PR c/93640 - The write_only and read_write attributes can be mistyped due to…

PR c/93640 - The write_only and read_write attributes can be mistyped due to invalid strncmp size argument

gcc/c-family/ChangeLog:

	PR c/93640
	* c-attribs.c (handle_access_attribute): Correct off-by-one mistakes.

gcc/testsuite/ChangeLog:

	PR c/93640
	* gcc.dg/attr-access.c: New test.

gcc/c-family/ChangeLog

+2020-02-10  Martin Sebor  <msebor@redhat.com>
+
+	PR c/93640
+	* c-attribs.c (handle_access_attribute): Correct off-by-one mistakes.
+
 2020-02-10  Jakub Jelinek  <jakub@redhat.com>
 
 	PR other/93641

gcc/c-family/c-attribs.c

@@ -3999,8 +3999,8 @@ handle_access_attribute (tree *node, tree name, tree args,
     }
 
   const bool read_only = strncmp (ps, "read_only", 9) == 0;
-  const bool write_only = strncmp (ps, "write_only", 9) == 0;
-  if (!read_only && !write_only && strncmp (ps, "read_write", 9))
+  const bool write_only = strncmp (ps, "write_only", 10) == 0;
+  if (!read_only && !write_only && strncmp (ps, "read_write", 10))
     {
       error ("attribute %qE invalid mode %qs; expected one of "
 	     "%qs, %qs, or %qs", name, access_str,

gcc/testsuite/ChangeLog

+2020-02-10  Martin Sebor  <msebor@redhat.com>
+
+	PR c/93640
+	* gcc.dg/attr-access.c: New test.
+
 2020-02-10  Hans-Peter Nilsson  <hp@axis.com>
 
 	* gcc.target/cris/cris.exp (check_effective_target_cc0): New.

gcc/testsuite/gcc.dg/attr-access.c

+/* PR c/93640 - The write_only and read_write attributes can be mistyped
+   due to invalid strncmp size argument
+   { dg-do compile }
+   { dg-options "-Wall" } */
+
+__attribute__ ((access (read_onl))) int f0 (char*);         // { dg-error "attribute 'access' invalid mode 'read_onl'" }
+__attribute__ ((access (write_onl))) int f1 (char*);        // { dg-error "attribute 'access' invalid mode 'write_onl'" }
+__attribute__ ((access (read_writ))) int f2 (char*);        // { dg-error "attribute 'access' invalid mode 'read_writ'" }
+
+__attribute__ ((access (read_onlX))) int f3 (char*);        // { dg-error "attribute 'access' invalid mode 'read_onlX'" }
+__attribute__ ((access (write_onlX))) int f4 (char*);       // { dg-error "attribute 'access' invalid mode 'write_onlX'" }
+__attribute__ ((access (read_writX))) int f5 (char*);       // { dg-error "attribute 'access' invalid mode 'read_writX'" }
+
+
+__attribute__ ((access (read_onl, 1))) int f7 (char*);      // { dg-error "attribute 'access' invalid mode 'read_onl'" }
+__attribute__ ((access (write_onl, 1))) int f8 (char*);     // { dg-error "attribute 'access' invalid mode 'write_onl'" }
+__attribute__ ((access (read_writ, 1))) int f9 (char*);     // { dg-error "attribute 'access' invalid mode 'read_writ'" }
+
+__attribute__ ((access (read_onlX, 1))) int f10 (char*);    // { dg-error "attribute 'access' invalid mode 'read_onlX'" }
+__attribute__ ((access (write_onlX, 1))) int f11 (char*);   // { dg-error "attribute 'access' invalid mode 'write_onlX'" }
+__attribute__ ((access (read_writX, 1))) int f12 (char*);   // { dg-error "attribute 'access' invalid mode 'read_writX'" }