/*
- * udevd.c
+ * udevd.c - hotplug event serializer
*
- * Userspace devfs
- *
- * Copyright (C) 2004 Ling, Xiaofeng <xiaofeng.ling@intel.com>
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
*
*
* This program is free software; you can redistribute it and/or modify it
*
*/
-#include <sys/types.h>
-#include <sys/ipc.h>
+#include <stddef.h>
#include <sys/wait.h>
-#include <sys/msg.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <fcntl.h>
+#include "klibc_fixups.h"
+#include <sys/sysinfo.h>
+#include "list.h"
#include "udev.h"
+#include "udev_lib.h"
+#include "udev_version.h"
#include "udevd.h"
#include "logging.h"
-#define BUFFER_SIZE 1024
-#define TIMEOUT_SECONDS 10
-
-static void reset_timer(void);
-static void reset_queue(void);
-
+static int pipefds[2];
+static unsigned long long expected_seqnum = 0;
+volatile static int children_waiting;
+volatile static int run_msg_q;
+volatile static int sig_flag;
+static int run_exec_q;
+
+static LIST_HEAD(msg_list);
+static LIST_HEAD(exec_list);
+static LIST_HEAD(running_list);
+
+static void exec_queue_manager(void);
+static void msg_queue_manager(void);
+static void user_sighandler(void);
+static void reap_kids(void);
+char *udev_bin;
+
+#ifdef LOG
+unsigned char logname[LOGNAME_SIZE];
+void log_message (int level, const char *format, ...)
+{
+ va_list args;
-static int expect_seqnum = 0;
-static int timeout_value = TIMEOUT_SECONDS;
-static int timeout = 0;
-static struct hotplug_msg *head = NULL;
-static char exec_program[100];
+ va_start(args, format);
+ vsyslog(level, format, args);
+ va_end(args);
+}
+#endif
+#define msg_dump(msg) \
+ dbg("msg_dump: sequence %llu, '%s', '%s', '%s'", \
+ msg->seqnum, msg->action, msg->devpath, msg->subsystem);
-static void sig_handler(int signum)
+static void msg_dump_queue(void)
{
- dbg("caught signal %d", signum);
- switch (signum) {
- case SIGHUP:
- dbg("reset requested, all waiting events killed");
- reset_timer();
- reset_queue();
- timeout = 0;
- expect_seqnum = 0;
- break;
+#ifdef DEBUG
+ struct hotplug_msg *msg;
- case SIGINT:
- case SIGTERM:
- case SIGKILL:
- exit(20 + signum);
- break;
-
- default:
- dbg("unhandled signal");
- }
+ list_for_each_entry(msg, &msg_list, list)
+ dbg("sequence %llu in queue", msg->seqnum);
+#endif
}
-static void sig_alarmhandler(int signum)
+static struct hotplug_msg *msg_create(void)
{
- dbg("caught signal %d", signum);
- switch (signum) {
- case SIGALRM:
- timeout = 1;
- dbg("event timeout reached");
- break;
+ struct hotplug_msg *new_msg;
- default:
- dbg("unhandled signal");
- }
+ new_msg = malloc(sizeof(struct hotplug_msg));
+ if (new_msg == NULL)
+ dbg("error malloc");
+ return new_msg;
}
-static void dump_queue(void)
+static void run_queue_delete(struct hotplug_msg *msg)
{
- struct hotplug_msg *p;
- p = head;
-
- dbg("next expected sequence is %d", expect_seqnum);
- while(p) {
- dbg("sequence %d in queue", p->seqnum);
- p=p->next;
- }
+ list_del(&msg->list);
+ free(msg);
}
-static void dump_msg(struct hotplug_msg *pmsg)
+/* orders the message in the queue by sequence number */
+static void msg_queue_insert(struct hotplug_msg *msg)
{
- dbg("sequence %d, '%s', '%s', '%s'",
- pmsg->seqnum, pmsg->action, pmsg->devpath, pmsg->subsystem);
