lib/libc/upmap/ukp_getpid.c

   1 /*
   2  * Copyright (c) 2014 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #include <sys/types.h>
  37 #include <sys/syscall.h>
  38 #include <sys/upmap.h>
  39 #include <sys/time.h>
  40 #include <machine/cpufunc.h>
  41 #include <errno.h>
  42 #include <time.h>
  43 #include <stdio.h>
  44 #include <unistd.h>
  45 /*#include "un-namespace.h"*/
  46 #include "libc_private.h"
  47 #include "upmap.h"
  48
  49 extern pid_t __sys_getpid(void);
  50 int __getpid(void);
  51
  52 static int fast_getpid_state;
  53 static int fast_getpid_count;
  54 static pid_t *pidp;
  55 static int   *invforkp;
  56
  57 /*
  58  * Optimize getpid() if it is called a lot.  We have to be careful when
  59  * getpid() is called in a vfork child prior to exec as the shared area
  60  * is still the parent's shared area.
  61  */
  62 pid_t
  63 __getpid(void)
  64 {
  65         if (fast_getpid_state == 0 && fast_getpid_count++ >= 10) {
  66                 __upmap_map(&pidp, &fast_getpid_state, UPTYPE_PID);
  67                 __upmap_map(&invforkp, &fast_getpid_state, UPTYPE_INVFORK);
  68                 __upmap_map(NULL, &fast_getpid_state, 0);
  69         }
  70         if (fast_getpid_state > 0 && *invforkp == 0)
  71                 return(*pidp);
  72         else
  73                 return(__sys_getpid());
  74 }
  75
  76 __weak_reference(__getpid, getpid);
  77
  78 #if 0 /* DEBUG */
  79 pid_t xxx_getpid(void);
  80
  81 pid_t
  82 xxx_getpid(void)
  83 {
  84         return(__sys_getpid());
  85 }
  86 #endif