1/* Bug 18125: Verify setcontext calls exit() and not _exit().
2 Copyright (C) 2015-2022 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#include <errno.h>
20#include <signal.h>
21#include <stdio.h>
22#include <stdlib.h>
23#include <string.h>
24#include <ucontext.h>
25#include <unistd.h>
26#include <limits.h>
27#include <sys/types.h>
28#include <sys/stat.h>
29#include <fcntl.h>
30
31/* Please note that depending on the outcome of Bug 18135 this test
32 may become invalid, and instead of testing for calling exit it
33 should be reworked to test for the last context calling
34 pthread_exit(). */
35
36static ucontext_t ctx;
37static char *filename;
38
39/* It is intended that this function does nothing. */
40static void
41cf (void)
42{
43 printf (format: "called context function\n");
44}
45
46static void
47exit_called (void)
48{
49 int fd;
50 ssize_t res;
51 const char buf[] = "Called exit function\n";
52
53 fd = open (file: filename, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
54 if (fd == -1)
55 {
56 printf (format: "FAIL: Unable to create test file %s\n", filename);
57 exit (1);
58 }
59 res = write (fd, buf, sizeof (buf));
60 if (res != sizeof (buf))
61 {
62 printf (format: "FAIL: Expected to write test file in one write call.\n");
63 exit (1);
64 }
65 res = close (fd: fd);
66 if (res == -1)
67 {
68 printf (format: "FAIL: Failed to close test file.\n");
69 exit (1);
70 }
71 printf (format: "PASS: %s", buf);
72}
73
74/* The test expects a filename given by the wrapper calling script.
75 The test then registers an atexit handler that will create the
76 file to indicate that the atexit handler ran. Then the test
77 creates a context, modifies it with makecontext, and sets it.
78 The context has only a single context which then must exit.
79 If it incorrectly exits via _exit then the atexit handler is
80 not run, the file is not created, and the wrapper detects this
81 and fails the test. This test cannot be done using an _exit
82 interposer since setcontext avoids the PLT and calls _exit
83 directly. */
84static int
85do_test (int argc, char **argv)
86{
87 int ret;
88 char st1[32768];
89 ucontext_t tempctx = ctx;
90
91 if (argc < 2)
92 {
93 printf (format: "FAIL: Test missing filename argument.\n");
94 exit (1);
95 }
96
97 filename = argv[1];
98
99 atexit (func: exit_called);
100
101 puts (s: "making contexts");
102 if (getcontext (ucp: &ctx) != 0)
103 {
104 if (errno == ENOSYS)
105 {
106 /* Exit with 77 to mark the test as UNSUPPORTED. */
107 printf (format: "UNSUPPORTED: getcontext not implemented.\n");
108 exit (77);
109 }
110
111 printf (format: "FAIL: getcontext failed.\n");
112 exit (1);
113 }
114
115 ctx.uc_stack.ss_sp = st1;
116 ctx.uc_stack.ss_size = sizeof (st1);
117 ctx.uc_link = 0;
118 makecontext (ucp: &ctx, func: cf, argc: 0);
119
120 /* Without this check, a stub makecontext can make us spin forever. */
121 if (memcmp (&tempctx, &ctx, sizeof ctx) == 0)
122 {
123 puts (s: "UNSUPPORTED: makecontext was a no-op, presuming not implemented");
124 exit (77);
125 }
126
127 ret = setcontext (&ctx);
128 if (ret != 0)
129 {
130 printf (format: "FAIL: setcontext returned with %d and errno of %d.\n", ret, errno);
131 exit (1);
132 }
133
134 printf (format: "FAIL: Impossibly returned to main.\n");
135 exit (1);
136}
137
138#include "../test-skeleton.c"
139

source code of glibc/stdlib/tst-setcontext3.c