+ struct hotplug_msg *loop_msg;
+ struct sysinfo info;
+
+ /* sort message by sequence number into list. events
+ * will tend to come in order, so scan the list backwards
+ */
+ list_for_each_entry_reverse(loop_msg, &msg_list, list)
+ if (loop_msg->seqnum < msg->seqnum)
+ break;
+
+ /* store timestamp of queuing */
+ sysinfo(&info);
+ msg->queue_time = info.uptime;
+
+ list_add(&msg->list, &loop_msg->list);
+ dbg("queued message seq %llu", msg->seqnum);
+
+ /* run msg queue manager */
+ run_msg_q = 1;
+
+ return ;
}
-static int dispatch_msg(struct hotplug_msg *pmsg)
+/* forks event and removes event from run queue when finished */
+static void udev_run(struct hotplug_msg *msg)
{
pid_t pid;
- char *argv[3];
- int retval;
- extern char **environ;
-
- dump_msg(pmsg);
- dbg("exec '%s'", exec_program);
-
- setenv("ACTION", pmsg->action, 1);
- setenv("DEVPATH", pmsg->devpath, 1);
+ char action[ACTION_SIZE];
+ char devpath[DEVPATH_SIZE];
+ char seqnum[SEQNUM_SIZE];
+ char *env[] = { action, devpath, seqnum, NULL };
- argv[0] = exec_program;
- argv[1] = pmsg->subsystem;
- argv[2] = NULL;
+ snprintf(action, ACTION_SIZE-1, "ACTION=%s", msg->action);
+ action[ACTION_SIZE-1] = '\0';
+ snprintf(devpath, DEVPATH_SIZE-1, "DEVPATH=%s", msg->devpath);
+ devpath[DEVPATH_SIZE-1] = '\0';
+ sprintf(seqnum, "SEQNUM=%llu", msg->seqnum);
pid = fork();
switch (pid) {
case 0:
- retval = execve(argv[0], argv, environ);
- if (retval != 0) {
- dbg("child execve failed");
- exit(1);
- }
+ /* child */
+ execle(udev_bin, "udev", msg->subsystem, NULL, env);
+ dbg("exec of child failed");
+ exit(1);
break;
case -1:
- dbg("fork failed");
- return -1;
- default:
- wait(0);
+ dbg("fork of child failed");
+ run_queue_delete(msg);
+ /* note: we never managed to run, so we had no impact on
+ * running_with_devpath(), so don't bother setting run_exec_q
+ */
break;
+ default:
+ /* get SIGCHLD in main loop */
+ dbg("==> exec seq %llu [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
+ msg->pid = pid;
}
- return 0;
}
-static void reset_timer(void)
+/* returns already running task with devpath */
+static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
{
- alarm(0);
+ struct hotplug_msg *loop_msg;
+ list_for_each_entry(loop_msg, &running_list, list)
+ if (strncmp(loop_msg->devpath, msg->devpath, sizeof(loop_msg->devpath)) == 0)
+ return loop_msg;
+ return NULL;
}
-static void set_timer(void)
+/* exec queue management routine executes the events and delays events for the same devpath */
+static void exec_queue_manager()
{
- signal(SIGALRM, sig_alarmhandler);
- alarm(timeout_value);
+ struct hotplug_msg *loop_msg;
+ struct hotplug_msg *tmp_msg;
+ struct hotplug_msg *msg;
+
+ list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, list) {
+ msg = running_with_devpath(loop_msg);
+ if (!msg) {
+ /* move event to run list */
+ list_move_tail(&loop_msg->list, &running_list);
+ udev_run(loop_msg);
+ dbg("moved seq %llu to running list", loop_msg->seqnum);
+ } else {
+ dbg("delay seq %llu, cause seq %llu already working on '%s'",
+ loop_msg->seqnum, msg->seqnum, msg->devpath);
+ }
+ }
}
-static void reset_queue(void)
+static void msg_move_exec(struct hotplug_msg *msg)
{
- struct hotplug_msg *p;
- p = head;
