Annotation of sql/pgsql/libltdl/loaders/shl_load.c, revision 1.1
1.1 ! moko 1: /* loader-shl_load.c -- dynamic linking with shl_load (HP-UX)
! 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 shl_load_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_shl_load";
! 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_DL_H)
! 94: # include <dl.h>
! 95: #endif
! 96:
! 97: /* some flags are missing on some systems, so we provide
! 98: * harmless defaults.
! 99: *
! 100: * Mandatory:
! 101: * BIND_IMMEDIATE - Resolve symbol references when the library is loaded.
! 102: * BIND_DEFERRED - Delay code symbol resolution until actual reference.
! 103: *
! 104: * Optionally:
! 105: * BIND_FIRST - Place the library at the head of the symbol search
! 106: * order.
! 107: * BIND_NONFATAL - The default BIND_IMMEDIATE behavior is to treat all
! 108: * unsatisfied symbols as fatal. This flag allows
! 109: * binding of unsatisfied code symbols to be deferred
! 110: * until use.
! 111: * [Perl: For certain libraries, like DCE, deferred
! 112: * binding often causes run time problems. Adding
! 113: * BIND_NONFATAL to BIND_IMMEDIATE still allows
! 114: * unresolved references in situations like this.]
! 115: * BIND_NOSTART - Do not call the initializer for the shared library
! 116: * when the library is loaded, nor on a future call to
! 117: * shl_unload().
! 118: * BIND_VERBOSE - Print verbose messages concerning possible
! 119: * unsatisfied symbols.
! 120: *
! 121: * hp9000s700/hp9000s800:
! 122: * BIND_RESTRICTED - Restrict symbols visible by the library to those
! 123: * present at library load time.
! 124: * DYNAMIC_PATH - Allow the loader to dynamically search for the
! 125: * library specified by the path argument.
! 126: */
! 127:
! 128: #if !defined(DYNAMIC_PATH)
! 129: # define DYNAMIC_PATH 0
! 130: #endif
! 131: #if !defined(BIND_RESTRICTED)
! 132: # define BIND_RESTRICTED 0
! 133: #endif
! 134:
! 135: #define LT_BIND_FLAGS (BIND_IMMEDIATE | BIND_NONFATAL | DYNAMIC_PATH)
! 136:
! 137:
! 138: /* A function called through the vtable when this loader is no
! 139: longer needed by the application. */
! 140: static int
! 141: vl_exit (lt_user_data LT__UNUSED loader_data)
! 142: {
! 143: vtable = NULL;
! 144: return 0;
! 145: }
! 146:
! 147: /* A function called through the vtable to open a module with this
! 148: loader. Returns an opaque representation of the newly opened
! 149: module for processing with this loader's other vtable functions. */
! 150: static lt_module
! 151: vm_open (lt_user_data LT__UNUSED loader_data, const char *filename,
! 152: lt_dladvise LT__UNUSED advise)
! 153: {
! 154: static shl_t self = (shl_t) 0;
! 155: lt_module module = shl_load (filename, LT_BIND_FLAGS, 0L);
! 156:
! 157: /* Since searching for a symbol against a NULL module handle will also
! 158: look in everything else that was already loaded and exported with
! 159: the -E compiler flag, we always cache a handle saved before any
! 160: modules are loaded. */
! 161: if (!self)
! 162: {
! 163: void *address;
! 164: shl_findsym (&self, "main", TYPE_UNDEFINED, &address);
! 165: }
! 166:
! 167: if (!filename)
! 168: {
! 169: module = self;
! 170: }
! 171: else
! 172: {
! 173: module = shl_load (filename, LT_BIND_FLAGS, 0L);
! 174:
! 175: if (!module)
! 176: {
! 177: LT__SETERROR (CANNOT_OPEN);
! 178: }
! 179: }
! 180:
! 181: return module;
! 182: }
! 183:
! 184: /* A function called through the vtable when a particular module
! 185: should be unloaded. */
! 186: static int
! 187: vm_close (lt_user_data LT__UNUSED loader_data, lt_module module)
! 188: {
! 189: int errors = 0;
! 190:
! 191: if (module && (shl_unload ((shl_t) (module)) != 0))
! 192: {
! 193: LT__SETERROR (CANNOT_CLOSE);
! 194: ++errors;
! 195: }
! 196:
! 197: return errors;
! 198: }
! 199:
! 200:
! 201: /* A function called through the vtable to get the address of
! 202: a symbol loaded from a particular module. */
! 203: static void *
! 204: vm_sym (lt_user_data LT__UNUSED loader_data, lt_module module, const char *name)
! 205: {
! 206: void *address = 0;
! 207:
! 208: /* sys_shl_open should never return a NULL module handle */
! 209: if (module == (lt_module) 0)
! 210: {
! 211: LT__SETERROR (INVALID_HANDLE);
! 212: }
! 213: else if (!shl_findsym((shl_t*) &module, name, TYPE_UNDEFINED, &address))
! 214: {
! 215: if (!address)
! 216: {
! 217: LT__SETERROR (SYMBOL_NOT_FOUND);
! 218: }
! 219: }
! 220:
! 221: return address;
! 222: }
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