1 /* Test recursive dlopen using malloc hooks.
2 Copyright (C) 2015-2023 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 <stdio.h>
20 #include <stdlib.h>
21 #include <dlfcn.h>
22 #include <stdbool.h>
23 #include <stdalign.h>
24 #include <sys/mman.h>
25 #include <unistd.h>
26 #include <string.h>
27
28 #define DSO "moddummy1.so"
29 #define FUNC "dummy1"
30
31 #define DSO1 "moddummy2.so"
32 #define FUNC1 "dummy2"
33
34 /* Result of the called function. */
35 int func_result;
36
37 /* Call function func_name in DSO dso_name via dlopen. */
38 void
39 call_func (const char *dso_name, const char *func_name)
40 {
41 int ret;
42 void *dso;
43 int (*func) (void);
44 char *err;
45
46 /* Open the DSO. */
47 dso = dlopen (dso_name, RTLD_NOW|RTLD_GLOBAL);
48 if (dso == NULL)
49 {
50 err = dlerror ();
51 fprintf (stderr, "%s\n", err);
52 exit (1);
53 }
54 /* Clear any errors. */
55 dlerror ();
56
57 /* Lookup func. */
58 func = (int (*) (void)) dlsym (dso, func_name);
59 if (func == NULL)
60 {
61 err = dlerror ();
62 if (err != NULL)
63 {
64 fprintf (stderr, "%s\n", err);
65 exit (1);
66 }
67 }
68 /* Call func. */
69 func_result = (*func) ();
70
71 /* Close the library and look for errors too. */
72 ret = dlclose (dso);
73 if (ret != 0)
74 {
75 err = dlerror ();
76 fprintf (stderr, "%s\n", err);
77 exit (1);
78 }
79
80 }
81
82 /* If true, call another function from malloc. */
83 static bool call_function;
84
85 /* Set to true to indicate that the interposed malloc was called. */
86 static bool interposed_malloc_called;
87
88 /* Interposed malloc which optionally calls another function. */
89 void *
90 malloc (size_t size)
91 {
92 interposed_malloc_called = true;
93 static void *(*original_malloc) (size_t);
94
95 if (original_malloc == NULL)
96 {
97 static bool in_initialization;
98 if (in_initialization)
99 {
100 const char *message
101 = "error: malloc called recursively during initialization\n";
102 (void) write (STDOUT_FILENO, message, strlen (message));
103 _exit (2);
104 }
105 in_initialization = true;
106
107 original_malloc
108 = (__typeof (original_malloc)) dlsym (RTLD_NEXT, "malloc");
109 if (original_malloc == NULL)
110 {
111 const char *message
112 = "error: dlsym for malloc failed\n";
113 (void) write (STDOUT_FILENO, message, strlen (message));
114 _exit (2);
115 }
116 }
117
118 if (call_function)
119 {
120 call_function = false;
121 call_func (DSO1, FUNC1);
122 call_function = true;
123 }
124 return original_malloc (size);
125 }
126
127 static int
128 do_test (void)
129 {
130 /* Ensure initialization. */
131 {
132 void *volatile ptr = malloc (1);
133 free (ptr);
134 }
135
136 if (!interposed_malloc_called)
137 {
138 printf ("error: interposed malloc not called during initialization\n");
139 return 1;
140 }
141
142 call_function = true;
143
144 /* Bug 17702 fixes two things:
145 * A recursive dlopen unmapping the ld.so.cache.
146 * An assertion that _r_debug is RT_CONSISTENT at entry to dlopen.
147 We can only test the latter. Testing the former requires modifying
148 ld.so.conf to cache the dummy libraries, then running ldconfig,
149 then run the test. If you do all of that (and glibc's test
150 infrastructure doesn't support that yet) then the test will
151 SEGFAULT without the fix. If you don't do that, then the test
152 will abort because of the assert described in detail below. */
153 call_func (DSO, FUNC);
154
155 call_function = false;
156
157 /* The function dummy2() is called by the malloc hook. Check to
158 see that it was called. This ensures the second recursive
159 dlopen happened and we called the function in that library.
160 Before the fix you either get a SIGSEGV when accessing mmap'd
161 ld.so.cache data or an assertion failure about _r_debug not
162 beint RT_CONSISTENT. We don't test for the SIGSEGV since it
163 would require finding moddummy1 or moddummy2 in the cache and
164 we don't have any infrastructure to test that, but the _r_debug
165 assertion triggers. */
166 printf ("Returned result is %d\n", func_result);
167 if (func_result <= 0)
168 {
169 printf ("FAIL: Function call_func() not called.\n");
170 exit (1);
171 }
172
173 printf ("PASS: Function call_func() called more than once.\n");
174 return 0;
175 }
176
177 #define TEST_FUNCTION do_test ()
178 #include "../test-skeleton.c"