How can I use terminfo entries on FreeBSD?

Question

On my local Linux machine, I'm using termite (VTE-based). It comes with its own terminfo file (xterm-termite), which is not distributed with ncurses by default.

I try to connect to a remote FreeBSD server. Unfortunately, FreeBSD by default only uses the older termcap format. I haven't been able to find a way to convert terminfo to termcap. So, while I can compile a version of ncurses which includes terminfo support from the ports (devel/ncurses), ncurses applications will link to the system-supplied lib by default. This results in apps failing to launch:

$ echo $TERM
xterm-termite
$ toe | grep termite
xterm-termite   VTE-based terminal
$ tmux
open terminal failed: can't find terminfo database
$ htop
Error opening terminal: xterm-termite.

(toe lists terminfo entries)

How can I make FreeBSD use terminfo by default, or force applications to use the port-supplied ncurses lib, or at least convert terminfo to termcap data?

(I'm aware of the workarounds like setting TERM to a safe value like xterm-256color, but I think that defeats the purpose of terminfo)

Answer 1

The conventional way to convert terminfo to termcap is with

infocmp -Cr

The infocmp option -C tells infocmp to use termcap names, and the -r option tells it to translate terminfo capabilities to termcap format. Some (such as the expressions used in sgr) will not translate, and infocmp may leave commented-out capabilities if there is enough space.

By "enough space", refers to the fact that real termcap applications allow only 1023 bytes in a description. FreeBSD uses ncurses underneath, but some applications make assumptions about the entry length.

FreeBSD however does have a termcap file which is independent of ncurses. There also is a "port" for ncurses, which some find useful.

By the way, you may be referring to this: termite/termite.terminfo. If you translated it, you might see something like

# vim: noet:ts=8:sw=8:sts=0
# (untranslatable capabilities removed to fit entry within 1023 bytes)
# (sgr removed to fit entry within 1023 bytes)
# (acsc removed to fit entry within 1023 bytes)
# (terminfo-only capabilities suppressed to fit entry within 1023 bytes)
xterm-termite|VTE-based terminal:\
        :am:hs:km:mi:ms:xn:\
        :co#80:it#8:li#24:\
        :AL=\E[%dL:DC=\E[%dP:DL=\E[%dM:DO=\E[%dB:IC=\E[%d@:\
        :K2=\EOE:LE=\E[%dD:RI=\E[%dC:SF=\E[%dS:SR=\E[%dT:\
        :UP=\E[%dA:ae=\E(B:al=\E[L:as=\E(0:bl=^G:bt=\E[Z:cd=\E[J:\
        :ce=\E[K:cl=\E[H\E[2J:cm=\E[%i%d;%dH:cr=^M:\
        :cs=\E[%i%d;%dr:ct=\E[3g:dc=\E[P:dl=\E[M:do=^J:\
        :ds=\E]2;\007:ec=\E[%dX:ei=\E[4l:fs=^G:ho=\E[H:im=\E[4h:\
        :is=\E[!p\E[?3;4l\E[4l\E>:k1=\EOP:k2=\EOQ:k3=\EOR:\
        :k4=\EOS:k5=\E[15~:k6=\E[17~:k7=\E[18~:k8=\E[19~:\
        :k9=\E[20~:kD=\E[3~:kI=\E[2~:kN=\E[6~:kP=\E[5~:kb=\177:\
        :kd=\EOB:ke=\E[?1l\E>:kh=\EOH:kl=\EOD:kr=\EOC:\
        :ks=\E[?1h\E=:ku=\EOA:le=^H:md=\E[1m:me=\E[0m:mh=\E[2m:\
        :mm=\E[?1034h:mo=\E[?1034l:mr=\E[7m:nd=\E[C:rc=\E8:sc=\E7:\
        :se=\E[27m:sf=^J:so=\E[7m:sr=\EM:st=\EH:ta=^I:te=\E[?1049l:\
        :ti=\E[?1049h:ts=\E]2;:ue=\E[24m:up=\E[A:us=\E[4m:\
        :vb=\E[?5h\E[?5l:ve=\E[?12l\E[?25h:vi=\E[?25l:\
        :vs=\E[?12;25h:

There are a few errors in the terminfo entry (VTE does not support meta mode, for instance). Also, in termcap format you may notice that most of the function-keys go away (1023-byte limit).

