BR 3392667: more reasonable limit for expression descent

Set an expression descent limit to 8192, which is more reasonable to
expect to work on most platforms. Furthermore, if getrlimit() exists,
then try to use it to see if we need to further limit the size.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/nasmlib/rlimit.c b/nasmlib/rlimit.c
new file mode 100644
index 00000000..096879f8
--- /dev/null
+++ b/nasmlib/rlimit.c
@@ -0,0 +1,78 @@
+ /* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2020 The NASM Authors - All Rights Reserved
+ *   See the file AUTHORS included with the NASM distribution for
+ *   the specific copyright holders.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following
+ *   conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * 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 COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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 "compiler.h"
+#include "nasmlib.h"
+
+#ifdef HAVE_SYS_RESOURCE_H
+# include <sys/resource.h>
+#endif
+
+#if defined(HAVE_GETRLIMIT) && defined(RLIMIT_STACK)
+
+size_t nasm_get_stack_size_limit(void)
+{
+    struct rlimit rl;
+
+    if (getrlimit(RLIMIT_STACK, &rl))
+        return SIZE_MAX;
+
+# ifdef RLIM_SAVED_MAX
+    if (rl.rlim_cur == RLIM_SAVED_MAX)
+        rl.rlim_cur = rl.rlim_max;
+# endif
+
+    if (
+# ifdef RLIM_INFINITY
+        rl.rlim_cur >= RLIM_INFINITY ||
+# endif
+# ifdef RLIM_SAVED_CUR
+        rl.rlim_cur == RLIM_SAVED_CUR ||
+# endif
+# ifdef RLIM_SAVED_MAX
+        rl.rlim_cur == RLIM_SAVED_MAX ||
+# endif
+        (size_t)rl.rlim_cur != rl.rlim_cur)
+        return SIZE_MAX;
+
+    return rl.rlim_cur;
+}
+
+#else
+
+size_t nasm_get_stack_size_limit(void)
+{
+    return SIZE_MAX;
+}
+
+#endif