glibc/support/xptrace.h
Stefan Liebler 2f9046fb05 Add UNSUPPORTED check in elf/tst-pldd.
The testcase forks a child process and runs pldd with PID of
this child.  On systems where /proc/sys/kernel/yama/ptrace_scope
differs from zero, pldd will fail with
/usr/bin/pldd: cannot attach to process 3: Operation not permitted

This patch checks if ptrace_scope exists, is zero "classic ptrace permissions"
or one "restricted ptrace".  If ptrace_scope exists and has a higher
restriction, then the test is marked as UNSUPPORTED.

The case "restricted ptrace" is handled by rearranging the processes involved
during the test.  Now we have the following process tree:
-parent: do_test (performs output checks)
--subprocess 1: pldd_process (becomes pldd via execve)
---subprocess 2: target_process (ptraced via pldd)

ChangeLog:

	* elf/tst-pldd.c (do_test): Add UNSUPPORTED check.
	Rearrange subprocesses.
	(pldd_process): New function.
	* support/Makefile (libsupport-routines): Add support_ptrace.
	* support/xptrace.h: New file.
	* support/support_ptrace.c: Likewise.
2019-09-18 12:42:39 +02:00

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C

/* Support functions handling ptrace_scope.
Copyright (C) 2019 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, see
<https://www.gnu.org/licenses/>. */
#ifndef SUPPORT_PTRACE_H
#define SUPPORT_PTRACE_H
#include <sys/cdefs.h>
__BEGIN_DECLS
/* Return the current YAMA mode set on the machine (0 to 3) or -1
if YAMA is not supported. */
int support_ptrace_scope (void);
__END_DECLS
#endif