libsyscall/wrappers/select-base.c

   1 /*
   2  * Copyright (c) 2005, 2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #if defined(__LP64__) && (defined(VARIANT_CANCELABLE) || defined(VARIANT_PRE1050))
  25 #undef __DARWIN_NON_CANCELABLE
  26 #define __DARWIN_NON_CANCELABLE 0
  27 #endif /* __LP64__ && (VARIANT_CANCELABLE || VARIANT_PRE1050) */
  28
  29 #if defined(VARIANT_DARWIN_EXTSN)
  30 #define _DARWIN_C_SOURCE
  31 #define _DARWIN_UNLIMITED_SELECT
  32 #endif
  33
  34 #include <sys/select.h>
  35 #include <sys/time.h>
  36 #include <sys/signal.h>
  37 #include "_errno.h"
  38
  39 #if defined(VARIANT_CANCELABLE) || defined(VARIANT_PRE1050)
  40 #if !defined(VARIANT_DARWIN_EXTSN)
  41 extern int __select(int, fd_set * __restrict, fd_set * __restrict,
  42         fd_set * __restrict, struct timeval * __restrict);
  43 #endif
  44 int __pselect(int, fd_set * __restrict, fd_set * __restrict,
  45         fd_set * __restrict, const struct timespec * __restrict, const sigset_t * __restrict);
  46 #else /* !VARIANT_CANCELABLE && !VARIANT_PRE1050 */
  47 #if !defined(VARIANT_DARWIN_EXTSN)
  48 int __select_nocancel(int, fd_set * __restrict, fd_set * __restrict,
  49         fd_set * __restrict, struct timeval * __restrict);
  50 #endif
  51 int __pselect_nocancel(int, fd_set * __restrict, fd_set * __restrict,
  52         fd_set * __restrict, const struct timespec * __restrict, const sigset_t * __restrict);
  53 #endif /* VARIANT_CANCELABLE || VARIANT_PRE1050 */
  54
  55 #if !defined(VARIANT_DARWIN_EXTSN)
  56 /*
  57  * select() implementation for 1050 and legacy (cancelable and non-cancelable)
  58  * variants. The darwin extension variants (both cancelable & non-cancelable) are
  59  * mapped directly to the syscall stub.
  60  */
  61 int
  62 select(int nfds, fd_set * __restrict readfds, fd_set * __restrict writefds,
  63         fd_set * __restrict exceptfds, struct timeval * __restrict
  64 #if defined(VARIANT_LEGACY) || defined(VARIANT_PRE1050)
  65         intimeout
  66 #else /* !VARIANT_LEGACY && !VARIANT_PRE1050 */
  67         timeout
  68 #endif /* VARIANT_LEGACY || VARIANT_PRE1050 */
  69         )
  70 {
  71 #if defined(VARIANT_LEGACY) || defined(VARIANT_PRE1050)
  72         struct timeval tb, *timeout;
  73
  74         /*
  75          * Legacy select behavior is minimum 10 msec when tv_usec is non-zero
  76          */
  77         if (intimeout && intimeout->tv_sec == 0 && intimeout->tv_usec > 0 && intimeout->tv_usec < 10000) {
  78                 tb.tv_sec = 0;
  79                 tb.tv_usec = 10000;
  80                 timeout = &tb;
  81         } else {
  82                 timeout = intimeout;
  83         }
  84 #else /* !VARIANT_LEGACY && !VARIANT_PRE1050 */
  85         if (nfds > FD_SETSIZE) {
  86                 errno = EINVAL;
  87                 return -1;
  88         }
  89 #endif
  90
  91 #if defined(VARIANT_CANCELABLE) || defined(VARIANT_PRE1050)
  92         return __select(nfds, readfds, writefds, exceptfds, timeout);
  93 #else /* !VARIANT_CANCELABLE && !VARIANT_PRE1050 */
  94         return __select_nocancel(nfds, readfds, writefds, exceptfds, timeout);
  95 #endif /* VARIANT_CANCELABLE || VARIANT_PRE1050 */
  96 }
  97 #endif /* !defined(VARIANT_DARWIN_EXTSN) */
  98
  99
 100 /*
 101  * User-space emulation of pselect() syscall for B&I
