1/* Test dlopen of modules with initial-exec TLS.
2 Copyright (C) 2016-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19/* This test tries to check that surplus static TLS is not used up for
20 dynamic TLS optimizations and 3*192 + 4*144 = 1152 bytes of static
21 TLS is available for dlopening modules with initial-exec TLS. It
22 depends on rtld.nns=4 and rtld.optional_static_tls=512 tunable setting. */
23
24#include <errno.h>
25#include <pthread.h>
26#include <stdio.h>
27#include <stdlib.h>
28#include <string.h>
29
30static int do_test (void);
31#include <support/xthread.h>
32#include <support/xdlfcn.h>
33#include <support/check.h>
34#include <support/test-driver.c>
35
36/* Have some big TLS in the main exe: should not use surplus TLS. */
37__thread char maintls[1000];
38
39static pthread_barrier_t barrier;
40
41/* Forces multi-threaded behaviour. */
42static void *
43blocked_thread_func (void *closure)
44{
45 xpthread_barrier_wait (barrier: &barrier);
46 /* TLS load and access tests run here in the main thread. */
47 xpthread_barrier_wait (barrier: &barrier);
48 return NULL;
49}
50
51static void *
52load_and_access (const char *mod, const char *func)
53{
54 /* Load module with TLS. */
55 void *p = xdlopen (filename: mod, RTLD_NOW);
56 /* Access the TLS variable to ensure it is allocated. */
57 void (*f) (void) = (void (*) (void))xdlsym (handle: p, symbol: func);
58 f ();
59 return p;
60}
61
62static int
63do_test (void)
64{
65 void *mods[6];
66
67 {
68 int ret = pthread_barrier_init (barrier: &barrier, NULL, count: 2);
69 if (ret != 0)
70 {
71 errno = ret;
72 printf (format: "error: pthread_barrier_init: %m\n");
73 exit (status: 1);
74 }
75 }
76
77 pthread_t blocked_thread = xpthread_create (NULL, thread_func: blocked_thread_func, NULL);
78 xpthread_barrier_wait (barrier: &barrier);
79
80 printf (format: "maintls[%zu]:\t %p .. %p\n",
81 sizeof maintls, maintls, maintls + sizeof maintls);
82 memset (s: maintls, c: 1, n: sizeof maintls);
83
84 /* Load modules with dynamic TLS (may use surplus static TLS
85 opportunistically). */
86 mods[0] = load_and_access (mod: "tst-tls-ie-mod0.so", func: "access0");
87 mods[1] = load_and_access (mod: "tst-tls-ie-mod1.so", func: "access1");
88 mods[2] = load_and_access (mod: "tst-tls-ie-mod2.so", func: "access2");
89 mods[3] = load_and_access (mod: "tst-tls-ie-mod3.so", func: "access3");
90 /* Load modules with initial-exec TLS (can only use surplus static TLS). */
91 mods[4] = load_and_access (mod: "tst-tls-ie-mod4.so", func: "access4");
92 mods[5] = load_and_access (mod: "tst-tls-ie-mod5.so", func: "access5");
93
94 /* Here 1152 bytes of surplus static TLS is in use and at most 512 bytes
95 are available (depending on TLS optimizations). */
96 printf (format: "The next dlopen should fail...\n");
97 void *p = dlopen (file: "tst-tls-ie-mod6.so", RTLD_NOW);
98 if (p != NULL)
99 FAIL_EXIT1 ("error: expected dlopen to fail because there is "
100 "not enough surplus static TLS.\n");
101 printf (format: "...OK failed with: %s.\n", dlerror ());
102
103 xpthread_barrier_wait (barrier: &barrier);
104 xpthread_join (thr: blocked_thread);
105
106 /* Close the modules. */
107 for (int i = 0; i < 6; ++i)
108 xdlclose (handle: mods[i]);
109
110 return 0;
111}
112

source code of glibc/elf/tst-tls-ie.c