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/* Determine the virtual memory area of a given address.
Copyright (C) 2002, 2006, 2008 Bruno Haible <bruno@clisp.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#include "stackvma.h"
#include <unistd.h> /* open, close */
#include <fcntl.h> /* open */
#include <sys/types.h>
#include <sys/mman.h> /* mmap, munmap */
#include <sys/procfs.h> /* PIOC*, prmap_t */
#include "stackvma-simple.c"
#if HAVE_MINCORE
# define sigsegv_get_vma mincore_get_vma
# define STATIC static
# include "stackvma-mincore.c"
# undef sigsegv_get_vma
#else
/* Cache for getpagesize(). */
static unsigned long pagesize;
/* Initialize pagesize. */
static void
init_pagesize (void)
{
pagesize = getpagesize ();
}
#endif
int
sigsegv_get_vma (unsigned long address, struct vma_struct *vma)
{
char fnamebuf[6+10+1];
char *fname;
int fd;
int nmaps;
size_t memneed;
#if HAVE_MMAP_ANON
# define zero_fd -1
# define map_flags MAP_ANON
#elif HAVE_MMAP_ANONYMOUS
# define zero_fd -1
# define map_flags MAP_ANONYMOUS
#else
int zero_fd;
# define map_flags 0
#endif
void *auxmap;
unsigned long auxmap_start;
unsigned long auxmap_end;
prmap_t* maps;
prmap_t* mp;
unsigned long start, end;
#if STACK_DIRECTION < 0
unsigned long prev;
#endif
if (pagesize == 0)
init_pagesize ();
/* Construct fname = sprintf (fnamebuf+i, "/proc/%u", getpid ()). */
fname = fnamebuf + sizeof (fnamebuf) - 1;
*fname = '\0';
{
unsigned int value = getpid ();
do
*--fname = (value % 10) + '0';
while ((value = value / 10) > 0);
}
fname -= 6;
memcpy (fname, "/proc/", 6);
fd = open (fname, O_RDONLY);
if (fd < 0)
goto failed;
if (ioctl (fd, PIOCNMAP, &nmaps) < 0)
goto fail2;
memneed = (nmaps + 10) * sizeof (prmap_t);
/* Allocate memneed bytes of memory.
We cannot use alloca here, because we are low on stack space.
We also cannot use malloc here, because a malloc() call may have been
interrupted.
So use mmap(), and ignore the resulting VMA. */
memneed = ((memneed - 1) / pagesize + 1) * pagesize;
#if !(HAVE_MMAP_ANON || HAVE_MMAP_ANONYMOUS)
zero_fd = open ("/dev/zero", O_RDONLY, 0644);
if (zero_fd < 0)
goto fail2;
#endif
auxmap = (void *) mmap ((void *) 0, memneed, PROT_READ | PROT_WRITE, map_flags | MAP_PRIVATE, zero_fd, 0);
#if !(HAVE_MMAP_ANON || HAVE_MMAP_ANONYMOUS)
close (zero_fd);
#endif
if (auxmap == (void *) -1)
goto fail2;
auxmap_start = (unsigned long) auxmap;
auxmap_end = auxmap_start + memneed;
maps = (prmap_t *) auxmap;
if (ioctl (fd, PIOCMAP, maps) < 0)
goto fail1;
#if STACK_DIRECTION < 0
prev = 0;
#endif
for (mp = maps;;)
{
start = (unsigned long) mp->pr_vaddr;
end = start + mp->pr_size;
if (start == 0 && end == 0)
break;
mp++;
if (start <= auxmap_start && auxmap_end - 1 <= end - 1)
{
/* Consider [start,end-1] \ [auxmap_start,auxmap_end-1]
= [start,auxmap_start-1] u [auxmap_end,end-1]. */
if (start != auxmap_start)
{
if (address >= start && address <= auxmap_start - 1)
{
end = auxmap_start;
goto found;
}
#if STACK_DIRECTION < 0
prev = auxmap_start;
#endif
}
if (end != auxmap_end)
{
if (address >= auxmap_end && address <= end - 1)
{
start = auxmap_end;
goto found;
}
#if STACK_DIRECTION < 0
prev = end;
#endif
}
}
else
{
if (address >= start && address <= end - 1)
goto found;
#if STACK_DIRECTION < 0
prev = end;
#endif
}
}
fail1:
munmap (auxmap, memneed);
fail2:
close (fd);
failed:
#if HAVE_MINCORE
return mincore_get_vma (address, vma);
#else
return -1;
#endif
found:
vma->start = start;
vma->end = end;
#if STACK_DIRECTION < 0
vma->prev_end = prev;
#else
vma->next_start = (unsigned long) mp->pr_vaddr;
#endif
munmap (auxmap, memneed);
close (fd);
vma->is_near_this = simple_is_near_this;
return 0;
}
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