winsup/cygwin/dlfcn.cc

   1 /* dlfcn.cc
   2
   3    Copyright 1998, 2000, 2001, 2002, 2003, 2004, 2008 Red Hat, Inc.
   4
   5 This file is part of Cygwin.
   6
   7 This software is a copyrighted work licensed under the terms of the
   8 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
   9 details. */
  10
  11 #include "winsup.h"
  12 #include <psapi.h>
  13 #include <stdlib.h>
  14 #include <ctype.h>
  15 #include "path.h"
  16 #include "perprocess.h"
  17 #include "dlfcn.h"
  18 #include "cygtls.h"
  19 #include "tls_pbuf.h"
  20
  21 static void __stdcall
  22 set_dl_error (const char *str)
  23 {
  24   strcpy (_my_tls.locals.dl_buffer, strerror (get_errno ()));
  25   _my_tls.locals.dl_error = 1;
  26 }
  27
  28 /* Look for an executable file given the name and the environment
  29    variable to use for searching (eg., PATH); returns the full
  30    pathname (static buffer) if found or NULL if not. */
  31 inline const char * __stdcall
  32 check_path_access (const char *mywinenv, const char *name, path_conv& buf)
  33 {
  34   return find_exec (name, buf, mywinenv, FE_NNF | FE_NATIVE | FE_CWD | FE_DLL);
  35 }
  36
  37 /* Search LD_LIBRARY_PATH for dll, if it exists.
  38    Return Windows version of given path. */
  39 static const char * __stdcall
  40 get_full_path_of_dll (const char* str, char *name)
  41 {
  42   int len = strlen (str);
  43
  44   /* empty string or too long to be legal win32 pathname? */
  45   if (len == 0 || len >= PATH_MAX)
  46     return str;         /* Yes.  Let caller deal with it. */
  47
  48   const char *ret;
  49
  50   strcpy (name, str);   /* Put it somewhere where we can manipulate it. */
  51
  52   /* Add extension if necessary */
  53   if (str[len - 1] != '.')
  54     {
  55       /* Add .dll only if no extension provided. */
  56       const char *p = strrchr (str, '.');
  57       if (!p || strpbrk (p, "\\/"))
  58         strcat (name, ".dll");
  59     }
  60
  61   path_conv real_filename;
  62
  63   if (isabspath (name) ||
  64       (ret = check_path_access ("LD_LIBRARY_PATH=", name, real_filename)
  65              ?: check_path_access ("/usr/lib", name, real_filename)) == NULL)
  66     real_filename.check (name, PC_SYM_FOLLOW | PC_NOFULL | PC_NULLEMPTY);       /* Convert */
  67
  68   if (!real_filename.error)
  69     ret = strcpy (name, real_filename.get_win32 ());
  70   else
  71     {
  72       set_errno (real_filename.error);
  73       ret = NULL;
  74     }
  75
  76   return ret;
  77 }
  78
  79 void *
  80 dlopen (const char *name, int)
  81 {
  82   void *ret;
  83
  84   if (name == NULL)
  85     ret = (void *) GetModuleHandle (NULL); /* handle for the current module */
  86   else
  87     {
  88       tmp_pathbuf tp;
  89       char *buf = tp.c_get ();
  90       /* handle for the named library */
  91       const char *fullpath = get_full_path_of_dll (name, buf);
  92       if (!fullpath)
  93         ret = NULL;
  94       else
  95         {
  96           ret = (void *) LoadLibrary (fullpath);
  97           if (ret == NULL)
  98             __seterrno ();
  99         }
 100     }
 101
 102   if (!ret)
 103     set_dl_error ("dlopen");
 104   debug_printf ("ret %p", ret);
 105
 106   return ret;
 107 }
 108
 109 void *
 110 dlsym (void *handle, const char *name)
 111 {
 112   void *ret = NULL;
 113   if (handle == RTLD_DEFAULT)
 114     { /* search all modules */
 115       HANDLE cur_proc = GetCurrentProcess ();
 116       HMODULE *modules;
 117       DWORD needed, i;
 118       if (!EnumProcessModules (cur_proc, NULL, 0, &needed))
 119         {
 120         dlsym_fail:
 121           set_dl_error ("dlsym");
 122           return NULL;
 123         }
 124       modules = (HMODULE*) alloca (needed);
 125       if (!EnumProcessModules (cur_proc, modules, needed, &needed))
 126         goto dlsym_fail;
 127       for (i = 0; i < needed / sizeof (HMODULE); i++)
 128         if ((ret = (void *) GetProcAddress (modules[i], name)))
 129           break;
 130     }
 131   else
 132     ret = (void *) GetProcAddress ((HMODULE)handle, name);
 133   if (!ret)
 134     set_dl_error ("dlsym");
 135   debug_printf ("ret %p", ret);
 136   return ret;
 137 }
 138
 139 int
 140 dlclose (void *handle)
 141 {
 142   int ret = -1;
 143   if (handle == GetModuleHandle (NULL) || FreeLibrary ((HMODULE) handle))
 144     ret = 0;
 145   if (ret)
 146     set_dl_error ("dlclose");
 147   return ret;
 148 }
 149
 150 char *
 151 dlerror ()
 152 {
 153   char *res;
 154   if (!_my_tls.locals.dl_error)
 155     res = NULL;
 156   else
 157     {
 158       _my_tls.locals.dl_error = 0;
 159       res = _my_tls.locals.dl_buffer;
 160     }
 161   return res;
 162 }