chiark / gitweb /
[PATCH] DEVPATH for netdev
[elogind.git] / udevd.c
diff --git a/udevd.c b/udevd.c
index efcb65bb53f3d78da04a723d213f90e0e3332fd9..d464b9a196fd46506084fb093270d3ba2d416849 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 "klibc_fixups.h"
+#ifndef __KLIBC__
+#include <sys/sysinfo.h>
+#endif
 
 #include "list.h"
 #include "udev.h"
+#include "udev_lib.h"
 #include "udev_version.h"
 #include "udevd.h"
 #include "logging.h"
 
+static int pipefds[2];
 static int expected_seqnum = 0;
 volatile static int children_waiting;
-volatile static int msg_q_timeout;
+volatile static int run_msg_q;
+volatile static int sig_flag;
+static int run_exec_q;
 
-LIST_HEAD(msg_list);
-LIST_HEAD(exec_list);
-LIST_HEAD(running_list);
+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);
 
 #ifdef LOG
 unsigned char logname[LOGNAME_SIZE];
@@ -65,10 +75,12 @@ void log_message (int level, const char *format, ...)
 
 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);
+#endif
 }
 
 static void msg_dump(struct hotplug_msg *msg)
@@ -91,26 +103,30 @@ 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 %d", msg->seqnum);
 
        /* run msg queue manager */
-       msg_queue_manager();
+       run_msg_q = 1;
 
        return ;
 }
@@ -123,8 +139,10 @@ static void udev_run(struct hotplug_msg *msg)
        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);
+       strcpy(action, "ACTION=");
+       strfieldcat(action, msg->action);
+       strcpy(devpath, "DEVPATH=");
+       strfieldcat(devpath, msg->devpath);
 
        pid = fork();
        switch (pid) {
@@ -137,6 +155,9 @@ static void udev_run(struct hotplug_msg *msg)
        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 */
@@ -179,7 +200,7 @@ 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",
                msg->seqnum, expected_seqnum);
@@ -190,7 +211,8 @@ static void msg_queue_manager()
 {
        struct hotplug_msg *loop_msg;
        struct hotplug_msg *tmp_msg;
-       time_t msg_age = 0;
+       struct sysinfo info;
+       long msg_age = 0;
 
        dbg("msg queue manager, next expected is %d", expected_seqnum);
 recheck:
@@ -202,7 +224,9 @@ recheck:
                }
 
                /* move event with expired timeout to the exec list */
-               msg_age = time(NULL) - loop_msg->queue_time;
+               sysinfo(&info);
+               msg_age = info.uptime - loop_msg->queue_time;
+               dbg("seq %d is %li seconds old", loop_msg->seqnum, msg_age);
                if (msg_age > EVENT_TIMEOUT_SEC-1) {
                        msg_move_exec(loop_msg);
                        goto recheck;
@@ -213,11 +237,10 @@ 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);
+               dbg("next event expires in %li seconds", EVENT_TIMEOUT_SEC - msg_age);
                setitimer(ITIMER_REAL, &itv, 0);
        }
 }
@@ -275,7 +298,7 @@ static void handle_msg(int sock)
        /* if no seqnum is given, we move straight to exec queue */
        if (msg->seqnum == -1) {
                list_add(&msg->list, &exec_list);
-               exec_queue_manager();
+               run_exec_q = 1;
        } else {
                msg_queue_insert(msg);
        }
@@ -288,19 +311,37 @@ skip:
 
 static void 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:
+                       /* set flag, then write to pipe if needed */
                        children_waiting = 1;
+                       goto do_write;
                        break;
                default:
                        dbg("unhandled signal");
+                       return;
+       }
+       
+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;
        }
 }
 
@@ -313,19 +354,53 @@ static void udev_done(int pid)
                if (msg->pid == pid) {
                        dbg("<== exec seq %d 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;
                }
        }
 }
 
+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);
+       }
+}
+
+/* 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[])
 {
-       int ssock;
+       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);
@@ -335,15 +410,31 @@ int main(int argc, char *argv[])
                exit(1);
        }
 
-       /* set signal handler */
+       /* 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);
+       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);
 
@@ -369,23 +460,49 @@ int main(int argc, char *argv[])
        /* enable receiving of the sender credentials */
        setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 
+       FD_ZERO(&readfds);
+       FD_SET(ssock, &readfds);
+       FD_SET(pipefds[0], &readfds);
+       maxsockplus = ssock+1;
        while (1) {
-               handle_msg(ssock);
+               fd_set workreadfds = readfds;
+               retval = select(maxsockplus, &workreadfds, NULL, NULL, NULL);
 
-               while(msg_q_timeout) {
-                       msg_q_timeout = 0;
-                       msg_queue_manager();
+               if (retval < 0) {
+                       if (errno != EINTR)
+                               dbg("error in select: %s", strerror(errno));
+                       continue;
                }
 
-               while(children_waiting) {
+               if (FD_ISSET(ssock, &workreadfds))
+                       handle_msg(ssock);
+
+               if (FD_ISSET(pipefds[0], &workreadfds))
+                       user_sighandler();
+
+               if (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);
+                       reap_kids();
+               }
+
+               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: