openbsd-compat/xmmap.c

   1 /*
   2  * Copyright (c) 2002 Tim Rice.  All rights reserved.
   3  * MAP_FAILED code by Solar Designer.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 /* $Id: xmmap.c,v 1.9 2006/07/24 04:51:01 djm Exp $ */
  27
  28 #include "includes.h"
  29
  30 #include <sys/types.h>
  31 #ifdef HAVE_SYS_MMAN_H
  32 #include <sys/mman.h>
  33 #endif
  34 #include <sys/stat.h>
  35
  36 #include <errno.h>
  37 #include <string.h>
  38 #include <unistd.h>
  39
  40 #include "log.h"
  41
  42 void *xmmap(size_t size)
  43 {
  44         void *address;
  45
  46 #ifdef HAVE_MMAP
  47 # ifdef MAP_ANON
  48         address = mmap(NULL, size, PROT_WRITE|PROT_READ, MAP_ANON|MAP_SHARED,
  49             -1, (off_t)0);
  50 # else
  51         address = mmap(NULL, size, PROT_WRITE|PROT_READ, MAP_SHARED,
  52             open("/dev/zero", O_RDWR), (off_t)0);
  53 # endif
  54
  55 #define MM_SWAP_TEMPLATE "/var/run/sshd.mm.XXXXXXXX"
  56         if (address == (void *)MAP_FAILED) {
  57                 char tmpname[sizeof(MM_SWAP_TEMPLATE)] = MM_SWAP_TEMPLATE;
  58                 int tmpfd;
  59                 mode_t old_umask;
  60
  61                 old_umask = umask(0177);
  62                 tmpfd = mkstemp(tmpname);
  63                 umask(old_umask);
  64                 if (tmpfd == -1)
  65                         fatal("mkstemp(\"%s\"): %s",
  66                             MM_SWAP_TEMPLATE, strerror(errno));
  67                 unlink(tmpname);
  68                 ftruncate(tmpfd, size);
  69                 address = mmap(NULL, size, PROT_WRITE|PROT_READ, MAP_SHARED,
  70                     tmpfd, (off_t)0);
  71                 close(tmpfd);
  72         }
  73
  74         return (address);
  75 #else
  76         fatal("%s: UsePrivilegeSeparation=yes and Compression=yes not supported",
  77             __func__);
  78 #endif /* HAVE_MMAP */
  79
  80 }
  81