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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "libc_init_common.h"
#include <elf.h>
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/auxv.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <unistd.h>
#include "atexit.h"
#include "private/bionic_auxv.h"
#include "private/bionic_ssp.h"
#include "private/bionic_tls.h"
#include "private/KernelArgumentBlock.h"
#include "pthread_internal.h"
extern "C" abort_msg_t** __abort_message_ptr;
extern "C" uintptr_t __get_sp(void);
extern "C" int __system_properties_init(void);
extern "C" int __set_tls(void* ptr);
extern "C" int __set_tid_address(int* tid_address);
// Not public, but well-known in the BSDs.
const char* __progname;
// Declared in <unistd.h>.
char** environ;
// Declared in "private/bionic_ssp.h".
uintptr_t __stack_chk_guard = 0;
static size_t get_main_thread_stack_size() {
rlimit stack_limit;
int rlimit_result = getrlimit(RLIMIT_STACK, &stack_limit);
if ((rlimit_result == 0) &&
(stack_limit.rlim_cur != RLIM_INFINITY) &&
(stack_limit.rlim_cur > PTHREAD_STACK_MIN)) {
return (stack_limit.rlim_cur & ~(PAGE_SIZE - 1));
}
return PTHREAD_STACK_SIZE_DEFAULT;
}
/* Init TLS for the initial thread. Called by the linker _before_ libc is mapped
* in memory. Beware: all writes to libc globals from this function will
* apply to linker-private copies and will not be visible from libc later on.
*
* Note: this function creates a pthread_internal_t for the initial thread and
* stores the pointer in TLS, but does not add it to pthread's thread list. This
* has to be done later from libc itself (see __libc_init_common).
*
* This function also stores a pointer to the kernel argument block in a TLS slot to be
* picked up by the libc constructor.
*/
void __libc_init_tls(KernelArgumentBlock& args) {
__libc_auxv = args.auxv;
uintptr_t stack_top = (__get_sp() & ~(PAGE_SIZE - 1)) + PAGE_SIZE;
size_t stack_size = get_main_thread_stack_size();
uintptr_t stack_bottom = stack_top - stack_size;
static void* tls[BIONIC_TLS_SLOTS];
static pthread_internal_t main_thread;
main_thread.tls = tls;
// Tell the kernel to clear our tid field when we exit, so we're like any other pthread.
main_thread.tid = __set_tid_address(&main_thread.tid);
// We already have a stack, and we don't want to free it up on exit (because things like
// environment variables with global scope live on it).
pthread_attr_init(&main_thread.attr);
pthread_attr_setstack(&main_thread.attr, (void*) stack_bottom, stack_size);
main_thread.attr.flags = PTHREAD_ATTR_FLAG_USER_ALLOCATED_STACK | PTHREAD_ATTR_FLAG_MAIN_THREAD;
__init_thread(&main_thread, false);
__init_tls(&main_thread);
__set_tls(main_thread.tls);
tls[TLS_SLOT_BIONIC_PREINIT] = &args;
__init_alternate_signal_stack(&main_thread);
}
void __libc_init_common(KernelArgumentBlock& args) {
// Initialize various globals.
environ = args.envp;
errno = 0;
__libc_auxv = args.auxv;
__progname = args.argv[0] ? args.argv[0] : "<unknown>";
__abort_message_ptr = args.abort_message_ptr;
// AT_RANDOM is a pointer to 16 bytes of randomness on the stack.
__stack_chk_guard = *reinterpret_cast<uintptr_t*>(getauxval(AT_RANDOM));
// Get the main thread from TLS and add it to the thread list.
pthread_internal_t* main_thread = __get_thread();
_pthread_internal_add(main_thread);
__system_properties_init(); // Requires 'environ'.
}
/* This function will be called during normal program termination
* to run the destructors that are listed in the .fini_array section
* of the executable, if any.
*
* 'fini_array' points to a list of function addresses. The first
* entry in the list has value -1, the last one has value 0.
*/
void __libc_fini(void* array) {
void** fini_array = reinterpret_cast<void**>(array);
const size_t minus1 = ~(size_t)0; /* ensure proper sign extension */
/* Sanity check - first entry must be -1 */
if (array == NULL || (size_t)fini_array[0] != minus1) {
return;
}
/* skip over it */
fini_array += 1;
/* Count the number of destructors. */
int count = 0;
while (fini_array[count] != NULL) {
++count;
}
/* Now call each destructor in reverse order. */
while (count > 0) {
void (*func)() = (void (*)()) fini_array[--count];
/* Sanity check, any -1 in the list is ignored */
if ((size_t)func == minus1) {
continue;
}
func();
}
#ifndef LIBC_STATIC
{
extern void __libc_postfini(void) __attribute__((weak));
if (__libc_postfini) {
__libc_postfini();
}
}
#endif
}
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