diff options
| -rw-r--r-- | fetchmail.c | 202 |
1 files changed, 106 insertions, 96 deletions
diff --git a/fetchmail.c b/fetchmail.c index fa79a30e..24dfc00a 100644 --- a/fetchmail.c +++ b/fetchmail.c @@ -163,6 +163,103 @@ static void dropprivs(void) } #endif +static flag idle(int seconds) +/* time for a pause in the action; return TRUE if awakened by signal */ +{ +#ifndef __EMX__ +#ifdef SLEEP_WITH_ALARM /* not normally on */ + /* + * We can't use sleep(3) here because we need an alarm(3) + * equivalent in order to implement server nonresponse timeout. + * We'll just assume setitimer(2) is available since fetchmail + * has to have a BSDoid socket layer to work at all. + */ + /* + * This code stopped working under glibc-2, apparently due + * to the change in signal(2) semantics. (The siginterrupt + * line, added later, should fix this problem.) John Stracke + * <francis@netscape.com> wrote: + * + * The problem seems to be that, after hitting the interval + * timer while talking to the server, the process no longer + * responds to SIGALRM. I put in printf()s to see when it + * reached the pause() for the poll interval, and I checked + * the return from setitimer(), and everything seemed to be + * working fine, except that the pause() just ignored SIGALRM. + * I thought maybe the itimer wasn't being fired, so I hit + * it with a SIGALRM from the command line, and it ignored + * that, too. SIGUSR1 woke it up just fine, and it proceeded + * to repoll--but, when the dummy server didn't respond, it + * never timed out, and SIGALRM wouldn't make it. + * + * (continued below...) + */ + struct itimerval ntimeout; + + ntimeout.it_interval.tv_sec = 5; /* repeat alarm every 5 secs */ + ntimeout.it_interval.tv_usec = 0; + ntimeout.it_value.tv_sec = seconds; + ntimeout.it_value.tv_usec = 0; + + siginterrupt(SIGALRM, 1); + alarm_latch = FALSE; + signal(SIGALRM, gotsigalrm); /* first trap signals */ + setitimer(ITIMER_REAL,&ntimeout,NULL); /* then start timer */ + /* there is a very small window between the next two lines */ + /* which could result in a deadlock. But this will now be */ + /* caught by periodical alarms (see it_interval) */ + if (!alarm_latch) + pause(); + /* stop timer */ + ntimeout.it_interval.tv_sec = ntimeout.it_interval.tv_usec = 0; + ntimeout.it_value.tv_sec = ntimeout.it_value.tv_usec = 0; + setitimer(ITIMER_REAL,&ntimeout,NULL); /* now stop timer */ + signal(SIGALRM, SIG_IGN); +#else + /* + * So the workaround I used is to make it sleep by using + * select() instead of setitimer()/pause(). select() is + * perfectly happy being called with a timeout and + * no file descriptors; it just sleeps until it hits the + * timeout. The only concern I had was that it might + * implement its timeout with SIGALRM--there are some + * Unices where this is done, because select() is a library + * function--but apparently not. + */ + struct timeval timeout; + + timeout.tv_sec = run.poll_interval; + timeout.tv_usec = 0; + do { + lastsig = 0; + select(0,0,0,0, &timeout); + } while (lastsig == SIGCHLD); +#endif +#else /* EMX */ + alarm_latch = FALSE; + signal(SIGALRM, gotsigalrm); + _beginthread(itimerthread, NULL, 32768, NULL); + /* see similar code above */ + if (!alarm_latch) + pause(); + signal(SIGALRM, SIG_IGN); +#endif /* ! EMX */ + if (lastsig == SIGUSR1 + || ((run.poll_interval && !getuid()) && lastsig == SIGHUP)) + { +#ifdef SYS_SIGLIST_DECLARED + report(stdout, + _("awakened by %s\n"), sys_siglist[lastsig]); +#else + report(stdout, + _("awakened by signal %d\n"), lastsig); +#endif + return(TRUE); + } + + return(FALSE); +} + int main(int argc, char **argv) { int st, bkgd = FALSE; @@ -780,102 +877,15 @@ int main(int argc, char **argv) if (!getuid()) signal(SIGHUP, donothing); - /* time for a