dlfcn/dlinfo.c

   1 /* dlinfo -- Get information from the dynamic linker.
   2    Copyright (C) 2003-2022 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 <dlfcn.h>
  20 #include <link.h>
  21 #include <ldsodefs.h>
  22 #include <libintl.h>
  23 #include <dl-tls.h>
  24 #include <shlib-compat.h>
  25
  26 struct dlinfo_args
  27 {
  28   void *handle;
  29   int request;
  30   void *arg;
  31
  32   /* This is the value that is returned from dlinfo if no error is
  33      signaled.  */
  34   int result;
  35 };
  36
  37 static void
  38 dlinfo_doit (void *argsblock)
  39 {
  40   struct dlinfo_args *const args = argsblock;
  41   struct link_map *l = args->handle;
  42
  43   switch (args->request)
  44     {
  45     case RTLD_DI_CONFIGADDR:
  46     default:
  47       args->result = -1;
  48       _dl_signal_error (0, NULL, NULL, N_("unsupported dlinfo request"));
  49       break;
  50
  51     case RTLD_DI_LMID:
  52       *(Lmid_t *) args->arg = l->l_ns;
  53       break;
  54
  55     case RTLD_DI_LINKMAP:
  56       *(struct link_map **) args->arg = l;
  57       break;
  58
  59     case RTLD_DI_SERINFO:
  60       _dl_rtld_di_serinfo (l, args->arg, false);
  61       break;
  62     case RTLD_DI_SERINFOSIZE:
  63       _dl_rtld_di_serinfo (l, args->arg, true);
  64       break;
  65
  66     case RTLD_DI_ORIGIN:
  67       strcpy (args->arg, l->l_origin);
  68       break;
  69
  70     case RTLD_DI_TLS_MODID:
  71       *(size_t *) args->arg = 0;
  72       *(size_t *) args->arg = l->l_tls_modid;
  73       break;
  74
  75     case RTLD_DI_TLS_DATA:
  76       {
  77         void *data = NULL;
  78         if (l->l_tls_modid != 0)
  79           data = GLRO(dl_tls_get_addr_soft) (l);
  80         *(void **) args->arg = data;
  81         break;
  82       }
  83
  84     case RTLD_DI_PHDR:
  85       *(const ElfW(Phdr) **) args->arg = l->l_phdr;
  86       args->result = l->l_phnum;
  87       break;
  88     }
  89 }
  90
  91 static int
  92 dlinfo_implementation (void *handle, int request, void *arg)
  93 {
  94   struct dlinfo_args args = { handle, request, arg };
  95   _dlerror_run (&dlinfo_doit, &args);
  96   return args.result;
  97 }
  98
  99 #ifdef SHARED
 100 int
 101 ___dlinfo (void *handle, int request, void *arg)
 102 {
 103   if (GLRO (dl_dlfcn_hook) != NULL)
 104     return GLRO (dl_dlfcn_hook)->dlinfo (handle, request, arg);
 105   else
 106     return dlinfo_implementation (handle, request, arg);
 107 }
 108 versioned_symbol (libc, ___dlinfo, dlinfo, GLIBC_2_34);
 109
 110 # if OTHER_SHLIB_COMPAT (libdl, GLIBC_2_3_3, GLIBC_2_34)
 111 compat_symbol (libc, ___dlinfo, dlinfo, GLIBC_2_3_3);
 112 # endif
 113 #else /* !SHARED */
 114 /* Also used with _dlfcn_hook.  */
 115 int
 116 __dlinfo (void *handle, int request, void *arg)
 117 {
 118   return dlinfo_implementation (handle, request, arg);
 119 }
 120 weak_alias (__dlinfo, dlinfo)
 121 #endif