On 8/31/22 16:55, enh wrote: > and if i `CONFIG_TOYBOX_NORECURSE=y`, it calls sed and works... > > ...though this might be about to come back and bite me. i'm hearing as-yet > unconfirmed reports that toybox `tar czf` is a lot slower than gnu tar, and -- > given that they're using --transform` while they're assuming it's tar or gzip, > i'm wondering whether it's actually the fact that we're forking out to sed for > every file? > > i've asked for repro steps or a `perf record` i can look at...
When I said I had more work to do there, part of what I wanted to do was add a sed --tar-xform mode with some sort of protocol that would allow a single persistent sed to get a name and send back a response without exiting. (That would also allow me to implement the trailing type indicators.) Right now exiting lets you know that it's done processing, even if your sed invocation included a "d" or something and thus produced no output (so you wait forever if it DOESN'T exit). And even if I use -z mode you can include \0 manually in a substitution and thus force it out of sync. So the persistent mode would need some sort of "expect X bytes of output" indicator, probably just a decimal number of bytes ending with a newline, followed by the transformed payload. And of course the type indicator needs the incoming name to be annotated with type information as part of the call-and-response protocol... It's not perfect, you can always sed ':a;b a' or something if you want to cause Horrible Goose levels of trouble. (Tempted to add something like the symlink resolution limit so 1 billion jumps in a single sed pattern evaluation exit with an error...) The downside of doing that is it would require TOYBOX sed. Right now it should work with the host sed. I vaguely plan to try to launch "sed --tar-xform -e $PATTERN" and then fall back to the old one at a time logic not undestanding suffixes if sed exits with an error, because toybox commands try NOT to require other toybox commands. But I can't figure out a better way to do this than copying half the sed plumbing to lib/sed.c and it really wasn't designed to be broken up... Rob _______________________________________________ Toybox mailing list Toybox@lists.landley.net http://lists.landley.net/listinfo.cgi/toybox-landley.net
