shithub: scc

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ref: 08ddb8968c1ad3297d0a91efa646ba828fca6afe
parent: 6946e8df6d64cfd59a1c4ad9c22bbfb6914543d4
author: Hiltjo Posthuma <[email protected]>
date: Fri May 6 18:57:14 EDT 2016

[cc1] fix uninitialized value after include(), fixes test001

The issue manifests after the line "#include <stdio.h>" is parsed.
The codeflow is like this:

- in cpp.c calls (*bp->fun)();
- this calls include().
- in includefile() calls addinput(path);
- ip->begin[0] = uninitialized
- in include() its_done label next() is called.
- next() checks ip->begin[0].

This is triggered when using OpenBSD with MALLOC_OPTIONS="J" set,
this option fills allocated and free'd memory with junk (useful for finding
this kind of issues).

--- a/cc1/lex.c

+++ b/cc1/lex.c

@@ -30,6 +30,7 @@

 	ip = xmalloc(sizeof(Input));

 	ip->fname = xstrdup(fname);

 	ip->p = ip->begin = ip->line = xmalloc(INPUTSIZ);

+	ip->p[0] = '\0';

 	ip->nline = 0;

 	ip->next = input;

 	ip->fp = fp;

@@ -89,7 +90,6 @@

 		}

 	}

 	allocinput(fname, fp);

-	*input->begin = '\0';

 	keywords(keys, NS_KEYWORD);

 }