This has been sitting in my local tree long enough. Remove the use

of an alternate signal stack for handling signals.  Let the kernel
send signals on the stack of the current thread and teach the threads
signal handler how to deliver signals to the current thread if it
needs to.  Also, always store a threads context as a jmp_buf.  Eventually
this will change to be a ucontext_t or mcontext_t.

Other small nits.  Use struct pthread * instead of pthread_t in internal
library routines.  The threads code wants struct pthread *, and pthread_t
doesn't necessarily have to be the same.

Reviewed by:	jasone

1 files changed, 9 insertions, 46 deletions

diff --git a/lib/libpthread/thread/thr_private.h b/lib/libpthread/thread/thr_private.h
index 65661f7..c294693 100644
--- a/lib/libpthread/thread/thr_private.h
+++ b/lib/libpthread/thread/thr_private.h
@@ -603,38 +603,13 @@ struct pthread_state_data {
 
 struct join_status {
 	struct pthread	*thread;
-	int		ret;
+	void		*ret;
 	int		error;
 };
 
 /*
- * Normally thread contexts are stored as jmp_bufs via _setjmp()/_longjmp(),
- * but they may also be sigjmp_buf and ucontext_t.  When a thread is
- * interrupted by a signal, it's context is saved as a ucontext_t.  An
- * application is also free to use [_]longjmp()/[_]siglongjmp() to jump
- * between contexts within the same thread.  Future support will also
- * include setcontext()/getcontext().
- *
- * Define an enumerated type that can identify the 4 different context
- * types.
- */
-typedef enum {
-	CTX_JB_NOSIG,	/* context is jmp_buf without saved sigset */
-	CTX_JB,		/* context is jmp_buf (with saved sigset) */
-	CTX_SJB,	/* context is sigjmp_buf (with saved sigset) */
-	CTX_UC		/* context is ucontext_t (with saved sigset) */
-} thread_context_t;
-
-/*
- * There are 2 basic contexts that a frame may contain at any
- * one time:
- *
- *   o ctx - The context that the thread should return to after normal
- *     completion of the signal handler.
- *   o sig_jb - The context just before the signal handler is invoked.
- *     Attempts at abnormal returns from user supplied signal handlers
- *     will return back to the signal context to perform any necessary
- *     cleanup.
+ * The frame that is added to the top of a threads stack when setting up
+ * up the thread to run a signal handler.
  */
 struct pthread_signal_frame {
 	/*
@@ -643,19 +618,12 @@ struct pthread_signal_frame {
 	struct pthread_state_data saved_state;
 
 	/*
-	 * Threads return context; ctxtype identifies the type of context.
-	 * For signal frame 0, these point to the context storage area
-	 * within the pthread structure.  When handling signals (frame > 0),
-	 * these point to a context storage area that is allocated off the
-	 * threads stack.
+	 * Threads return context; we use only jmp_buf's for now.
 	 */
 	union {
 		jmp_buf		jb;
-		sigjmp_buf	sigjb;
 		ucontext_t	uc;
 	} ctx;
-	thread_context_t	ctxtype;
-	int			longjmp_val;
 	int			signo;	/* signal, arg 1 to sighandler */
 	int			sig_has_args;	/* use signal args if true */
 	ucontext_t		uc;
@@ -696,15 +664,12 @@ struct pthread {
 	struct pthread_attr	attr;
 
 	/*
-	 * Threads return context; ctxtype identifies the type of context.
+	 * Threads return context; we use only jmp_buf's for now.
 	 */
 	union {
 		jmp_buf		jb;
-		sigjmp_buf	sigjb;
 		ucontext_t	uc;
 	} ctx;
-	thread_context_t	ctxtype;
-	int			longjmp_val;
 
 	/*
 	 * Used for tracking delivery of signal handlers.
@@ -1145,9 +1110,6 @@ SCLASS	volatile int	_sigq_check_reqd
 #endif
 ;
 
-/* The signal stack. */
-SCLASS struct sigaltstack _thread_sigstack;
-
 /* Thread switch hook. */
 SCLASS pthread_switch_routine_t _sched_switch_hook
 #ifdef GLOBAL_PTHREAD_PRIVATE
@@ -1257,11 +1219,12 @@ void    _thread_kern_set_timeout(const struct timespec *);
 void    _thread_kern_sig_defer(void);
 void    _thread_kern_sig_undefer(void);
 void    _thread_sig_handler(int, siginfo_t *, ucontext_t *);
-void    _thread_sig_check_pending(pthread_t pthread);
+void    _thread_sig_check_pending(struct pthread *pthread);
 void    _thread_sig_handle_pending(void);
-void	_thread_sig_send(pthread_t pthread, int sig);
+void	_thread_sig_send(struct pthread *pthread, int sig);
 void	_thread_sig_wrapper(void);
-void	_thread_sigframe_restore(pthread_t thread, struct pthread_signal_frame *psf);
+void	_thread_sigframe_restore(struct pthread *thread,
+	    struct pthread_signal_frame *psf);
 void    _thread_start(void);
 void	_thread_seterrno(pthread_t, int);
 int     _thread_fd_table_init(int fd);