[PING][PATCH] iconvconfig: Fix behaviour with --prefix [BZ #28199]

[Siddhesh Poyarekar <siddhesh@gotplt.org>]

Ping!

On 8/9/21 11:57 AM, Siddhesh Poyarekar via Libc-alpha wrote:
> The consolidation of configuration parsing broke behaviour with
> --prefix, where the prefix bled into the modules cache.  Accept a
> prefix which, when non-NULL, is prepended to the path when looking for
> configuration files but only the original directory is added to the
> modules cache.
> 
> This has no effect on the codegen of gconv_conf since it passes NULL.
> 
> Reported-by: Patrick McCarty <patrick.mccarty@intel.com>
> Reported-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
> Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
> ---
>   iconv/gconv_conf.c         |  2 +-
>   iconv/gconv_parseconfdir.h | 21 +++++++++++++++------
>   iconv/iconvconfig.c        | 16 ++++++++++++----
>   3 files changed, 28 insertions(+), 11 deletions(-)
> 
> diff --git a/iconv/gconv_conf.c b/iconv/gconv_conf.c
> index 62bee28769..cc391d8f93 100644
> --- a/iconv/gconv_conf.c
> +++ b/iconv/gconv_conf.c
> @@ -478,7 +478,7 @@ __gconv_read_conf (void)
>     __gconv_get_path ();
>   
>     for (cnt = 0; __gconv_path_elem[cnt].name != NULL; ++cnt)
> -    gconv_parseconfdir (__gconv_path_elem[cnt].name,
> +    gconv_parseconfdir (NULL, __gconv_path_elem[cnt].name,
>   			__gconv_path_elem[cnt].len);
>   #endif
>   
> diff --git a/iconv/gconv_parseconfdir.h b/iconv/gconv_parseconfdir.h
> index 2f062689ec..38ffa9353a 100644
> --- a/iconv/gconv_parseconfdir.h
> +++ b/iconv/gconv_parseconfdir.h
> @@ -38,8 +38,9 @@
>   
>   /* Name of the file containing the module information in the directories
>      along the path.  */
> -static const char gconv_conf_filename[] = "gconv-modules";
> -static const char gconv_conf_dirname[] = "gconv-modules.d";
> +#define GCONV_CONF_FILENAME "gconv-modules"
> +static const char gconv_conf_filename[] = GCONV_CONF_FILENAME;
> +static const char gconv_conf_dirname[] = GCONV_CONF_FILENAME ".d";
>   
>   static void add_alias (char *);
>   static void add_module (char *, const char *, size_t, int);
> @@ -110,19 +111,27 @@ read_conf_file (const char *filename, const char *directory, size_t dir_len)
>     return true;
>   }
>   
> +/* Prefix DIR (with length DIR_LEN) with PREFIX if the latter is non-NULL and
> +   parse configuration in it.  */
> +
>   static __always_inline bool
> -gconv_parseconfdir (const char *dir, size_t dir_len)
> +gconv_parseconfdir (const char *prefix, const char *dir, size_t dir_len)
>   {
>     /* No slash needs to be inserted between dir and gconv_conf_filename;
>        dir already ends in a slash.  */
> -  char *buf = malloc (dir_len + sizeof (gconv_conf_dirname));
> +  size_t buflen = dir_len + sizeof (gconv_conf_dirname);
> +  char *buf = malloc (buflen + (prefix != NULL ? strlen (prefix) : 0));
> +  char *cp = buf;
>     bool found = false;
>   
>     if (buf == NULL)
>       return false;
>   
> -  char *cp = mempcpy (mempcpy (buf, dir, dir_len), gconv_conf_filename,
> -		      sizeof (gconv_conf_filename));
> +  if (prefix != NULL)
> +    cp = stpcpy (cp, prefix);
> +
> +  cp = mempcpy (mempcpy (cp, dir, dir_len), gconv_conf_filename,
> +		sizeof (gconv_conf_filename));
>   
>     /* Read the gconv-modules configuration file first.  */
>     found = read_conf_file (buf, dir, dir_len);
> diff --git a/iconv/iconvconfig.c b/iconv/iconvconfig.c
> index 783b2bbdbb..273a71f673 100644
> --- a/iconv/iconvconfig.c
> +++ b/iconv/iconvconfig.c
> @@ -653,13 +653,21 @@ add_module (char *rp, const char *directory,
>   static int
>   handle_dir (const char *dir)
>   {
> +  char *newp = NULL;
>     size_t dirlen = strlen (dir);
>     bool found = false;
>   
> -  char *fulldir = xasprintf ("%s%s%s", dir[0] == '/' ? prefix : "",
> -			     dir, dir[dirlen - 1] != '/' ? "/" : "");
> +  /* End directory path with a '/' if it doesn't already.  */
> +  if (dir[dirlen - 1] != '/')
> +    {
> +      newp = xmalloc (dirlen + 2);
> +      memcpy (newp, dir, dirlen);
> +      newp[dirlen++] = '/';
> +      newp[dirlen] = '\0';
> +      dir = newp;
> +    }
>   
> -  found = gconv_parseconfdir (fulldir, strlen (fulldir));
> +  found = gconv_parseconfdir (dir[0] == '/' ? prefix : NULL, dir, dirlen);
>   
>     if (!found)
>       {
> @@ -671,7 +679,7 @@ handle_dir (const char *dir)
>   	     "configuration files with names ending in .conf.");
>       }
>   
> -  free (fulldir);
> +  free (newp);
>   
>     return found ? 0 : 1;
>   }
>