1/* Run initializers for newly loaded objects.
2 Copyright (C) 1995-2019 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 <http://www.gnu.org/licenses/>. */
18
19#include <stddef.h>
20#include <ldsodefs.h>
21
22
23/* Type of the initializer. */
24typedef void (*init_t) (int, char **, char **);
25
26
27static void
28call_init (struct link_map *l, int argc, char **argv, char **env)
29{
30 if (l->l_init_called)
31 /* This object is all done. */
32 return;
33
34 /* Avoid handling this constructor again in case we have a circular
35 dependency. */
36 l->l_init_called = 1;
37
38 /* Check for object which constructors we do not run here. */
39 if (__builtin_expect (l->l_name[0], 'a') == '\0'
40 && l->l_type == lt_executable)
41 return;
42
43 /* Are there any constructors? */
44 if (l->l_info[DT_INIT] == NULL
45 && __builtin_expect (l->l_info[DT_INIT_ARRAY] == NULL, 1))
46 return;
47
48 /* Print a debug message if wanted. */
49 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
50 _dl_debug_printf ("\ncalling init: %s\n\n",
51 DSO_FILENAME (l->l_name));
52
53 /* Now run the local constructors. There are two forms of them:
54 - the one named by DT_INIT
55 - the others in the DT_INIT_ARRAY.
56 */
57 if (l->l_info[DT_INIT] != NULL)
58 DL_CALL_DT_INIT(l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr, argc, argv, env);
59
60 /* Next see whether there is an array with initialization functions. */
61 ElfW(Dyn) *init_array = l->l_info[DT_INIT_ARRAY];
62 if (init_array != NULL)
63 {
64 unsigned int j;
65 unsigned int jm;
66 ElfW(Addr) *addrs;
67
68 jm = l->l_info[DT_INIT_ARRAYSZ]->d_un.d_val / sizeof (ElfW(Addr));
69
70 addrs = (ElfW(Addr) *) (init_array->d_un.d_ptr + l->l_addr);
71 for (j = 0; j < jm; ++j)
72 ((init_t) addrs[j]) (argc, argv, env);
73 }
74}
75
76
77void
78_dl_init (struct link_map *main_map, int argc, char **argv, char **env)
79{
80 ElfW(Dyn) *preinit_array = main_map->l_info[DT_PREINIT_ARRAY];
81 ElfW(Dyn) *preinit_array_size = main_map->l_info[DT_PREINIT_ARRAYSZ];
82 unsigned int i;
83
84 if (__glibc_unlikely (GL(dl_initfirst) != NULL))
85 {
86 call_init (GL(dl_initfirst), argc, argv, env);
87 GL(dl_initfirst) = NULL;
88 }
89
90 /* Don't do anything if there is no preinit array. */
91 if (__builtin_expect (preinit_array != NULL, 0)
92 && preinit_array_size != NULL
93 && (i = preinit_array_size->d_un.d_val / sizeof (ElfW(Addr))) > 0)
94 {
95 ElfW(Addr) *addrs;
96 unsigned int cnt;
97
98 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
99 _dl_debug_printf ("\ncalling preinit: %s\n\n",
100 DSO_FILENAME (main_map->l_name));
101
102 addrs = (ElfW(Addr) *) (preinit_array->d_un.d_ptr + main_map->l_addr);
103 for (cnt = 0; cnt < i; ++cnt)
104 ((init_t) addrs[cnt]) (argc, argv, env);
105 }
106
107 /* Stupid users forced the ELF specification to be changed. It now
108 says that the dynamic loader is responsible for determining the
109 order in which the constructors have to run. The constructors
110 for all dependencies of an object must run before the constructor
111 for the object itself. Circular dependencies are left unspecified.
112
113 This is highly questionable since it puts the burden on the dynamic
114 loader which has to find the dependencies at runtime instead of
115 letting the user do it right. Stupidity rules! */
116
117 i = main_map->l_searchlist.r_nlist;
118 while (i-- > 0)
119 call_init (main_map->l_initfini[i], argc, argv, env);
120
121#ifndef HAVE_INLINED_SYSCALLS
122 /* Finished starting up. */
123 _dl_starting_up = 0;
124#endif
125}
126