chiark / gitweb /
[PATCH] fix log option code so that it actually works for all udev programs.
[elogind.git] / udevd.c
diff --git a/udevd.c b/udevd.c
index 22c3865..476cb64 100644 (file)
--- a/udevd.c
+++ b/udevd.c
@@ -1,10 +1,8 @@
 /*
- * 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 <stddef.h>
-#include <sys/types.h>
-#include <sys/ipc.h>
 #include <sys/wait.h>
-#include <sys/msg.h>
 #include <signal.h>
 #include <unistd.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <string.h>
 #include <time.h>
-#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/time.h>
 
 #include "list.h"
 #include "udev.h"
 #include "udevd.h"
 #include "logging.h"
 
-
-#define BUFFER_SIZE                    1024
-
-static int running_remove_queue(pid_t pid);
-static int msg_exec(struct hotplug_msg *msg);
-
-static int expect_seqnum = 0;
-static int lock_file = -1;
-static char *lock_filename = ".udevd_lock";
+static int expected_seqnum = 0;
+volatile static int children_waiting;
+volatile static int msg_q_timeout;
 
 LIST_HEAD(msg_list);
+LIST_HEAD(exec_list);
 LIST_HEAD(running_list);
-LIST_HEAD(delayed_list);
 
-static void sig_handler(int signum)
-{
-       pid_t pid;
+static void exec_queue_manager(void);
+static void msg_queue_manager(void);
 
-       dbg("caught signal %d", signum);
-       switch (signum) {
-       case SIGALRM:
-               dbg("event timeout reached");
-               break;
-       case SIGCHLD:
-               /* catch signals from exiting childs */
-               while ( (pid = waitpid(-1, NULL, WNOHANG)) > 0) {
-                       dbg("exec finished, pid %d", pid);
-                       running_remove_queue(pid);
-               }
-               break;
-       case SIGINT:
-       case SIGTERM:
-               if (lock_file >= 0) {
-                       close(lock_file);
-                       unlink(lock_filename);
-               }
-               exit(20 + signum);
-               break;
-       default:
-               dbg("unhandled signal");
-       }
-}
+unsigned char logname[42];
 
-static void set_timeout(int seconds)
+int log_ok(void)
 {
-       alarm(seconds);
-       dbg("set timeout in %d seconds", seconds);
+       return 1;
 }
 
-static int running_moveto_queue(struct hotplug_msg *msg)
+static void msg_dump_queue(void)
 {
-       dbg("move sequence %d [%d] to running queue '%s'",
-           msg->seqnum, msg->pid, msg->devpath);
-       list_move_tail(&msg->list, &running_list);
-       return 0;
-}
+       struct hotplug_msg *msg;
 
-static int running_remove_queue(pid_t  pid)
-{
-       struct hotplug_msg *child;
-       struct hotplug_msg *tmp_child;
-
-       list_for_each_entry_safe(child, tmp_child, &running_list, list)
-               if (child->pid == pid) {
-                       list_del_init(&child->list);
-                       free(child);
-                       return 0;
-               }
-       return -EINVAL;
+       list_for_each_entry(msg, &msg_list, list)
+               dbg("sequence %d in queue", msg->seqnum);
 }
 
-static pid_t running_getpid_by_devpath(struct hotplug_msg *msg)
+static void msg_dump(struct hotplug_msg *msg)
 {
-       struct hotplug_msg *child;
-       struct hotplug_msg *tmp_child;
-
-       list_for_each_entry_safe(child, tmp_child, &running_list, list)
-               if (strncmp(child->devpath, msg->devpath, sizeof(child->devpath)) == 0)
-                       return child->pid;
-       return 0;
+       dbg("sequence %d, '%s', '%s', '%s'",
+           msg->seqnum, msg->action, msg->devpath, msg->subsystem);
 }
 
-static void delayed_dump_queue(void)
+static struct hotplug_msg *msg_create(void)
 {
-       struct hotplug_msg *child;
+       struct hotplug_msg *new_msg;
 
-       list_for_each_entry(child, &delayed_list, list)
-               dbg("event for '%s' in queue", child->devpath);
+       new_msg = malloc(sizeof(struct hotplug_msg));
+       if (new_msg == NULL)
+               dbg("error malloc");
+       return new_msg;
 }
 
-static int delayed_moveto_queue(struct hotplug_msg *msg)
+static void run_queue_delete(struct hotplug_msg *msg)
 {
-       dbg("move event to delayed queue '%s'", msg->devpath);
-       list_move_tail(&msg->list, &delayed_list);
-       return 0;
+       list_del(&msg->list);
+       free(msg);
+       exec_queue_manager();
 }
 
