1 /* Run initializers for newly loaded objects.
2 Copyright (C) 1995-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
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 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <assert.h>
20 #include <stddef.h>
21 #include <ldsodefs.h>
22 #include <elf-initfini.h>
23
24
25 static void
26 call_init (struct link_map *l, int argc, char **argv, char **env)
27 {
28 /* If the object has not been relocated, this is a bug. The
29 function pointers are invalid in this case. (Executables do not
30 need relocation, and neither do proxy objects.) */
31 assert (l->l_real->l_relocated || l->l_real->l_type == lt_executable);
32
33 if (l->l_init_called)
34 /* This object is all done. */
35 return;
36
37 /* Avoid handling this constructor again in case we have a circular
38 dependency. */
39 l->l_init_called = 1;
40
41 /* Check for object which constructors we do not run here. */
42 if (__builtin_expect (l->l_name[0], 'a') == '\0'
43 && l->l_type == lt_executable)
44 return;
45
46 /* Print a debug message if wanted. */
47 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
48 _dl_debug_printf ("\ncalling init: %s\n\n",
49 DSO_FILENAME (l->l_name));
50
51 /* Now run the local constructors. There are two forms of them:
52 - the one named by DT_INIT
53 - the others in the DT_INIT_ARRAY.
54 */
55 if (ELF_INITFINI && l->l_info[DT_INIT] != NULL)
56 DL_CALL_DT_INIT(l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr, argc, argv, env);
57
58 /* Next see whether there is an array with initialization functions. */
59 ElfW(Dyn) *init_array = l->l_info[DT_INIT_ARRAY];
60 if (init_array != NULL)
61 {
62 unsigned int j;
63 unsigned int jm;
64 ElfW(Addr) *addrs;
65
66 jm = l->l_info[DT_INIT_ARRAYSZ]->d_un.d_val / sizeof (ElfW(Addr));
67
68 addrs = (ElfW(Addr) *) (init_array->d_un.d_ptr + l->l_addr);
69 for (j = 0; j < jm; ++j)
70 ((dl_init_t) addrs[j]) (argc, argv, env);
71 }
72 }
73
74
75 void
76 _dl_init (struct link_map *main_map, int argc, char **argv, char **env)
77 {
78 ElfW(Dyn) *preinit_array = main_map->l_info[DT_PREINIT_ARRAY];
79 ElfW(Dyn) *preinit_array_size = main_map->l_info[DT_PREINIT_ARRAYSZ];
80 unsigned int i;
81
82 if (__glibc_unlikely (GL(dl_initfirst) != NULL))
83 {
84 call_init (GL(dl_initfirst), argc, argv, env);
85 GL(dl_initfirst) = NULL;
86 }
87
88 /* Don't do anything if there is no preinit array. */
89 if (__builtin_expect (preinit_array != NULL, 0)
90 && preinit_array_size != NULL
91 && (i = preinit_array_size->d_un.d_val / sizeof (ElfW(Addr))) > 0)
92 {
93 ElfW(Addr) *addrs;
94 unsigned int cnt;
95
96 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
97 _dl_debug_printf ("\ncalling preinit: %s\n\n",
98 DSO_FILENAME (main_map->l_name));
99
100 addrs = (ElfW(Addr) *) (preinit_array->d_un.d_ptr + main_map->l_addr);
101 for (cnt = 0; cnt < i; ++cnt)
102 ((dl_init_t) addrs[cnt]) (argc, argv, env);
103 }
104
105 /* Stupid users forced the ELF specification to be changed. It now
106 says that the dynamic loader is responsible for determining the
107 order in which the constructors have to run. The constructors
108 for all dependencies of an object must run before the constructor
109 for the object itself. Circular dependencies are left unspecified.
110
111 This is highly questionable since it puts the burden on the dynamic
112 loader which has to find the dependencies at runtime instead of
113 letting the user do it right. Stupidity rules! */
114
115 i = main_map->l_searchlist.r_nlist;
116 while (i-- > 0)
117 call_init (main_map->l_initfini[i], argc, argv, env);
118
119 #ifndef HAVE_INLINED_SYSCALLS
120 /* Finished starting up. */
121 _dl_starting_up = 0;
122 #endif
123 }