1/* Run initializers for newly loaded objects.
2 Copyright (C) 1995-2021 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/* Type of the initializer. */
26typedef void (*init_t) (int, char **, char **);
27
28
29static void
30call_init (struct link_map *l, int argc, char **argv, char **env)
31{
32 /* If the object has not been relocated, this is a bug. The
33 function pointers are invalid in this case. (Executables do not
34 need relocation, and neither do proxy objects.) */
35 assert (l->l_real->l_relocated || l->l_real->l_type == lt_executable);
36
37 if (l->l_init_called)
38 /* This object is all done. */
39 return;
40
41 /* Avoid handling this constructor again in case we have a circular
42 dependency. */
43 l->l_init_called = 1;
44
45 /* Check for object which constructors we do not run here. */
46 if (__builtin_expect (l->l_name[0], 'a') == '\0'
47 && l->l_type == lt_executable)
48 return;
49
50 /* Print a debug message if wanted. */
51 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
52 _dl_debug_printf ("\ncalling init: %s\n\n",
53 DSO_FILENAME (l->l_name));
54
55 /* Now run the local constructors. There are two forms of them:
56 - the one named by DT_INIT
57 - the others in the DT_INIT_ARRAY.
58 */
59 if (ELF_INITFINI && l->l_info[DT_INIT] != NULL)
60 DL_CALL_DT_INIT(l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr, argc, argv, env);
61
62 /* Next see whether there is an array with initialization functions. */
63 ElfW(Dyn) *init_array = l->l_info[DT_INIT_ARRAY];
64 if (init_array != NULL)
65 {
66 unsigned int j;
67 unsigned int jm;
68 ElfW(Addr) *addrs;
69
70 jm = l->l_info[DT_INIT_ARRAYSZ]->d_un.d_val / sizeof (ElfW(Addr));
71
72 addrs = (ElfW(Addr) *) (init_array->d_un.d_ptr + l->l_addr);
73 for (j = 0; j < jm; ++j)
74 ((init_t) addrs[j]) (argc, argv, env);
75 }
76}
77
78
79void
80_dl_init (struct link_map *main_map, int argc, char **argv, char **env)
81{
82 ElfW(Dyn) *preinit_array = main_map->l_info[DT_PREINIT_ARRAY];
83 ElfW(Dyn) *preinit_array_size = main_map->l_info[DT_PREINIT_ARRAYSZ];
84 unsigned int i;
85
86 if (__glibc_unlikely (GL(dl_initfirst) != NULL))
87 {
88 call_init (GL(dl_initfirst), argc, argv, env);
89 GL(dl_initfirst) = NULL;
90 }
91
92 /* Don't do anything if there is no preinit array. */
93 if (__builtin_expect (preinit_array != NULL, 0)
94 && preinit_array_size != NULL
95 && (i = preinit_array_size->d_un.d_val / sizeof (ElfW(Addr))) > 0)
96 {
97 ElfW(Addr) *addrs;
98 unsigned int cnt;
99
100 if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
101 _dl_debug_printf ("\ncalling preinit: %s\n\n",
102 DSO_FILENAME (main_map->l_name));
103
104 addrs = (ElfW(Addr) *) (preinit_array->d_un.d_ptr + main_map->l_addr);
105 for (cnt = 0; cnt < i; ++cnt)
106 ((init_t) addrs[cnt]) (argc, argv, env);
107 }
108
109 /* Stupid users forced the ELF specification to be changed. It now
110 says that the dynamic loader is responsible for determining the
111 order in which the constructors have to run. The constructors
112 for all dependencies of an object must run before the constructor
113 for the object itself. Circular dependencies are left unspecified.
114
115 This is highly questionable since it puts the burden on the dynamic
116 loader which has to find the dependencies at runtime instead of
117 letting the user do it right. Stupidity rules! */
118
119 i = main_map->l_searchlist.r_nlist;
120 while (i-- > 0)
121 call_init (main_map->l_initfini[i], argc, argv, env);
122
123#ifndef HAVE_INLINED_SYSCALLS
124 /* Finished starting up. */
125 _dl_starting_up = 0;
126#endif
127}
128