chiark / gitweb /
[PATCH] limit the initial timeout of the udevd event handling
[elogind.git] / udevd.c
diff --git a/udevd.c b/udevd.c
index efcb65b..c6642f4 100644 (file)
--- a/udevd.c
+++ b/udevd.c
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
+#include <sys/time.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/un.h>
-#include <sys/time.h>
+#include <fcntl.h>
+#include <sys/sysinfo.h>
+#include <sys/stat.h>
 
 #include "list.h"
 #include "udev.h"
 #include "udev_version.h"
+#include "udev_utils.h"
 #include "udevd.h"
 #include "logging.h"
 
-static int expected_seqnum = 0;
-volatile static int children_waiting;
-volatile static int msg_q_timeout;
+/* global variables*/
+static int udevsendsock;
 
-LIST_HEAD(msg_list);
-LIST_HEAD(exec_list);
-LIST_HEAD(running_list);
+static int pipefds[2];
+static long startup_time;
+static unsigned long long expected_seqnum = 0;
+static volatile int sigchilds_waiting;
+static volatile int run_msg_q;
+static volatile 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_sigchilds(void);
+char *udev_bin;
 
 #ifdef LOG
-unsigned char logname[LOGNAME_SIZE];
 void log_message (int level, const char *format, ...)
 {
        va_list args;
@@ -63,54 +75,48 @@ void log_message (int level, const char *format, ...)
 }
 #endif
 
+#define msg_dump(msg) \
+       dbg("msg_dump: sequence %llu, '%s', '%s', '%s'", \
+       msg->seqnum, msg->action, msg->devpath, msg->subsystem);
+
 static void msg_dump_queue(void)
 {
+#ifdef DEBUG
        struct hotplug_msg *msg;
 
        list_for_each_entry(msg, &msg_list, list)
-               dbg("sequence %d in queue", msg->seqnum);
-}
-
-static void msg_dump(struct hotplug_msg *msg)
-{
-       dbg("sequence %d, '%s', '%s', '%s'",
-           msg->seqnum, msg->action, msg->devpath, msg->subsystem);
-}
-
-static struct hotplug_msg *msg_create(void)
-{
-       struct hotplug_msg *new_msg;
-
-       new_msg = malloc(sizeof(struct hotplug_msg));
-       if (new_msg == NULL)
-               dbg("error malloc");
-       return new_msg;
+               dbg("sequence %llu in queue", msg->seqnum);
+#endif
 }
 
 static void run_queue_delete(struct hotplug_msg *msg)
 {
        list_del(&msg->list);
        free(msg);
-       exec_queue_manager();
 }
 
 /* orders the message in the queue by sequence number */
 static void msg_queue_insert(struct hotplug_msg *msg)
 {
        struct hotplug_msg *loop_msg;
+       struct sysinfo info;
 
-       /* sort message by sequence number into list*/
-       list_for_each_entry(loop_msg, &msg_list, list)
-               if (loop_msg->seqnum > msg->seqnum)
+       /* 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;
-       list_add_tail(&msg->list, &loop_msg->list);
-       dbg("queued message seq %d", msg->seqnum);
 
        /* store timestamp of queuing */
-       msg->queue_time = time(NULL);
+       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 */
-       msg_queue_manager();
+       run_msg_q = 1;
 
        return ;
 }
@@ -118,45 +124,68 @@ static void msg_queue_insert(struct hotplug_msg *msg)
 /* forks event and removes event from run queue when finished */
 static void udev_run(struct hotplug_msg *msg)
 {
+       char *const argv[] = { "udev", msg->subsystem, NULL };
        pid_t pid;
-       char action[ACTION_SIZE];
-       char devpath[DEVPATH_SIZE];
-       char *env[] = { action, devpath, NULL };
-
-       snprintf(action, sizeof(action), "ACTION=%s", msg->action);
-       snprintf(devpath, sizeof(devpath), "DEVPATH=%s", msg->devpath);
 
        pid = fork();
        switch (pid) {
        case 0:
                /* child */
-               execle(UDEV_BIN, "udev", msg->subsystem, NULL, env);
+               close(udevsendsock);
+               logging_close();
+               execve(udev_bin, argv, msg->envp);
                dbg("exec of child failed");
-               exit(1);
+               _exit(1);
                break;
        case -1:
                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 %d [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
+               dbg("==> exec seq %llu [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
                msg->pid = pid;
        }
 }
 
