fix minor bugs due to incorrect threaded-predicate semantics

some functions that should have been testing whether pthread_self()
had been called and initialized the thread pointer were instead
testing whether pthread_create() had been called and actually made the
program "threaded". while it's unlikely any mismatch would occur in
real-world problems, this could have introduced subtle bugs. now, we
store the address of the main thread's thread descriptor in the libc
structure and use its presence as a flag that the thread register is
initialized. note that after fork, the calling thread (not necessarily
the original main thread) is the new main thread.
This commit is contained in:
Rich Felker 2011-04-20 21:41:45 -04:00
parent f9a6372a98
commit 870cc67977
4 changed files with 6 additions and 6 deletions

View File

@ -16,6 +16,7 @@ struct __libc {
volatile int threads_minus_1;
int ofl_lock;
FILE *ofl_head;
void *main_thread;
};

View File

@ -8,10 +8,11 @@ pid_t fork(void)
pid_t ret;
if (libc.fork_handler) libc.fork_handler(-1);
ret = syscall(SYS_fork);
if (libc.threaded && !ret) {
if (libc.main_thread && !ret) {
pthread_t self = __pthread_self();
self->tid = self->pid = syscall(SYS_getpid);
libc.threads_minus_1 = 0;
libc.main_thread = self;
}
if (libc.fork_handler) libc.fork_handler(!ret);
return ret;

View File

@ -6,7 +6,6 @@ static struct pthread main_thread;
static const void *dummy[1] = { 0 };
weak_alias(dummy, __pthread_tsd_main);
#undef errno
static int *errno_location()
{
return __pthread_self()->errno_ptr;
@ -14,11 +13,10 @@ static int *errno_location()
static int init_main_thread()
{
if (__set_thread_area(&main_thread) < 0) return -1;
main_thread.canceldisable = libc.canceldisable;
main_thread.tsd = (void **)__pthread_tsd_main;
main_thread.self = &main_thread;
if (__set_thread_area(&main_thread) < 0)
return -1;
main_thread.self = libc.main_thread = &main_thread;
main_thread.errno_ptr = __errno_location();
libc.errno_location = errno_location;
main_thread.tid = main_thread.pid =

View File

@ -3,7 +3,7 @@
int pthread_setcancelstate(int new, int *old)
{
if (new > 1U) return EINVAL;
if (libc.threaded) {
if (libc.main_thread) {
struct pthread *self = __pthread_self();
if (old) *old = self->canceldisable;
self->canceldisable = new;