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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;
libc.has_thread_pointer = 1;
td->tid = __syscall(SYS_set_tid_address, &td->tid);
td->locale = &libc.global_locale;
return 0;
}
#ifndef SHARED
static struct builtin_tls {
char c;
struct pthread pt;
void *space[16];
} builtin_tls[1];
#define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
struct tls_image {
void *image;
size_t len, size, align;
} __static_tls ATTR_LIBC_VISIBILITY;
#define T __static_tls
void *__copy_tls(unsigned char *mem)
{
pthread_t td;
if (!T.image) return mem;
void **dtv = (void *)mem;
dtv[0] = (void *)1;
#ifdef TLS_ABOVE_TP
mem += sizeof(void *) * 2;
mem += -((uintptr_t)mem + sizeof(struct pthread)) & (T.align-1);
td = (pthread_t)mem;
mem += sizeof(struct pthread);
#else
mem += libc.tls_size - sizeof(struct pthread);
mem -= (uintptr_t)mem & (T.align-1);
td = (pthread_t)mem;
mem -= T.size;
#endif
td->dtv = dtv;
dtv[1] = mem;
memcpy(mem, T.image, T.len);
return td;
}
#if ULONG_MAX == 0xffffffff
typedef Elf32_Phdr Phdr;
#else
typedef Elf64_Phdr Phdr;
#endif
void __init_tls(size_t *aux)
{
unsigned char *p;
size_t n;
Phdr *phdr, *tls_phdr=0;
size_t base = 0;
void *mem;
libc.tls_size = sizeof(struct pthread);
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_TLS)
tls_phdr = phdr;
}
if (tls_phdr) {
T.image = (void *)(base + tls_phdr->p_vaddr);
T.len = tls_phdr->p_filesz;
T.size = tls_phdr->p_memsz;
T.align = tls_phdr->p_align;
}
T.size += (-T.size - (uintptr_t)T.image) & (T.align-1);
if (T.align < MIN_TLS_ALIGN) T.align = MIN_TLS_ALIGN;
libc.tls_size = 2*sizeof(void *)+T.size+T.align+sizeof(struct pthread);
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 fatal if TLS is used. */
if (__init_tp(__copy_tls(mem)) < 0 && tls_phdr)
a_crash();
}
#else
void __init_tls(size_t *auxv) { }
#endif
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