[PATCH] config: do not overwrite symlinks when saving config file

[Tomi Ollila]

On Sat, Mar 02 2013, Jani Nikula <jani at nikula.org> wrote:

> Use realpath on the config path before writing. If that fails,
> fallback to the previous behaviour.
>
> Previously 'notmuch setup' and 'notmuch config set' overwrote the
> config file even if it was a symbolic link.
> ---
>  notmuch-config.c |   10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/notmuch-config.c b/notmuch-config.c
> index b5c2066..1e7389f 100644
> --- a/notmuch-config.c
> +++ b/notmuch-config.c
> @@ -461,7 +461,7 @@ int
>  notmuch_config_save (notmuch_config_t *config)
>  {
>      size_t length;
> -    char *data;
> +    char *data, *filename;
>      GError *error = NULL;
>  
>      data = g_key_file_to_data (config->key_file, &length, NULL);
> @@ -470,14 +470,20 @@ notmuch_config_save (notmuch_config_t *config)
>  	return 1;
>      }
>  
> -    if (! g_file_set_contents (config->filename, data, length, &error)) {
> +    /* Try not to overwrite symlinks. */
> +    filename = realpath (config->filename, NULL);

The code looks good to me. But should we handle realpath returning NULL
differently. It should return NULL only on error. I suggest that
when realpath returns NULL, descriptive enough error message is returned
to the user so that the problem can be resolved and then tried again.

Tomi

> +
> +    if (! g_file_set_contents (filename ? filename : config->filename,
> +			       data, length, &error)) {
>  	fprintf (stderr, "Error saving configuration to %s: %s\n",
>  		 config->filename, error->message);
>  	g_error_free (error);
> +	free (filename);
>  	g_free (data);
>  	return 1;
>      }
>  
> +    free (filename);
>      g_free (data);
>      return 0;
>  }
> -- 
> 1.7.10.4
>
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