[v2,3/3] inet: Return EAI_MEMORY when nrl_domainname() fails to allocate memory

It aligns NI_NOFQDN with default behavior for getnameinfo().

Checked on x86_64-linux-gnu.
---
 inet/getnameinfo.c | 140 +++++++++++++++++++++++----------------------
 1 file changed, 72 insertions(+), 68 deletions(-)

Ping.

On 10/12/2021 08:07, Adhemerval Zanella wrote:
> It aligns NI_NOFQDN with default behavior for getnameinfo().
> 
> Checked on x86_64-linux-gnu.
> ---
>  inet/getnameinfo.c | 140 +++++++++++++++++++++++----------------------
>  1 file changed, 72 insertions(+), 68 deletions(-)
> 
> diff --git a/inet/getnameinfo.c b/inet/getnameinfo.c
> index 2d2397e7dc..acf1538a37 100644
> --- a/inet/getnameinfo.c
> +++ b/inet/getnameinfo.c
> @@ -83,94 +83,95 @@ libc_freeres_ptr (static char *domain);
>     now ignored.  */
>  #define DEPRECATED_NI_IDN 192
>  
> -static void
> +static bool
>  nrl_domainname_core (struct scratch_buffer *tmpbuf)
>  {
>    char *c;
>    struct hostent *h, th;
>    int herror;
>  
> -  while (__gethostbyname_r ("localhost", &th,
> -			    tmpbuf->data, tmpbuf->length,
> +  while (__gethostbyname_r ("localhost", &th, tmpbuf->data, tmpbuf->length,
>  			    &h, &herror))
>      {
>        if (herror == NETDB_INTERNAL && errno == ERANGE)
>  	{
>  	  if (!scratch_buffer_grow (tmpbuf))
> -	    return;
> +	    return false;
>  	}
>        else
>  	break;
>      }
>  
>    if (h != NULL && (c = strchr (h->h_name, '.')) != NULL)
> -    domain = __strdup (++c);
> -  else
>      {
> -      /* The name contains no domain information.  Use the name
> -	 now to get more information.  */
> -      while (__gethostname (tmpbuf->data, tmpbuf->length))
> -	if (!scratch_buffer_grow (tmpbuf))
> -	  return;
> -
> -      if ((c = strchr (tmpbuf->data, '.')) != NULL)
> -	domain = __strdup (++c);
> -      else
> -	{
> -	  /* We need to preserve the hostname.  */
> -	  size_t hstnamelen = strlen (tmpbuf->data) + 1;
> -	  while (__gethostbyname_r (tmpbuf->data, &th,
> -				    tmpbuf->data + hstnamelen,
> -				    tmpbuf->length - hstnamelen,
> -				    &h, &herror))
> -	    {
> -	      if (herror == NETDB_INTERNAL && errno == ERANGE)
> -		{
> -		  if (!scratch_buffer_grow_preserve (tmpbuf))
> -		    return;
> -		}
> -	      else
> -		break;
> -	    }
> +      domain = __strdup (++c);
> +      return domain != NULL;
> +    }
>  
> -	  if (h != NULL && (c = strchr(h->h_name, '.')) != NULL)
> -	    domain = __strdup (++c);
> -	  else
> -	    {
> -	      struct in_addr in_addr;
> +  /* The name contains no domain information.  Use the name
> +     now to get more information.  */
> +  while (__gethostname (tmpbuf->data, tmpbuf->length))
> +    if (!scratch_buffer_grow (tmpbuf))
> +      return false;
>  
> -	      in_addr.s_addr = htonl (INADDR_LOOPBACK);
> +  if ((c = strchr (tmpbuf->data, '.')) != NULL)
> +    {
> +      domain = __strdup (++c);
> +      return domain != NULL;
> +    }
>  
> -	      while (__gethostbyaddr_r ((const char *) &in_addr,
> -					sizeof (struct in_addr),
> -					AF_INET, &th,
> -					tmpbuf->data,
