From a695feaeff0551745e1a397be2daa61b8cd0cc42 Mon Sep 17 00:00:00 2001 From: "kay.sievers@vrfy.org" Date: Mon, 26 Jan 2004 18:19:33 -0800 Subject: [PATCH] [PATCH] udevd - cleanup and better timeout handling Here is the next revision for udevd: o Small cleanups all over the place. o Swich to the usual linked list format "list.h". o Better timeout handling. We store a timestamp in in every queued event, so we don't wait longer than the timeout specified, if the hole in the list is not shrinking. o ignore udevd target if klibc is used --- Makefile | 8 +- udevd.c | 231 ++++++++++++++++++++++++++--------------------------- udevd.h | 15 ++-- udevsend.c | 10 ++- 4 files changed, 133 insertions(+), 131 deletions(-) diff --git a/Makefile b/Makefile index 30ebd45e..5c265492 100644 --- a/Makefile +++ b/Makefile @@ -151,6 +151,7 @@ ifeq ($(strip $(USE_KLIBC)),true) -I$(LINUX_INCLUDE_DIR) LIB_OBJS = LDFLAGS = --static --nostdlib -nostartfiles -nodefaultlibs + UDEVD = else WARNINGS += -Wshadow -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations CRT0 = @@ -158,11 +159,12 @@ else CFLAGS += $(WARNINGS) -I$(GCCINCDIR) LIB_OBJS = -lc LDFLAGS = + UDEVD = $(DAEMON) $(SENDER) endif CFLAGS += -I$(PWD)/libsysfs -all: $(ROOT) $(DAEMON) $(SENDER) +all: $(ROOT) $(UDEVD) @extras="$(EXTRAS)" ; for target in $$extras ; do \ echo $$target ; \ $(MAKE) prefix=$(prefix) LD="$(LD)" SYSFS="$(SYSFS)" \ @@ -236,11 +238,11 @@ $(ROOT): $(OBJS) udev.h namedev.h udev_version.h udev_dbus.h udevdb.h klibc_fixu $(LD) $(LDFLAGS) -o $(ROOT) $(CRT0) $(OBJS) $(LIB_OBJS) $(ARCH_LIB_OBJS) $(STRIPCMD) $(ROOT) -$(DAEMON): $(ROOT) udevd.h udevd.o +$(DAEMON): udevd.h udevd.o udevd.o logging.o $(LD) $(LDFLAGS) -o $(DAEMON) $(CRT0) udevd.o logging.o $(LIB_OBJS) $(ARCH_LIB_OBJS) $(STRIPCMD) $(ROOT) -$(SENDER): $(ROOT) udevd.h udevsend.o +$(SENDER): udevd.h udevsend.o udevd.o logging.o $(LD) $(LDFLAGS) -o $(SENDER) $(CRT0) udevsend.o logging.o $(LIB_OBJS) $(ARCH_LIB_OBJS) $(STRIPCMD) $(ROOT) diff --git a/udevd.c b/udevd.c index 2e63d803..26e6b234 100644 --- a/udevd.c +++ b/udevd.c @@ -22,6 +22,7 @@ * */ +#include #include #include #include @@ -32,29 +33,38 @@ #include #include #include +#include #include +#include "list.h" #include "udev.h" #include "udevd.h" #include "logging.h" #define BUFFER_SIZE 1024 -#define EVENT_TIMEOUT_SECONDS 10 -#define DAEMON_TIMEOUT_SECONDS 30 - static int expect_seqnum = 0; -static struct hotplug_msg *head = NULL; +static int lock_file = -1; +static char *lock_filename = ".udevd_lock"; +LIST_HEAD(msg_list); -static void sig_alarmhandler(int signum) +static void sig_handler(int signum) { dbg("caught signal %d", signum); switch (signum) { case SIGALRM: dbg("event timeout reached"); break; - + case SIGINT: + case SIGTERM: + case SIGKILL: + if (lock_file >= 0) { + close(lock_file); + unlink(lock_filename); + } + exit(20 + signum); + break; default: dbg("unhandled signal"); } @@ -62,41 +72,32 @@ static void sig_alarmhandler(int signum) static void dump_queue(void) { - struct hotplug_msg *p; - p = head; + struct hotplug_msg *msg; - dbg("next expected sequence is %d", expect_seqnum); - while(p != NULL) { - dbg("sequence %d in queue", p->seqnum); - p = p->next; - } + list_for_each_entry(msg, &msg_list, list) + dbg("sequence %d in queue", msg->seqnum); } -static void dump_msg(struct hotplug_msg *pmsg) +static void dump_msg(struct hotplug_msg *msg) { dbg("sequence %d, '%s', '%s', '%s'", - pmsg->seqnum, pmsg->action, pmsg->devpath, pmsg->subsystem); + msg->seqnum, msg->action, msg->devpath, msg->subsystem); } -static int dispatch_msg(struct hotplug_msg *pmsg) +static int dispatch_msg(struct hotplug_msg *msg) { pid_t pid; - char *argv[3]; - extern char **environ; - dump_msg(pmsg); + dump_msg(msg); - setenv("ACTION", pmsg->action, 1); - setenv("DEVPATH", pmsg->devpath, 1); - argv[0] = DEFAULT_UDEV_EXEC; - argv[1] = pmsg->subsystem; - argv[2] = NULL; + setenv("ACTION", msg->action, 1); + setenv("DEVPATH", msg->devpath, 1); pid = fork(); switch (pid) { case 0: /* child */ - execve(argv[0], argv, environ); + execl(UDEV_EXEC, "udev", msg->subsystem, NULL); dbg("exec of child failed"); exit(1); break; @@ -104,108 +105,119 @@ static int dispatch_msg(struct hotplug_msg *pmsg) dbg("fork of child failed"); return -1; default: - wait(0); + wait(NULL); } return 0; } -static void set_timer(int seconds) +static void set_timeout(int seconds) { - signal(SIGALRM, sig_alarmhandler); alarm(seconds); + dbg("set timeout in %d seconds", seconds); } static void check_queue(void) { - struct hotplug_msg *p; - p = head; - - dump_queue(); - while(head != NULL && head->seqnum == expect_seqnum) { - dispatch_msg(head); + struct hotplug_msg *msg; + struct hotplug_msg *tmp_msg; + time_t msg_age; + +recheck: + /* dispatch events until one is missing */ + list_for_each_entry_safe(msg, tmp_msg, &msg_list, list) { + if (msg->seqnum != expect_seqnum) + break; + dispatch_msg(msg); expect_seqnum++; - p = head; - head = head->next; - free(p); + list_del_init(&msg->list); + free(msg); + } + + /* recalculate timeout */ + if (list_empty(&msg_list) == 0) { + msg_age = time(NULL) - msg->queue_time; + if (msg_age > EVENT_TIMEOUT_SECONDS-1) { + info("event %d, age %li seconds, skip event %d-%d", + msg->seqnum, msg_age, expect_seqnum, msg->seqnum-1); + expect_seqnum = msg->seqnum; + goto recheck; + } + set_timeout(EVENT_TIMEOUT_SECONDS - msg_age); + return; } - if (head != NULL) - set_timer(EVENT_TIMEOUT_SECONDS); - else - set_timer(DAEMON_TIMEOUT_SECONDS); + + /* queue is empty */ + set_timeout(UDEVD_TIMEOUT_SECONDS); } -static void add_queue(struct hotplug_msg *pmsg) +static int queue_msg(struct hotplug_msg *msg) { - 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 != NULL && pmsg->seqnum > p->seqnum) { - p1 = p; - p = p->next; - } - pnewmsg->next = p; - if (p1 == NULL) { - head = pnewmsg; - } else { - p1->next = pnewmsg; + struct hotplug_msg *new_msg; + struct hotplug_msg *tmp_msg; + + new_msg = malloc(sizeof(*new_msg)); + if (new_msg == NULL) { + dbg("error malloc"); + return -ENOMEM; } - dump_queue(); -} + memcpy(new_msg, msg, sizeof(*new_msg)); -static int lock_file = -1; -static char *lock_filename = ".udevd_lock"; + /* 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); + + return 0; +} -static int process_queue(void) +static void work(void) { + struct hotplug_msg *msg; int msgid; key_t key; - struct hotplug_msg *pmsg; char buf[BUFFER_SIZE]; int ret; - key = ftok(DEFAULT_UDEVD_EXEC, IPC_KEY_ID); - pmsg = (struct hotplug_msg *) buf; + key = ftok(UDEVD_EXEC, IPC_KEY_ID); + msg = (struct hotplug_msg *) buf; msgid = msgget(key, IPC_CREAT); if (msgid == -1) { dbg("open message queue error"); - return -1; + exit(1); } 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 */ + /* init the expected sequence with value from first call */ if (expect_seqnum == 0) { - expect_seqnum = pmsg->seqnum; + expect_seqnum = msg->seqnum; dbg("init next expected sequence number to %d", expect_seqnum); } - - if (pmsg->seqnum > expect_seqnum) { - add_queue(pmsg); - set_timer(EVENT_TIMEOUT_SECONDS); - } else { - if (pmsg->seqnum == expect_seqnum) { - dispatch_msg(pmsg); - expect_seqnum++; - check_queue(); - } else { - dbg("timeout event for unexpected sequence number %d", pmsg->seqnum); - } + dbg("current sequence %d, expected sequence %d", msg->seqnum, expect_seqnum); + if (msg->seqnum == expect_seqnum) { + /* execute expected event */ + dispatch_msg(msg); + expect_seqnum++; + check_queue(); + dump_queue(); + continue; } + if (msg->seqnum > expect_seqnum) { + /* something missing, queue event*/ + queue_msg(msg); + check_queue(); + dump_queue(); + continue; + } + dbg("too late for event with sequence %d, even skipped ", msg->seqnum); } else { if (errno == EINTR) { - if (head != NULL) { - /* 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 { + /* timeout */ + if (list_empty(&msg_list)) { info("we have nothing to do, so daemon exits..."); if (lock_file >= 0) { close(lock_file); @@ -214,31 +226,12 @@ static int process_queue(void) exit(0); } check_queue(); - } else { - dbg("ipc message receive error '%s'", strerror(errno)); + dump_queue(); + continue; } + dbg("ipc message receive error '%s'", strerror(errno)); } } - return 0; -} - -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) @@ -249,18 +242,18 @@ static int one_and_only(void) /* see if we can open */ if (lock_file < 0) - return -EINVAL; + return -1; /* see if we can lock */ if (lockf(lock_file, F_TLOCK, 0) < 0) { close(lock_file); unlink(lock_filename); - return -EINVAL; + return -1; } snprintf(string, sizeof(string), "%d\n", getpid()); write(lock_file, string, strlen(string)); - + return 0; } @@ -274,11 +267,11 @@ int main(int argc, char *argv[]) signal(SIGINT, sig_handler); signal(SIGTERM, sig_handler); signal(SIGKILL, sig_handler); + signal(SIGALRM, sig_handler); /* we exit if we have nothing to do, next event will start us again */ - set_timer(DAEMON_TIMEOUT_SECONDS); + set_timeout(UDEVD_TIMEOUT_SECONDS); - /* main loop */ - process_queue(); - return 0; + work(); + exit(0); } diff --git a/udevd.h b/udevd.h index 43fe6b42..c9b69bbc 100644 --- a/udevd.h +++ b/udevd.h @@ -21,17 +21,22 @@ * */ -#define DEFAULT_UDEV_EXEC "./udev" -#define DEFAULT_UDEVD_EXEC "./udevd" +#include "list.h" -#define IPC_KEY_ID 0 -#define HOTPLUGMSGTYPE 44 +#define UDEV_EXEC "./udev" +#define UDEVD_EXEC "./udevd" +#define UDEVD_TIMEOUT_SECONDS 60 +#define EVENT_TIMEOUT_SECONDS 5 + +#define IPC_KEY_ID 0 +#define HOTPLUGMSGTYPE 44 struct hotplug_msg { long mtype; - struct hotplug_msg *next; + struct list_head list; int seqnum; + time_t queue_time; char action[8]; char devpath[128]; char subsystem[16]; diff --git a/udevsend.c b/udevsend.c index bdc8293d..3f3bbacb 100644 --- a/udevsend.c +++ b/udevsend.c @@ -64,6 +64,7 @@ static inline char *get_seqnum(void) static int build_hotplugmsg(struct hotplug_msg *msg, char *action, char *devpath, char *subsystem, int seqnum) { + memset(msg, 0x00, sizeof(msg)); msg->mtype = HOTPLUGMSGTYPE; msg->seqnum = seqnum; strncpy(msg->action, action, 8); @@ -85,7 +86,8 @@ static int start_daemon(void) switch (child_pid) { case 0: /* daemon */ - execl(DEFAULT_UDEVD_EXEC, NULL); + setsid(); + execl(UDEVD_EXEC, "udevd", NULL); dbg("exec of daemon failed"); exit(1); case -1: @@ -99,7 +101,7 @@ static int start_daemon(void) dbg("fork of helper failed"); return -1; default: - wait(0); + wait(NULL); } return 0; } @@ -147,7 +149,7 @@ int main(int argc, char* argv[]) seq = atoi(seqnum); /* create ipc message queue or get id of our existing one */ - key = ftok(DEFAULT_UDEVD_EXEC, IPC_KEY_ID); + key = ftok(UDEVD_EXEC, IPC_KEY_ID); size = build_hotplugmsg(&message, action, devpath, subsystem, seq); msgid = msgget(key, IPC_CREAT); if (msgid == -1) { @@ -165,7 +167,7 @@ int main(int argc, char* argv[]) /* get state of ipc queue */ tspec.tv_sec = 0; tspec.tv_nsec = 10000000; /* 10 millisec */ - loop = 20; + loop = 30; while (loop--) { retval = msgctl(msgid, IPC_STAT, &msg_queue); if (retval == -1) { -- 2.39.5