usr/src/lib/libfakekernel/common/sema.c

   1 /*
   2  * This file and its contents are supplied under the terms of the
   3  * Common Development and Distribution License ("CDDL"), version 1.0.
   4  * You may only use this file in accordance with the terms of version
   5  * 1.0 of the CDDL.
   6  *
   7  * A full copy of the text of the CDDL should have accompanied this
   8  * source.  A copy of the CDDL is also available via the Internet at
   9  * http://www.illumos.org/license/CDDL.
  10  */
  11
  12 /*
  13  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
  14  */
  15
  16 /*
  17  * semaphore(9f)
  18  */
  19
  20 /* This is the API we're emulating */
  21 #include <sys/semaphore.h>
  22
  23 #include <sys/errno.h>
  24 #include <sys/debug.h>
  25
  26 /* <synch.h> */
  27 int     _lwp_sema_init(lwp_sema_t *, int);
  28 int     _lwp_sema_wait(lwp_sema_t *);
  29 int     _lwp_sema_trywait(lwp_sema_t *);
  30 int     _lwp_sema_post(lwp_sema_t *);
  31
  32
  33 /* ARGSUSED */
  34 void
  35 ksema_init(ksema_t *sem, uint32_t val,
  36         char *name, ksema_type_t st, void *arg)
  37 {
  38         (void) _lwp_sema_init(sem, val);
  39 }
  40
  41 /* ARGSUSED */
  42 void
  43 ksema_destroy(ksema_t *sem)
  44 {
  45 }
  46
  47 void
  48 sema_p(ksema_t *sem)
  49 {
  50         int rv;
  51         do {
  52                 rv = _lwp_sema_wait(sem);
  53         } while (rv == EINTR);
  54 }
  55
  56 void
  57 sema_v(ksema_t *sem)
  58 {
  59         (void) _lwp_sema_post(sem);
  60 }
  61
  62 /*
  63  * Return values:
  64  * 1: interrupted
  65  * 0: success
  66  */
  67 int
  68 sema_p_sig(ksema_t *sem)
  69 {
  70         int rv;
  71         rv = _lwp_sema_wait(sem);
  72         switch (rv) {
  73         case 0:
  74                 /* rv = 0 ; success */
  75                 break;
  76         case EINTR:
  77         default:
  78                 rv = 1; /* interrrupted */
  79                 break;
  80         }
  81
  82         return (rv);
  83 }
  84
  85 /*
  86  * Return values:
  87  * 0: could not get semaphore
  88  * 1: successful (backwards from sema_p_sig!)
  89  */
  90 int
  91 sema_tryp(ksema_t *sem)
  92 {
  93         int rv;
  94         rv = _lwp_sema_trywait(sem);
  95
  96         switch (rv) {
  97         case 0:
  98                 rv = 1; /* success */
  99                 break;
 100         case EBUSY:
 101         default:
 102                 rv = 0; /* failed */
 103                 break;
 104         }
 105
 106         return (rv);
 107 }