[RFC PATCH] GETADDRINFO: Make RFC 3484 sorting thread safe.

[Jakub Jelinek]

On Wed, Oct 17, 2007 at 10:13:53PM +0900, YOSHIFUJI Hideaki / ?$B5HF#1QL@ wrote:
> Currently getaddrinfo() is not thread safe due to RFC 3484
> sorting.  Try making it thread safe by introducing a lock.

Only if gai.conf is present and contains reload yes, right?

If so, the locking should be only done in that case IMNSHO.

> --- glibc-2.6.1/sysdeps/posix/getaddrinfo.c	2007-04-29 01:09:07.000000000 +0900
> +++ glibc-2.6.1-ipv6fix/sysdeps/posix/getaddrinfo.c	2007-10-17 22:05:11.000000000 +0900
> @@ -1926,6 +1926,10 @@
>  
>    if (naddrs > 1)
>      {
> +      /* Obtain the lock for RFC 3484 sorting. */
> +      __libc_lock_define_initialized (static, lock);
> +      __libc_lock_lock (lock);
> +
>        /* Read the config file.  */
>        __libc_once_define (static, once);
>        __typeof (once) old_once = once;
> @@ -2017,6 +2021,9 @@
>  	 the information.  */
>        qsort (results, nresults, sizeof (results[0]), rfc3484_sort);
>  
> +      /* Release lock for sorting. */
> +      __libc_lock_unlock (lock);
> +
>        /* Queue the results up as they come out of sorting.  */
>        q = p = results[0].dest_addr;
>        for (i = 1; i < nresults; ++i)

	Jakub