X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=udevd.c;h=2e63d8030e4035827e28a8fb42e780c7d8feda74;hb=25f8a5ad642e4338dacaf892e4ad47577c1cbf11;hp=6af265a3898b811a07a8d08a915698beda679902;hpb=90c210eb6bfc2ae294202fffb080315f3c47a57b;p=elogind.git diff --git a/udevd.c b/udevd.c index 6af265a38..2e63d8030 100644 --- a/udevd.c +++ b/udevd.c @@ -32,54 +32,26 @@ #include #include #include +#include #include "udev.h" #include "udevd.h" #include "logging.h" -#define BUFFER_SIZE 1024 -#define TIMEOUT_SECONDS 10 - -static void reset_timer(void); -static void reset_queue(void); +#define BUFFER_SIZE 1024 +#define EVENT_TIMEOUT_SECONDS 10 +#define DAEMON_TIMEOUT_SECONDS 30 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]; - - -static void sig_handler(int signum) -{ - 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; - case SIGINT: - case SIGTERM: - case SIGKILL: - exit(20 + signum); - break; - - default: - dbg("unhandled signal"); - } -} static void sig_alarmhandler(int signum) { dbg("caught signal %d", signum); switch (signum) { case SIGALRM: - timeout = 1; dbg("event timeout reached"); break; @@ -94,9 +66,9 @@ static void dump_queue(void) p = head; dbg("next expected sequence is %d", expect_seqnum); - while(p) { + while(p != NULL) { dbg("sequence %d in queue", p->seqnum); - p=p->next; + p = p->next; } } @@ -110,59 +82,37 @@ static int dispatch_msg(struct hotplug_msg *pmsg) { pid_t pid; char *argv[3]; - int retval; extern char **environ; dump_msg(pmsg); - dbg("exec '%s'", exec_program); setenv("ACTION", pmsg->action, 1); setenv("DEVPATH", pmsg->devpath, 1); - - argv[0] = exec_program; + argv[0] = DEFAULT_UDEV_EXEC; argv[1] = pmsg->subsystem; argv[2] = NULL; pid = fork(); switch (pid) { case 0: - retval = execve(argv[0], argv, environ); - if (retval != 0) { - dbg("child execve failed"); - exit(1); - } + /* child */ + execve(argv[0], argv, environ); + dbg("exec of child failed"); + exit(1); break; case -1: - dbg("fork failed"); + dbg("fork of child failed"); return -1; default: wait(0); - break; } return 0; } -static void reset_timer(void) -{ - alarm(0); -} - -static void set_timer(void) +static void set_timer(int seconds) { signal(SIGALRM, sig_alarmhandler); - alarm(timeout_value); -} - -static void reset_queue(void) -{ - struct hotplug_msg *p; - p = head; - - while(head) { - p = head; - head = head->next; - free(p); - } + alarm(seconds); } static void check_queue(void) @@ -171,7 +121,7 @@ static void check_queue(void) p = head; dump_queue(); - while(head && head->seqnum == expect_seqnum) { + while(head != NULL && head->seqnum == expect_seqnum) { dispatch_msg(head); expect_seqnum++; p = head; @@ -179,9 +129,9 @@ static void check_queue(void) free(p); } if (head != NULL) - set_timer(); + set_timer(EVENT_TIMEOUT_SECONDS); else - reset_timer(); + set_timer(DAEMON_TIMEOUT_SECONDS); } static void add_queue(struct hotplug_msg *pmsg) @@ -195,7 +145,7 @@ static void add_queue(struct hotplug_msg *pmsg) pnewmsg = malloc(sizeof(struct hotplug_msg)); *pnewmsg = *pmsg; pnewmsg->next = NULL; - while(p && pmsg->seqnum > p->seqnum) { + while(p != NULL && pmsg->seqnum > p->seqnum) { p1 = p; p = p->next; } @@ -208,6 +158,9 @@ static void add_queue(struct hotplug_msg *pmsg) dump_queue(); } +static int lock_file = -1; +static char *lock_filename = ".udevd_lock"; + static int process_queue(void) { int msgid; @@ -216,12 +169,12 @@ static int process_queue(void) char buf[BUFFER_SIZE]; int ret; - key = ftok(DEFAULT_EXEC_PROGRAM, IPC_KEY_ID); + key = ftok(DEFAULT_UDEVD_EXEC, IPC_KEY_ID); pmsg = (struct hotplug_msg *) buf; msgid = msgget(key, IPC_CREAT); if (msgid == -1) { dbg("open message queue error"); - goto exit; + return -1; } while (1) { ret = msgrcv(msgid, (struct msgbuf *) buf, BUFFER_SIZE-4, HOTPLUGMSGTYPE, 0); @@ -236,7 +189,7 @@ static int process_queue(void) if (pmsg->seqnum > expect_seqnum) { add_queue(pmsg); - set_timer(); + set_timer(EVENT_TIMEOUT_SECONDS); } else { if (pmsg->seqnum == expect_seqnum) { dispatch_msg(pmsg); @@ -246,37 +199,84 @@ static int process_queue(void) dbg("timeout event for unexpected sequence number %d", pmsg->seqnum); } } - } else + } 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); + /* event timeout, skip all missing, proceed with next queued event */ + info("timeout reached, skip events %d - %d", expect_seqnum, head->seqnum-1); expect_seqnum = head->seqnum; + } else { + info("we have nothing to do, so daemon exits..."); + if (lock_file >= 0) { + close(lock_file); + unlink(lock_filename); + } + exit(0); } check_queue(); - timeout = 0; } else { dbg("ipc message receive error '%s'", strerror(errno)); } + } } return 0; -exit: - return -1; +} + +static void sig_handler(int signum) +{ + dbg("caught signal %d", signum); + switch (signum) { + case SIGINT: + case SIGTERM: + case SIGKILL: + if (lock_file >= 0) { + close(lock_file); + unlink(lock_filename); + } + exit(20 + signum); + break; + + default: + dbg("unhandled signal"); + } +} + +static int one_and_only(void) +{ + char string[100]; + + lock_file = open(lock_filename, O_RDWR | O_CREAT, 0x640); + + /* see if we can open */ + if (lock_file < 0) + return -EINVAL; + + /* see if we can lock */ + if (lockf(lock_file, F_TLOCK, 0) < 0) { + close(lock_file); + unlink(lock_filename); + return -EINVAL; + } + + snprintf(string, sizeof(string), "%d\n", getpid()); + write(lock_file, string, strlen(string)); + + return 0; } 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); + /* only let one version of the daemon run at any one time */ + if (one_and_only() != 0) + exit(0); /* set up signal handler */ signal(SIGINT, sig_handler); signal(SIGTERM, sig_handler); signal(SIGKILL, sig_handler); - signal(SIGHUP, sig_handler); + + /* we exit if we have nothing to do, next event will start us again */ + set_timer(DAEMON_TIMEOUT_SECONDS); /* main loop */ process_queue();