pidgin/pidgin

Fix a crash when hovering over an exceptionally long URL (4074 characters,
release-2.x.y
2014-01-13, Mark Doliner
2bb66ef1475e
Fix a crash when hovering over an exceptionally long URL (4074 characters,
but it might be different for you) in a gtkimhtml widget (such as the IM
window).

This was reported on the support mailing list:
http://pidgin.im/pipermail/support/2013-March/012980.html
http://pidgin.im/pipermail/support/2013-March/012981.html

Repro steps:
1. "gdb pidgin"

2. "break gdk_x_error"
You'll probably need to type "y" to make breakpoint pending on future shared library load. (Or you could run first then add the breakpoint.)

3. "run --sync"
--sync probably isn't actually necessary. Theoretically it should make the backtrace more useful. Like, maybe it could actually show the Pidgin calls that trigger the problem? Or maybe the problem call starts from the gtk main loop, so there would never be Pidgin code in the backtrace? It's also possible we don't pass our args to the right places to make --sync work.

4. "cont"
I hit the breakpoint at startup for some reason. I've just been continuing past it. Doesn't seem to affect anything.

5. Open an IM window.

6. Paste a long URL.

7. Mouse over the long URL.

8. The breakpoint is hit.

9. "bt"

#0 gdk_x_error (display=0x740e30, error=0x7fffffffbc20)
at /build/buildd/gtk+2.0-2.24.13/gdk/x11/gdkmain-x11.c:458
#1 0x00007ffff73b94f6 in _XError () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#2 0x00007ffff73b6741 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#3 0x00007ffff73b6785 in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#4 0x00007ffff73b7378 in _XReply () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#5 0x00007ffff73b2d3d in XSync () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#6 0x00007ffff73b2dcb in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#7 0x00007ffff73b9e2f in ?? () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#8 0x00007ffff7395d14 in XCreatePixmap () from /usr/lib/x86_64-linux-gnu/libX11.so.6
#9 0x00007ffff62bd0d2 in _gdk_pixmap_new (drawable=0x186ec60, width=width@entry=32774, height=25, depth=24,
depth@entry=-1) at /build/buildd/gtk+2.0-2.24.13/gdk/x11/gdkpixmap-x11.c:175
#10 0x00007ffff6289617 in IA__gdk_pixmap_new (drawable=drawable@entry=0x186ec60, width=width@entry=32774,
height=, depth=depth@entry=-1) at /build/buildd/gtk+2.0-2.24.13/gdk/gdkpixmap.c:249
#11 0x00007ffff6297036 in gdk_window_begin_implicit_paint (rect=0x7fffffffbed0, window=0x186ec60)
at /build/buildd/gtk+2.0-2.24.13/gdk/gdkwindow.c:2779
#12 gdk_window_process_updates_internal (window=0x186ec60) at /build/buildd/gtk+2.0-2.24.13/gdk/gdkwindow.c:5574
#13 0x00007ffff6299201 in IA__gdk_window_process_all_updates ()
at /build/buildd/gtk+2.0-2.24.13/gdk/gdkwindow.c:5696
#14 0x00007ffff6299269 in gdk_window_update_idle (data=)
at /build/buildd/gtk+2.0-2.24.13/gdk/gdkwindow.c:5322
#15 0x00007ffff6276e77 in gdk_threads_dispatch (data=0x1a45c40) at /build/buildd/gtk+2.0-2.24.13/gdk/gdk.c:512
#16 0x00007ffff53d8ab5 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#17 0x00007ffff53d8de8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#18 0x00007ffff53d91e2 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#19 0x00007ffff663ec77 in IA__gtk_main () at /build/buildd/gtk+2.0-2.24.13/gtk/gtkmain.c:1271
#20 0x0000000000499950 in main (argc=1, argv=0x7fffffffe538) at gtkmain.c:933

This is the message it prints when it exits:
The program 'Pidgin' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadAlloc (insufficient resources for operation)'.
(Details: serial 14454 error_code 11 request_code 53 minor_code 0)
(Note to programmers: normally, X errors are reported asynchronously;
that is, you will receive the error a while after causing it.
To debug your program, run it with the --sync command line
option to change this behavior. You can then get a meaningful
backtrace from your debugger if you break on the gdk_x_error() function.)

I think it's kinda lame that gdk/gtk/xlib/whatever barfs when we give it a
ridiculously wide pango layout, but whatever. I'm assuming this problem is
gtkimhtml specific, and so I don't want to spend a whole lot of time fixing
it. As an easy fix I want to just truncate the URL displayed in the tooltip
to 200 characters.

