sh: Fix two issues when an alias is redefined:

 * The last character is not displayed.
 * If the alias ends with itself (as a word), an infinite memory-eating loop
   occurs.

If an alias is defined initially, a space is appended to avoid recursion but
this did not happen when an alias was later modified.

PR:		bin/173418
Submitted by:	Daniel F.
MFC after:	1 week

1 files changed, 11 insertions, 0 deletions

diff --git a/bin/sh/alias.c b/bin/sh/alias.c
index fb0e922..da995bb 100644
--- a/bin/sh/alias.c
+++ b/bin/sh/alias.c
@@ -68,7 +68,18 @@ setalias(const char *name, const char *val)
 		if (equal(name, ap->name)) {
 			INTOFF;
 			ckfree(ap->val);
+			/* See HACK below. */
+#ifdef notyet
 			ap->val	= savestr(val);
+#else
+			{
+			size_t len = strlen(val);
+			ap->val = ckmalloc(len + 2);
+			memcpy(ap->val, val, len);
+			ap->val[len] = ' ';
+			ap->val[len+1] = '\0';
+			}
+#endif
 			INTON;
 			return;
 		}