[Xcb] [PATCH libxcb] Introduce new funcion xcb_connect_with_auth_file().
Laércio de Sousa
laerciosousa at sme-mogidascruzes.sp.gov.br
Mon Oct 20 04:06:19 PDT 2014
2014-10-18 5:17 GMT-03:00 Uli Schlachter <psychon at znc.in>:
> Hi,
>
> typo in the subject: funcTion
>
Fixed. Thanks!
> I have not much clue about X11 authentication. Could someone else comment
> on the
> idea behind this patch?
>
> Am 17.10.2014 um 20:23 schrieb Laércio de Sousa:
> > This patch introduces a function called xcb_connect_with_auth_file(),
> > which is similar to xcb_connect_to_display_with_auth_info(), but expects
> > an authorization file path rather than a xcb_auth_info_t struct.
> >
> > Signed-off-by: Laércio de Sousa <
> laerciosousa at sme-mogidascruzes.sp.gov.br>
> > ---
> > src/xcb.h | 21 +++++++++++++++++++++
> > src/xcb_auth.c | 15 +++++++++++++--
> > src/xcb_util.c | 27 ++++++++++++++++++++-------
> > src/xcbint.h | 2 +-
> > 4 files changed, 55 insertions(+), 10 deletions(-)
> >
> > diff --git a/src/xcb.h b/src/xcb.h
> > index 23fe74e..0314ce5 100644
> > --- a/src/xcb.h
> > +++ b/src/xcb.h
> > @@ -535,6 +535,27 @@ int xcb_parse_display(const char *name, char
> **host, int *display, int *screen);
> > xcb_connection_t *xcb_connect(const char *displayname, int *screenp);
> >
> > /**
> > + * @brief Connects to the X server, using and authorization file.
> > + * @param displayname: The name of the display.
> > + * @param authfile: The authorization file path.
> > + * @param screenp: A pointer to a preferred screen number.
> > + * @return A newly allocated xcb_connection_t structure.
> > + *
> > + * Connects to the X server specified by @p displayname, using the
> > + * authorization file @p authfile. If @p authfile value @c NULL, uses
> > + * the value of the XAUTHORITY environment variable. If a particular
> > + * screen on that server is preferred, the int pointed to by @p screenp
> > + * (if not @c NULL) will be set to that screen; otherwise @p screenp
> > + * will be set to 0.
> > + *
> > + * Always returns a non-NULL pointer to a xcb_connection_t, even on
> failure.
> > + * Callers need to use xcb_connection_has_error() to check for failure.
> > + * When finished, use xcb_disconnect() to close the connection and free
> > + * the structure.
> > + */
> > +xcb_connection_t *xcb_connect_with_auth_file(const char *displayname,
> const char *authfile, int *screenp);
> > +
> > +/**
> > * @brief Connects to the X server, using an authorization information.
> > * @param display: The name of the display.
> > * @param auth: The authorization information.
> > diff --git a/src/xcb_auth.c b/src/xcb_auth.c
> > index 29e2b6f..284a582 100644
> > --- a/src/xcb_auth.c
> > +++ b/src/xcb_auth.c
> > @@ -34,6 +34,7 @@
> > #include <sys/param.h>
> > #include <unistd.h>
> > #include <stdlib.h>
> > +#include <stdio.h>
> >
> > #ifdef __INTERIX
> > /* _don't_ ask. interix has INADDR_LOOPBACK in here. */
> > @@ -309,7 +310,7 @@ static struct sockaddr *get_peer_sock_name(int
> (*socket_func)(int,
> > return NULL;
> > }
> >
> > -int _xcb_get_auth_info(int fd, xcb_auth_info_t *info, int display)
> > +int _xcb_get_auth_info(int fd, xcb_auth_info_t *info, int display,
> const char *authfile)
> > {
> > /* code adapted from Xlib/ConnDis.c, xtrans/Xtranssocket.c,
> > xtrans/Xtransutils.c */
> > @@ -334,7 +335,17 @@ int _xcb_get_auth_info(int fd, xcb_auth_info_t
> *info, int display)
> > gotsockname = 1;
> > }
> >
> > - authptr = get_authptr(sockname, display);
> > + if (authfile) {
> > + FILE *f = fopen(authfile, "r");
> > +
> > + if (f) {
>
> Instead of ignoring errors, shouldn't this return an error connection to
> the
> caller?
>
> > + authptr = XauReadAuth(f);
>
> Ok, now I actually googled this code and the man page says:
>
> XauReadAuth reads the next entry from auth_file. The entry is not
> statically allocated and should be freed by calling XauDisposeAuth.
>
> I have no clue about Xau, but the part that says "the next entry" makes me
> think
> that this code doesn't actually work well. And yeah, "xauth list" in a
> terminal
> obviously indicates that an XAUTHORITY file can contain multiple
> authentications. Your code will only use the first one.
