + } + msg_queue_insert(msg); + } + } + + if (FD_ISSET(ueventsock, &workreadfds)) { + msg = get_uevent_msg(); + if (msg) { msg_queue_insert(msg); + /* disable udevsend with first netlink message */ + if (!uevent_active) { + info("netlink message received, disable kernel udevsend messages"); + uevent_active = 1; + } + } } if (FD_ISSET(pipefds[0], &workreadfds))