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/* Copyright (C) 2004, 2005, 2009 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/sysctl.h>
#include <sys/user.h>
#include "libio/libioP.h"
/* Return 1 if the whole area PTR .. PTR+SIZE is not writable.
Return -1 if it is writable. */
int
__readonly_area (const char *ptr, size_t size)
{
const void *ptr_end = ptr + size;
int mib[4];
size_t kve_len = 0;
char *kve_buf, *kve_bufp;
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_VMMAP;
mib[3] = __getpid ();
if (__sysctl (mib, 4, NULL, &kve_len, NULL, 0) != 0)
{
__set_errno (ENOSYS);
return 1;
}
kve_buf = alloca (kve_len);
if (__sysctl (mib, 4, kve_buf, &kve_len, NULL, 0) != 0)
{
__set_errno (ENOSYS);
return 1;
}
kve_bufp = kve_buf;
while (kve_bufp < kve_buf + kve_len)
{
struct kinfo_vmentry *kve = (struct kinfo_vmentry *) (uintptr_t) kve_bufp;
kve_bufp += kve->kve_structsize;
uintptr_t from = kve->kve_start;
uintptr_t to = kve->kve_end;
if (from < (uintptr_t) ptr_end && to > (uintptr_t) ptr)
{
/* Found an entry that at least partially covers the area. */
if (!(kve->kve_protection & KVME_PROT_READ)
|| (kve->kve_protection & KVME_PROT_WRITE))
break;
if (from <= (uintptr_t) ptr && to >= (uintptr_t) ptr_end)
{
size = 0;
break;
}
else if (from <= (uintptr_t) ptr)
size -= to - (uintptr_t) ptr;
else if (to >= (uintptr_t) ptr_end)
size -= (uintptr_t) ptr_end - from;
else
size -= to - from;
if (!size)
break;
}
}
/* If the whole area between ptr and ptr_end is covered by read-only
VMAs, return 1. Otherwise return -1. */
return size == 0 ? 1 : -1;
}
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