Annotation of sql/pgsql/libltdl/loaders/dld_link.c, revision 1.1
1.1 ! moko 1: /* loader-dld_link.c -- dynamic linking with dld
! 2:
! 3: Copyright (C) 1998, 1999, 2000, 2004, 2006,
! 4: 2007, 2008 Free Software Foundation, Inc.
! 5: Written by Thomas Tanner, 1998
! 6:
! 7: NOTE: The canonical source of this file is maintained with the
! 8: GNU Libtool package. Report bugs to bug-libtool@gnu.org.
! 9:
! 10: GNU Libltdl is free software; you can redistribute it and/or
! 11: modify it under the terms of the GNU Lesser General Public
! 12: License as published by the Free Software Foundation; either
! 13: version 2 of the License, or (at your option) any later version.
! 14:
! 15: As a special exception to the GNU Lesser General Public License,
! 16: if you distribute this file as part of a program or library that
! 17: is built using GNU Libtool, you may include this file under the
! 18: same distribution terms that you use for the rest of that program.
! 19:
! 20: GNU Libltdl is distributed in the hope that it will be useful,
! 21: but WITHOUT ANY WARRANTY; without even the implied warranty of
! 22: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
! 23: GNU Lesser General Public License for more details.
! 24:
! 25: You should have received a copy of the GNU Lesser General Public
! 26: License along with GNU Libltdl; see the file COPYING.LIB. If not, a
! 27: copy can be downloaded from http://www.gnu.org/licenses/lgpl.html,
! 28: or obtained by writing to the Free Software Foundation, Inc.,
! 29: 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
! 30: */
! 31:
! 32: #include "lt__private.h"
! 33: #include "lt_dlloader.h"
! 34:
! 35: /* Use the preprocessor to rename non-static symbols to avoid namespace
! 36: collisions when the loader code is statically linked into libltdl.
! 37: Use the "<module_name>_LTX_" prefix so that the symbol addresses can
! 38: be fetched from the preloaded symbol list by lt_dlsym(): */
! 39: #define get_vtable dld_link_LTX_get_vtable
! 40:
! 41: LT_BEGIN_C_DECLS
! 42: LT_SCOPE lt_dlvtable *get_vtable (lt_user_data loader_data);
! 43: LT_END_C_DECLS
! 44:
! 45:
! 46: /* Boilerplate code to set up the vtable for hooking this loader into
! 47: libltdl's loader list: */
! 48: static int vl_exit (lt_user_data loader_data);
! 49: static lt_module vm_open (lt_user_data loader_data, const char *filename,
! 50: lt_dladvise advise);
! 51: static int vm_close (lt_user_data loader_data, lt_module module);
! 52: static void * vm_sym (lt_user_data loader_data, lt_module module,
! 53: const char *symbolname);
! 54:
! 55: static lt_dlvtable *vtable = 0;
! 56:
! 57: /* Return the vtable for this loader, only the name and sym_prefix
! 58: attributes (plus the virtual function implementations, obviously)
! 59: change between loaders. */
! 60: lt_dlvtable *
! 61: get_vtable (lt_user_data loader_data)
! 62: {
! 63: if (!vtable)
! 64: {
! 65: vtable = lt__zalloc (sizeof *vtable);
! 66: }
! 67:
! 68: if (vtable && !vtable->name)
! 69: {
! 70: vtable->name = "lt_dld_link";
! 71: vtable->module_open = vm_open;
! 72: vtable->module_close = vm_close;
! 73: vtable->find_sym = vm_sym;
! 74: vtable->dlloader_exit = vl_exit;
! 75: vtable->dlloader_data = loader_data;
! 76: vtable->priority = LT_DLLOADER_APPEND;
! 77: }
! 78:
! 79: if (vtable && (vtable->dlloader_data != loader_data))
! 80: {
! 81: LT__SETERROR (INIT_LOADER);
! 82: return 0;
! 83: }
! 84:
! 85: return vtable;
! 86: }
! 87:
! 88:
! 89:
! 90: /* --- IMPLEMENTATION --- */
! 91:
! 92:
! 93: #if defined(HAVE_DLD_H)
! 94: # include <dld.h>
! 95: #endif
! 96:
! 97: /* A function called through the vtable when this loader is no
! 98: longer needed by the application. */
! 99: static int
! 100: vl_exit (lt_user_data LT__UNUSED loader_data)
! 101: {
! 102: vtable = NULL;
! 103: return 0;
! 104: }
! 105:
! 106: /* A function called through the vtable to open a module with this
! 107: loader. Returns an opaque representation of the newly opened
! 108: module for processing with this loader's other vtable functions. */
! 109: static lt_module
! 110: vm_open (lt_user_data LT__UNUSED loader_data, const char *filename,
! 111: lt_dladvise LT__UNUSED advise)
! 112: {
! 113: lt_module module = lt__strdup (filename);
! 114:
! 115: if (dld_link (filename) != 0)
! 116: {
! 117: LT__SETERROR (CANNOT_OPEN);
! 118: FREE (module);
! 119: }
! 120:
! 121: return module;
! 122: }
! 123:
! 124: /* A function called through the vtable when a particular module
! 125: should be unloaded. */
! 126: static int
! 127: vm_close (lt_user_data LT__UNUSED loader_data, lt_module module)
! 128: {
! 129: int errors = 0;
! 130:
! 131: if (dld_unlink_by_file ((char*)(module), 1) != 0)
! 132: {
! 133: LT__SETERROR (CANNOT_CLOSE);
! 134: ++errors;
! 135: }
! 136: else
! 137: {
! 138: FREE (module);
! 139: }
! 140:
! 141: return errors;
! 142: }
! 143:
! 144: /* A function called through the vtable to get the address of
! 145: a symbol loaded from a particular module. */
! 146: static void *
! 147: vm_sym (lt_user_data LT__UNUSED loader_data, lt_module LT__UNUSED module,
! 148: const char *name)
! 149: {
! 150: void *address = dld_get_func (name);
! 151:
! 152: if (!address)
! 153: {
! 154: LT__SETERROR (SYMBOL_NOT_FOUND);
! 155: }
! 156:
! 157: return address;
! 158: }
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