diff options
| -rw-r--r-- | udevd.c | 135 | ||||
| -rw-r--r-- | udevd.h | 10 |
2 files changed, 136 insertions, 9 deletions
@@ -28,11 +28,13 @@ #include <stdio.h> #include <stdlib.h> #include <string.h> +#include <ctype.h> +#include <dirent.h> +#include <fcntl.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> @@ -45,6 +47,7 @@ /* global variables*/ static int udevsendsock; +static pid_t sid; static int pipefds[2]; static long startup_time; @@ -144,6 +147,8 @@ 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"); _exit(1); @@ -151,9 +156,6 @@ 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 */ @@ -162,6 +164,100 @@ 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; @@ -218,13 +314,30 @@ 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, list) { + /* 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; + } + } + 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); + running++; dbg("moved seq %llu to running list", loop_msg->seqnum); } else { dbg("delay seq %llu (%s), cause seq %llu (%s) is still running", @@ -529,10 +642,17 @@ 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) { @@ -544,9 +664,6 @@ int main(int argc, char *argv[], char *envp[]) } else dbg("error opening /dev/null %s", strerror(errno)); - /* become session leader */ - setsid(); - /* setup signal handler pipe */ retval = pipe(pipefds); if (retval < 0) { @@ -597,14 +714,14 @@ int main(int argc, char *argv[], char *envp[]) 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); } - /* get current time to provide shorter startup timeout */ + /* get current time to provide shorter timeout on startup */ sysinfo(&info); startup_time = info.uptime; @@ -28,10 +28,20 @@ #define UDEVD_SOCK_PATH "udevd" #define SEND_WAIT_MAX_SECONDS 3 #define SEND_WAIT_LOOP_PER_SECOND 10 + +#define UDEVD_PRIORITY -4 +#define UDEV_PRIORITY -2 + +/* duration of initialization phase with shorter timeout */ #define INIT_TIME_SEC 5 #define EVENT_INIT_TIMEOUT_SEC 2 + +/* timeout to wait for missing events */ #define EVENT_TIMEOUT_SEC 10 +/* start to throttle forking if maximum number of running childs in our session is reached */ +#define THROTTLE_MAX_RUNNING_CHILDS 10 + /* environment buffer, should match the kernel's size in lib/kobject_uevent.h */ #define HOTPLUG_BUFFER_SIZE 1024 #define HOTPLUG_NUM_ENVP 32 |