+ list_move_tail(&msg->list, &exec_list);
+ run_exec_q = 1;
+ expected_seqnum = msg->seqnum+1;
+ dbg("moved seq %llu to exec, next expected is %llu",
+ msg->seqnum, expected_seqnum);
+}
- while(head) {
- p = head;
- head = head->next;
- free(p);
+/* msg queue management routine handles the timeouts and dispatches the events */
+static void msg_queue_manager()
+{
+ struct hotplug_msg *loop_msg;
+ struct hotplug_msg *tmp_msg;
+ struct sysinfo info;
+ long msg_age = 0;
+
+ dbg("msg queue manager, next expected is %llu", expected_seqnum);
+recheck:
+ list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
+ /* move event with expected sequence to the exec list */
+ if (loop_msg->seqnum == expected_seqnum) {
+ msg_move_exec(loop_msg);
+ continue;
+ }
+
+ /* move event with expired timeout to the exec list */
+ sysinfo(&info);
+ msg_age = info.uptime - loop_msg->queue_time;
+ dbg("seq %llu is %li seconds old", loop_msg->seqnum, msg_age);
+ if (msg_age > EVENT_TIMEOUT_SEC-1) {
+ msg_move_exec(loop_msg);
+ goto recheck;
+ } else {
+ break;
+ }
+ }
+
+ msg_dump_queue();
+
+ /* set timeout for remaining queued events */
+ if (list_empty(&msg_list) == 0) {
+ struct itimerval itv = {{0, 0}, {EVENT_TIMEOUT_SEC - msg_age, 0}};
+ dbg("next event expires in %li seconds", EVENT_TIMEOUT_SEC - msg_age);
+ setitimer(ITIMER_REAL, &itv, 0);
}
}
-static void check_queue(void)
+/* receive the msg, do some basic sanity checks, and queue it */
+static void handle_msg(int sock)
{
- struct hotplug_msg *p;
- p = head;
-
- dump_queue();
- while(head && head->seqnum == expect_seqnum) {
- dispatch_msg(head);
- expect_seqnum++;
- p = head;
- head = head->next;
- free(p);
+ struct hotplug_msg *msg;
+ int retval;
+ struct msghdr smsg;
+ struct cmsghdr *cmsg;
+ struct iovec iov;
+ struct ucred *cred;
+ char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
+
+ msg = msg_create();
+ if (msg == NULL) {
+ dbg("unable to store message");
+ return;
}
- if (head != NULL)
- set_timer();
- else
- reset_timer();
+
+ iov.iov_base = msg;
+ iov.iov_len = sizeof(struct hotplug_msg);
+
+ memset(&smsg, 0x00, sizeof(struct msghdr));
+ smsg.msg_iov = &iov;
+ smsg.msg_iovlen = 1;
+ smsg.msg_control = cred_msg;
+ smsg.msg_controllen = sizeof(cred_msg);
+
+ retval = recvmsg(sock, &smsg, 0);
+ if (retval < 0) {
+ if (errno != EINTR)
+ dbg("unable to receive message");
+ return;
+ }
+ cmsg = CMSG_FIRSTHDR(&smsg);
+ cred = (struct ucred *) CMSG_DATA(cmsg);
+
+ if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
+ dbg("no sender credentials received, message ignored");
+ goto skip;
+ }
+
+ if (cred->uid != 0) {
+ dbg("sender uid=%i, message ignored", cred->uid);
+ goto skip;
+ }
+
+ if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
+ dbg("message magic '%s' doesn't match, ignore it", msg->magic);
+ goto skip;
+ }
+
+ /* if no seqnum is given, we move straight to exec queue */
+ if (msg->seqnum == 0) {
+ list_add(&msg->list, &exec_list);
+ run_exec_q = 1;
+ } else {
+ msg_queue_insert(msg);
+ }
+ return;
+
+skip:
+ free(msg);
+ return;
}
-static void add_queue(struct hotplug_msg *pmsg)
+asmlinkage static void sig_handler(int signum)
{
- struct hotplug_msg *pnewmsg;
- struct hotplug_msg *p;
- struct hotplug_msg *p1;
