src/mman/mmap.c

   1 #include <unistd.h>
   2 #include <sys/mman.h>
   3 #include <errno.h>
   4 #include <stdint.h>
   5 #include <limits.h>
   6 #include "syscall.h"
   7
   8 static void dummy(void) { }
   9 weak_alias(dummy, __vm_wait);
  10
  11 #define UNIT SYSCALL_MMAP2_UNIT
  12 #define OFF_MASK ((-0x2000ULL << (8*sizeof(syscall_arg_t)-1)) | (UNIT-1))
  13
  14 void *__mmap(void *start, size_t len, int prot, int flags, int fd, off_t off)
  15 {
  16         long ret;
  17         if (off & OFF_MASK) {
  18                 errno = EINVAL;
  19                 return MAP_FAILED;
  20         }
  21         if (len >= PTRDIFF_MAX) {
  22                 errno = ENOMEM;
  23                 return MAP_FAILED;
  24         }
  25         if (flags & MAP_FIXED) {
  26                 __vm_wait();
  27         }
  28 #ifdef SYS_mmap2
  29         ret = __syscall(SYS_mmap2, start, len, prot, flags, fd, off/UNIT);
  30 #else
  31         ret = __syscall(SYS_mmap, start, len, prot, flags, fd, off);
  32 #endif
  33         /* Fixup incorrect EPERM from kernel. */
  34         if (ret == -EPERM && !start && (flags&MAP_ANON) && !(flags&MAP_FIXED))
  35                 ret = -ENOMEM;
  36         return (void *)__syscall_ret(ret);
  37 }
  38
  39 weak_alias(__mmap, mmap);