kitten/kernel/linux_syscalls/mmap.c

   1 #include <lwk/kernel.h>
   2 #include <lwk/task.h>
   3 #include <lwk/aspace.h>
   4 #include <arch/mman.h>
   5
   6 long
   7 sys_mmap(
   8         unsigned long addr,
   9         unsigned long len,
  10         unsigned long prot,
  11         unsigned long flags,
  12         unsigned long fd,
  13         unsigned long off
  14 )
  15 {
  16         unsigned long mmap_brk;
  17
  18         /* For now we only support private/anonymous mappings */
  19         if (!(flags & MAP_PRIVATE) || !(flags & MAP_ANONYMOUS))
  20                 return -EINVAL;
  21
  22         if (len != round_up(len, PAGE_SIZE))
  23                 return -EINVAL;
  24
  25         mmap_brk = current->aspace->mmap_brk;
  26         mmap_brk = round_down(mmap_brk - len, PAGE_SIZE);
  27
  28         /* Protect against extending into the UNIX data segment */
  29         if (mmap_brk <= current->aspace->brk)
  30                 return -ENOMEM;
  31
  32         current->aspace->mmap_brk = mmap_brk;
  33         return mmap_brk;
  34 }
  35