>
I'm thinking about this. libxcb currently calls XauGetBestAuthByAddr(),
which calls XauReadAuth() on the file name returned by XauFileName() ---
namely, the value of XAUTHORITY environment variable or ~/.Xauthority.
Maybe the best option would be patching libXau so we can pass explicitly a
file name path to XauGetBestAuthByAddr() --- if none is passed, get one by
calling XauFileName().
I'm affraid all this is becoming too complex. Maybe I should just give up
and call setenv("XAUTHORITY", ...) from my client application before
calling xcb_connect(). My main motivation for proposing this patch is about
symmetry: if I can call xcb_connect() with an explicit display number ---
instead of calling setenv("DISPLAY", ...) and then xcb_connect(NULL,...)
--- shouldn't I be able to do the same with the authorization file?
> + fclose(f);
> > + }
> > + }
> > + else
> > + authptr = get_authptr(sockname, display);
> > +
> > if (authptr == 0)
> > {
> > free(sockname);
> > diff --git a/src/xcb_util.c b/src/xcb_util.c
> > index ba0f108..aafb73d 100644
> > --- a/src/xcb_util.c
> > +++ b/src/xcb_util.c
> > @@ -475,12 +475,10 @@ static int _xcb_open_abstract(char *protocol,
> const char *file, size_t filelen)
> > }
> > #endif
> >
> > -xcb_connection_t *xcb_connect(const char *displayname, int *screenp)
> > -{
> > - return xcb_connect_to_display_with_auth_info(displayname, NULL,
> screenp);
> > -}
> > -
> > -xcb_connection_t *xcb_connect_to_display_with_auth_info(const char
> *displayname, xcb_auth_info_t *auth, int *screenp)
> > +static xcb_connection_t
> *_xcb_connect_to_display_with_auth_info_or_file(const char *displayname,
> > +
> const char *authfile,
> > +
> xcb_auth_info_t *auth,
> > +
> int *screenp)
> > {
> > int fd, display = 0;
> > char *host = NULL;
> > @@ -518,7 +516,7 @@ xcb_connection_t
> *xcb_connect_to_display_with_auth_info(const char *displayname,
> > goto out;
> > }
> >
> > - if(_xcb_get_auth_info(fd, &ourauth, display))
> > + if(_xcb_get_auth_info(fd, &ourauth, display, authfile))
> > {
> > c = xcb_connect_to_fd(fd, &ourauth);
> > free(ourauth.name);
> > @@ -542,3 +540,18 @@ out:
> > free(protocol);
> > return c;
> > }
> > +
> > +xcb_connection_t *xcb_connect(const char *displayname, int *screenp)
> > +{
> > + return xcb_connect_to_display_with_auth_info(displayname, NULL,
> screenp);
>
> I'd propose to call _xcb_connect_to_display_with_auth_info_or_file()
> directly
>
Fixed. Thanks!
> (urgh, what a function name...).
>
I've renamed it to _xcb_connect_to_display_with_auth(). Does it look better
now? :-)
>
> > +}
> > +
> > +xcb_connection_t *xcb_connect_with_auth_file(const char *displayname,
> const char *authfile, int *screenp)
> > +{
> > + return _xcb_connect_to_display_with_auth_info_or_file(displayname,
> authfile, NULL, screenp);
> > +}
> > +
> > +xcb_connection_t *xcb_connect_to_display_with_auth_info(const char
> *displayname, xcb_auth_info_t *auth, int *screenp)
> > +{
> > + return _xcb_connect_to_display_with_auth_info_or_file(displayname,
> NULL, auth, screenp);
> > +}
> > diff --git a/src/xcbint.h b/src/xcbint.h
> > index f89deba..01aca8c 100644
> > --- a/src/xcbint.h
> > +++ b/src/xcbint.h
> > @@ -218,7 +218,7 @@ int _xcb_conn_wait(xcb_connection_t *c,
> pthread_cond_t *cond, struct iovec **vec
> >
> > /* xcb_auth.c */
> >
> > -int _xcb_get_auth_info(int fd, xcb_auth_info_t *info, int display);
> > +int _xcb_get_auth_info(int fd, xcb_auth_info_t *info, int display,
> const char *authfile);
> >
> > #ifdef GCC_HAS_VISIBILITY
> > #pragma GCC visibility pop
> >
>
> Cheers,
> Uli
> --
> A normal person is just someone you don't know well enough yet.
> - Nettie Wiebe
>
--
*Laércio de Sousa*
*Orientador de Informática*
*Escola Municipal "Professor Eulálio Gruppi"*
*Rua Ismael da Silva Mello, 559, Mogi Moderno*
*Mogi das Cruzes - SPCEP 08717-390*
Telefone: (11) 4726-8313
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