[PATCH] Account for alloca use when collecting interface addresses

[Siddhesh Poyarekar]

On Mon, Mar 24, 2014 at 03:04:23PM +0100, Andreas Schwab wrote:
> # ip li add name dummy0 type dummy
> # site_id=$(head -c6 /dev/urandom | od -tx2 -An | tr ' ' ':')
> # for ((i = 0; i < 65536; i++)) do
> > ip ad ad $(printf fd80$site_id::%04x $i)/128 dev dummy0
> > done
> # (ulimit -s 900; getent ahosts localhost)
> # ip li de dummy0

This needs a more verbose description for the commit log.  The change
itself looks OK to me.

Thanks,
Siddhesh

> 	[BZ #16002]
> 	* sysdeps/unix/sysv/linux/check_pf.c (make_request): Use
> 	alloca_account and account alloca use for struct in6ailist.
> ---
>  sysdeps/unix/sysv/linux/check_pf.c | 32 ++++++++++++++++++++++++++++----
>  1 file changed, 28 insertions(+), 4 deletions(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/check_pf.c b/sysdeps/unix/sysv/linux/check_pf.c
> index 5c8e75a..6d8468d 100644
> --- a/sysdeps/unix/sysv/linux/check_pf.c
> +++ b/sysdeps/unix/sysv/linux/check_pf.c
> @@ -139,9 +139,10 @@ make_request (int fd, pid_t pid)
>  #endif
>    bool use_malloc = false;
>    char *buf;
> +  size_t alloca_used = 0;
>  
>    if (__libc_use_alloca (buf_size))
> -    buf = alloca (buf_size);
> +    buf = alloca_account (buf_size, alloca_used);
>    else
>      {
>        buf = malloc (buf_size);
> @@ -163,6 +164,7 @@ make_request (int fd, pid_t pid)
>    {
>      struct in6addrinfo info;
>      struct in6ailist *next;
> +    bool use_malloc;
>    } *in6ailist = NULL;
>    size_t in6ailistlen = 0;
>    bool seen_ipv4 = false;
> @@ -239,7 +241,19 @@ make_request (int fd, pid_t pid)
>  		    }
>  		}
>  
> -	      struct in6ailist *newp = alloca (sizeof (*newp));
> +	      struct in6ailist *newp;
> +	      if (__libc_use_alloca (alloca_used + sizeof (*newp)))
> +		{
> +		  newp = alloca_account (sizeof (*newp), alloca_used);
> +		  newp->use_malloc = false;
> +		}
> +	      else
> +		{
> +		  newp = malloc (sizeof (*newp));
> +		  if (newp == NULL)
> +		    goto out_fail;
> +		  newp->use_malloc = true;
> +		}
>  	      newp->info.flags = (((ifam->ifa_flags
>  				    & (IFA_F_DEPRECATED
>  				       | IFA_F_OPTIMISTIC))
> @@ -286,7 +300,10 @@ make_request (int fd, pid_t pid)
>        do
>  	{
>  	  result->in6ai[--in6ailistlen] = in6ailist->info;
> -	  in6ailist = in6ailist->next;
> +	  struct in6ailist *next = in6ailist->next;
> +	  if (in6ailist->use_malloc)
> +	    free (in6ailist);
> +	  in6ailist = next;
>  	}
>        while (in6ailist != NULL);
>      }
> @@ -302,7 +319,14 @@ make_request (int fd, pid_t pid)
>      free (buf);
>    return result;
>  
> -out_fail:
> + out_fail:
> +  while (in6ailist != NULL)
> +    {
> +      struct in6ailist *next = in6ailist->next;
> +      if (in6ailist->use_malloc)
> +	free (in6ailist);
> +      in6ailist = next;
> +    }
>    if (use_malloc)
>      free (buf);
>    return NULL;
> -- 
> 1.9.1
> 
> 
> -- 
> Andreas Schwab, SUSE Labs, schwab@suse.de
> GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
> "And now for something completely different."
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