mapping.h

   1 /* Minimal - the simplest thing that could possibly work
   2  * Copyright (C) 2007  Jay Freeman (saurik)
   3 */
   4
   5 /*
   6  *        Redistribution and use in source and binary
   7  * forms, with or without modification, are permitted
   8  * provided that the following conditions are met:
   9  *
  10  * 1. Redistributions of source code must retain the
  11  *    above copyright notice, this list of conditions
  12  *    and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the
  14  *    above copyright notice, this list of conditions
  15  *    and the following disclaimer in the documentation
  16  *    and/or other materials provided with the
  17  *    distribution.
  18  * 3. The name of the author may not be used to endorse
  19  *    or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS''
  23  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
  24  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  25  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
  27  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  28  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  29  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  30  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  32  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
  33  * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  34  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  35  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36 */
  37
  38 #include <sys/mman.h>
  39
  40 #include <errno.h>
  41 #include <unistd.h>
  42
  43 #include <sys/types.h>
  44 #include <sys/stat.h>
  45 #include <fcntl.h>
  46
  47 void *map(const char *path, size_t offset, size_t size, size_t *psize, bool ro) {
  48     int fd;
  49     _syscall(fd = open(path, ro ? O_RDONLY : O_RDWR));
  50
  51     if (size == _not(size_t)) {
  52         struct stat stat;
  53         _syscall(fstat(fd, &stat));
  54         size = stat.st_size;
  55     }
  56
  57     if (psize != NULL)
  58         *psize = size;
  59
  60     void *base;
  61     _syscall(base = mmap(NULL, size, ro ? PROT_READ : PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset));
  62
  63     _syscall(close(fd));
  64     return base;
  65 }