Please don't do this.
Ingo Schwarze <schwa...@usta.de> wrote:
> Hi Stuart,
>
> Stuart Henderson wrote on Fri, Oct 29, 2021 at 01:59:38PM +0100:
> > On 2021/10/29 14:08, Ingo Schwarze wrote:
> >> Stuart Henderson wrote on Fri, Oct 29, 2021 at 10:53:41AM +0100:
> >>> On 2021/10/28 23:19, Klemens Nanni wrote:
> >>>> On Fri, Oct 29, 2021 at 12:57:54AM +0200, Ingo Schwarze wrote:
>
> >>>>> MANPAGER=firefox man -T html $(ifconfig -C)
>
> >>>> This doesn't work if firefox is already running as the MANPAGER firefox
> >>>> process exits immediately after sending the file/link to the running
> >>>> process, which causes mandoc to exit after removing the temporary file,
> >>>> by which time firefox fails to open the no longer exiting file.
>
> >>> I use mutt_bgrun for things like this
>
> >> I don't see how that can possibly help.
>
> > Oh, of course you're right - I was confused between my helper
> > scripts. The one I actually use for html in mutt looks like this,
> > so it's not any user for MANPAGER..
> >
> > tmp=`mktemp -d /tmp/mutthtml.XXXXXXXXX` || exit 1
> > mhonarc -rcfile ~/.m2h_rcfile -single > $tmp/mail.html
> > (chrome $tmp/mail.html 2>/dev/null; sleep 30; rm -r $tmp) &
>
> Indeed, if i added sleep(30) to the place in question
> in usr.bin/mandoc/main.c, i would expect quite an outrage...
> A protest rally on my front lawn or something like that...
>
> Then again, the man(1) process that is about to exit could maybe fork
> a child before exiting. The parent exiting right away makes sure that
> the user gets back their shell prompt instantly after exiting the pager.
> The child process, now being in the background, could sleep a few seconds
> before deleting the temporary output files, then exit, too.
>
> This does appear to successfully work around the firefox bug.
> With the patch below, "MANPAGER=firefox man -T html ..."
> now works reliably for me.
>
> It does seem somewhat ugly, though, so i'm not sure whether i should
> commit it. In particular, fork(2)ing merely to go to the background
> seems both cumbersome and expensive - admittedly, your script cited
> above does the same, but that doesn't imply i have to like that, right?
>
> Is there a cleaner way to let man(1) go into the background and
> let the shell offer a fresh prompt while man(1) still sleeps,
> without needing to fork(2)?
>
> Yours,
> Ingo
>
>
> Index: main.c
> ===================================================================
> RCS file: /cvs/src/usr.bin/mandoc/main.c,v
> retrieving revision 1.262
> diff -u -p -r1.262 main.c
> --- main.c 4 Oct 2021 21:28:50 -0000 1.262
> +++ main.c 29 Oct 2021 14:12:08 -0000
> @@ -1203,6 +1203,7 @@ woptions(char *arg, enum mandoc_os *os_e
> static void
> run_pager(struct outstate *outst, char *tag_target)
> {
> + const struct timespec delay = { 5, 0 };
> int signum, status;
> pid_t man_pgid, tc_pgid;
> pid_t pager_pid, wait_pid;
> @@ -1245,13 +1246,16 @@ run_pager(struct outstate *outst, char *
> if (wait_pid == -1) {
> mandoc_msg(MANDOCERR_WAIT, 0, 0,
> "%s", strerror(errno));
> - break;
> + return;
> }
> if (!WIFSTOPPED(status))
> break;
>
> signum = WSTOPSIG(status);
> }
> + if (fork() > 0)
> + _exit(mandoc_msg_getrc());
> + nanosleep(&delay, NULL);
> }
>
> static pid_t
>
