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/*
* Copyright (C) 2020 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 <sys/thread_properties.h>
#include <async_safe/CHECK.h>
#include <async_safe/log.h>
#include <elf.h>
#include <pthread.h>
#include <unistd.h>
#include <sys/ptrace.h>
#include <sys/uio.h>
#include <sys/user.h>
#if defined(__i386__)
#include <asm/ldt.h>
#endif
#include "private/ErrnoRestorer.h"
#include "private/bionic_elf_tls.h"
#include "private/bionic_globals.h"
#include "private/bionic_tls.h"
#include "pthread_internal.h"
void __libc_get_static_tls_bounds(void** stls_begin, void** stls_end) {
const StaticTlsLayout& layout = __libc_shared_globals()->static_tls_layout;
*stls_begin = reinterpret_cast<char*>(__get_bionic_tcb()) - layout.offset_bionic_tcb();
*stls_end = reinterpret_cast<char*>(*stls_begin) + layout.size();
}
void __libc_register_thread_exit_callback(thread_exit_cb_t cb) {
TlsModules& modules = __libc_shared_globals()->tls_modules;
if (modules.first_thread_exit_callback == nullptr) {
modules.first_thread_exit_callback = cb;
return;
};
BionicAllocator& allocator = __libc_shared_globals()->tls_allocator;
CallbackHolder* new_node =
reinterpret_cast<CallbackHolder*>(allocator.alloc(sizeof(CallbackHolder)));
new_node->cb = cb;
new_node->prev = modules.thread_exit_callback_tail_node;
modules.thread_exit_callback_tail_node = new_node;
}
static inline __always_inline bionic_tcb* __get_bionic_tcb_for_thread(pid_t tid) {
// If tid is same as self, then we don't need ptrace.
if (gettid() == tid) return __get_bionic_tcb();
// Find the thread-pointer register for the given thread.
void** tp_reg = nullptr;
#if defined(__x86_64__)
{
ErrnoRestorer errno_restorer;
errno = 0;
uintptr_t fs_base = ptrace(PTRACE_PEEKUSER, tid, offsetof(user_regs_struct, fs_base), nullptr);
if (errno == 0) {
tp_reg = reinterpret_cast<void**>(fs_base);
}
}
#elif defined(__i386__)
struct user_regs_struct regs;
struct iovec pt_iov = {
.iov_base = ®s,
.iov_len = sizeof(regs),
};
if (ptrace(PTRACE_GETREGSET, tid, NT_PRSTATUS, &pt_iov) == 0) {
struct user_desc u_info;
u_info.entry_number = regs.xgs >> 3;
if (ptrace(PTRACE_GET_THREAD_AREA, tid, u_info.entry_number, &u_info) == 0) {
tp_reg = reinterpret_cast<void**>(u_info.base_addr);
}
}
#elif defined(__aarch64__)
uint64_t reg;
struct iovec pt_iov {
.iov_base = ®, .iov_len = sizeof(reg),
};
if (ptrace(PTRACE_GETREGSET, tid, NT_ARM_TLS, &pt_iov) == 0) {
tp_reg = reinterpret_cast<void**>(reg);
}
#elif defined(__arm__)
if (ptrace(PTRACE_GET_THREAD_AREA, tid, nullptr, &tp_reg) != 0) {
// Reset the tp_reg if ptrace was unsuccessful.
tp_reg = nullptr;
}
#endif
if (tp_reg == nullptr) {
async_safe_write_log(ANDROID_LOG_FATAL, "libc",
"__get_bionic_tcb_for_thread failed to read thread register.");
}
return reinterpret_cast<bionic_tcb*>(&tp_reg[MIN_TLS_SLOT]);
}
void __libc_iterate_dynamic_tls(pid_t tid,
void (*cb)(void* __dynamic_tls_begin, void* __dynamic_tls_end,
size_t __dso_id, void* __arg),
void* arg) {
TlsModules& modules = __libc_shared_globals()->tls_modules;
bionic_tcb* const tcb = __get_bionic_tcb_for_thread(tid);
TlsDtv* const dtv = __get_tcb_dtv(tcb);
BionicAllocator& allocator = __libc_shared_globals()->tls_allocator;
for (size_t i = modules.static_module_count; i < dtv->count; ++i) {
void* dtls_begin = dtv->modules[i];
if (dtls_begin == nullptr) continue;
void* dtls_end =
static_cast<void*>(static_cast<char*>(dtls_begin) + allocator.get_chunk_size(dtls_begin));
size_t dso_id = __tls_module_idx_to_id(i);
cb(dtls_begin, dtls_end, dso_id, arg);
}
}
void __libc_register_dynamic_tls_listeners(dtls_listener_t on_creation,
dtls_listener_t on_destruction) {
TlsModules& tls_modules = __libc_shared_globals()->tls_modules;
tls_modules.on_creation_cb = on_creation;
tls_modules.on_destruction_cb = on_destruction;
}
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