-/* returns already running task with devpath */
+/* returns still running task for the same event sequence */
 static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
 {
        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;
+       int i;
+
+       list_for_each_entry(loop_msg, &running_list, list) {
+               if (loop_msg->devpath == NULL || msg->devpath == NULL)
+                       continue;
+
+               /* is a parent or child device event still running */
+               for (i = 0; i < DEVPATH_SIZE; i++) {
+                       if (loop_msg->devpath[i] == '\0' || msg->devpath[i] == '\0')
+                               return loop_msg;
+
+                       if (loop_msg->devpath[i] != msg->devpath[i])
+                               break;
+               }
+
+               /* is the physical device event still running on an add sequence */
+               if (msg->physdevpath && msg->action && strcmp(msg->action, "add") == 0)
+                       for (i = 0; i < DEVPATH_SIZE; i++) {
+                               if (loop_msg->devpath[i] == '\0' || msg->physdevpath[i] == '\0')
+                                       return loop_msg;
+
+                               if (loop_msg->devpath[i] != msg->physdevpath[i])
+                                       break;
+                       }
+       }
+
        return NULL;
 }
 
-/* exec queue management routine executes the events and delays events for the same devpath */
-static void exec_queue_manager()
+/* exec queue management routine executes the events and serializes events in the same sequence */
+static void exec_queue_manager(void)
 {
        struct hotplug_msg *loop_msg;
        struct hotplug_msg *tmp_msg;
@@ -168,10 +197,10 @@ static void exec_queue_manager()
                        /* move event to run list */
                        list_move_tail(&loop_msg->list, &running_list);
                        udev_run(loop_msg);
-                       dbg("moved seq %d to running list", loop_msg->seqnum);
+                       dbg("moved seq %llu to running list", loop_msg->seqnum);
                } else {
-                       dbg("delay seq %d, cause seq %d already working on '%s'",
-                               loop_msg->seqnum, msg->seqnum, msg->devpath);
+                       dbg("delay seq %llu (%s), cause seq %llu (%s) is still running",
+                           loop_msg->seqnum, loop_msg->devpath, msg->seqnum, msg->devpath);
                }
        }
 }
@@ -179,20 +208,23 @@ static void exec_queue_manager()
 static void msg_move_exec(struct hotplug_msg *msg)
 {
        list_move_tail(&msg->list, &exec_list);
-       exec_queue_manager();
+       run_exec_q = 1;
        expected_seqnum = msg->seqnum+1;
-       dbg("moved seq %d to exec, next expected is %d",
+       dbg("moved seq %llu to exec, next expected is %llu",
                msg->seqnum, expected_seqnum);
 }
 
 /* msg queue management routine handles the timeouts and dispatches the events */
-static void msg_queue_manager()
+static void msg_queue_manager(void)
 {
        struct hotplug_msg *loop_msg;
        struct hotplug_msg *tmp_msg;
-       time_t msg_age = 0;
+       struct sysinfo info;
+       long msg_age = 0;
+       static int timeout = EVENT_INIT_TIMEOUT_SEC;
+       static int init = 1;
 
-       dbg("msg queue manager, next expected is %d", expected_seqnum);
+       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 */
@@ -201,9 +233,18 @@ recheck:
                        continue;
                }
 
+               /* see if we are in the initialization phase and wait for the very first events */
+               if (init && (info.uptime - startup_time >= INIT_TIME_SEC)) {
+                       init = 0;
+                       timeout = EVENT_TIMEOUT_SEC;
+                       dbg("initialization phase passed, set timeout to %i seconds", EVENT_TIMEOUT_SEC);
+               }
+
                /* move event with expired timeout to the exec list */
-               msg_age = time(NULL) - loop_msg->queue_time;
-               if (msg_age > EVENT_TIMEOUT_SEC-1) {
+               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 >= timeout) {
                        msg_move_exec(loop_msg);
                        goto recheck;
                } else {
@@ -213,34 +254,32 @@ recheck:
 
        msg_dump_queue();
 
+       /* set timeout for remaining queued events */
        if (list_empty(&msg_list) == 0) {
-               /* set timeout for remaining queued events */
-               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);
+               struct itimerval itv = {{0, 0}, {timeout - msg_age, 0}};
+               dbg("next event expires in %li seconds", timeout - msg_age);
+               setitimer(ITIMER_REAL, &itv, NULL);
        }
 }
 
 /* receive the msg, do some basic sanity checks, and queue it */
-static void handle_msg(int sock)
+static void handle_udevsend_msg(int sock)
 {
+       static struct udevsend_msg usend_msg;
        struct hotplug_msg *msg;
-       int retval;
+       int bufpos;
+       int i;
+       ssize_t size;
        struct msghdr smsg;
        struct cmsghdr *cmsg;
        struct iovec iov;
        struct ucred *cred;
        char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
+       int envbuf_size;
 
