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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 <unistd.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" int __system_properties_init(void);
extern "C" int __set_tls(void* ptr);
extern "C" int __set_tid_address(int* tid_address);
__LIBC_HIDDEN__ void __libc_init_vdso();
// 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;
/* 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;
static pthread_internal_t main_thread;
// Tell the kernel to clear our tid field when we exit, so we're like any other pthread.
// As a side-effect, this tells us our pid (which is the same as the main thread's tid).
main_thread.tid = __set_tid_address(&main_thread.tid);
main_thread.set_cached_pid(main_thread.tid);
// We don't want to free the main thread's stack even when the main thread exits
// because things like environment variables with global scope live on it.
// We also can't free the pthread_internal_t itself, since that lives on the main
// thread's stack rather than on the heap.
// The main thread has no mmap allocated space for stack or pthread_internal_t.
main_thread.mmap_size = 0;
pthread_attr_init(&main_thread.attr);
main_thread.attr.flags = PTHREAD_ATTR_FLAG_MAIN_THREAD;
main_thread.attr.guard_size = 0; // The main thread has no guard page.
main_thread.attr.stack_size = 0; // User code should never see this; we'll compute it when asked.
// TODO: the main thread's sched_policy and sched_priority need to be queried.
__init_thread(&main_thread, false);
__init_tls(&main_thread);
__set_tls(main_thread.tls);
main_thread.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'.
__libc_init_vdso();
}
/* 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) {
typedef void (*Dtor)();
Dtor* fini_array = reinterpret_cast<Dtor*>(array);
const Dtor minus1 = reinterpret_cast<Dtor>(static_cast<uintptr_t>(-1));
// Sanity check - first entry must be -1.
if (array == NULL || 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) {
Dtor dtor = fini_array[--count];
// Sanity check, any -1 in the list is ignored.
if (dtor == minus1) {
continue;
}
dtor();
}
#ifndef LIBC_STATIC
{
extern void __libc_postfini(void) __attribute__((weak));
if (__libc_postfini) {
__libc_postfini();
}
}
#endif
}
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