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.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/process/fork.c b/src/process/fork.c
index bcd47c97..a04e8929 100644
--- a/src/process/fork.c
+++ b/src/process/fork.c
@@ -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;