thread.c

linux 路由软件 可支持RIP OSPF BGP等

/* Thread management routine
 * Copyright (C) 1998, 2000 Kunihiro Ishiguro <[e-mail]>
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra 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; either version 2, or (at your option) any
 * later version.
 *
 * GNU Zebra 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 GNU Zebra; see the file COPYING.  If not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.  
 */

/* #define DEBUG */

#include <zebra.h>

#include "thread.h"
#include "memory.h"
#include "log.h"

/* Struct timeval's tv_usec one second value.  */
#define TIMER_SECOND_MICRO 1000000L

struct timeval
timeval_adjust (struct timeval a)
{
  while (a.tv_usec >= TIMER_SECOND_MICRO)
    {
      a.tv_usec -= TIMER_SECOND_MICRO;
      a.tv_sec++;
    }

  while (a.tv_usec < 0)
    {
      a.tv_usec += TIMER_SECOND_MICRO;
      a.tv_sec--;
    }

  if (a.tv_sec < 0)
    {
      a.tv_sec = 0;
      a.tv_usec = 10;
    }

  if (a.tv_sec > TIMER_SECOND_MICRO)
    a.tv_sec = TIMER_SECOND_MICRO;    

  return a;
}

static struct timeval
timeval_subtract (struct timeval a, struct timeval b)
{
  struct timeval ret;

  ret.tv_usec = a.tv_usec - b.tv_usec;
  ret.tv_sec = a.tv_sec - b.tv_sec;

  return timeval_adjust (ret);
}

static int
timeval_cmp (struct timeval a, struct timeval b)
{
  return (a.tv_sec == b.tv_sec
	  ? a.tv_usec - b.tv_usec : a.tv_sec - b.tv_sec);
}

static unsigned long
timeval_elapsed (struct timeval a, struct timeval b)
{
  return (((a.tv_sec - b.tv_sec) * TIMER_SECOND_MICRO)
	  + (a.tv_usec - b.tv_usec));
}

/* List allocation and head/tail print out. */
static void
thread_list_debug (struct thread_list *list)
{
  printf ("count [%d] head [%p] tail [%p]\n",
	  list->count, list->head, list->tail);
}

/* Debug print for thread_master. */
void
thread_master_debug (struct thread_master *m)
{
  printf ("-----------\n");
  printf ("readlist  : ");
  thread_list_debug (&m->read);
  printf ("writelist : ");
  thread_list_debug (&m->write);
  printf ("timerlist : ");
  thread_list_debug (&m->timer);
  printf ("eventlist : ");
  thread_list_debug (&m->event);
  printf ("unuselist : ");
  thread_list_debug (&m->unuse);
  printf ("total alloc: [%ld]\n", m->alloc);
  printf ("-----------\n");
}

/* Allocate new thread master.  */
struct thread_master *
thread_master_create ()
{
  return (struct thread_master *) XCALLOC (MTYPE_THREAD_MASTER,
					   sizeof (struct thread_master));
}

/* Add a new thread to the list.  */
static void
thread_list_add (struct thread_list *list, struct thread *thread)
{
  thread->next = NULL;
  thread->prev = list->tail;
  if (list->tail)
    list->tail->next = thread;
  else
    list->head = thread;
  list->tail = thread;
  list->count++;
}

/* Add a new thread just before the point.  */
static void
thread_list_add_before (struct thread_list *list, 
			struct thread *point, 
			struct thread *thread)
{
  thread->next = point;
  thread->prev = point->prev;
  if (point->prev)
    point->prev->next = thread;
  else
    list->head = thread;
  point->prev = thread;
  list->count++;
}

/* Delete a thread from the list. */
static struct thread *
thread_list_delete (struct thread_list *list, struct thread *thread)
{
  if (thread->next)
    thread->next->prev = thread->prev;
  else
    list->tail = thread->prev;
  if (thread->prev)
    thread->prev->next = thread->next;
  else
    list->head = thread->next;
  thread->next = thread->prev = NULL;
  list->count--;
  return thread;
}

/* Move thread to unuse list. */
static void
thread_add_unuse (struct thread_master *m, struct thread *thread)
{
  assert (m != NULL);
  assert (thread->next == NULL);
  assert (thread->prev == NULL);
  assert (thread->type == THREAD_UNUSED);
  thread_list_add (&m->unuse, thread);
}

