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Re: Bug#645346: pax: FTBFS on hurd-i386



Hi!

On Fri, 2011-10-14 at 18:33:13 +0200, Svante Signell wrote:
> Package: pax
> Version: 20090728-2
> Severity: important
> Tags: patch
> Usertags: hurd
> 
> Attached is a small patch to make pax-20090728 build under GNU/Hurd.
> The first part is using the already issued lstat(2) call to find out
> the size for a dynamic allocation of a character string, avoiding the
> MAXPATHLEN issue. Secondly the reaplath(3) call is conditionally
> replaced with canonicalize_file_name(3).

> diff -ur pax-20090728/file_subs.c pax-20090728.modified/file_subs.c
> --- pax-20090728/file_subs.c	2009-07-28 17:38:28.000000000 +0000
> +++ pax-20090728.modified/file_subs.c	2011-10-13 14:45:13.000000000 +0000
> @@ -374,8 +374,15 @@
>  			if (strcmp(NM_TAR, argv0) == 0 && Lflag) {
>  				while (lstat(nm, &sb) == 0 &&
>  				    S_ISLNK(sb.st_mode)) {
> +					target = malloc(sb.st_size + 1);
> +					if (target == NULL) {
> +						oerrno = ENOMEM;
> +						syswarn(1, oerrno,
> +						    "Insufficient memory");
> +						return(-1);
> +					}
>  					len = readlink(nm, target,
> -					    sizeof target - 1);
> +					    strlen(target));

This is not right, target can contain garbage so strlen(target) could
return anything, or segfault. The correct value is the same used in
the malloc call.

>  					if (len == -1) {
>  						syswarn(0, errno,
>  						   "cannot follow symlink %s in chain for %s",
[...]

You forgot a free on the return(0) case.

> diff -ur pax-20090728/tables.c pax-20090728.modified/tables.c
> --- pax-20090728/tables.c	2009-07-28 17:38:28.000000000 +0000
> +++ pax-20090728.modified/tables.c	2011-10-13 14:20:10.000000000 +0000
> @@ -1126,13 +1126,21 @@
>  add_dir(char *name, struct stat *psb, int frc_mode)
>  {
>  	DIRDATA *dblk;
> +#ifdef __GNU__
> +	char *rp = NULL;
> +#else
>  	char realname[MAXPATHLEN], *rp;
> +#endif

After considering this, I think it would be a better option and way more
portable to use realpath(path, NULL) when _POSIX_VERSION >= 200809L.

regards,
guillem


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