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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 // Contains wrapper to missing dladdr in API < 8
     30 
     31 #if !__LP64__
     32 
     33 #include <dlfcn.h>
     34 #include <android/api-level.h>
     35 
     36 #if __ANDROID_API__ < 8
     37 typedef int Dl_info;
     38 #endif // __ANDROID_API__ >= 8
     39 
     40 typedef int (*dladdr_func_t)(const void *addr, Dl_info *info);
     41 
     42 #if defined(__cplusplus)
     43 extern "C"
     44 #endif
     45 int my_dladdr(const void *addr, Dl_info *info)
     46 {
     47     static int initialized = 0;
     48     static dladdr_func_t p_dladdr = 0;
     49     if (!p_dladdr && !initialized) {
     50         void *libdl = dlopen("libdl.so", RTLD_NOW);
     51       // Other thread may enter here simultaneously but p_dladdr should be
     52       // set to the same addres for "dladdr"
     53         if (libdl) {
     54 #if __ANDROID_API__ < 8
     55 	   p_dladdr = 0;
     56 #else
     57 	   p_dladdr = (dladdr_func_t)dlsym(libdl, "dladdr");
     58 #endif
     59         }
     60         initialized = 1;
     61     }
     62     return p_dladdr? p_dladdr(addr, info) : 0;
     63 }
     64 
     65 
     66 #ifdef TEST
     67 #include <stdio.h>
     68 int main()
     69 {
     70     void *libdl = dlopen("libc.so", RTLD_NOW);
     71     void *h = dlsym(libdl, "printf");
     72     Dl_info info;
     73     int r = my_dladdr((char*)h+1, &info);
     74     if (r)
     75         printf("%p: %s, %x, %s, %p\n", h, info.dli_fname, info.dli_fbase, info.dli_sname, info.dli_saddr);
     76 }
     77 
     78 #endif // TEST
     79 #endif // __LP64__
     80