/* Free all unused thread. */
static void
thread_list_free (struct thread_master *m, struct thread_list *list)
{
  struct thread *t;
  struct thread *next;

  for (t = list->head; t; t = next)
    {
      next = t->next;
      XFREE (MTYPE_THREAD, t);
      list->count--;
      m->alloc--;
    }
}

/* Stop thread scheduler. */
void
thread_master_free (struct thread_master *m)
{
  thread_list_free (m, &m->read);
  thread_list_free (m, &m->write);
  thread_list_free (m, &m->timer);
  thread_list_free (m, &m->event);
  thread_list_free (m, &m->ready);
  thread_list_free (m, &m->unuse);

  XFREE (MTYPE_THREAD_MASTER, m);
}

/* Delete top of the list and return it. */
static struct thread *
thread_trim_head (struct thread_list *list)
{
  if (list->head)
    return thread_list_delete (list, list->head);
  return NULL;
}

/* Thread list is empty or not.  */
int
thread_empty (struct thread_list *list)
{
  return  list->head ? 0 : 1;
}

/* Return remain time. */
char *
thread_timer_remain_second (struct thread *thread)
{
  struct timeval timer_now;
  struct tm *tm;
  time_t remain_time;
  char buf[25];
  int len = 25;

  gettimeofday (&timer_now, NULL);

  remain_time = thread->u.sands.tv_sec - timer_now.tv_sec;

  if (remain_time < 0)
    remain_time = 0;

  tm = gmtime (&remain_time);

  /* Making formatted timer strings. */
#define ONE_DAY_SECOND 60*60*24
#define ONE_WEEK_SECOND 60*60*24*7

  if (remain_time < ONE_DAY_SECOND)
    snprintf (buf, len, "%02d:%02d:%02d",
              tm->tm_hour, tm->tm_min, tm->tm_sec);
  else if (remain_time < ONE_WEEK_SECOND)
    snprintf (buf, len, "%dd%02dh%02dm",
              tm->tm_yday, tm->tm_hour, tm->tm_min);
  else
    snprintf (buf, len, "%02dw%dd%02dh",
              tm->tm_yday/7, tm->tm_yday - ((tm->tm_yday/7) * 7), tm->tm_hour);
  return buf;
}

/* Get new thread.  */
static struct thread *
thread_get (struct thread_master *m, u_char type,
	    int (*func) (struct thread *), void *arg)
{
  struct thread *thread;

  if (m->unuse.head)
    thread = thread_trim_head (&m->unuse);
  else
    {
      thread = XCALLOC (MTYPE_THREAD, sizeof (struct thread));
      m->alloc++;
    }
  thread->type = type;
  thread->master = m;
  thread->func = func;
  thread->arg = arg;
  
  return thread;
}

/* Add new read thread. */
struct thread *
thread_add_read (struct thread_master *m, 
		 int (*func) (struct thread *), void *arg, int fd)
{
  struct thread *thread;

  assert (m != NULL);

  if (FD_ISSET (fd, &m->readfd))
    {
      zlog (NULL, LOG_WARNING, "There is already read fd [%d]", fd);
      return NULL;
    }

  thread = thread_get (m, THREAD_READ, func, arg);
  FD_SET (fd, &m->readfd);
  thread->u.fd = fd;
  thread_list_add (&m->read, thread);

  return thread;
}

/* Add new write thread. */
struct thread *
thread_add_write (struct thread_master *m,
		 int (*func) (struct thread *), void *arg, int fd)
{
  struct thread *thread;

  assert (m != NULL);

  if (FD_ISSET (fd, &m->writefd))
    {
      zlog (NULL, LOG_WARNING, "There is already write fd [%d]", fd);
      return NULL;
    }

  thread = thread_get (m, THREAD_WRITE, func, arg);
  FD_SET (fd, &m->writefd);
  thread->u.fd = fd;
  thread_list_add (&m->write, thread);

  return thread;
}

/* Add timer event thread. */
struct thread *
thread_add_timer (struct thread_master *m,
		  int (*func) (struct thread *), void *arg, long timer)
{
  struct timeval timer_now;
  struct thread *thread;
#ifndef TIMER_NO_SORT
  struct thread *tt;
#endif /* TIMER_NO_SORT */

  assert (m != NULL);

  thread = thread_get (m, THREAD_TIMER, func, arg);

  /* Do we need jitter here? */
  gettimeofday (&timer_now, NULL);
  timer_now.tv_sec += timer;
  thread->u.sands = timer_now;