> -					tmpbuf->length,
> -					&h, &herror))
> -		{
> -		  if (herror == NETDB_INTERNAL && errno == ERANGE)
> -		    {
> -		      if (!scratch_buffer_grow (tmpbuf))
> -			return;
> -		    }
> -		  else
> -		    break;
> -		}
> +  /* We need to preserve the hostname.  */
> +  size_t hstnamelen = strlen (tmpbuf->data) + 1;
> +  while (__gethostbyname_r (tmpbuf->data, &th, tmpbuf->data + hstnamelen,
> +			    tmpbuf->length - hstnamelen, &h, &herror))
> +    {
> +      if (herror == NETDB_INTERNAL && errno == ERANGE)
> +	{
> +	  if (!scratch_buffer_grow_preserve (tmpbuf))
> +	    return false;
> +	}
> +      else
> +	break;
> +    }
>  
> -	      if (h != NULL && (c = strchr (h->h_name, '.')) != NULL)
> -		domain = __strdup (++c);
> -	    }
> +  if (h != NULL && (c = strchr(h->h_name, '.')) != NULL)
> +    {
> +      domain = __strdup (++c);
> +      return domain != NULL;
> +    }
> +
> +  struct in_addr in_addr = { .s_addr = htonl (INADDR_LOOPBACK) };
> +
> +  while (__gethostbyaddr_r ((const char *) &in_addr, sizeof (struct in_addr),
> +			    AF_INET, &th, tmpbuf->data, tmpbuf->length, &h,
> +			    &herror))
> +    {
> +      if (herror == NETDB_INTERNAL && errno == ERANGE)
> +	{
> +	  if (!scratch_buffer_grow (tmpbuf))
> +	    return false;
>  	}
> +      else
> +	break;
> +    }
> +
> +  if (h != NULL && (c = strchr (h->h_name, '.')) != NULL)
> +    {
> +      domain = __strdup (++c);
> +      return domain != NULL;
>      }
> +  return true;
>  }
>  
> -static char *
> +static bool
>  nrl_domainname (void)
>  {
>    static int not_first;
>  
>    if (__glibc_likely (atomic_load_acquire (&not_first) != 0))
> -    return domain;
> +    return true;
> +
> +  int r = true;
>  
>    __libc_lock_define_initialized (static, lock);
>    __libc_lock_lock (lock);
> @@ -180,16 +181,15 @@ nrl_domainname (void)
>        struct scratch_buffer tmpbuf;
>        scratch_buffer_init (&tmpbuf);
>  
> -      nrl_domainname_core (&tmpbuf);
> +      if ((r = nrl_domainname_core (&tmpbuf)))
> +	atomic_store_release (&not_first, 1);
>  
>        scratch_buffer_free (&tmpbuf);
> -
> -      atomic_store_release (&not_first, 1);
>      }
>  
>    __libc_lock_unlock (lock);
>  
> -  return domain;
> +  return r;
>  };
>  
>  /* Copy a string to a destination buffer with length checking.  Return
> @@ -285,13 +285,17 @@ gni_host_inet_name (struct scratch_buffer *tmpbuf,
>  
>    if (h)
>      {
> -      char *c;
> -      if ((flags & NI_NOFQDN)
> -	  && (c = nrl_domainname ())
> -	  && (c = strstr (h->h_name, c))
> -	  && (c != h->h_name) && (*(--c) == '.'))
> -	/* Terminate the string after the prefix.  */
> -	*c = '\0';
> +      if (flags & NI_NOFQDN)
> +	{
> +	  if (!nrl_domainname ())
> +	    return EAI_MEMORY;
> +
> +	  char *c = domain;
> +	  if (c != NULL && (c = strstr (h->h_name, c))
> +	       && (c != h->h_name) && (*(--c) == '.'))
> +	    /* Terminate the string after the prefix.  */
> +	    *c = '\0';
> +	}
>  
>        /* If requested, convert from the IDN format.  */
>        bool do_idn = flags & NI_IDN;