1 /* Test disabling of rseq registration via tunable.
2    Copyright (C) 2021 Free Software Foundation, Inc.
3 
4    The GNU C Library is free software; you can redistribute it and/or
5    modify it under the terms of the GNU Lesser General Public
6    License as published by the Free Software Foundation; either
7    version 2.1 of the License, or (at your option) any later version.
8 
9    The GNU C Library is distributed in the hope that it will be useful,
10    but WITHOUT ANY WARRANTY; without even the implied warranty of
11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12    Lesser General Public License for more details.
13 
14    You should have received a copy of the GNU Lesser General Public
15    License along with the GNU C Library; if not, see
16    <https://www.gnu.org/licenses/>.  */
17 
18 #include <errno.h>
19 #include <stdio.h>
20 #include <support/check.h>
21 #include <support/namespace.h>
22 #include <support/xthread.h>
23 #include <sysdep.h>
24 #include <thread_pointer.h>
25 #include <unistd.h>
26 
27 #ifdef RSEQ_SIG
28 
29 /* Check that rseq can be registered and has not been taken by glibc.  */
30 static void
check_rseq_disabled(void)31 check_rseq_disabled (void)
32 {
33   struct pthread *pd = THREAD_SELF;
34 
35   TEST_COMPARE (__rseq_flags, 0);
36   TEST_VERIFY ((char *) __thread_pointer () + __rseq_offset
37                == (char *) &pd->rseq_area);
38   TEST_COMPARE (__rseq_size, 0);
39   TEST_COMPARE ((int) pd->rseq_area.cpu_id, RSEQ_CPU_ID_REGISTRATION_FAILED);
40 
41   int ret = syscall (__NR_rseq, &pd->rseq_area, sizeof (pd->rseq_area),
42                      0, RSEQ_SIG);
43   if (ret == 0)
44     {
45       ret = syscall (__NR_rseq, &pd->rseq_area, sizeof (pd->rseq_area),
46                      RSEQ_FLAG_UNREGISTER, RSEQ_SIG);
47       TEST_COMPARE (ret, 0);
48       pd->rseq_area.cpu_id = RSEQ_CPU_ID_REGISTRATION_FAILED;
49     }
50   else
51     {
52       TEST_VERIFY (errno != -EINVAL);
53       TEST_VERIFY (errno != -EBUSY);
54     }
55 }
56 
57 static void *
thread_func(void * ignored)58 thread_func (void *ignored)
59 {
60   check_rseq_disabled ();
61   return NULL;
62 }
63 
64 static void
proc_func(void * ignored)65 proc_func (void *ignored)
66 {
67   check_rseq_disabled ();
68 }
69 
70 static int
do_test(void)71 do_test (void)
72 {
73   puts ("info: checking main thread");
74   check_rseq_disabled ();
75 
76   puts ("info: checking main thread (2)");
77   check_rseq_disabled ();
78 
79   puts ("info: checking new thread");
80   xpthread_join (xpthread_create (NULL, thread_func, NULL));
81 
82   puts ("info: checking subprocess");
83   support_isolate_in_subprocess (proc_func, NULL);
84 
85   return 0;
86 }
87 #else /* !RSEQ_SIG */
88 static int
do_test(void)89 do_test (void)
90 {
91   FAIL_UNSUPPORTED ("glibc does not define RSEQ_SIG, skipping test");
92 }
93 #endif
94 
95 #include <support/test-driver.c>
96