Re: [PATCH 5/5] libmultipath: Accept "*" as a valid regular expression

[Sebastian Herbszt <herbszt@gmx.de>]

Bart Van Assche wrote:
> Inside libmultipath regcomp() is used to compile regular expressions
> specified in /etc/multipath.conf. Many multipath.conf examples contain
> 'product_type "*"'. However, "*" is not a valid POSIX regular expression.
> Hence this patch that changes the regular expression "*" into ".*".
> 
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>  libmultipath/blacklist.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/libmultipath/blacklist.c b/libmultipath/blacklist.c
> index 651bd7e..e5c287e 100644
> --- a/libmultipath/blacklist.c
> +++ b/libmultipath/blacklist.c
> @@ -63,6 +63,13 @@ alloc_ble_device (vector blist)
>  	return 0;
>  }
>  
> +static int lm_regcomp(regex_t *preg, const char *pattern, int cflags)
> +{
> +	if (strcmp(pattern, "*") == 0)
> +		pattern = ".*";
> +	return regcomp(preg, pattern, cflags);
> +}
> +
>  extern int
>  set_ble_device (vector blist, char * vendor, char * product, int origin)
>  {
> @@ -77,16 +84,16 @@ set_ble_device (vector blist, char * vendor, char * product, int origin)
>  		return 1;
>  
>  	if (vendor) {
> -		if (regcomp(&ble->vendor_reg, vendor,
> -			    REG_EXTENDED|REG_NOSUB)) {
> +		if (lm_regcomp(&ble->vendor_reg, vendor,
> +			       REG_EXTENDED|REG_NOSUB)) {
>  			FREE(vendor);
>  			return 1;
>  		}
>  		ble->vendor = vendor;
>  	}
>  	if (product) {
> -		if (regcomp(&ble->product_reg, product,
> -			    REG_EXTENDED|REG_NOSUB)) {
> +		if (lm_regcomp(&ble->product_reg, product,
> +			       REG_EXTENDED|REG_NOSUB)) {
>  			FREE(product);
>  			return 1;
>  		}

Is this change really required? With patch 4 we now get a proper error:
multipath.conf +14 parsing failed:            vendor "*"
multipath.conf +15 parsing failed:            product "*"
error parsing config file

I think it should be enough to modify the man page to mention vendor/product
are both regular expressions. This change might also confuse users since this
automagic "*" to ".*" only applies to the blacklist exceptions.

Sebastian