chiark / gitweb /
[PATCH] add RUN key to be able to run rule based notification
[elogind.git] / udevd.c
diff --git a/udevd.c b/udevd.c
index a8328bbb81a60d2a093089d6490ddb8f7e58577b..91033b068844a42965d48d46db91dc2c6b2558da 100644 (file)
--- a/udevd.c
+++ b/udevd.c
@@ -1,7 +1,7 @@
 /*
  * udevd.c - hotplug event serializer
  *
- * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2004-2005 Kay Sievers <kay.sievers@vrfy.org>
  * Copyright (C) 2004 Chris Friesen <chris_friesen@sympatico.ca>
  *
  *
  */
 
 #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 <ctype.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <sys/select.h>
+#include <sys/wait.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/un.h>
-#include <fcntl.h>
 #include <sys/sysinfo.h>
 #include <sys/stat.h>
 
 #include "list.h"
+#include "udev_libc_wrapper.h"
 #include "udev.h"
 #include "udev_version.h"
 #include "udev_utils.h"
@@ -45,6 +49,7 @@
 
 /* global variables*/
 static int udevsendsock;
+static pid_t sid;
 
 static int pipefds[2];
 static long startup_time;
@@ -64,34 +69,33 @@ static void user_sighandler(void);
 static void reap_sigchilds(void);
 char *udev_bin;
 
-#ifdef LOG
-void log_message (int level, const char *format, ...)
+#ifdef USE_LOG
+void log_message (int priority, const char *format, ...)
 {
-       va_list args;
+       va_list args;
+
+       if (priority > udev_log_priority)
+               return;
 
        va_start(args, format);
-       vsyslog(level, format, args);
+       vsyslog(priority, 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 msg_dump_queue(void)
 {
 #ifdef DEBUG
        struct hotplug_msg *msg;
 
-       list_for_each_entry(msg, &msg_list, list)
+       list_for_each_entry(msg, &msg_list, node)
                dbg("sequence %llu in queue", msg->seqnum);
 #endif
 }
 
 static void run_queue_delete(struct hotplug_msg *msg)
 {
-       list_del(&msg->list);
+       list_del(&msg->node);
        free(msg);
 }
 
@@ -103,18 +107,26 @@ static void msg_queue_insert(struct hotplug_msg *msg)
 
        if (msg->seqnum == 0) {
                dbg("no SEQNUM, move straight to the exec queue");
-               list_add(&msg->list, &exec_list);
+               list_add(&msg->node, &exec_list);
+               run_exec_q = 1;
+               return;
+       }
+
+       /* don't delay messages with timeout set */
+       if (msg->timeout) {
+               dbg("move seq %llu with timeout %u to exec queue", msg->seqnum, msg->timeout);
+               list_add(&msg->node, &exec_list);
                run_exec_q = 1;
                return;
        }
 
        /* sort message by sequence number into list */
-       list_for_each_entry_reverse(loop_msg, &msg_list, list) {
+       list_for_each_entry_reverse(loop_msg, &msg_list, node) {
                if (loop_msg->seqnum < msg->seqnum)
                        break;
 
                if (loop_msg->seqnum == msg->seqnum) {
-                       dbg("ignoring duplicate message seq %llu", msg->seqnum);
+                       info("ignoring duplicate message seq %llu", msg->seqnum);
                        return;
                }
        }
@@ -123,7 +135,7 @@ static void msg_queue_insert(struct hotplug_msg *msg)
        sysinfo(&info);
        msg->queue_time = info.uptime;
 
-       list_add(&msg->list, &loop_msg->list);
+       list_add(&msg->node, &loop_msg->node);
        dbg("queued message seq %llu", msg->seqnum);
 
        /* run msg queue manager */
@@ -133,7 +145,7 @@ 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)
+static void execute_udev(struct hotplug_msg *msg)
 {
        char *const argv[] = { "udev", msg->subsystem, NULL };
        pid_t pid;
@@ -144,16 +156,15 @@ static void udev_run(struct hotplug_msg *msg)
                /* child */
                close(udevsendsock);
                logging_close();
+
+               setpriority(PRIO_PROCESS, 0, UDEV_PRIORITY);
                execve(udev_bin, argv, msg->envp);
-               dbg("exec of child failed");
+               err("exec of child failed");
                _exit(1);
                break;
        case -1:
-               dbg("fork of child failed");
+               err("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 */
@@ -162,11 +173,105 @@ static void udev_run(struct hotplug_msg *msg)
        }
 }
 