pause in the action... */ - { -#ifndef __EMX__ -#ifdef SLEEP_WITH_ALARM /* not normally on */ - /* - * We can't use sleep(3) here because we need an alarm(3) - * equivalent in order to implement server nonresponse timeout. - * We'll just assume setitimer(2) is available since fetchmail - * has to have a BSDoid socket layer to work at all. - */ - /* - * This code stopped working under glibc-2, apparently due - * to the change in signal(2) semantics. (The siginterrupt - * line, added later, should fix this problem.) John Stracke - * <francis@netscape.com> wrote: - * - * The problem seems to be that, after hitting the interval - * timer while talking to the server, the process no longer - * responds to SIGALRM. I put in printf()s to see when it - * reached the pause() for the poll interval, and I checked - * the return from setitimer(), and everything seemed to be - * working fine, except that the pause() just ignored SIGALRM. - * I thought maybe the itimer wasn't being fired, so I hit - * it with a SIGALRM from the command line, and it ignored - * that, too. SIGUSR1 woke it up just fine, and it proceeded - * to repoll--but, when the dummy server didn't respond, it - * never timed out, and SIGALRM wouldn't make it. - * - * (continued below...) - */ - struct itimerval ntimeout; - - ntimeout.it_interval.tv_sec = 5; /* repeat alarm every 5 secs */ - ntimeout.it_interval.tv_usec = 0; - ntimeout.it_value.tv_sec = run.poll_interval; - ntimeout.it_value.tv_usec = 0; - - siginterrupt(SIGALRM, 1); - alarm_latch = FALSE; - signal(SIGALRM, gotsigalrm); /* first trap signals */ - setitimer(ITIMER_REAL,&ntimeout,NULL); /* then start timer */ - /* there is a very small window between the next two lines */ - /* which could result in a deadlock. But this will now be */ - /* caught by periodical alarms (see it_interval) */ - if (!alarm_latch) - pause(); - /* stop timer */ - ntimeout.it_interval.tv_sec = ntimeout.it_interval.tv_usec = 0; - ntimeout.it_value.tv_sec = ntimeout.it_value.tv_usec = 0; - setitimer(ITIMER_REAL,&ntimeout,NULL); /* now stop timer */ - signal(SIGALRM, SIG_IGN); -#else - /* - * So the workaround I used is to make it sleep by using - * select() instead of setitimer()/pause(). select() is - * perfectly happy being called with a timeout and - * no file descriptors; it just sleeps until it hits the - * timeout. The only concern I had was that it might - * implement its timeout with SIGALRM--there are some - * Unices where this is done, because select() is a library - * function--but apparently not. - */ - struct timeval timeout; - - timeout.tv_sec = run.poll_interval; - timeout.tv_usec = 0; - do { - lastsig = 0; - select(0,0,0,0, &timeout); - } while (lastsig == SIGCHLD); -#endif -#else /* EMX */ - alarm_latch = FALSE; - signal(SIGALRM, gotsigalrm); - _beginthread(itimerthread, NULL, 32768, NULL); - /* see similar code above */ - if (!alarm_latch) - pause(); - signal(SIGALRM, SIG_IGN); -#endif /* ! EMX */ - if (lastsig == SIGUSR1 - || ((run.poll_interval && !getuid()) && lastsig == SIGHUP)) - { -#ifdef SYS_SIGLIST_DECLARED - report(stdout, - _("awakened by %s\n"), sys_siglist[lastsig]); -#else - report(stdout, - _("awakened by signal %d\n"), lastsig); -#endif - /* received a wakeup - unwedge all servers in case */ - /* the problem has been manually repaired */ - for (ctl = querylist; ctl; ctl = ctl->next) - ctl->wedged = FALSE; - } - } + /* + * OK, now pause util it's time for the next poll cycle. + * A TRUE return indicates we received a wakeup signal; + * unwedge all servers in case the problem has been + * manually repaired. + */ + if (idle(run.poll_interval)) + for (ctl = querylist; ctl; ctl = ctl->next) + ctl->wedged = FALSE; /* now lock out interrupts again */ signal(SIGUSR1, SIG_IGN); |