1 /* libunwind - a platform-independent unwind library
2    Copyright (C) 2011 Google, Inc
3 	Contributed by Paul Pluzhnikov <ppluzhnikov@google.com>
4 
5 Permission is hereby granted, free of charge, to any person obtaining
6 a copy of this software and associated documentation files (the
7 "Software"), to deal in the Software without restriction, including
8 without limitation the rights to use, copy, modify, merge, publish,
9 distribute, sublicense, and/or sell copies of the Software, and to
10 permit persons to whom the Software is furnished to do so, subject to
11 the following conditions:
12 
13 The above copyright notice and this permission notice shall be
14 included in all copies or substantial portions of the Software.
15 
16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
22 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
23 
24 #define UNW_LOCAL_ONLY
25 #include <libunwind.h>
26 
27 #include <unistd.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <dlfcn.h>
31 #include <pthread.h>
32 
33 #define panic(args...)				\
34 	{ fprintf (stderr, args); exit (-1); }
35 
36 int num_mallocs;
37 int num_callocs;
38 int in_unwind;
39 
40 void *
41 calloc(size_t n, size_t s)
42 {
43   static void * (*func)(size_t, size_t);
44 
45 #ifdef __GLIBC__
46   /* In glibc, dlsym() calls calloc. Calling dlsym(RTLD_NEXT, "calloc") here
47      causes infinite recursion.  Instead, we simply use it by its other
48      name.  */
49   extern void *__libc_calloc(size_t, size_t);
50   if (!func)
51     func = &__libc_calloc;
52 #else
53   if(!func)
54     func = dlsym(RTLD_NEXT, "calloc");
55 #endif
56 
57   if (in_unwind) {
58     num_callocs++;
59     return NULL;
60   } else {
61     return func(n, s);
62   }
63 }
64 
65 void *
66 malloc(size_t s)
67 {
68   static void * (*func)(size_t);
69 
70   if(!func)
71     func = dlsym(RTLD_NEXT, "malloc");
72 
73   if (in_unwind) {
74     num_mallocs++;
75     return NULL;
76   } else {
77     return func(s);
78   }
79 }
80 
81 static void
82 do_backtrace (void)
83 {
84   const int num_levels = 100;
85   void *pc[num_levels];
86 
87   in_unwind = 1;
88   unw_backtrace(pc, num_levels);
89   in_unwind = 0;
90 }
91 
92 void
93 foo3 (void)
94 {
95   do_backtrace ();
96 }
97 
98 void
99 foo2 (void)
100 {
101   foo3 ();
102 }
103 
104 void
105 foo1 (void)
106 {
107   foo2 ();
108 }
109 
110 int
111 main (void)
112 {
113   int i, num_errors;
114 
115   /* Create (and leak) 100 TSDs, then call backtrace()
116      and check that it doesn't call malloc()/calloc().  */
117   for (i = 0; i < 100; ++i) {
118     pthread_key_t key;
119     if (pthread_key_create (&key, NULL))
120       panic ("FAILURE: unable to create key %d\n", i);
121   }
122   /* Call backtrace right after thread creation,
123    * where we are sure that we're not inside malloc */
124   do_backtrace();
125   num_mallocs = num_callocs = 0;
126   foo1 ();
127   num_errors = num_mallocs + num_callocs;
128   if (num_errors > 0)
129     {
130       fprintf (stderr,
131 	       "FAILURE: detected %d error%s (malloc: %d, calloc: %d)\n",
132 	       num_errors, num_errors > 1 ? "s" : "",
133 	       num_mallocs, num_callocs);
134       exit (-1);
135     }
136   return 0;
137 }
138