-static void delayed_check_queue(void)
+/* orders the message in the queue by sequence number */
+static void msg_queue_insert(struct hotplug_msg *msg)
 {
-       struct hotplug_msg *delayed_child;
-       struct hotplug_msg *running_child;
-       struct hotplug_msg *tmp_child;
-
-       /* see if we have delayed exec's that can run now */
-       list_for_each_entry_safe(delayed_child, tmp_child, &delayed_list, list)
-               list_for_each_entry_safe(running_child, tmp_child, &running_list, list)
-                       if (strncmp(delayed_child->devpath, running_child->devpath,
-                           sizeof(running_child->devpath)) == 0) {
-                               dbg("delayed exec for '%s' can run now", delayed_child->devpath);
-                               msg_exec(delayed_child);
-                       }
-}
+       struct hotplug_msg *loop_msg;
 
-static void msg_dump(struct hotplug_msg *msg)
-{
-       dbg("sequence %d, '%s', '%s', '%s'",
-           msg->seqnum, msg->action, msg->devpath, msg->subsystem);
+       /* sort message by sequence number into list*/
+       list_for_each_entry(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);
+
+       /* run msg queue manager */
+       msg_queue_manager();
+
+       return ;
 }
 
-static int msg_exec(struct hotplug_msg *msg)
+/* forks event and removes event from run queue when finished */
+static void udev_run(struct hotplug_msg *msg)
 {
        pid_t pid;
-
-       msg_dump(msg);
-
        setenv("ACTION", msg->action, 1);
        setenv("DEVPATH", msg->devpath, 1);
 
-       /* delay exec, if we already have a udev working on the same devpath */
-       pid = running_getpid_by_devpath(msg);
-       if (pid != 0) {
-               dbg("delay exec of sequence %d, [%d] already working on '%s'",
-                   msg->seqnum, pid, msg->devpath);
-               delayed_moveto_queue(msg);
-       }
-
        pid = fork();
        switch (pid) {
        case 0:
@@ -188,157 +127,215 @@ static int msg_exec(struct hotplug_msg *msg)
                break;
        case -1:
                dbg("fork of child failed");
-               return -1;
+               run_queue_delete(msg);
+               break;
        default:
-               /* exec in background, get the SIGCHLD with the sig handler */
+               /* get SIGCHLD in main loop */
+               dbg("==> exec seq %d [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
                msg->pid = pid;
-               running_moveto_queue(msg);
-               break;
        }
-       return 0;
 }
 
-static void msg_dump_queue(void)
+/* returns already running task with devpath */
+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;
+       return NULL;
+}
+
+/* exec queue management routine executes the events and delays events for the same devpath */
+static void exec_queue_manager()
+{
+       struct hotplug_msg *loop_msg;
+       struct hotplug_msg *tmp_msg;
        struct hotplug_msg *msg;
 
-       list_for_each_entry(msg, &msg_list, list)
-               dbg("sequence %d in queue", msg->seqnum);
+       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 %d 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);
+               }
+       }
 }
 
-static void msg_check_queue(void)
+static void msg_move_exec(struct hotplug_msg *msg)
 {
-       struct hotplug_msg *msg;
+       list_move_tail(&msg->list, &exec_list);
+       exec_queue_manager();
+       expected_seqnum = msg->seqnum+1;
+       dbg("moved seq %d to exec, next expected is %d",
+               msg->seqnum, expected_seqnum);
+}
+
+/* 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;
-       time_t msg_age;
+       time_t msg_age = 0;
 
+       dbg("msg queue manager, next expected is %d", expected_seqnum);
 recheck:
-       /* dispatch events until one is missing */
-       list_for_each_entry_safe(msg, tmp_msg, &msg_list, list) {
-               if (msg->seqnum != expect_seqnum)
-                       break;
-               msg_exec(msg);
-               expect_seqnum++;
-       }
+       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;
+               }
 
-       /* recalculate next timeout */
-       if (list_empty(&msg_list) == 0) {
-               msg_age = time(NULL) - msg->queue_time;
+               /* move event with expired timeout to the exec list */
+               msg_age = time(NULL) - loop_msg->queue_time;
                if (msg_age > EVENT_TIMEOUT_SEC-1) {
-                       info("event %d, age %li seconds, skip event %d-%d",
-                            msg->seqnum, msg_age, expect_seqnum, msg->seqnum-1);
-                       expect_seqnum = msg->seqnum;
+                       msg_move_exec(loop_msg);
                        goto recheck;
+               } else {
+                       break;
                }
+       }
 
-               /* the first sequence gets its own timeout */
-               if (expect_seqnum == 0) {
-                       msg_age = EVENT_TIMEOUT_SEC - FIRST_EVENT_TIMEOUT_SEC;
-                       expect_seqnum = 1;
-               }
+       msg_dump_queue();
 
-               set_timeout(EVENT_TIMEOUT_SEC - msg_age);
-               return;
+       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);
        }
 }
 
-static int msg_add_queue(struct hotplug_msg *msg)
+/* receive the msg, do some basic sanity checks, and queue it */
+static void handle_msg(int sock)
 {
-       struct hotplug_msg *new_msg;
-       struct hotplug_msg *tmp_msg;
+       struct hotplug_msg *msg;
+       int retval;
 
