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/*
* udevd.c
*
* Userspace devfs
*
* Copyright (C) 2004 Ling, Xiaofeng <xiaofeng.ling@intel.com>
* Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
*
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#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);
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;
default:
dbg("unhandled signal");
}
}
static void dump_queue(void)
{
struct hotplug_msg *p;
p = head;
dbg("next expected sequence is %d", expect_seqnum);
while(p) {
dbg("sequence %d in queue", p->seqnum);
p=p->next;
}
}
static void dump_msg(struct hotplug_msg *pmsg)
{
dbg("sequence %d, '%s', '%s', '%s'",
pmsg->seqnum, pmsg->action, pmsg->devpath, pmsg->subsystem);
}
static void dispatch_msg(struct hotplug_msg *pmsg)
{
dump_msg(pmsg);
dbg("exec '%s'", exec_program);
setenv("ACTION", pmsg->action, 1);
setenv("DEVPATH", pmsg->devpath, 1);
execl(exec_program, pmsg->subsystem);
}
static void reset_timer(void)
{
alarm(0);
}
static void set_timer(void)
{
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);
}
}
static void check_queue(void)
{
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);
}
if (head != NULL)
set_timer();
else
reset_timer();
}
static void add_queue(struct hotplug_msg *pmsg)
{
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;
}
pnewmsg->next = p;
if (p1 == NULL) {
head = pnewmsg;
} else {
p1->next = pnewmsg;
}
dump_queue();
}
static int process_queue(void)
{
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;
}
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));
}
}
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);
/* set up signal handler */
signal(SIGINT, sig_handler);
signal(SIGTERM, sig_handler);
signal(SIGKILL, sig_handler);
signal(SIGHUP, sig_handler);
/* main loop */
process_queue();
return 0;
}
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