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 08dede3..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 <sys/types.h>
-#include <sys/ipc.h>
-#include <sys/msg.h>
+#include <stddef.h>
+#include <sys/wait.h>
 #include <signal.h>
 #include <unistd.h>
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/time.h>
 
+#include "list.h"
 #include "udev.h"
+#include "udev_version.h"
 #include "udevd.h"
 #include "logging.h"
 
-#define BUFFER_SIZE            1024
-#define TIMEOUT_SECONDS                10
+static int expected_seqnum = 0;
+volatile static int children_waiting;
+volatile static int msg_q_timeout;
 
-static void reset_timer(void);
-static void reset_queue(void);
+LIST_HEAD(msg_list);
+LIST_HEAD(exec_list);
+LIST_HEAD(running_list);
 
+static void exec_queue_manager(void);
+static void msg_queue_manager(void);
 
-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];
+unsigned char logname[42];
 
-static void sig_handler(int signum)
+int log_ok(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;
+       return 1;
+}
 
-               case SIGINT:
-               case SIGTERM:
-               case SIGKILL:
-                       exit(20 + signum);
-                       break;
+static void msg_dump_queue(void)
+{
+       struct hotplug_msg *msg;
 
-               default:
-                       dbg("unhandled signal");
-       }
+       list_for_each_entry(msg, &msg_list, list)
+               dbg("sequence %d in queue", msg->seqnum);
 }
 
-static void sig_alarmhandler(int signum)
+static void msg_dump(struct hotplug_msg *msg)
 {
-       dbg("caught signal %d", signum);
-       switch (signum) {
-       case SIGALRM:
-               timeout = 1;
-               dbg("event timeout reached");
-               break;
-
-       default:
-               dbg("unhandled signal");
-       }
+       dbg("sequence %d, '%s', '%s', '%s'",
+           msg->seqnum, msg->action, msg->devpath, msg->subsystem);
 }
 
-static void dump_queue(void)
+static struct hotplug_msg *msg_create(void)
 {
-       struct hotplug_msg *p;
-       p = head;
+       struct hotplug_msg *new_msg;
 
-       dbg("next expected sequence is %d", expect_seqnum);
-       while(p) {
-               dbg("sequence %d in queue", p->seqnum);
-               p=p->next;
-       }
+       new_msg = malloc(sizeof(struct hotplug_msg));
+       if (new_msg == NULL)
+               dbg("error malloc");
+       return new_msg;
 }
 
-static void dump_msg(struct hotplug_msg *pmsg)
+static void run_queue_delete(struct hotplug_msg *msg)
 {
-       dbg("sequence %d, '%s', '%s', '%s'",
-           pmsg->seqnum, pmsg->action, pmsg->devpath, pmsg->subsystem);
+       list_del(&msg->list);
+       free(msg);
+       exec_queue_manager();
 }
 
-static void dispatch_msg(struct hotplug_msg *pmsg)
+/* orders the message in the queue by sequence number */
+static void msg_queue_insert(struct hotplug_msg *msg)
 {
-       dump_msg(pmsg);
-       dbg("exec '%s'", exec_program);
-       setenv("ACTION", pmsg->action, 1);
-       setenv("DEVPATH", pmsg->devpath, 1);
-       execl(exec_program, pmsg->subsystem);
+       struct hotplug_msg *loop_msg;
+
+       /* 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 void reset_timer(void)
+/* forks event and removes event from run queue when finished */
+static void udev_run(struct hotplug_msg *msg)
 {
-       alarm(0);
+       pid_t pid;
+       setenv("ACTION", msg->action, 1);
+       setenv("DEVPATH", msg->devpath, 1);
+
+       pid = fork();
+       switch (pid) {
+       case 0:
+               /* child */
+               execl(UDEV_BIN, "udev", msg->subsystem, NULL);
+               dbg("exec of child failed");
+               exit(1);
+               break;
+       case -1:
+               dbg("fork of child failed");
+               run_queue_delete(msg);
+               break;
+       default:
+               /* get SIGCHLD in main loop */
+               dbg("==> exec seq %d [%d] working at '%s'", msg->seqnum, pid, msg->devpath);
+               msg->pid = pid;
+       }
 }
 
-static void set_timer(void)
+/* returns already running task with devpath */
+static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
 {
-       signal(SIGALRM, sig_alarmhandler);
-       alarm(timeout_value);
+       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 reset_queue(void)
+/* exec queue management routine executes the events and delays events for the same devpath */
+static void exec_queue_manager()
 {
-       struct hotplug_msg *p;
-       p = head;
+       struct hotplug_msg *loop_msg;
+       struct hotplug_msg *tmp_msg;
+       struct hotplug_msg *msg;
 
-       while(head) {
-               p = head;
-               head = head->next;
-               free(p);
+       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 check_queue(void)
+static void msg_move_exec(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 *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 *loop_msg;
+       struct hotplug_msg *tmp_msg;
+       time_t msg_age = 0;
+
+       dbg("msg queue manager, next expected is %d", 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 */
+               msg_age = time(NULL) - loop_msg->queue_time;
+               if (msg_age > EVENT_TIMEOUT_SEC-1) {
+                       msg_move_exec(loop_msg);
+                       goto recheck;
+               } else {
+                       break;
+               }
+       }
+
+       msg_dump_queue();
+
+       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);
        }
-       if (head != NULL)
-               set_timer();
-       else
-               reset_timer();
 }
 
-static void add_queue(struct hotplug_msg *pmsg)
+/* receive the msg, do some basic sanity checks, and queue it */
+static void handle_msg(int sock)
 {
-       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;
+       struct hotplug_msg *msg;
+       int retval;
+
+       msg = msg_create();
+       if (msg == NULL) {
+               dbg("unable to store message");
+               return;
+       }
+
+       retval = recv(sock, msg, sizeof(struct hotplug_msg), 0);
+       if (retval <  0) {
+               if (errno != EINTR)
+                       dbg("unable to receive message");
+               return;
        }
-       pnewmsg->next = p;
-       if (p1 == NULL) {
-               head = pnewmsg;
+       
+       if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
+               dbg("message magic '%s' doesn't match, ignore it", msg->magic);
+               free(msg);
+               return;
+       }
+
+       /* 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 {
-               p1->next = pnewmsg;
+               msg_queue_insert(msg);
        }
-       dump_queue();
 }
 
-static int process_queue(void)
+static void sig_handler(int signum)
 {
-       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;
+       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");
        }
-       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 udev_done(int pid)
+{
+       /* 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 %d came back", msg->seqnum);
+                       run_queue_delete(msg);
+                       return;
+               }
        }
-       return 0;
-exit:
-       return -1;
 }
 
 int main(int argc, char *argv[])
 {
-       /* get program to exec on events */
-       if (argc == 2)
-               strncpy(exec_program, argv[1], sizeof(exec_program));
-       else
-               strcpy(exec_program, DEFAULT_EXEC_PROGRAM);
+       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(SIGKILL, sig_handler);
-       signal(SIGHUP, sig_handler);
+       signal(SIGALRM, sig_handler);
+       signal(SIGCHLD, sig_handler);
+
+       /* 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();
+               }
 
-       /* main loop */
-       process_queue();
-       return 0;
+               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);
 }