Abort endless loops during roff macro and string expansion.

For now, use the simplest conceivable approach, like groff does:
Just a fixed, ugly input stack limit.
Kristaps@ agrees.

3 files changed, 22 insertions, 2 deletions

diff --git a/regress/usr.bin/mandoc/roff/string/Makefile b/regress/usr.bin/mandoc/roff/string/Makefile
index 38c6c1f5afc..5577da4097e 100644
--- a/regress/usr.bin/mandoc/roff/string/Makefile
+++ b/regress/usr.bin/mandoc/roff/string/Makefile
@@ -1,5 +1,5 @@
-# $OpenBSD: Makefile,v 1.1 2010/12/09 20:56:30 schwarze Exp $
+# $OpenBSD: Makefile,v 1.2 2010/12/09 23:01:18 schwarze Exp $
 
-REGRESS_TARGETS=escape
+REGRESS_TARGETS=escape infinite
 
 .include <bsd.regress.mk>
diff --git a/regress/usr.bin/mandoc/roff/string/infinite.in b/regress/usr.bin/mandoc/roff/string/infinite.in
new file mode 100644
index 00000000000..6c25f7ca7af
--- /dev/null
+++ b/regress/usr.bin/mandoc/roff/string/infinite.in
@@ -0,0 +1,8 @@
+.TH STRING-INFINITE 1 "December 3, 2010"
+.SH NAME
+string-infinite - endless recursion in string expansion
+.SH DESCRIPTION
+.ds recur \\*[recur]
+Blow up,
+(and do not \*[recur] print this)
+but still render following text correctly.
diff --git a/regress/usr.bin/mandoc/roff/string/infinite.out_ascii b/regress/usr.bin/mandoc/roff/string/infinite.out_ascii
new file mode 100644
index 00000000000..0e1bee3680f
--- /dev/null
+++ b/regress/usr.bin/mandoc/roff/string/infinite.out_ascii
@@ -0,0 +1,12 @@
+STRING-INFINITE(1)                                          STRING-INFINITE(1)
+
+
+
+NNAAMMEE
+       string-infinite - endless recursion in string expansion
+
+DDEESSCCRRIIPPTTIIOONN
+       Blow up, but still render following text correctly.
+
+
+