+static int running_processes(void)
+{
+       int f;
+       static char buf[4096];
+       int len;
+       int running;
+       const char *pos;
+
+       f = open("/proc/stat", O_RDONLY);
+       if (f == -1)
+               return -1;
+
+       len = read(f, buf, sizeof(buf));
+       close(f);
+
+       if (len <= 0)
+               return -1;
+       else
+               buf[len] = '\0';
+
+       pos = strstr(buf, "procs_running ");
+       if (pos == NULL)
+               return -1;
+
+       if (sscanf(pos, "procs_running %u", &running) != 1)
+               return -1;
+
+       return running;
+}
+
+/* return the number of process es in our session, count only until limit */
+static int running_processes_in_session(pid_t session, int limit)
+{
+       DIR *dir;
+       struct dirent *dent;
+       int running = 0;
+
+       dir = opendir("/proc");
+       if (!dir)
+               return -1;
+
+       /* read process info from /proc */
+       for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
+               int f;
+               char procdir[64];
+               char line[256];
+               const char *pos;
+               char state;
+               pid_t ppid, pgrp, sess;
+               int len;
+
+               if (!isdigit(dent->d_name[0]))
+                       continue;
+
+               snprintf(procdir, sizeof(procdir), "/proc/%s/stat", dent->d_name);
+               procdir[sizeof(procdir)-1] = '\0';
+
+               f = open(procdir, O_RDONLY);
+               if (f == -1)
+                       continue;
+
+               len = read(f, line, sizeof(line));
+               close(f);
+
+               if (len <= 0)
+                       continue;
+               else
+                       line[len] = '\0';
+
+               /* skip ugly program name */
+               pos = strrchr(line, ')') + 2;
+               if (pos == NULL)
+                       continue;
+
+               if (sscanf(pos, "%c %d %d %d ", &state, &ppid, &pgrp, &sess) != 4)
+                       continue;
+
+               /* count only processes in our session */
+               if (sess != session)
+                       continue;
+
+               /* count only running, no sleeping processes */
+               if (state != 'R')
+                       continue;
+
+               running++;
+               if (limit > 0 && running >= limit)
+                       break;
+       }
+       closedir(dir);
+
+       return running;
+}
+
 static int compare_devpath(const char *running, const char *waiting)
 {
        int i;
 
-       for (i = 0; i < DEVPATH_SIZE; i++) {
+       for (i = 0; i < PATH_SIZE; i++) {
                /* identical device event found */
                if (running[i] == '\0' && waiting[i] == '\0')
                        return 1;
@@ -195,7 +300,11 @@ static struct hotplug_msg *running_with_devpath(struct hotplug_msg *msg)
        if (msg->devpath == NULL)
                return NULL;
 
-       list_for_each_entry(loop_msg, &running_list, list) {
+       /* skip any events with a timeout set */
+       if (msg->timeout)
+               return NULL;
+
+       list_for_each_entry(loop_msg, &running_list, node) {
                if (loop_msg->devpath == NULL)
                        continue;
 
@@ -218,13 +327,30 @@ static void exec_queue_manager(void)
        struct hotplug_msg *loop_msg;
        struct hotplug_msg *tmp_msg;
        struct hotplug_msg *msg;
+       int running;
+
+       running = running_processes();
+       dbg("%d processes runnning on system", running);
+       if (running < 0)
+               running = THROTTLE_MAX_RUNNING_CHILDS;
+
+       list_for_each_entry_safe(loop_msg, tmp_msg, &exec_list, node) {
+               /* check running processes in our session and possibly throttle */
+               if (running >= THROTTLE_MAX_RUNNING_CHILDS) {
+                       running = running_processes_in_session(sid, THROTTLE_MAX_RUNNING_CHILDS+10);
+                       dbg("%d processes running in session", running);
+                       if (running >= THROTTLE_MAX_RUNNING_CHILDS) {
+                               dbg("delay seq %llu, cause too many processes already running", loop_msg->seqnum);
+                               return;
+                       }
+               }
 
-       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);
+                       list_move_tail(&loop_msg->node, &running_list);
+                       execute_udev(loop_msg);
+                       running++;
                        dbg("moved seq %llu to running list", loop_msg->seqnum);
                } else {
                        dbg("delay seq %llu (%s), cause seq %llu (%s) is still running",
@@ -235,7 +361,7 @@ static void exec_queue_manager(void)
 
 static void msg_move_exec(struct hotplug_msg *msg)
 {
-       list_move_tail(&msg->list, &exec_list);
+       list_move_tail(&msg->node, &exec_list);
        run_exec_q = 1;
        expected_seqnum = msg->seqnum+1;
        dbg("moved seq %llu to exec, next expected is %llu",
@@ -254,7 +380,7 @@ static void msg_queue_manager(void)
 
        dbg("msg queue manager, next expected is %llu", expected_seqnum);
 recheck:
-       list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, list) {
+       list_for_each_entry_safe(loop_msg, tmp_msg, &msg_list, node) {
                /* move event with expected sequence to the exec list */
                if (loop_msg->seqnum == expected_seqnum) {
                        msg_move_exec(loop_msg);
@@ -325,17 +451,17 @@ static struct hotplug_msg *get_udevsend_msg(void)
        cred = (struct ucred *) CMSG_DATA(cmsg);
 
        if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
-               dbg("no sender credentials received, message ignored");
+               info("no sender credentials received, message ignored");
                return NULL;
        }
 
        if (cred->uid != 0) {
-               dbg("sender uid=%i, message ignored", cred->uid);
+               info("sender uid=%i, message ignored", cred->uid);
                return NULL;
        }
 
        if (strncmp(usend_msg.magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
-               dbg("message magic '%s' doesn't match, ignore it", usend_msg.magic);
+               info("message magic '%s' doesn't match, ignore it", usend_msg.magic);
                return NULL;
        }
 
