Implement sigaltstack() as per-threaded. Current only scope process thread

is supported, for scope system process, kernel signal bits need to be
changed.

Reviewed by: deischen
Tested on  : i386 amd64 ia64

1 files changed, 104 insertions, 0 deletions

diff --git a/lib/libpthread/thread/thr_sigaltstack.c b/lib/libpthread/thread/thr_sigaltstack.c
new file mode 100644
index 0000000..8a4a457
--- /dev/null
+++ b/lib/libpthread/thread/thr_sigaltstack.c
@@ -0,0 +1,104 @@
+/*-
+ * Copyright (c) 2003 David Xu <davidxu@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <errno.h>
+#include <signal.h>
+#include "thr_private.h"
+
+__weak_reference(_sigaltstack, sigaltstack);
+
+int
+_sigaltstack(stack_t *_ss, stack_t *_oss)
+{
+	struct pthread *curthread = _get_curthread();
+	stack_t ss, oss;
+	int oonstack, errsave, ret;
+	kse_critical_t crit;
+
+	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
+		crit = _kse_critical_enter();
+		ret = __sys_sigaltstack(_ss, _oss);
+		errsave = errno;
+		/* Get a copy */
+		if (ret == 0 && _ss != NULL)
+			curthread->sigstk = *_ss;
+		_kse_critical_leave(crit);
+		errno = errsave;
+		return (ret);
+	}
+
+	if (_ss)
+		ss = *_ss;
+	if (_oss)
+		oss = *_oss;
+
+	/* Should get and set stack in atomic way */
+	crit = _kse_critical_enter();
+	oonstack = _thr_sigonstack(&ss);
+	if (_oss != NULL) {
+		oss = curthread->sigstk;
+		oss.ss_flags = (curthread->sigstk.ss_flags & SS_DISABLE)
+		    ? SS_DISABLE : ((oonstack) ? SS_ONSTACK : 0);
+	}
+
+	if (_ss != NULL) {
+		if (oonstack) {
+			_kse_critical_leave(crit);
+			return (EPERM);
+		}
+		if ((ss.ss_flags & ~SS_DISABLE) != 0) {
+			_kse_critical_leave(crit);
+			return (EINVAL);
+		}
+		if (!(ss.ss_flags & SS_DISABLE)) {
+			if (ss.ss_size < MINSIGSTKSZ) {
+				_kse_critical_leave(crit);
+				return (ENOMEM);
+			}
+			curthread->sigstk = ss;
+		} else {
+			curthread->sigstk.ss_flags |= SS_DISABLE;
+		}
+	}
+	_kse_critical_leave(crit);
+	if (_oss != NULL)
+		*_oss = oss;
+	return (0);
+}
+
+int
+_thr_sigonstack(void *sp)
+{
+	struct pthread *curthread = _get_curthread();
+
+	return ((curthread->sigstk.ss_flags & SS_DISABLE) == 0 ?
+	    (((size_t)sp - (size_t)curthread->sigstk.ss_sp) < curthread->sigstk.ss_size)
+	    : 0);
+}
+