usr/src/lib/libdll/common/dllnext.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1997-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                                                                      *
  19 ***********************************************************************/
  20 #pragma prototyped
  21 /*
  22  * Glenn Fowler
  23  * AT&T Research
  24  */
  25
  26 #ifndef _GNU_SOURCE
  27 #define _GNU_SOURCE     1
  28 #endif
  29 #ifndef __EXTENSIONS__
  30 #define __EXTENSIONS__  1
  31 #endif
  32
  33 #include <ast.h>
  34 #include <dlldefs.h>
  35
  36 #if _hdr_rld_interface
  37 #include <rld_interface.h>
  38 #endif
  39
  40 /*
  41  * return a handle for the next layer down,
  42  * i.e., the next layer that has symbols covered
  43  * by the main prog and dll's loaded so far
  44  *
  45  * intentionally light on external lib calls
  46  * so this routine can be used early in process
  47  * startup
  48  */
  49
  50 #ifdef  _DLL_RLD_SYM
  51
  52 #define DEBUG           1
  53
  54 #if DEBUG
  55
  56 typedef ssize_t (*Write_f)(int, const void*, size_t);
  57
  58 #endif
  59
  60 #undef  dllnext
  61
  62 void*
  63 _dll_next(int flags, _DLL_RLD_SYM_TYPE* here)
  64 {
  65         register char*  vp;
  66         register void*  lp;
  67         register int    found = 0;
  68         char*           s;
  69         char*           b;
  70         char*           e;
  71         char            dummy[256];
  72 #if DEBUG
  73         Write_f         wr = 0;
  74         Write_f         xr;
  75         char            buf[1024];
  76 #endif
  77
  78 #if DEBUG
  79         if (getenv("DLL_DEBUG") && (vp = (char*)_rld_new_interface(_RLD_FIRST_PATHNAME)))
  80         {
  81                 do
  82                 {
  83                         if (strcmp(vp, "MAIN") && (lp = dllopen(vp, flags)))
  84                         {
  85                                 if (xr = (Write_f)dlsym(lp, "write"))
  86                                         wr = xr;
  87                         }
  88                 } while (vp = (char*)_rld_new_interface(_RLD_NEXT_PATHNAME));
  89         }
  90 #endif
  91         if (vp = (char*)_rld_new_interface(_RLD_FIRST_PATHNAME))
  92         {
  93                 do
  94                 {
  95                         if (lp = dllopen(strcmp(vp, "MAIN") ? vp : (char*)0, flags))
  96                         {
  97                                 if (found)
  98                                 {
  99                                         b = e = 0;
 100                                         s = vp;
 101                                         for (;;)
 102                                         {
 103                                                 switch (*s++)
 104                                                 {
 105                                                 case 0:
 106                                                         break;
 107                                                 case '/':
 108                                                         b = s;
 109                                                         e = 0;
 110                                                         continue;
 111                                                 case '.':
 112                                                         if (!e)
 113                                                                 e = s - 1;
 114                                                         continue;
 115                                                 default:
 116                                                         continue;
 117                                                 }
 118                                                 break;
 119                                         }
 120                                         if (b && e)
 121                                         {
 122                                                 s = dummy;
 123                                                 *s++ = '_';
 124                                                 *s++ = '_';
 125                                                 while (b < e)
 126                                                         *s++ = *b++;
 127                                                 b = "_dummy";
 128                                                 while (*s++ = *b++);
 129                                                 if (dlsym(lp, dummy))
 130                                                 {
 131                                                         dlclose(lp);
 132                                                         lp = 0;
 133                                                 }
 134                                         }
 135                                         if (lp)
 136                                         {
 137 #if DEBUG
 138                                                 if (wr)
 139                                                         (*wr)(2, buf, sfsprintf(buf, sizeof(buf), "dll: next %s\n", vp));
 140 #endif
 141                                                 return lp;
 142                                         }
 143 #if DEBUG
 144                                         else if (wr)
 145                                                 (*wr)(2, buf, sfsprintf(buf, sizeof(buf), "dll: skip %s\n", vp));
 146 #endif
 147                                 }
 148                                 else if ((_DLL_RLD_SYM_TYPE*)dlsym(lp, _DLL_RLD_SYM_STR) == here)
 149                                 {
 150 #if DEBUG
 151                                         if (wr)
 152                                                 (*wr)(2, buf, sfsprintf(buf, sizeof(buf), "dll: this %s\n", vp));
 153 #endif
 154                                         found = 1;
 155                                 }
 156                         }
 157                 } while (vp = (char*)_rld_new_interface(_RLD_NEXT_PATHNAME));
 158         }
 159         return dllnext(flags);
 160 }
 161
 162 #endif
 163
 164 #ifndef RTLD_NEXT
 165 #if _dll_DYNAMIC
 166
 167 #include <link.h>
 168
 169 extern struct link_dynamic      _DYNAMIC;
 170
 171 #endif
 172 #endif
 173
 174 void*
 175 dllnext(int flags)
 176 {
 177         register void*                  dll;
 178 #ifndef RTLD_NEXT
 179 #if _dll_DYNAMIC
 180         register struct link_map*       map;
 181         register char*                  s;
 182         register char*                  b;
 183 #endif
 184         register char*                  ver;
 185         char*                           path;
 186
 187         static char                     next[] = { _DLL_NEXT_PATH };
 188 #endif
 189
 190 #ifdef RTLD_NEXT
 191         dll = RTLD_NEXT;
 192 #else
 193         path = next;
 194 #if _dll_DYNAMIC
 195         for (map = _DYNAMIC.ld_un.ld_1->ld_loaded; map; map = map->lm_next)
 196         {
 197                 b = 0;
 198                 s = map->lm_name;
 199                 while (*s)
 200                         if (*s++ == '/')
 201                                 b = s;
 202                 if (b && b[0] == 'l' && b[1] == 'i' && b[2] == 'b' && b[3] == 'c' && b[4] == '.')
 203                 {
 204                         path = map->lm_name;
 205                         break;
 206                 }
 207         }
 208 #endif
 209         ver = path + strlen(path);
 210         while (!(dll = dllopen(path, flags)))
 211         {
 212                 do
 213                 {
 214                         if (ver <= path)
 215                                 return 0;
 216                 } while (*--ver != '.');
 217                 if (*(ver + 1) <= '0' || *(ver + 1) >= '9')
 218                         return 0;
 219                 *ver = 0;
 220         }
 221 #endif
 222         return dll;
 223 }