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#include <elf.h>
#include <limits.h>
#include <sys/mman.h>
#include <string.h>
#include <stddef.h>
#include "pthread_impl.h"
#include "libc.h"
#include "atomic.h"
#include "syscall.h"
int __init_tp(void *p)
{
pthread_t td = p;
td->self = td;
int r = __set_thread_area(TP_ADJ(p));
if (r < 0) return -1;
if (!r) libc.can_do_threads = 1;
td->tid = __syscall(SYS_set_tid_address, &td->tid);
td->locale = &libc.global_locale;
td->robust_list.head = &td->robust_list.head;
return 0;
}
static struct builtin_tls {
char c;
struct pthread pt;
void *space[16];
} builtin_tls[1];
#define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
static struct tls_module main_tls;
void *__copy_tls(unsigned char *mem)
{
pthread_t td;
struct tls_module *p;
size_t i;
void **dtv;
#ifdef TLS_ABOVE_TP
dtv = (void **)(mem + libc.tls_size) - (libc.tls_cnt + 1);
mem += -((uintptr_t)mem + sizeof(struct pthread)) & (libc.tls_align-1);
td = (pthread_t)mem;
mem += sizeof(struct pthread);
for (i=1, p=libc.tls_head; p; i++, p=p->next) {
dtv[i] = mem + p->offset;
memcpy(dtv[i], p->image, p->len);
}
#else
dtv = (void **)mem;
mem += libc.tls_size - sizeof(struct pthread);
mem -= (uintptr_t)mem & (libc.tls_align-1);
td = (pthread_t)mem;
for (i=1, p=libc.tls_head; p; i++, p=p->next) {
dtv[i] = mem - p->offset;
memcpy(dtv[i], p->image, p->len);
}
#endif
dtv[0] = (void *)libc.tls_cnt;
td->dtv = td->dtv_copy = dtv;
return td;
}
#if ULONG_MAX == 0xffffffff
typedef Elf32_Phdr Phdr;
#else
typedef Elf64_Phdr Phdr;
#endif
__attribute__((__weak__, __visibility__("hidden")))
extern const size_t _DYNAMIC[];
static void static_init_tls(size_t *aux)
{
unsigned char *p;
size_t n;
Phdr *phdr, *tls_phdr=0;
size_t base = 0;
void *mem;
for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
phdr = (void *)p;
if (phdr->p_type == PT_PHDR)
base = aux[AT_PHDR] - phdr->p_vaddr;
if (phdr->p_type == PT_DYNAMIC && _DYNAMIC)
base = (size_t)_DYNAMIC - phdr->p_vaddr;
if (phdr->p_type == PT_TLS)
tls_phdr = phdr;
}
if (tls_phdr) {
main_tls.image = (void *)(base + tls_phdr->p_vaddr);
main_tls.len = tls_phdr->p_filesz;
main_tls.size = tls_phdr->p_memsz;
main_tls.align = tls_phdr->p_align;
libc.tls_cnt = 1;
libc.tls_head = &main_tls;
}
main_tls.size += (-main_tls.size - (uintptr_t)main_tls.image)
& (main_tls.align-1);
if (main_tls.align < MIN_TLS_ALIGN) main_tls.align = MIN_TLS_ALIGN;
#ifndef TLS_ABOVE_TP
main_tls.offset = main_tls.size;
#endif
libc.tls_align = main_tls.align;
libc.tls_size = 2*sizeof(void *) + sizeof(struct pthread)
+ main_tls.size + main_tls.align
+ MIN_TLS_ALIGN-1 & -MIN_TLS_ALIGN;
if (libc.tls_size > sizeof builtin_tls) {
#ifndef SYS_mmap2
#define SYS_mmap2 SYS_mmap
#endif
mem = (void *)__syscall(
SYS_mmap2,
0, libc.tls_size, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
/* -4095...-1 cast to void * will crash on dereference anyway,
* so don't bloat the init code checking for error codes and
* explicitly calling a_crash(). */
} else {
mem = builtin_tls;
}
/* Failure to initialize thread pointer is always fatal. */
if (__init_tp(__copy_tls(mem)) < 0)
a_crash();
}
weak_alias(static_init_tls, __init_tls);
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