src/backend/port/dynloader/bsdi.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * dynloader.c
   4  *        Dynamic Loader for Postgres for Linux, generated from those for
   5  *        Ultrix.
   6  *
   7  *        You need to install the dld library on your Linux system!
   8  *
   9  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  10  * Portions Copyright (c) 1994, Regents of the University of California
  11  *
  12  *
  13  * IDENTIFICATION
  14  *        $PostgreSQL$
  15  *
  16  *-------------------------------------------------------------------------
  17  */
  18 #include "postgres.h"
  19 #ifndef HAVE_DLOPEN
  20
  21 extern char my_exec_path[];
  22
  23 void *
  24 pg_dlopen(char *filename)
  25 {
  26         static int      dl_initialized = 0;
  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 (dld_init(dld_find_executable(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_initialized = 1;
  42         }
  43
  44         /*
  45          * link the file, then check for undefined symbols!
  46          */
  47         if (dld_link(filename))
  48                 return NULL;
  49
  50         /*
  51          * If undefined symbols: try to link with the C and math libraries! This
  52          * could be smarter, if the dynamic linker was able to handle shared libs!
  53          */
  54         if (dld_undefined_sym_count > 0)
  55         {
  56                 if (dld_link("/usr/lib/libc.a"))
  57                 {
  58                         elog(WARNING, "could not link C library");
  59                         return NULL;
  60                 }
  61                 if (dld_undefined_sym_count > 0)
  62                 {
  63                         if (dld_link("/usr/lib/libm.a"))
  64                         {
  65                                 elog(WARNING, "could not link math library");
  66                                 return NULL;
  67                         }
  68                         if (dld_undefined_sym_count > 0)
  69                         {
  70                                 int                     count = dld_undefined_sym_count;
  71                                 char      **list = dld_list_undefined_sym();
  72
  73                                 /* list the undefined symbols, if any */
  74                                 do
  75                                 {
  76                                         elog(WARNING, "\"%s\" is undefined", *list);
  77                                         list++;
  78                                         count--;
  79                                 } while (count > 0);
  80
  81                                 dld_unlink_by_file(filename, 1);
  82                                 return NULL;
  83                         }
  84                 }
  85         }
  86
  87         return (void *) strdup(filename);
  88 }
  89
  90 char *
  91 pg_dlerror()
  92 {
  93         return dld_strerror(dld_errno);
  94 }
  95
  96 #endif   /* not HAVE_DLOPEN */