Re: CVS commit: src/lib/csu/common

[maya%netbsd.org@localhost]

ack. we should probably leave the build broken, anyone who tries out the
resulting netbsd might have to spend some time figuring out how to boot
without /sbin/init (it's boot -a and then pick /rescue/init).

On Fri, Jul 13, 2018 at 01:00:17AM +0000, Robert Elz wrote:
> Module Name:	src
> Committed By:	kre
> Date:		Fri Jul 13 01:00:17 UTC 2018
> 
> Modified Files:
> 	src/lib/csu/common: crt0-common.c
> 
> Log Message:
> i386/amd64 build fix.   Fix "possibly used uninitialized" from gcc.
> These changes should make no practical effect - but because external
> data is being examined, it would be possible to contrive a situation
> (perhaps) where uninit'd vars could actually be used (unless the format
> has been checked elsewhere earlier - I did not look ... we have to
> appease gcc anyway).
> 
> Joerg: Please review (& fix)
> 
> 
> To generate a diff of this commit:
> cvs rdiff -u -r1.18 -r1.19 src/lib/csu/common/crt0-common.c
> 
> Please note that diffs are not public domain; they are subject to the
> copyright notices on the relevant files.
> 

> Modified files:
> 
> Index: src/lib/csu/common/crt0-common.c
> diff -u src/lib/csu/common/crt0-common.c:1.18 src/lib/csu/common/crt0-common.c:1.19
> --- src/lib/csu/common/crt0-common.c:1.18	Thu Jul 12 21:36:45 2018
> +++ src/lib/csu/common/crt0-common.c	Fri Jul 13 01:00:17 2018
> @@ -1,4 +1,4 @@
> -/* $NetBSD: crt0-common.c,v 1.18 2018/07/12 21:36:45 joerg Exp $ */
> +/* $NetBSD: crt0-common.c,v 1.19 2018/07/13 01:00:17 kre Exp $ */
>  
>  /*
>   * Copyright (c) 1998 Christos Zoulas
> @@ -36,7 +36,7 @@
>   */
>  
>  #include <sys/cdefs.h>
> -__RCSID("$NetBSD: crt0-common.c,v 1.18 2018/07/12 21:36:45 joerg Exp $");
> +__RCSID("$NetBSD: crt0-common.c,v 1.19 2018/07/13 01:00:17 kre Exp $");
>  
>  #include <sys/types.h>
>  #include <sys/exec.h>
> @@ -214,9 +214,9 @@ relocate_self(struct ps_strings *ps_stri
>  {
>  	AuxInfo *aux = (AuxInfo *)(ps_strings->ps_argvstr + ps_strings->ps_nargvstr +
>  	    ps_strings->ps_nenvstr + 2);
> -	uintptr_t relocbase;
> -	const Elf_Phdr *phdr;
> -	Elf_Half phnum;
> +	uintptr_t relocbase = (uintptr_t)~0U;
> +	const Elf_Phdr *phdr = NULL;
> +	Elf_Half phnum = (Elf_Half)~0;
>  
>  	for (; aux->a_type != AT_NULL; ++aux) {
>  		switch (aux->a_type) {
> @@ -232,7 +232,11 @@ relocate_self(struct ps_strings *ps_stri
>  			break;
>  		}
>  	}
> -	const Elf_Phdr *phlimit = phdr + phnum, *dynphdr;
> +
> +	if (phdr == NULL || phnum == (Elf_Half)~0)
> +		return;
> +
> +	const Elf_Phdr *phlimit = phdr + phnum, *dynphdr = NULL;
>  
>  	for (; phdr < phlimit; ++phdr) {
>  		if (phdr->p_type == PT_DYNAMIC)
> @@ -240,6 +244,9 @@ relocate_self(struct ps_strings *ps_stri
>  		if (phdr->p_type == PT_PHDR)
>  			relocbase = (uintptr_t)phdr - phdr->p_vaddr;
>  	}
> +	if (dynphdr == NULL || relocbase == (uintptr_t)~0U)
> +		return;
> +
>  	Elf_Dyn *dynp = (Elf_Dyn *)((uint8_t *)dynphdr->p_vaddr + relocbase);
>  
>  	const REL_TYPE *relocs = 0, *relocslim;
>