Re: screen and curses problem

[Miroslaw Dach]

Hi Thomas,

        Thank you very much for your feedback. This what I see that the 
crucial thing is the terminfo.
I have copied across that to my embedded system and it seems to be that 
the problem has disappeared. I am even able to run the news version of 
ncurses (5.6).

Many thanks for all your hints. 

Best Regards

Mirek

On Tue, 3 Jul 2007, Thomas Dickey wrote:

> On Tue, Jul 03, 2007 at 02:06:08PM +0200, Miroslaw Dach wrote:
> > Hi Thomas,
> > 
> >     Thanks a lot for your hint. I have set the NCURSES_TRACE variable 
> > to TRACE_MAXIMUM.
> > 
> > Next what I did, I have started my server:
> > export TERM=linux-m
> > ../screen  -t MYSERVER -d -m myServer
> 
> ok.  To make a comparison, I built a tracing ncurses and statically linked
> screen to that, calling trace(0xffff) from the main program.  (I also
> turned on screen's debug feature, thinking I could get some separate
> tracing - find that screen writes to the same stream as ncurses's trace,
> perhaps because it assumes too much about the file descriptor).
> 
> > The trace file looked like that:
> > ------------------------------------------------------------------------
> > TRACING NCURSES version 5.4.20050122 (tracelevel=0x1fff)
> > called {tgetent()
> > + called {setupterm("screen",1,0x7f9601e8)
> > your terminal name is screen
> > cannot open terminfo /root/.terminfo/s/screen (errno=2)
> > cannot open terminfo /usr/share/terminfo/s/screen (errno=2)
> > TERMPATH is /etc/termcap:/usr/share/misc/termcap
> > Adding termpath /etc/termcap
> > Looking for screen in /etc/termcap
> > cannot open terminfo /root/.terminfo/a/ansi-m (errno=2)
> > cannot open terminfo /usr/share/terminfo/a/ansi-m (errno=2)
> 
> I've assuming there is some missing text here.
> If I force screen to read the termcap file, I get a very long listing
> showing the parsing of the termcap, e.g., text starting with
> 
>       TERMPATH is /tmp/BUILD/etc/termcap
>       Adding termpath /tmp/BUILD/etc/termcap
>       Looking for linux-m in /tmp/BUILD/etc/termcap
>       Token: Names; value='dumb|80-column dumb tty'
>       token: `dumb|80-column dumb tty', class 4
> 
> That also fails (I'm not sure why at the moment - it is a long trace), with a
> 
>       Clear screen capability required.
> 
> message.
> 
> When it reads the terminfo, there's no "Looking for", etc.
> But there should still be some data:
> 
>       read terminfo /tmp/BUILD/share/terminfo/l/linux
>       READ termtype header @0
>       TERMTYPE name_size=20, bool=29/44, num=16/39 str=381/414(809)
>       get Numbers[0]=-1
>       get Numbers[1]=8
> 
> > _nc_free_termtype(klone+acs|alternate character set for ansi.sys displays)
> > _nc_free_termtype(3u264v301w302x263y371z372{373|374}375~376.031-030054021+^P0333p3)
> > _nc_free_termtype(04r304y363z362{343|330}234)
> 
> There's something wrong here - the parameter to _nc_free_termtype()
> should be a list of terminal names.  In the two preceding calls,
> it looks like a fragment from an acsc string:
> 
>       
> acsc=+\020\,\021-\030.^Y0\333`\004a\261f\370g\361h\260i\316j\331k\277l\332m\300n\305o~p\304q\304r\304s_t\303u\264v\301w\302x\263y\363z\362{\343|\330}\234~\376,
> 
> > _nc_free_termtype(klone+sgr|attribute control for ansi.sys displays)
> > _nc_free_termtype(klone+color|color control for ansi.sys and 
> > ISO6429-compatible displays)
> > _nc_free_termtype(linux|linux console)
> > _nc_free_termtype(linux-m|Linux console no color)
> > _nc_free_termtype(xf|xterm-xfree86|XFree86 xterm)
> > _nc_free_termtype(xterm-debian|xterm with modifications to follow Debian 
