On Fri, Dec 25, 2020 at 09:08:14PM +0100, Christian Melki wrote:
> Ptxdist seems to assume things about the ncurses local build that doesn't
> always turn up to be usable.
>
> I use a ncurses-6.2 build in Slackware. Pretty normal build.
>
> mconf headers point to the ncurses library, not ncursesw.
>
> mconf gets built with:
> -O2 -D_DEFAULT_SOURCE -D_XOPEN_SOURCE=600
> and is linked with:
> linux-vdso.so.1 (0x00007ffcd5f30000)
> libncurses.so.6 => /lib64/libncurses.so.6 (0x00007f6914c68000)
> libtinfo.so.6 => /lib64/libtinfo.so.6 (0x00007f6914c37000)
> libc.so.6 => /lib64/libc.so.6 (0x00007f6914a52000)
> libdl.so.2 => /lib64/libdl.so.2 (0x00007f6914a4d000)
> /lib64/ld-linux-x86-64.so.2 (0x00007f6914cbd000)
>
> And mconf segfaults with:
> Program received signal SIGSEGV, Segmentation fault.
> 0x00007ffff7f84b9a in waddch () from /lib64/libncurses.so.6
>
> (gdb) bt
> #0 0x00007ffff7f84b9a in waddch () from /lib64/libncurses.so.6
> #1 0x0000000000415c78 in attr_clear (win=0xcdf820, height=49, width=299,
> attr=<optimized out>) at lxdialog/util.c:250
> #2 0x0000000000415cfc in dialog_clear () at lxdialog/util.c:262
> #3 0x0000000000416274 in init_dialog (backtitle=backtitle@entry=0x0) at
> lxdialog/util.c:336
> #4 0x000000000040272c in main (ac=2, av=0x7ffffffefd78) at mconf.c:1017
>
> ... second loop pass. Height = 0 passes the width loop. Height = 1, Width =
> 0 segfaults.
>
> (gdb) print j
> $8 = 298
> (gdb) n
> 250 waddch(win, ' ');
> (gdb) n
> 249 for (j = 0; j < width; j++)
> (gdb) n
> 247 for (i = 0; i < height; i++) {
> (gdb) n
> 248 wmove(win, i, 0);
> (gdb) print i
> $9 = 1
> (gdb) n
> 249 for (j = 0; j < width; j++)
> (gdb) n
> 250 waddch(win, ' ');
> (gdb) n
> Program received signal SIGSEGV, Segmentation fault.
>
> I am not sure what to blame here or if I understand things.
> Or if it's resonable that ncurses should explode like this.
>
> Seems pkg-config cflags answers:
> pkg-config --cflags ncurses -D_DEFAULT_SOURCE -D_XOPEN_SOURCE=600
>
> But if I understand things >= 600 = wide char header?
> the pkg-config answers the same for ncursesw.
I see the same pkg-config results here on Debian.
I have no idea how this is supposed to work.
> So the program will compile and link just fine.
> If I use xterm and rxvt as $TERM the mconf program crashes, but is fine with
> vt100.
>
> Is this related to ext-colors support somehow?
> If I force the program to link with ncursesw, then all is fine.
Hmmm, what happens if you add -DNCURSES_WIDECHAR=0 to the cflags and link
with ncurses? Does it work correctly now?
> My best guess is that the terminal is ext-color, program gets built with
> wchar-support but linked with ncurses.
> This probably shouldn't explode in ncurses, but I think it's also a
> misconfiguration build.
>
> I would suggest that ptxdist uses ncursesw + headers if found and ncurses
> without wchar if not found.
>
> Kernel seems to prefer something similar?
> https://elixir.bootlin.com/linux/v5.10.2/source/scripts/kconfig/mconf-cfg.sh
The whole ncurses handling in configure.ac should probably cleaned up and
simplified.
Michael
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