Here's an example URL that I used to trigger the crash:
http://www.example.com/?%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%30123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789%3012345678901234567890123456789012345678901234567890123456789012345678
/** @page jabber-signals Jabber Signals
@signals
@signal jabber-receiving-iq
@signal jabber-receiving-message
@signal jabber-receiving-presence
@signal jabber-watched-iq
@signal jabber-register-namespace-watcher
@signal jabber-unregister-namespace-watcher
@signal jabber-sending-xmlnode
@signal jabber-receiving-xmlnode
@endsignals
<hr>
@signaldef jabber-receiving-iq
@signalproto
gboolean (*iq_received)(PurpleConnection *gc, const char *type, const char *id,
const char *from, xmlnode *iq);
@endsignalproto
@signaldesc
Emitted when an XMPP IQ stanza is received. Allows a plugin to process IQ
stanzas.
@param gc The connection on which the stanza is received
@param type The IQ type ('get', 'set', 'result', or 'error')
@param id The ID attribute from the stanza. MUST NOT be NULL.
@param from The originator of the stanza. MAY BE NULL if the stanza
originated from the user's server.
@param iq The full stanza received.
@return TRUE if the plugin processed this stanza and *nobody else* should
process it. FALSE otherwise.
@endsignaldef
@signaldef jabber-receiving-message
@signalproto
gboolean (*message_received)(PurpleConnection *gc, const char *type,
const char *id, const char *from, const char *to,
xmlnode *message);
@endsignalproto
@signaldesc
Emitted when an XMPP message stanza is received. Allows a plugin to
process message stanzas.
@param gc The connection on which the stanza is received
@param type The message type (see rfc3921 or rfc3921bis)
@param id The ID attribute from the stanza. MAY BE NULL.
@param from The originator of the stanza. MAY BE NULL if the stanza
originated from the user's server.
@param to The destination of the stanza. This is probably either the
full JID of the receiver or the receiver's bare JID.
@param message The full stanza received.
@return TRUE if the plugin processed this stanza and *nobody else* should
process it. FALSE otherwise.
@endsignaldef
@signaldef jabber-receiving-presence
@signalproto
gboolean (*presence_received)(PurpleConnection *gc, const char *type,
const char *from, xmlnode *presence);
@endsignalproto
@signaldesc
Emitted when an XMPP presence stanza is received. Allows a plugin to process
presence stanzas.
@param gc The connection on which the stanza is received
@param type The presence type (see rfc3921 or rfc3921bis). NULL indicates
this is an "available" (i.e. online) presence.
@param from The originator of the stanza. MAY BE NULL if the stanza
originated from the user's server.
@param presence The full stanza received.
@return TRUE if the plugin processed this stanza and *nobody else* should
process it. FALSE otherwise.
@endsignaldef
@signaldef jabber-watched-iq
@signalproto
gboolean (*watched_iq)(PurpleConnection *gc, const char *type, const char *id,
const char *from, xmlnode *child);
@endsignalproto
@signaldesc
Emitted when an IQ with a watched (child, namespace) pair is received. See
jabber-register-namespace-watcher and jabber-unregister-namespace-watcher.
@param gc The connection on which the stanza is received
@param type The IQ type ('get', 'set', 'result', or 'error')
@param id The ID attribute from the stanza. MUST NOT be NULL.
@param from The originator of the stanza. MAY BE NULL if the stanza
originated from the user's server.
@param child The child node with namespace.
@return TRUE if the plugin processed this stanza and *nobody else* should
process it. FALSE otherwise.
@endsignaldef
@signaldef jabber-register-namespace-watcher
@signalproto
void (register_namespace_watcher)(const char *node, const char *namespace);
@endsignalproto
@signaldesc
Emit this signal to register your desire to have specific IQ stanzas to be
emitted via the jabber-watched-iq signal when received.
@param node The IQ child name to longer watch.
@param namespace The IQ child namespace to longer watch.
@endsignaldef
@signaldef jabber-unregister-namespace-watcher
@signalproto
void (unregister_namespace_watcher)(const char *node, const char *namespace);
@endsignalproto
@signaldesc
Emit this signal to unregister your desire to have specific IQ stanzas to be
emitted via the jabber-watched-iq signal when received.
@param node The IQ child name to no longer watch.
@param namespace The IQ child namespace to no longer watch.
@endsignaldef
@signaldef jabber-sending-xmlnode
@signalproto
void (sending_xmlnode)(PurpleConnection *gc, xmlnode **stanza);
@endsignalproto
@signaldesc
Emit this signal (@c purple_signal_emit) to send a stanza. It is preferred
to use this instead of prpl_info->send_raw.
@param gc The connection on which to send the stanza.
@param stanza The stanza to send. If stanza is not NULL after being sent,
the emitter should free it.
@endsignaldef
@signaldef jabber-receiving-xmlnode
@signalproto
void (receiving_xmlnode)(PurpleConnection *gc, xmlnode **stanza);
@endsignalproto
@signaldesc
Emitted when an XMPP stanza is received. Allows a plugin to process any
stanza.
@param gc The connection on which the stanza was received.
@param stanza The received stanza. Set stanza to NULL (and free it) to
stop processing the stanza.
@endsignaldef
*/
// vim: syntax=c.doxygen tw=75 et