 102  * TODO: remove when B&I move to xnu with native pselect()
 103  */
 104 extern int __pthread_sigmask(int, const sigset_t *, sigset_t *);
 105 static int
 106 _pselect_emulated(int count, fd_set * __restrict rfds, fd_set * __restrict wfds,
 107                 fd_set * __restrict efds, const struct timespec * __restrict timo,
 108                 const sigset_t * __restrict mask)
 109 {
 110         sigset_t omask;
 111         struct timeval tvtimo, *tvp;
 112         int rv, sverrno;
 113
 114         if (timo) {
 115                 tvtimo.tv_sec = timo->tv_sec;
 116                 tvtimo.tv_usec = (__darwin_suseconds_t)(timo->tv_nsec / 1000);
 117                 tvp = &tvtimo;
 118         } else {
 119                 tvp = 0;
 120         }
 121
 122         if (mask != 0) {
 123                 rv = __pthread_sigmask(SIG_SETMASK, mask, &omask);
 124                 if (rv != 0)
 125                         return rv;
 126         }
 127
 128         rv = select(count, rfds, wfds, efds, tvp);
 129         if (mask != 0) {
 130                 sverrno = errno;
 131                 __pthread_sigmask(SIG_SETMASK, &omask, (sigset_t *)0);
 132                 errno = sverrno;
 133         }
 134
 135         return rv;
 136 }
 137
 138 /*
 139  * pselect() implementation for all variants. Unlike select(), we implement the
 140  * darwin extension variants here to catch cases where xnu doesn't implement
 141  * pselect and we need to emulate.
 142  */
 143 int
 144 pselect(int nfds, fd_set * __restrict readfds, fd_set * __restrict writefds,
 145         fd_set * __restrict exceptfds, const struct timespec * __restrict
 146 #if defined(VARIANT_LEGACY) || defined(VARIANT_PRE1050)
 147         intimeout,
 148 #else /* !VARIANT_LEGACY && !VARIANT_PRE1050 */
 149         timeout,
 150 #endif /* VARIANT_LEGACY || VARIANT_PRE1050 */
 151         const sigset_t * __restrict sigmask)
 152 {
 153         int ret;
 154 #if defined(VARIANT_LEGACY) || defined(VARIANT_PRE1050)
 155         struct timespec tb;
 156         const struct timespec *timeout;
 157
 158         /*
 159          * Legacy select behavior is minimum 10 msec when tv_usec is non-zero
 160          */
 161         if (intimeout && intimeout->tv_sec == 0 && intimeout->tv_nsec > 0 && intimeout->tv_nsec < 10000000L) {
 162                 tb.tv_sec = 0;
 163                 tb.tv_nsec = 10000000L;
 164                 timeout = &tb;
 165         } else {
 166                 timeout = intimeout;
 167         }
 168 #elif defined(VARIANT_DARWIN_EXTSN)
 169 #else
 170         /* 1050 variant */
 171         if (nfds > FD_SETSIZE) {
 172                 errno = EINVAL;
 173                 return -1;
 174         }
 175 #endif
 176
 177 #if defined(VARIANT_CANCELABLE) || defined(VARIANT_PRE1050)
 178         ret = __pselect(nfds, readfds, writefds, exceptfds, timeout, sigmask);
 179 #else /* !VARIANT_CANCELABLE && !VARIANT_PRE1050 */
 180         ret = __pselect_nocancel(nfds, readfds, writefds, exceptfds, timeout, sigmask);
 181 #endif /* VARIANT_CANCELABLE || VARIANT_PRE1050 */
 182
 183         if (ret == -1 && errno == ENOSYS) {
 184                 ret = _pselect_emulated(nfds, readfds, writefds, exceptfds, timeout, sigmask);
 185         }
 186
 187         return ret;
 188 }