[Xcb] [PATCH] Add support for the abstract socket namespace under Linux

[Barton C Massey]

Gah.  I'd never heard of abstract sockets before.  What an
unspeakably ugly API.  Why in the name of all that is good
and pure couldn't the designers just have used an address
family to distinguish these, rather than the horrible,
horrible "zero followed by bytes" kludge?  It's not super
obvious to me that the whole thing is a good idea anyway---I
consider the lack of entries in the namespace for other
kinds of sockets to be a bug, not a feature.

Anyway, thanks much for adding the support! :-) :-)

	Bart

In message <1220931756-12953-3-git-send-email-jcristau at debian.org> you wrote:
> Based on same in Xtrans.
> ---
>  configure.ac   |    6 ++++++
>  src/xcb_util.c |   40 +++++++++++++++++++++++++++++++++++++---
>  2 files changed, 43 insertions(+), 3 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index c9cbd0c..062c0cb 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -70,6 +70,12 @@ AC_HEADER_STDC
>  AC_SEARCH_LIBS(getaddrinfo, socket)
>  AC_SEARCH_LIBS(connect, socket)
>  
> +case $host_os in
> +linux*)
> +	AC_DEFINE([HAVE_ABSTRACT_SOCKETS], 1, [Define if your platform supports abstract sockets])
> +	;;
> +esac
> +
>  dnl check for the sockaddr_un.sun_len member
>  AC_CHECK_MEMBER([struct sockaddr_un.sun_len],
>  		[AC_DEFINE(HAVE_SOCKADDR_SUN_LEN,1,[Have the sockaddr_un.sun_len member.])],
> diff --git a/src/xcb_util.c b/src/xcb_util.c
> index 6b80c80..7c6a4dd 100644
> --- a/src/xcb_util.c
> +++ b/src/xcb_util.c
> @@ -38,6 +38,7 @@
>  #include <errno.h>
>  #include <stdio.h>
>  #include <stdlib.h>
> +#include <stddef.h>
>  #include <unistd.h>
>  #include <string.h>
>  
> @@ -123,6 +124,9 @@ static int _xcb_open_unix(char *protocol, const char *file);
>  #ifdef DNETCONN
>  static int _xcb_open_decnet(const char *host, char *protocol, const unsigned short port);
>  #endif
> +#ifdef HAVE_ABSTRACT_SOCKETS
> +static int _xcb_open_abstract(char *protocol, const char *file);
> +#endif
>  
>  static int _xcb_open(char *host, char *protocol, const int display)
>  {
> @@ -156,10 +160,13 @@ static int _xcb_open(char *host, char *protocol, const int display)
>  
>      /* display specifies Unix socket */
>      snprintf(file, sizeof(file), "%s%d", base, display);
> -    return  _xcb_open_unix(protocol, file);
> -
> +#ifdef HAVE_ABSTRACT_SOCKETS
> +    fd = _xcb_open_abstract(protocol, file);
> +    if (fd >= 0 || (errno != ENOENT && errno != ECONNREFUSED))
> +        return fd;
>  
> -    return fd;
> +#endif
> +    return  _xcb_open_unix(protocol, file);
>  }
>  
>  #ifdef DNETCONN
> @@ -274,6 +281,33 @@ static int _xcb_open_unix(char *protocol, const char *file)
>      return fd;
>  }
>  
> +#ifdef HAVE_ABSTRACT_SOCKETS
> +static int _xcb_open_abstract(char *protocol, const char *file)
> +{
> +    int fd;
> +    struct sockaddr_un addr = {0};
> +    socklen_t namelen;
> +
> +    if (protocol && strcmp("unix",protocol))
> +        return -1;
> +
> +    strcpy(addr.sun_path + 1, file);
> +    addr.sun_family = AF_UNIX;
> +    namelen = offsetof(struct sockaddr_un, sun_path) + 1 + strlen(file);
> +#ifdef HAVE_SOCKADDR_SUN_LEN
> +    addr.sun_len = 1 + strlen(file);
> +#endif
> +    fd = socket(AF_UNIX, SOCK_STREAM, 0);
> +    if (fd == -1)
> +        return -1;
> +    if (connect(fd, (struct sockaddr *) &addr, namelen) == -1) {
> +        close(fd);
> +        return -1;
> +    }
> +    return fd;
> +}
> +#endif
> +
>  xcb_connection_t *xcb_connect(const char *displayname, int *screenp)
>  {
>      int fd, display = 0;
> -- 
> 1.5.6.5
> 
> _______________________________________________
> Xcb mailing list
> Xcb at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/xcb