Re: git-credential-cache--daemon quits on SIGHUP, can we change it to ignore instead?

From: Noam Postavsky <npostavs@users.sourceforge.net>
Date: Oct 21, 2015, 02:35 UTC
Message-ID: <CAM-tV-8VXtB5uRgqP9dFpww6AaLzasPV46tCiquz=nz=ksBNng@mail.gmail.com>
In-Reply-To: <xmqqfv18awj4.fsf@gitster.mtv.corp.google.com>

On Sun, Oct 18, 2015 at 1:58 PM, Junio C Hamano <gitster@pobox.com> wrote:

Show 7 quoted lines

> I cannot speak for the person who was primarily responsible for
> designing this behaviour, but I happen to agree with the current
> behaviour in the situation where it was designed to be used.  Upon
> the first use in your session, the "daemon" is auto-spawned, you can
> keep talking with that same instance during your session, and you do
> not have to do anything special to shut it down when you log out.
> Isn't that what happens here?

After looking at this some more, I've discovered this is NOT what actually happens here. If I "git push" from a shell and then log out and log in again, another "git push" does NOT ask me for a password. In other words, the daemon is NOT shut down automatically when I log out. Given that, does it make sense to change the daemon to ignore SIGHUP, or is there some way to change it so that it does exit on logout?

---------------------

I don't understand why this happens, but the attached self-contained pair of programs demonstrate the behaviour:

If I do

   make call-note-sighup note-sighup
   urxvt -e ./call-note-sighup ; cat note-sighup

sighup.log DOES contain "got sighup", but if I instead do

   make call-note-sighup note-sighup
   ./call-note-sighup ; exit

afterwards sighup.log does NOT contain "got sighup" (and I must do "pkill note-sighup" to get rid of the lingering note-sighup process).

#include <stdio.h> #include <unistd.h>

int main(void) {

    remove("sighup.log");

    int pid = fork();
    if (pid < 0) {
        perror("fork");
        return 1;
    } else if (pid == 0) {
        execl("./note-sighup", "./note-sighup", NULL);
        perror("execl(./note-sighup)");
        return 1;
    } else {
        fprintf(stderr, "waiting for sigup.log to appear\n");
        while (!access("sighup.log", F_OK)) {
        }
        fprintf(stderr, "okay, note-sighup.log has arrived, exiting in 5 seconds...\n");
        sleep(5);
    }

    return 0;
}

#include <unistd.h> #include <stdio.h> #include <string.h> #include <signal.h>

static volatile int got_sighup = 0;

void sighup_handler(int sig) {
    got_sighup = 1;
}

int main(void) {

    struct sigaction act;
    memset(&act, 0, sizeof act);
    act.sa_handler = sighup_handler;
    sigaction(SIGHUP, &act, NULL);

    FILE* out = fopen("sighup.log", "w");
    setbuf(out, NULL);
    fprintf(out, "starting note-sighup\n");

    for (;;) {
        sleep(1000);
        if (got_sighup) {
            got_sighup = 0;
            fprintf(out, "got sighup\n");
        }
    }

    return 0;
}