sh: Make sure defined functions can actually be called.

Add some conservative checks on function names:
- Disallow expansions or quoting characters; these can only be called via
  strange control characters
- Disallow '/'; these functions cannot be called anyway, as exec.c assumes
  they are pathnames
- Make the CTL* bytes work properly in function names.

These are syntax errors.

POSIX does not require us to support more than names (letters, digits and
underscores, not starting with a digit), but I do not want to restrict it
that much at this time.

Exp-run done by:	pav (with some other sh(1) changes)

1 files changed, 7 insertions, 3 deletions

diff --git a/bin/sh/parser.c b/bin/sh/parser.c
index 6c504e5..ec1510b 100644
--- a/bin/sh/parser.c
+++ b/bin/sh/parser.c
@@ -639,10 +639,14 @@ simplecmd(union node **rpp, union node *redir)
 			if (readtoken() != TRP)
 				synexpect(TRP);
 			funclinno = plinno;
-#ifdef notdef
-			if (! goodname(n->narg.text))
+			/*
+			 * - Require plain text.
+			 * - Functions with '/' cannot be called.
+			 */
+			if (!noexpand(n->narg.text) || quoteflag ||
+			    strchr(n->narg.text, '/'))
 				synerror("Bad function name");
-#endif
+			rmescapes(n->narg.text);
 			n->type = NDEFUN;
 			n->narg.next = command();
 			funclinno = 0;