@@ -375,6 +501,9 @@ static struct hotplug_msg *get_udevsend_msg(void)
 
                if (strncmp(key, "PHYSDEVPATH=", 12) == 0)
                        msg->physdevpath = &key[12];
+
+               if (strncmp(key, "TIMEOUT=", 8) == 0)
+                       msg->timeout = strtoull(&key[8], NULL, 10);
        }
        msg->envp[i++] = "UDEVD_EVENT=1";
        msg->envp[i] = NULL;
@@ -419,7 +548,7 @@ 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) {
+       list_for_each_entry(msg, &running_list, node) {
                if (msg->pid == pid) {
                        dbg("<== exec seq %llu came back", msg->seqnum);
                        run_queue_delete(msg);
@@ -475,14 +604,14 @@ static int init_udevsend_socket(void)
 
        udevsendsock = socket(AF_LOCAL, SOCK_DGRAM, 0);
        if (udevsendsock == -1) {
-               dbg("error getting socket, %s", strerror(errno));
+               err("error getting socket, %s", strerror(errno));
                return -1;
        }
 
        /* the bind takes care of ensuring only one copy running */
        retval = bind(udevsendsock, (struct sockaddr *) &saddr, addrlen);
        if (retval < 0) {
-               dbg("bind failed, %s", strerror(errno));
+               err("bind failed, %s", strerror(errno));
                close(udevsendsock);
                return -1;
        }
@@ -504,10 +633,11 @@ int main(int argc, char *argv[], char *envp[])
        const char *udevd_expected_seqnum;
 
        logging_init("udevd");
+       udev_init_config();
        dbg("version %s", UDEV_VERSION);
 
        if (getuid() != 0) {
-               dbg("need to be root, exit");
+               err("need to be root, exit");
                goto exit;
        }
 
@@ -521,7 +651,7 @@ int main(int argc, char *argv[], char *envp[])
                        dbg("damonized fork running");
                        break;
                case -1:
-                       dbg("fork of daemon failed");
+                       err("fork of daemon failed");
                        goto exit;
                default:
                        logging_close();
@@ -529,10 +659,17 @@ int main(int argc, char *argv[], char *envp[])
                }
        }
 
+       /* become session leader */
+       sid = setsid();
+       dbg("our session is %d", sid);
+
        /* make sure we don't lock any path */
        chdir("/");
        umask(umask(077) | 022);
 
+       /*set a reasonable scheduling priority for the daemon */
+       setpriority(PRIO_PROCESS, 0, UDEVD_PRIORITY);
+
        /* Set fds to dev/null */
        fd = open( "/dev/null", O_RDWR );
        if (fd >= 0)  {
@@ -542,38 +679,36 @@ int main(int argc, char *argv[], char *envp[])
                if (fd > 2)
                        close(fd);
        } else
-               dbg("error opening /dev/null %s", strerror(errno));
-
-       /* become session leader */
-       setsid();
+               err("error opening /dev/null %s", strerror(errno));
 
        /* setup signal handler pipe */
        retval = pipe(pipefds);
        if (retval < 0) {
-               dbg("error getting pipes: %s", strerror(errno));
+               err("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));
+               err("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));
+               err("error fcntl on read pipe: %s", strerror(errno));
 
        retval = fcntl(pipefds[1], F_SETFL, O_NONBLOCK);
        if (retval < 0) {
-               dbg("error fcntl on write pipe: %s", strerror(errno));
+               err("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));
+               err("error fcntl on write pipe: %s", strerror(errno));
 
        /* set signal handlers */
-       act.sa_handler = (void (*) (int))sig_handler;
+       memset(&act, 0x00, sizeof(struct sigaction));
+       act.sa_handler = (void (*)(int)) sig_handler;
        sigemptyset(&act.sa_mask);
        act.sa_flags = SA_RESTART;
        sigaction(SIGINT, &act, NULL);
@@ -593,18 +728,18 @@ int main(int argc, char *argv[], char *envp[])
        /* 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);
+               info("udev binary is set to '%s'", udev_bin);
        else
                udev_bin = UDEV_BIN;
 
-       /* possible set of expected_seqnum number */
+       /* possible init of expected_seqnum value */
        udevd_expected_seqnum = getenv("UDEVD_EXPECTED_SEQNUM");
        if (udevd_expected_seqnum != NULL) {
                expected_seqnum = strtoull(udevd_expected_seqnum, NULL, 10);
-               dbg("initialize expected_seqnum to %llu", expected_seqnum);
+               info("initialize expected_seqnum to %llu", expected_seqnum);
        }
 
-       /* get current time to provide shorter startup timeout */
+       /* get current time to provide shorter timeout on startup */
        sysinfo(&info);
        startup_time = info.uptime;