-       msg = msg_create();
-       if (msg == NULL) {
-               dbg("unable to store message");
-               return;
-       }
-
-       iov.iov_base = msg;
-       iov.iov_len = sizeof(struct hotplug_msg);
+       memset(&usend_msg, 0x00, sizeof(struct udevsend_msg));
+       iov.iov_base = &usend_msg;
+       iov.iov_len = sizeof(struct udevsend_msg);
 
        memset(&smsg, 0x00, sizeof(struct msghdr));
        smsg.msg_iov = &iov;
@@ -248,8 +287,8 @@ static void handle_msg(int sock)
        smsg.msg_control = cred_msg;
        smsg.msg_controllen = sizeof(cred_msg);
 
-       retval = recvmsg(sock, &smsg, 0);
-       if (retval <  0) {
+       size = recvmsg(sock, &smsg, 0);
+       if (size <  0) {
                if (errno != EINTR)
                        dbg("unable to receive message");
                return;
@@ -259,48 +298,97 @@ static void handle_msg(int sock)
 
        if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
                dbg("no sender credentials received, message ignored");
-               goto skip;
+               goto exit;
        }
 
        if (cred->uid != 0) {
                dbg("sender uid=%i, message ignored", cred->uid);
-               goto skip;
+               goto exit;
+       }
+
+       if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
+               dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic);
+               goto exit;
        }
 
-       if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
-               dbg("message magic '%s' doesn't match, ignore it", msg->magic);
-               goto skip;
+       envbuf_size = size - offsetof(struct udevsend_msg, envbuf);
+       dbg("envbuf_size=%i", envbuf_size);
+       msg = malloc(sizeof(struct hotplug_msg) + envbuf_size);
+       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;
+
+               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];
        }
+       msg->envp[i++] = "UDEVD_EVENT=1";
+       msg->envp[i] = NULL;
 
        /* if no seqnum is given, we move straight to exec queue */
-       if (msg->seqnum == -1) {
+       if (msg->seqnum == 0) {
                list_add(&msg->list, &exec_list);
-               exec_queue_manager();
+               run_exec_q = 1;
        } else {
                msg_queue_insert(msg);
        }
-       return;
 
-skip:
-       free(msg);
+exit:
        return;
 }
 
-static void sig_handler(int signum)
+static void asmlinkage sig_handler(int signum)
 {
+       int rc;
+
        switch (signum) {
                case SIGINT:
                case SIGTERM:
                        exit(20 + signum);
                        break;
                case SIGALRM:
-                       msg_q_timeout = 1;
+                       /* set flag, then write to pipe if needed */
+                       run_msg_q = 1;
+                       goto do_write;
                        break;
                case SIGCHLD:
-                       children_waiting = 1;
+                       /* set flag, then write to pipe if needed */
+                       sigchilds_waiting = 1;
+                       goto do_write;
                        break;
-               default:
-                       dbg("unhandled signal");
+       }
+
+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)
+                       sig_flag = 1;
        }
 }
 
@@ -311,39 +399,117 @@ static void udev_done(int pid)
 
        list_for_each_entry(msg, &running_list, list) {
                if (msg->pid == pid) {
-                       dbg("<== exec seq %d came back", msg->seqnum);
+                       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;
                }
        }
 }
 
-int main(int argc, char *argv[])
+static void reap_sigchilds(void)
 {
-       int ssock;
+       while(1) {
+               int pid = waitpid(-1, NULL, WNOHANG);
+               if ((pid == -1) || (pid == 0))
+                       break;
+               udev_done(pid);
+       }
+}
+
+/* just read everything from the pipe and clear the flag,
+ * the flags was set in the signal handler
+ */
+static void user_sighandler(void)
+{
+       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[], char *envp[])
+{
+       struct sysinfo info;
+       int maxsockplus;
        struct sockaddr_un saddr;
        socklen_t addrlen;
-       int retval;
-       const int on = 1;
+       int retval, fd;
+       const int feature_on = 1;
        struct sigaction act;
+       fd_set readfds;
 
-       init_logging("udevd");
+       logging_init("udevd");
        dbg("version %s", UDEV_VERSION);
 
        if (getuid() != 0) {
                dbg("need to be root, exit");
-               exit(1);
+               goto exit;
        }
 