-       new_msg = malloc(sizeof(*new_msg));
-       if (new_msg == NULL) {
-               dbg("error malloc");
-               return -ENOMEM;
+       msg = msg_create();
+       if (msg == NULL) {
+               dbg("unable to store message");
+               return;
        }
-       memcpy(new_msg, msg, sizeof(*new_msg));
-
-       /* store timestamp of queuing */
-       new_msg->queue_time = time(NULL);
 
-       /* sort message by sequence number into list*/
-       list_for_each_entry(tmp_msg, &msg_list, list)
-               if (tmp_msg->seqnum > new_msg->seqnum)
-                       break;
-       list_add_tail(&new_msg->list, &tmp_msg->list);
+       retval = recv(sock, msg, sizeof(struct hotplug_msg), 0);
+       if (retval <  0) {
+               if (errno != EINTR)
+                       dbg("unable to receive message");
+               return;
+       }
+       
+       if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
+               dbg("message magic '%s' doesn't match, ignore it", msg->magic);
+               free(msg);
+               return;
+       }
 
-       return 0;
+       /* if no seqnum is given, we move straight to exec queue */
+       if (msg->seqnum == -1) {
+               list_add(&msg->list, &exec_list);
+               exec_queue_manager();
+       } else {
+               msg_queue_insert(msg);
+       }
 }
 
-static void work(void)
+static void sig_handler(int signum)
 {
-       struct hotplug_msg *msg;
-       int msgid;
-       key_t key;
-       char buf[BUFFER_SIZE];
-       int ret;
-
-       key = ftok(UDEVD_BIN, IPC_KEY_ID);
-       msg = (struct hotplug_msg *) buf;
-       msgid = msgget(key, IPC_CREAT);
-       if (msgid == -1) {
-               dbg("open message queue error");
-               exit(1);
-       }
-       while (1) {
-               ret = msgrcv(msgid, (struct msgbuf *) buf, BUFFER_SIZE-4, HOTPLUGMSGTYPE, 0);
-               if (ret != -1) {
-                       dbg("received sequence %d, expected sequence %d", msg->seqnum, expect_seqnum);
-                       if (msg->seqnum >= expect_seqnum) {
-                               msg_add_queue(msg);
-                               msg_dump_queue();
-                               msg_check_queue();
-                               continue;
-                       }
-                       dbg("too late for event with sequence %d, event skipped ", msg->seqnum);
-               } else {
-                       if (errno == EINTR) {
-                               msg_check_queue();
-                               msg_dump_queue();
-                               delayed_check_queue();
-                               delayed_dump_queue();
-                               continue;
-                       }
-                       dbg("ipc message receive error '%s'", strerror(errno));
-               }
+       switch (signum) {
+               case SIGINT:
+               case SIGTERM:
+                       exit(20 + signum);
+                       break;
+               case SIGALRM:
+                       msg_q_timeout = 1;
+                       break;
+               case SIGCHLD:
+                       children_waiting = 1;
+                       break;
+               default:
+                       dbg("unhandled signal");
        }
 }
 
-static int one_and_only(void)
+static void udev_done(int pid)
 {
-       char string[100];
-
-       lock_file = open(lock_filename, O_RDWR | O_CREAT, 0x640);
+       /* find msg associated with pid and delete it */
+       struct hotplug_msg *msg;
 
-       /* see if we can open */
-       if (lock_file < 0)
-               return -1;
-       
-       /* see if we can lock */
-       if (lockf(lock_file, F_TLOCK, 0) < 0) {
-               close(lock_file);
-               return -1;
+       list_for_each_entry(msg, &running_list, list) {
+               if (msg->pid == pid) {
+                       dbg("<== exec seq %d came back", msg->seqnum);
+                       run_queue_delete(msg);
+                       return;
+               }
        }
-
-       snprintf(string, sizeof(string), "%d\n", getpid());
-       write(lock_file, string, strlen(string));
-
-       return 0;
 }
 
 int main(int argc, char *argv[])
 {
-       /* only let one version of the daemon run at any one time */
-       if (one_and_only() != 0)
-               exit(0);
+       int ssock;
+       struct sockaddr_un saddr;
+       socklen_t addrlen;
+       int retval;
+
+       init_logging("udevd");
 
-       /* set up signal handler */
        signal(SIGINT, sig_handler);
        signal(SIGTERM, sig_handler);
        signal(SIGALRM, sig_handler);
        signal(SIGCHLD, sig_handler);
 
-       work();
-       exit(0);
+       /* we want these two to interrupt system calls */
+       siginterrupt(SIGALRM, 1);
+       siginterrupt(SIGCHLD, 1);
+
+       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(1);
+       }
+
+       /* the bind takes care of ensuring only one copy running */
+       retval = bind(ssock, &saddr, addrlen);
+       if (retval < 0) {
+               dbg("bind failed\n");
+               goto exit;
+       }
+
+       while (1) {
+               handle_msg(ssock);
+
+               while(msg_q_timeout) {
+                       msg_q_timeout = 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);
+                       }
+               }
+       }
+exit:
+       close(ssock);
+       exit(1);
 }