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



Hi!

On Sat, 2011-10-15 at 15:51:11 +0200, Svante Signell wrote:
> On Sat, 2011-10-15 at 01:20 +0200, Guillem Jover wrote:
> > After considering this, I think it would be a better option and way more
> > portable to use realpath(path, NULL) when _POSIX_VERSION >= 200809L.
> 
> Attached is an updated patch, taking Guillems comments into
> consideration. We are looking forward to se it applied in the next
> Debian release of pax (and in upstream in due time).

> 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	2011-10-15 12:56:46.000000000 +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);
> +					    sb.st_size);

It might make sense to use sb.st_size + 1 and verify there's not been
truncation in between, please see the example code at:

  <http://man7.org/linux/man-pages/online/pages/man2/readlink.2.html>

>  					if (len == -1) {
>  						syswarn(0, errno,
>  						   "cannot follow symlink %s in chain for %s",
> 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	2011-10-15 13:39:29.000000000 +0000
> @@ -55,6 +55,7 @@
>  #include "pax.h"
>  #include "tables.h"
>  #include "extern.h"
> +#include "features.h"
>
>  /*
>   * Routines for controlling the contents of all the different databases pax
> @@ -1126,13 +1127,21 @@
>  add_dir(char *name, struct stat *psb, int frc_mode)
>  {
>  	DIRDATA *dblk;
> +#if (_POSIX_C_SOURCE - 0) >= 200809L
> +	char *rp = NULL;
> +#else
>  	char realname[MAXPATHLEN], *rp;
> +#endif

Unfortunately both "features.h" and _POSIX_C_SOURCE are non-portable.
The latter is a user defined variable, it does not specify what the
system supports, but what the user requests, also both are GNUisms.

The correct way to check for this is to include <unistd.h> and check
for _POSIX_VERSION, as I pointed out initially. More into at:

  <http://sourceforge.net/apps/mediawiki/predef/index.php?title=Standards>

thanks,
guillem


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