-
- p = head;
- p1 = NULL;
- pnewmsg = malloc(sizeof(struct hotplug_msg));
- *pnewmsg = *pmsg;
- pnewmsg->next = NULL;
- while(p && pmsg->seqnum > p->seqnum) {
- p1 = p;
- p = p->next;
+ int rc;
+
+ switch (signum) {
+ case SIGINT:
+ case SIGTERM:
+ exit(20 + signum);
+ break;
+ case SIGALRM:
+ /* set flag, then write to pipe if needed */
+ run_msg_q = 1;
+ goto do_write;
+ break;
+ case SIGCHLD:
+ /* set flag, then write to pipe if needed */
+ children_waiting = 1;
+ goto do_write;
+ break;
+ default:
+ dbg("unhandled signal %d", signum);
+ return;
}
- pnewmsg->next = p;
- if (p1 == NULL) {
- head = pnewmsg;
- } else {
- p1->next = pnewmsg;
+
+do_write:
+ /* if pipe is empty, write to pipe to force select to return
+ * immediately when it gets called
+ */
+ if (!sig_flag) {
+ rc = write(pipefds[1],&signum,sizeof(signum));
+ if (rc < 0)
+ dbg("unable to write to pipe");
+ else
+ sig_flag = 1;
}
- dump_queue();
}
-static int process_queue(void)
+static void udev_done(int pid)
{
- int msgid;
- key_t key;
- struct hotplug_msg *pmsg;
- char buf[BUFFER_SIZE];
- int ret;
-
- key = ftok(DEFAULT_EXEC_PROGRAM, IPC_KEY_ID);
- pmsg = (struct hotplug_msg *) buf;
- msgid = msgget(key, IPC_CREAT);
- if (msgid == -1) {
- dbg("open message queue error");
- goto exit;
+ /* find msg associated with pid and delete it */
+ struct hotplug_msg *msg;
+
+ list_for_each_entry(msg, &running_list, list) {
+ if (msg->pid == pid) {
+ dbg("<== exec seq %llu came back", msg->seqnum);
+ run_queue_delete(msg);
+
+ /* we want to run the exec queue manager since there may
+ * be events waiting with the devpath of the one that
+ * just finished
+ */
+ run_exec_q = 1;
+ return;
+ }
}
- while (1) {
- ret = msgrcv(msgid, (struct msgbuf *) buf, BUFFER_SIZE-4, HOTPLUGMSGTYPE, 0);
- if (ret != -1) {
- dbg("current sequence %d, expected sequence %d", pmsg->seqnum, expect_seqnum);
-
- /* init expected sequence with value from first call */
- if (expect_seqnum == 0) {
- expect_seqnum = pmsg->seqnum;
- dbg("init next expected sequence number to %d", expect_seqnum);
- }
+}
- if (pmsg->seqnum > expect_seqnum) {
- add_queue(pmsg);
- set_timer();
- } else {
- if (pmsg->seqnum == expect_seqnum) {
- dispatch_msg(pmsg);
- expect_seqnum++;
- check_queue();
- } else {
- dbg("timeout event for unexpected sequence number %d", pmsg->seqnum);
- }
- }
- } else
- if (errno == EINTR) {
- if (head != NULL) {
- /* timeout, skip all missing, proceed with next queued event */
- dbg("timeout reached, skip events %d - %d", expect_seqnum, head->seqnum-1);
- expect_seqnum = head->seqnum;
- }
- check_queue();
- timeout = 0;
- } else {
- dbg("ipc message receive error '%s'", strerror(errno));
- }
+static void reap_kids()
+{
+ /* reap all dead children */
+ while(1) {
+ int pid = waitpid(-1, 0, WNOHANG);
+ if ((pid == -1) || (pid == 0))
+ break;
+ udev_done(pid);
}
- return 0;
-exit:
- return -1;
}
+/* just read everything from the pipe and clear the flag,
+ * the useful flags were set in the signal handler
+ */
+static void user_sighandler()
+{
+ int sig;
+ while(1) {
+ int rc = read(pipefds[0],&sig,sizeof(sig));
+ if (rc < 0)
+ break;
+
+ sig_flag = 0;
+ }
+}
+
+
int main(int argc, char *argv[])
{
- /* get program to exec on events */
