src/backend/port/dynloader/ultrix4.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * ultrix4.c
   4  *        This dynamic loader uses Andrew Yu's libdl-1.0 package for Ultrix 4.x.
   5  *
   6  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL$
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "dl.h"
  18 #include "utils/dynamic_loader.h"
  19
  20 extern char my_exec_path[];
  21
  22 void *
  23 pg_dlopen(char *filename)
  24 {
  25         static int      dl_initialized = 0;
  26         void       *handle;
  27
  28         /*
  29          * initializes the dynamic loader with the executable's pathname. (only
  30          * needs to do this the first time pg_dlopen is called.)
  31          */
  32         if (!dl_initialized)
  33         {
  34                 if (!dl_init(my_exec_path))
  35                         return NULL;
  36
  37                 /*
  38                  * if there are undefined symbols, we want dl to search from the
  39                  * following libraries also.
  40                  */
  41                 dl_setLibraries("/usr/lib/libm_G0.a:/usr/lib/libc_G0.a");
  42                 dl_initialized = 1;
  43         }
  44
  45         /*
  46          * open the file. We do the symbol resolution right away so that we will
  47          * know if there are undefined symbols. (This is in fact the same
  48          * semantics as "ld -A". ie. you cannot have undefined symbols.
  49          */
  50         if ((handle = dl_open(filename, DL_NOW)) == NULL)
  51         {
  52                 int                     count;
  53                 char      **list = dl_undefinedSymbols(&count);
  54
  55                 /* list the undefined symbols, if any */
  56                 if (count)
  57                 {
  58                         while (*list)
  59                         {
  60                                 elog(WARNING, "\"%s\" is undefined", *list);
  61                                 list++;
  62                         }
  63                 }
  64         }
  65
  66         return (void *) handle;
  67 }