avoid infinite recursive exec()s of perl.exe when shebang

contains "Perl" rather than "perl" on DOSISH platforms

p4raw-id: //depot/perl@4225

diff --git a/toke.c b/toke.c
index 5280054..1691542 100644 (file)
--- a/toke.c
+++ b/toke.c
@@ -2425,8 +2425,24 @@ Perl_yylex(pTHX)
                 * Look for options.
                 */
                d = instr(s,"perl -");
-               if (!d)
+               if (!d) {
                    d = instr(s,"perl");
+#if defined(DOSISH)
+                   /* avoid getting into infinite loops when shebang
+                    * line contains "Perl" rather than "perl" */
+                   if (!d) {
+                       for (d = ipathend-4; d >= ipath; --d) {
+                           if ((*d == 'p' || *d == 'P')
+                               && !ibcmp(d, "perl", 4))
+                           {
+                               break;
+                           }
+                       }
+                       if (d < ipath)
+                           d = Nullch;
+                   }
+#endif
+               }
 #ifdef ALTERNATE_SHEBANG
                /*
                 * If the ALTERNATE_SHEBANG on this system starts with a