-       /* set signal handler */
-       act.sa_handler = sig_handler;
-       sigemptyset (&act.sa_mask);
+       /* make sure we don't lock any path */
+       chdir("/");
+       umask(umask(077) | 022);
+
+       /* Set fds to dev/null */
+       fd = open( "/dev/null", O_RDWR );
+       if ( fd < 0 ) {
+               dbg("error opening /dev/null %s", strerror(errno));
+               goto exit;
+       }
+       dup2(fd, 0);
+       dup2(fd, 1);
+       dup2(fd, 2);
+       if (fd > 2) 
+               close(fd);
+
+       /* become session leader */
+       setsid();
+
+       /* setup signal handler pipe */
+       retval = pipe(pipefds);
+       if (retval < 0) {
+               dbg("error getting pipes: %s", strerror(errno));
+               goto exit;
+       }
+
+       retval = fcntl(pipefds[0], F_SETFL, O_NONBLOCK);
+       if (retval < 0) {
+               dbg("error fcntl on read pipe: %s", strerror(errno));
+               goto exit;
+       }
+       retval = fcntl(pipefds[0], F_SETFD, FD_CLOEXEC);
+       if (retval < 0) {
+               dbg("error fcntl on read pipe: %s", strerror(errno));
+               goto exit;
+       }
+
+       retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
+       if (retval < 0) {
+               dbg("error fcntl on write pipe: %s", strerror(errno));
+               goto exit;
+       }
+       retval = fcntl(pipefds[1], F_SETFD, FD_CLOEXEC);
+       if (retval < 0) {
+               dbg("error fcntl on write pipe: %s", strerror(errno));
+               goto exit;
+       }
+
+       /* set signal handlers */
+       act.sa_handler = (void (*) (int))sig_handler;
+       sigemptyset(&act.sa_mask);
        act.sa_flags = SA_RESTART;
        sigaction(SIGINT, &act, NULL);
        sigaction(SIGTERM, &act, NULL);
-
-       /* we want these two to interrupt system calls */
-       act.sa_flags = 0;
        sigaction(SIGALRM, &act, NULL);
        sigaction(SIGCHLD, &act, NULL);
 
@@ -353,42 +519,77 @@ int main(int argc, char *argv[])
        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) {
+       udevsendsock = socket(AF_LOCAL, SOCK_DGRAM, 0);
+       if (udevsendsock == -1) {
                dbg("error getting socket, exit");
-               exit(1);
+               goto exit;
        }
 
        /* the bind takes care of ensuring only one copy running */
-       retval = bind(ssock, (struct sockaddr *) &saddr, addrlen);
+       retval = bind(udevsendsock, (struct sockaddr *) &saddr, addrlen);
        if (retval < 0) {
                dbg("bind failed, exit");
+               close(udevsendsock);
                goto exit;
        }
 
        /* enable receiving of the sender credentials */
-       setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
-
+       setsockopt(udevsendsock, SOL_SOCKET, SO_PASSCRED, &feature_on, sizeof(feature_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
+               udev_bin = UDEV_BIN;
+
+       /* handle special startup timeout*/
+       sysinfo(&info);
+       startup_time = info.uptime;
+
+       FD_ZERO(&readfds);
+       FD_SET(udevsendsock, &readfds);
+       FD_SET(pipefds[0], &readfds);
+       maxsockplus = udevsendsock+1;
        while (1) {
-               handle_msg(ssock);
+               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(udevsendsock, &workreadfds))
+                       handle_udevsend_msg(udevsendsock);
 
-               while(msg_q_timeout) {
-                       msg_q_timeout = 0;
+               if (FD_ISSET(pipefds[0], &workreadfds))
+                       user_sighandler();
+
+               if (sigchilds_waiting) {
+                       sigchilds_waiting = 0;
+                       reap_sigchilds();
+               }
+
+               if (run_msg_q) {
+                       run_msg_q = 0;
                        msg_queue_manager();
                }
 
-               while(children_waiting) {
-                       children_waiting = 0;
-                       /* reap all dead children */
-                       while(1) {
-                               int pid = waitpid(-1, 0, WNOHANG);
-                               if ((pid == -1) || (pid == 0))
-                                       break;
-                               udev_done(pid);
+               if (run_exec_q) {
+                        /* clean up running_list before calling exec_queue_manager() */
+                       if (sigchilds_waiting) {
+                               sigchilds_waiting = 0;
+                               reap_sigchilds();
                        }
+
+                       run_exec_q = 0;
+                       exec_queue_manager();
                }
        }
+
 exit:
-       close(ssock);
-       exit(1);
+       logging_close();
+       return 1;
 }