#include <linux/pagemap.h>
#include <linux/mm.h>
#include <linux/mman.h>
+#include <linux/syscalls.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
-#include <asm/pgalloc.h>
/*
* Later we can get more picky about what "in core" means precisely.
unsigned char __user * vec)
{
int index = 0;
- unsigned long end;
+ unsigned long end, limit;
struct vm_area_struct * vma;
+ size_t max;
int unmapped_error = 0;
- long error = -EINVAL;
+ long error;
- down_read(¤t->mm->mmap_sem);
+ /* check the arguments */
+ if (start & ~PAGE_CACHE_MASK)
+ goto einval;
+
+ if (start < FIRST_USER_PGD_NR * PGDIR_SIZE)
+ goto enomem;
+
+ limit = TASK_SIZE;
+ if (start >= limit)
+ goto enomem;
+
+ max = limit - start;
+ len = PAGE_CACHE_ALIGN(len);
+ if (len > max)
+ goto einval;
- if (start & ~PAGE_CACHE_MASK)
- goto out;
- len = (len + ~PAGE_CACHE_MASK) & PAGE_CACHE_MASK;
end = start + len;
- if (end < start)
- goto out;
+ /* check the output buffer whilst holding the lock */
error = -EFAULT;
- if (!access_ok(VERIFY_WRITE, vec, len >> PAGE_SHIFT))
- goto out;
+ down_read(¤t->mm->mmap_sem);
- error = 0;
- if (end == start)
+ if (!access_ok(VERIFY_WRITE, vec, len >> PAGE_SHIFT))
goto out;
/*
* If the interval [start,end) covers some unmapped address
* ranges, just ignore them, but return -ENOMEM at the end.
*/
- vma = find_vma(current->mm, start);
- for (;;) {
- /* Still start < end. */
- error = -ENOMEM;
- if (!vma)
- goto out;
+ error = 0;
+ vma = find_vma(current->mm, start);
+ while (vma) {
/* Here start < vma->vm_end. */
if (start < vma->vm_start) {
unmapped_error = -ENOMEM;
vma = vma->vm_next;
}
+ /* we found a hole in the area queried if we arrive here */
+ error = -ENOMEM;
+
out:
up_read(¤t->mm->mmap_sem);
return error;
+
+einval:
+ return -EINVAL;
+enomem:
+ return -ENOMEM;
}