1 /* Load a shared object at runtime, relocate it, and run its initializer.
2 Copyright (C) 1996 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If
17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
18 Cambridge, MA 02139, USA. */
26 extern void _dl_start (void); weak_extern (_dl_start
)
28 extern int __libc_multiple_libcs
; /* Defined in init-first.c. */
30 extern int __libc_argc
;
31 extern char **__libc_argv
;
33 extern char **__environ
;
35 size_t _dl_global_scope_alloc
;
38 _dl_open (const char *file
, int mode
)
40 struct link_map
*new, *l
;
43 /* To decide whether we are the static libc or not. We must use
44 this variable since gcc would otherwise optimize the test away. */
45 void (*dl_start_ptr
) (void) = &_dl_start
;
47 /* Load the named object. */
48 new = _dl_map_object (NULL
, file
, lt_loaded
);
49 if (new->l_searchlist
)
50 /* It was already open. */
53 /* Load that object's dependencies. */
54 _dl_map_object_deps (new, NULL
, 0);
57 /* Relocate the objects loaded. We do this in reverse order so that copy
58 relocs of earlier objects overwrite the data written by later objects. */
67 /* We use an indirect call call for _dl_relocate_object because
68 we must avoid using the PLT in the call. If our PLT entry for
69 _dl_relocate_object hasn't been used yet, then the dynamic
70 linker fixup routine will clobber _dl_global_scope during its
71 work. We must be sure that nothing will require a PLT fixup
72 between when _dl_object_relocation_scope returns and when we
73 enter the dynamic linker's code (_dl_relocate_object). */
74 __typeof (_dl_relocate_object
) *reloc
= &_dl_relocate_object
;
75 (*reloc
) (l
, _dl_object_relocation_scope (l
),
76 (mode
& RTLD_BINDING_MASK
) == RTLD_LAZY
);
77 *_dl_global_scope_end
= NULL
;
85 new->l_global
= (mode
& RTLD_GLOBAL
);
88 /* The symbols of the new object and its dependencies are to be
89 introduced into the global scope that will be used to resolve
90 references from other dynamically-loaded objects. */
92 if (_dl_global_scope_alloc
== 0)
94 /* This is the first dynamic object given global scope. */
95 _dl_global_scope_alloc
= 8;
96 _dl_global_scope
= malloc (8 * sizeof (struct link_map
*));
97 if (! _dl_global_scope
)
99 _dl_global_scope
= _dl_default_scope
;
102 _dl_signal_error (ENOMEM
, file
, "cannot extend global scope");
104 _dl_global_scope
[2] = _dl_default_scope
[2];
105 _dl_global_scope
[3] = new;
106 _dl_global_scope
[4] = NULL
;
107 _dl_global_scope
[5] = NULL
;
111 if (_dl_global_scope_alloc
<
112 (size_t) (_dl_global_scope_end
- _dl_global_scope
+ 2))
114 /* Must extend the list. */
115 struct link_map
**new = realloc (_dl_global_scope
,
116 _dl_global_scope_alloc
* 2);
119 _dl_global_scope_end
= new + (_dl_global_scope_end
-
121 _dl_global_scope
= new;
122 _dl_global_scope_alloc
*= 2;
125 /* Append the new object and re-terminate the list. */
126 *_dl_global_scope_end
++ = new;
127 /* We keep the list double-terminated so the last element
128 can be filled in for symbol lookups. */
129 _dl_global_scope_end
[0] = NULL
;
130 _dl_global_scope_end
[1] = NULL
;
135 /* Notify the debugger we have added some objects. We need to call
136 _dl_debug_initialize in a static program in case dynamic linking has
137 not been used before. */
138 r
= _dl_debug_initialize (0);
142 /* Run the initializer functions of new objects. */
143 while (init
= _dl_init_next (new))
144 (*(void (*) (int, char **, char **)) init
) (__libc_argc
, __libc_argv
,
147 if (dl_start_ptr
== NULL
)
148 /* We must be the static _dl_open in libc.a because ld.so.1 is not
149 in scope. A static program that has loaded a dynamic object
150 now has competition. */
151 __libc_multiple_libcs
= 1;