> > keyboard policy)
> > _nc_free_termtype(xterm-redhat|xterm with modifications to follow Debian 
> > keyboard policy)
> > _nc_free_termtype(v0|xterm|X11 terminal emulator)
> > _nc_free_termtype(ansi|ansi/pc-term compatible with color)
> > + + called {del_curterm(0x1006bb08)
> > _nc_free_termtype((null))
> > + + return }0
> > + return }-1
> > return }0
> 
> These look ok - but as I noted, there seems to be something missing.
> 
> > -----------------------------------------------------------------
> > 
> > Next I have tried to attache to the server:
> > 
> > screen -r 
> > 
> > trace file looked like that:
> > -----------------------------------------------------------------
> > called {tgetent()
> > + called {setupterm("linux-m",1,0x7f95fd18)
> > your terminal name is linux-m
> > cannot open terminfo /root/.terminfo/l/linux-m (errno=2)
> > cannot open terminfo /usr/share/terminfo/l/linux-m (errno=2)
> > TERMPATH is /etc/termcap:/usr/share/misc/termcap
> > Adding termpath /etc/termcap
> > Looking for linux-m in /etc/termcap
> > cannot open terminfo /root/.terminfo/a/ansi-m (errno=2)
> > cannot open terminfo /usr/share/terminfo/a/ansi-m (errno=2)
> > _nc_free_termtype(klone+acs|alternate character set for ansi.sys displays)
> > _nc_free_termtype(3u264v301w302x263y371z372{373|374}375~376.031-030054021+^P0333p3)
> > _nc_free_termtype(04r304y363z362{343|330}234)
> > _nc_free_termtype(klone+sgr|attribute control for ansi.sys displays)
> > _nc_free_termtype(klone+color|color control for ansi.sys and 
> > ISO6429-compatible displays)
> > _nc_free_termtype(linux|linux console)
> > _nc_free_termtype(linux-m|Linux console no color)
> > _nc_free_termtype(xf|xterm-xfree86|XFree86 xterm)
> > _nc_free_termtype(xterm-debian|xterm with modifications to follow Debian 
> > keyboard policy)
> > _nc_free_termtype(xterm-redhat|xterm with modifications to follow Debian 
> > keyboard policy)
> > _nc_free_termtype(v0|xterm|X11 terminal emulator)
> > _nc_free_termtype(ansi|ansi/pc-term compatible with color)
> > + + called {set_curterm(0x10074c80)
> > + + return }(nil)
> 
> Again, there's some missing data.  For comparison here's a fragment of
> trace:
> 
>       called {tgetent()
>       + called {setupterm("screen.linux",1,0xbfb229a8)
>       your terminal name is screen.linux
>       cannot open terminfo /users/tom/.terminfo/s/screen.linux (errno=13)
>       read terminfo /tmp/BUILD/share/terminfo/s/screen.linux
>       READ termtype header @0
>       TERMTYPE name_size=37, bool=15/44, num=16/39 str=361/414(526)
>       get Numbers[0]=80
>       get Numbers[1]=8
> 
> > screen size: terminfo lines = 4080 columns = 4103
> 
> Those numbers don't make any sense to me (decimal/octal/hex):
> 
> 4080: 4080 07760 0xff0 text "\017\360" utf8 \340\277\260
> 4103: 4103 010007 0x1007 text "\020\007" utf8 \341\200\207
> 
> But I think that if you go back and isolate the apparent data overrun
> in the first command, that might give a clue.
> 
> > Studding the output I see that LINES and COLUMNS are not correctly set.
> > Does ncurses detect that automatically?
> 
> ncurses tries to use a system call for getting that information.
> But I think that's only a symptom - something is not using a
> correct buffer size (or structure size), and is overrunning some
> data.  Rereading the database only gets worse.
> 
> 

-- 
=============================================================================
          Miroslaw Dach (address@hidden) - SLS/Controls Group 
                PSI - Paul Scherrer Institut CH-5232 Villigen
=============================================================================