Re: [PATCH] glob: fix / matching

[Rich Felker <dalias@libc.org>]

On Fri, May 19, 2017 at 04:59:13PM +0200, Julien Ramseier wrote:
> glob(3) currently fails matching "/", due to any '/' being
> removed from the start of the pattern before checking if
> it's empty.
> 

> diff --git a/src/regex/glob.c b/src/regex/glob.c
> index 5b6ff12..53f3a4e 100644
> --- a/src/regex/glob.c
> +++ b/src/regex/glob.c
> @@ -156,18 +156,11 @@ static int sort(const void *a, const void *b)
>  
>  int glob(const char *restrict pat, int flags, int (*errfunc)(const char *path, int err), glob_t *restrict g)
>  {
> -	const char *p=pat, *d;
> +	const char *p = pat;
>  	struct match head = { .next = NULL }, *tail = &head;
>  	size_t cnt, i;
>  	size_t offs = (flags & GLOB_DOOFFS) ? g->gl_offs : 0;
>  	int error = 0;
> -	
> -	if (*p == '/') {
> -		for (; *p == '/'; p++);
> -		d = "/";
> -	} else {
> -		d = "";
> -	}
>  
>  	if (!errfunc) errfunc = ignore_err;
>  
> @@ -179,12 +172,19 @@ int glob(const char *restrict pat, int flags, int (*errfunc)(const char *path, i
>  
>  	if (strnlen(p, PATH_MAX+1) > PATH_MAX) return GLOB_NOSPACE;
>  
> -	if (*p) error = match_in_dir(d, p, flags, errfunc, &tail);
> +	if (*p) {
> +		const char *d = "";
> +		if (*p == '/') {
> +			for (; *p == '/'; p++);
> +			d = "/";
> +		}
> +		error = match_in_dir(d, p, flags, errfunc, &tail);
> +	}

I'm confused how this patch differs from just removing the "if (*p)"
condition before calling match_in_dir. Does match_in_dir actually work
if p points to an empty string? I thought not...

> Also, any feedback concerning
> http://www.openwall.com/lists/musl/2017/01/12/5 ? 

I'll have to actually trace through what it does to figure out why
that's happening; the intent was that it work for all components, I
think..

Really the whole glob() implementation could use a complete rewrite.

Rich