- if (argc == 2)
- strncpy(exec_program, argv[1], sizeof(exec_program));
+ int ssock, maxsockplus;
+ struct sockaddr_un saddr;
+ socklen_t addrlen;
+ int retval;
+ const int on = 1;
+ struct sigaction act;
+ fd_set readfds;
+
+ init_logging("udevd");
+ dbg("version %s", UDEV_VERSION);
+
+ if (getuid() != 0) {
+ dbg("need to be root, exit");
+ exit(1);
+ }
+
+ /* setup signal handler pipe */
+ retval = pipe(pipefds);
+ if (retval < 0) {
+ dbg("error getting pipes: %s", strerror(errno));
+ exit(1);
+ }
+
+ retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
+ if (retval < 0) {
+ dbg("error fcntl on read pipe: %s", strerror(errno));
+ exit(1);
+ }
+
+ retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
+ if (retval < 0) {
+ dbg("error fcntl on write pipe: %s", strerror(errno));
+ exit(1);
+ }
+
+ /* set signal handlers */
+ act.sa_handler = sig_handler;
+ sigemptyset(&act.sa_mask);
+ act.sa_flags = SA_RESTART;
+ sigaction(SIGINT, &act, NULL);
+ sigaction(SIGTERM, &act, NULL);
+ sigaction(SIGALRM, &act, NULL);
+ sigaction(SIGCHLD, &act, NULL);
+
+ memset(&saddr, 0x00, sizeof(saddr));
+ saddr.sun_family = AF_LOCAL;
+ /* use abstract namespace for socket path */
+ strcpy(&saddr.sun_path[1], UDEVD_SOCK_PATH);
+ addrlen = offsetof(struct sockaddr_un, sun_path) + strlen(saddr.sun_path+1) + 1;
+
+ ssock = socket(AF_LOCAL, SOCK_DGRAM, 0);
+ if (ssock == -1) {
+ dbg("error getting socket, exit");
+ exit(1);
+ }
+
+ /* the bind takes care of ensuring only one copy running */
+ retval = bind(ssock, (struct sockaddr *) &saddr, addrlen);
+ if (retval < 0) {
+ dbg("bind failed, exit");
+ goto exit;
+ }
+
+ /* enable receiving of the sender credentials */
+ setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
+
+ /* possible override of udev binary, used for testing */
+ udev_bin = getenv("UDEV_BIN");
+ if (udev_bin != NULL)
+ dbg("udev binary is set to '%s'", udev_bin);
else
- strcpy(exec_program, DEFAULT_EXEC_PROGRAM);
+ udev_bin = UDEV_BIN;
- /* set up signal handler */
- signal(SIGINT, sig_handler);
- signal(SIGTERM, sig_handler);
- signal(SIGKILL, sig_handler);
- signal(SIGHUP, sig_handler);
+ FD_ZERO(&readfds);
+ FD_SET(ssock, &readfds);
+ FD_SET(pipefds[0], &readfds);
+ maxsockplus = ssock+1;
+ while (1) {
+ fd_set workreadfds = readfds;
+ retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
+
+ if (retval < 0) {
+ if (errno != EINTR)
+ dbg("error in select: %s", strerror(errno));
+ continue;
+ }
+
+ if (FD_ISSET(ssock, &workreadfds))
+ handle_msg(ssock);
+
+ if (FD_ISSET(pipefds[0], &workreadfds))
+ user_sighandler();
+
+ if (children_waiting) {
+ children_waiting = 0;
+ reap_kids();
+ }
- /* main loop */
- process_queue();
- return 0;
+ if (run_msg_q) {
+ run_msg_q = 0;
+ msg_queue_manager();
+ }
+
+ if (run_exec_q) {
+ /* this is tricky. exec_queue_manager() loops over exec_list, and
+ * calls running_with_devpath(), which loops over running_list. This gives
+ * O(N*M), which can get *nasty*. Clean up running_list before
+ * calling exec_queue_manager().
+ */
+ if (children_waiting) {
+ children_waiting = 0;
+ reap_kids();
+ }
+
+ run_exec_q = 0;
+ exec_queue_manager();
+ }
+ }
+exit:
+ close(ssock);
+ exit(1);
}
~ianmdlvl / elogind.git / blobdiff