clib/mmap.c

   1 #include "config.h"
   2
   3 #include <sys/types.h>
   4
   5 #include <stdlib.h>
   6 #include <unistd.h>
   7
   8 /*
   9  * This function fakes mmap() by reading `len' bytes from the file descriptor
  10  * `fd' and returning a pointer to that memory.  The "mapped" region can later
  11  * be deallocated with munmap().
  12  *
  13  * Note: ONLY reading is supported and only reading of the exact size of the
  14  * file will work.
  15  *
  16  * PUBLIC: #ifndef HAVE_MMAP
  17  * PUBLIC: char *mmap __P((char *, size_t, int, int, int, off_t));
  18  * PUBLIC: #endif
  19  */
  20 char *
  21 mmap(char *addr, size_t len, int prot, int flags, int fd, off_t off)
  22 {
  23         char *ptr;
  24
  25         if ((ptr = (char *)malloc(len)) == 0)
  26                 return ((char *)-1);
  27         if (read(fd, ptr, len) < 0) {
  28                 free(ptr);
  29                 return ((char *)-1);
  30         }
  31         return (ptr);
  32 }
  33
  34 /*
  35  * PUBLIC: #ifndef HAVE_MMAP
  36  * PUBLIC: int munmap __P((char *, size_t));
  37  * PUBLIC: #endif
  38  */
  39 int
  40 munmap(char *addr, size_t len)
  41 {
  42         free(addr);
  43         return (0);
  44 }