simon-git: putty (master): Simon Tatham

[Commits to Tartarus hosted VCS]

TL;DR:
  b8c4d04 Fix startup hang in Unix file transfer tools.

Repository:     https://git.tartarus.org/simon/putty.git
On the web:     https://git.tartarus.org/?p=simon/putty.git
Branch updated: master
Committer:      Simon Tatham <anakin at pobox.com>
Date:           2018-05-24 17:03:40

commit b8c4d042bd289bb4d75185d49cdf3ad2f7e695be
web diff https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=b8c4d042bd289bb4d75185d49cdf3ad2f7e695be;hp=7d0ade7eac694d63381054d38d3eb4f199c350d7
Author: Simon Tatham <anakin at pobox.com>
Date:   Thu May 24 16:54:16 2018 +0100

    Fix startup hang in Unix file transfer tools.
    
    This seems to be a knock-on effect of my recent reworking of the SSH
    code to be based around queues and callbacks. The loop iteration
    function in uxsftp.c (ssh_sftp_do_select) would keep going round its
    select loop until something had happened on one of its file
    descriptors, and then return to the caller in the assumption that the
    resulting data might have triggered whatever condition the caller was
    waiting for - and if not, then the caller checks, finds nothing
    interesting has happened, and resumes looping with no harm done.
    
    But now, when something happens on an fd, it doesn't _synchronously_
    trigger the follow-up condition PSFTP was waiting for (which, at
    startup time, happens to be back->sendok() starting to return TRUE).
    Instead, it schedules a callback, which will schedule a callback,
    which ... ends up setting that flag. But by that time, the loop
    function has already returned, the caller has found nothing
    interesting and resumed looping, and _now_ the interesting thing
    happens but it's too late because ssh_sftp_do_select will wait until
    the next file descriptor activity before it next returns.
    
    Solution: give run_toplevel_callbacks a return value which says
    whether it's actually done something, and if so, return immediately in
    case that was the droid the caller was looking for. As it were.

 callback.c    | 7 ++++++-
 putty.h       | 7 ++++++-
 unix/uxsftp.c | 5 +++--
 3 files changed, 15 insertions(+), 4 deletions(-)