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2003-11-26  Ulrich Drepper  <drepper@redhat.com>

	* sysdeps/unix/sysv/linux/kernel-features.h
	(__ASSUME_PROT_GROWSUPDOWN): Define for 2.6.1 and up.
	* sysdeps/unix/sysv/linux/dl-execstack.c: Omit compatibility code
	if __ASSUME_PROT_GROWSUPDOWN is defined.

2003-11-26  Andreas Jaeger  <aj@suse.de>

	* sysdeps/unix/sysv/linux/dl-execstack.c
	(_dl_make_stack_executable): Set dl_stack_flags always for
	success.
This commit is contained in:
Ulrich Drepper
2003-11-27 05:24:58 +00:00
parent ab18a27d54
commit 5cb48b8492
6 changed files with 57 additions and 8 deletions
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30
sysdeps/unix/sysv/linux/dl-execstack.c
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@ -23,6 +23,9 @@
#include <stdbool.h>
#include <stackinfo.h>
#include "kernel-features.h"
extern void *__libc_stack_end;
int
@ -35,15 +38,20 @@ _dl_make_stack_executable (void)
/* Newer Linux kernels support a flag to make our job easy. */
# ifdef PROT_GROWSDOWN
# if __ASSUME_PROT_GROWSUPDOWN == 0
static bool no_growsdown;
if (! no_growsdown)
# endif
{
if (__mprotect ((void *) page, GL(dl_pagesize),
PROT_READ|PROT_WRITE|PROT_EXEC|PROT_GROWSDOWN) == 0)
return 0;
if (errno != EINVAL)
goto return_success;
# if __ASSUME_PROT_GROWSUPDOWN == 0
if (errno == EINVAL)
no_growsdown = true;
else
# endif
return errno;
no_growsdown = true;
}
# endif
@ -54,6 +62,7 @@ _dl_make_stack_executable (void)
We start with a random guess at how deep the stack might have gotten
so as to have extended the GROWSDOWN mapping to lower pages. */
# if __ASSUME_PROT_GROWSUPDOWN == 0
size_t size = GL(dl_pagesize) * 8;
page = page + GL(dl_pagesize) - size;
while (1)
@ -78,6 +87,7 @@ _dl_make_stack_executable (void)
page += size;
}
}
# endif
#elif _STACK_GROWS_UP
@ -86,15 +96,20 @@ _dl_make_stack_executable (void)
/* Newer Linux kernels support a flag to make our job easy. */
# ifdef PROT_GROWSUP
# if __ASSUME_PROT_GROWSUPDOWN == 0
static bool no_growsup;
if (! no_growsup)
# endif
{
if (__mprotect ((void *) page, GL(dl_pagesize),
PROT_READ|PROT_WRITE|PROT_EXEC|PROT_GROWSUP) == 0)
return 0;
if (errno != EINVAL)
goto return_success;
# if __ASSUME_PROT_GROWSUPDOWN == 0
if (errno == EINVAL)
no_growsup = true;
else
# endif
return errno;
no_growsup = true;
}
# endif
@ -105,6 +120,7 @@ _dl_make_stack_executable (void)
We start with a random guess at how deep the stack might have gotten
so as to have extended the GROWSUP mapping to higher pages. */
# if __ASSUME_PROT_GROWSUPDOWN == 0
size_t size = GL(dl_pagesize) * 8;
while (1)
{
@ -127,11 +143,13 @@ _dl_make_stack_executable (void)
size /= 2;
}
}
# endif
#else
# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
#endif
return_success:
/* Remember that we changed the permission. */
GL(dl_stack_flags) |= PF_X;