Further reading:

• infocmp - compare or print out terminfo descriptions
• infotocap - convert a terminfo description into a termcap description
• tctest – A Termcap Test Utility

Answer 2

Sometimes you need to do some manual changes to translate things properly.

I've made the following changes, to get it to translate the "important" parts of the desription.

• Removed capabilities that cannot be represented in termcap format:
  • Dynamic color changing (ccc/initc)
  • Multi-attribute setting sequence (sgr)
  • Visual Bell (flash, requires intermediate delay which doesn't work in termcap)
• Removed capabilities that aren't useful:
  • VT100 box drawing characters (smacs/rmacs/acsc, also changed sgr0)
  • 8-bit meta key (km/smm/rmm), also Thomas Dickey mentioned it doesn't actually work.
  • Printing (mc5i/mc0/mc4/mc5)
  • Blinking cursor (cvvis, also changed cnorm)
  • HP curses extensions (meml/memu)
  • Dynamic changing of tab stops (hts/tbc)
  • Infrequently used attributes (dim/invis)
• Removed capabilities that are rarely used and excessively long
  • Shifted function/cursor keys (kf13+, kLFT/etc [upper-case names], kind, kri [used for shift-up/down])
  • Long-form init and reset sequences (is2/rs2)
  • Terminal identification and response (u8/u9)
• Rewrote some things to fit better / be compatible with termcap
  • Changed setab/setaf to less efficient termcap-compatible version
  • Changed smkx/rmkx/clear to be shorter

This got it down to 1001 characters without sacrificing anything "important" (in particular, it still supports 256 colors and setting the title bar text)

xterm-termite|VTE-based terminal:\
    :NP:am:hs:mi:ms:ut:xn:\
    :Co#256:co#80:it#8:li#24:pa#32767:\
    :@7=\EOF:@8=\EOM:AB=\E[48;5;%dm:AF=\E[38;5;%dm:AL=\E[%dL:\
    :DC=\E[%dP:DL=\E[%dM:DO=\E[%dB:F1=\E[23~:F2=\E[24~:\
    :IC=\E[%d@:K2=\EOE:Km=\E[M:LE=\E[%dD:RA=\E[?7l:RI=\E[%dC:\
    :SA=\E[?7h:SF=\E[%dS:SR=\E[%dT:UP=\E[%dA:ZH=\E[3m:\
    :ZR=\E[23m:al=\E[L:bl=^G:bt=\E[Z:cb=\E[1K:cd=\E[J:ce=\E[K:\
    :ch=\E[%i%dG:cl=\E[H\E[J:cm=\E[%i%d;%dH:cr=^M:\
    :cs=\E[%i%d;%dr:cv=\E[%i%dd:dc=\E[P:dl=\E[M:do=^J:\
    :ds=\E]2;\007:ec=\E[%dX:ei=\E[4l:fs=^G:ho=\E[H:im=\E[4h:\
    :k1=\EOP:k2=\EOQ:k3=\EOR:k4=\EOS:k5=\E[15~:k6=\E[17~:\
    :k7=\E[18~:k8=\E[19~:k9=\E[20~:k;=\E[21~:kB=\E[Z:kD=\E[3~:\
    :kI=\E[2~:kN=\E[6~:kP=\E[5~:kb=\177:kd=\EOB:ke=\E[?1l:\
    :kh=\EOH:kl=\EOD:kr=\EOC:ks=\E[?1h:ku=\EOA:le=^H:md=\E[1m:\
    :me=\E[m:mr=\E[7m:nd=\E[C:op=\E[39;49m:r1=\Ec:rc=\E8:\
    :sc=\E7:se=\E[27m:sf=^J:so=\E[7m:sr=\EM:ta=^I:te=\E[?1049l:\
    :ti=\E[?1049h:ts=\E]2;:u6=\E[%i%d;%dR:u7=\E[6n:ue=\E[24m:\
    :up=\E[A:us=\E[4m:ve=\E[?25h:vi=\E[?25l:

Note that all indented lines should use tabs for indentation.

The important thing for color support is the AB and AF capabilities - they couldn't be translated automatically from setab/setaf because it's a 256-color terminal. The relevant part of the termcap is :AB=\E[48;5;%dm:AF=\E[38;5;%dm:; for non-256-color mode it would be :AB=\E[4%dm:AF=\E[3%dm: (and Co#8, pa#64 to match).