1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <stddef.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <stdint.h>
33 #include <elf.h>
34 #include <asm/page.h>
35 #include "pthread_internal.h"
36 #include "atexit.h"
37 #include "libc_init_common.h"
38
39 #include <bionic_tls.h>
40 #include <errno.h>
41
42 extern unsigned __get_sp(void);
43 extern pid_t gettid(void);
44
45 char* __progname;
46 char **environ;
47
48 /* from asm/page.h */
49 unsigned int __page_size = PAGE_SIZE;
50 unsigned int __page_shift = PAGE_SHIFT;
51
52
53 int __system_properties_init(void);
54
55 /* Init TLS for the initial thread. Called by the linker _before_ libc is mapped
56 * in memory. Beware: all writes to libc globals from this function will
57 * apply to linker-private copies and will not be visible from libc later on.
58 *
59 * Note: this function creates a pthread_internal_t for the initial thread and
60 * stores the pointer in TLS, but does not add it to pthread's gThreadList. This
61 * has to be done later from libc itself (see __libc_init_common).
62 *
63 * This function also stores elfdata argument in a specific TLS slot to be later
64 * picked up by the libc constructor.
65 */
__libc_init_tls(unsigned ** elfdata)66 void __libc_init_tls(unsigned** elfdata)
67 {
68 pthread_attr_t thread_attr;
69 static pthread_internal_t thread;
70 static void* tls_area[BIONIC_TLS_SLOTS];
71
72 /* setup pthread runtime and main thread descriptor */
73 unsigned stacktop = (__get_sp() & ~(PAGE_SIZE - 1)) + PAGE_SIZE;
74 unsigned stacksize = 128 * 1024;
75 unsigned stackbottom = stacktop - stacksize;
76
77 pthread_attr_init(&thread_attr);
78 pthread_attr_setstack(&thread_attr, (void*)stackbottom, stacksize);
79 _init_thread(&thread, gettid(), &thread_attr, (void*)stackbottom);
80 __init_tls(tls_area, &thread);
81
82 tls_area[TLS_SLOT_BIONIC_PREINIT] = elfdata;
83 }
84
__libc_init_common(uintptr_t * elfdata)85 void __libc_init_common(uintptr_t *elfdata)
86 {
87 int argc = *elfdata;
88 char** argv = (char**)(elfdata + 1);
89 char** envp = argv + argc + 1;
90
91 /* get the initial thread from TLS and add it to gThreadList */
92 _pthread_internal_add(__get_thread());
93
94 /* clear errno */
95 errno = 0;
96
97 /* set program name */
98 __progname = argv[0] ? argv[0] : "<unknown>";
99
100 /* setup environment pointer */
101 environ = envp;
102
103 /* setup system properties - requires environment */
104 __system_properties_init();
105 }
106
107 /* This function will be called during normal program termination
108 * to run the destructors that are listed in the .fini_array section
109 * of the executable, if any.
110 *
111 * 'fini_array' points to a list of function addresses. The first
112 * entry in the list has value -1, the last one has value 0.
113 */
__libc_fini(void * array)114 void __libc_fini(void* array)
115 {
116 int count;
117 void** fini_array = array;
118 const size_t minus1 = ~(size_t)0; /* ensure proper sign extension */
119
120 /* Sanity check - first entry must be -1 */
121 if (array == NULL || (size_t)fini_array[0] != minus1) {
122 return;
123 }
124
125 /* skip over it */
126 fini_array += 1;
127
128 /* Count the number of destructors. */
129 for (count = 0; fini_array[count] != NULL; count++);
130
131 /* Now call each destructor in reverse order. */
132 while (count > 0) {
133 void (*func)() = (void (*)) fini_array[--count];
134
135 /* Sanity check, any -1 in the list is ignored */
136 if ((size_t)func == minus1)
137 continue;
138
139 func();
140 }
141
142 #ifndef LIBC_STATIC
143 {
144 extern void __libc_postfini(void) __attribute__((weak));
145 if (__libc_postfini)
146 __libc_postfini();
147 }
148 #endif
149 }
150