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/* ISC license. */
#include <stdint.h>
#include <unistd.h>
#include <signal.h>
#include <fcntl.h>
#include <limits.h>
#include <sys/wait.h>
#include <skalibs/types.h>
#include <skalibs/bytestr.h>
#include <skalibs/sgetopt.h>
#include <skalibs/strerr2.h>
#include <skalibs/tai.h>
#include <skalibs/djbunix.h>
#include <skalibs/selfpipe.h>
#include <skalibs/iopause.h>
#include <execline/config.h>
#include <s6/s6-supervise.h>
#include <s6/ftrigr.h>
#define USAGE "s6-notifyoncheck [ -d ] [ -3 fd ] [ -s initialsleep ] [ -T globaltimeout ] [ -t localtimeout ] [ -w waitingtime ] [ -n tries ] [ -c \"checkprog...\" ] prog..."
#define dieusage() strerr_dieusage(100, USAGE)
static inline int read_uint (char const *file, unsigned int *fd)
{
char buf[UINT_FMT + 1] ;
ssize_t r = openreadnclose_nb(file, buf, UINT_FMT) ;
if (r < 0) return -1 ;
buf[byte_chr(buf, r, '\n')] = 0 ;
return !!uint0_scan(buf, fd) ;
}
static inline int handle_signals (pid_t pid, int *w)
{
int gotit = 0 ;
for (;;)
{
switch (selfpipe_read())
{
case -1 : strerr_diefu1sys(111, "selfpipe_read") ;
case 0 : return gotit ;
case SIGCHLD :
{
int wstat ;
if (wait_pid_nohang(pid, &wstat) == pid)
{
*w = wstat ;
gotit = 1 ;
}
break ;
}
}
}
}
static int handle_event (ftrigr_t *a, uint16_t id, pid_t pid)
{
int r ;
char what ;
if (ftrigr_update(a) < 0) strerr_diefu1sys(111, "ftrigr_update") ;
r = ftrigr_check(a, id, &what) ;
if (r < 0) strerr_diefu1sys(111, "ftrigr_check") ;
if (r && what == 'd')
{
if (pid) kill(pid, SIGTERM) ;
return 1 ;
}
return 0 ;
}
int main (int argc, char const *const *argv, char const *const *envp)
{
ftrigr_t a = FTRIGR_ZERO ;
iopause_fd x[2] = { { .events = IOPAUSE_READ }, { .events = IOPAUSE_READ } } ;
char const *childargv[4] = { EXECLINE_EXTBINPREFIX "execlineb", "-c", 0, 0 } ;
char const *checkprog = 0 ;
unsigned int fd ;
int df = 0 ;
int autodetect = 1 ;
tain_t globaldeadline, sleeptto, localtto, waittto ;
unsigned int tries = 7 ;
uint16_t id ;
PROG = "s6-notifyoncheck" ;
{
subgetopt_t l = SUBGETOPT_ZERO ;
unsigned int initialsleep = 10, globaltimeout = 0, localtimeout = 0, waitingtime = 1000 ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "d3:s:T:t:w:n:c:", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'd' : df = 1 ; break ;
case '3' : if (!uint0_scan(l.arg, &fd)) dieusage() ; autodetect = 0 ; break ;
case 's' : if (!uint0_scan(l.arg, &initialsleep)) dieusage() ; break ;
case 'T' : if (!uint0_scan(l.arg, &globaltimeout)) dieusage() ; break ;
case 't' : if (!uint0_scan(l.arg, &localtimeout)) dieusage() ; break ;
case 'w' : if (!uint0_scan(l.arg, &waitingtime)) dieusage() ; break ;
case 'n' : if (!uint0_scan(l.arg, &tries)) dieusage() ; break ;
case 'c' : checkprog = l.arg ; break ;
default : dieusage() ;
}
}
argc -= l.ind ; argv += l.ind ;
if (!argc) dieusage() ;
if (!tain_from_millisecs(&sleeptto, initialsleep)) dieusage() ;
if (globaltimeout) tain_from_millisecs(&globaldeadline, globaltimeout) ;
else globaldeadline = tain_infinite_relative ;
if (localtimeout) tain_from_millisecs(&localtto, localtimeout) ;
else localtto = tain_infinite_relative ;
if (waitingtime) tain_from_millisecs(&waittto, waitingtime) ;
else waittto = tain_infinite_relative ;
if (!tries) tries = UINT_MAX ;
}
{
int r = s6_svc_ok(".") ;
if (r < 0) strerr_diefu1sys(111, "sanity-check current service directory") ;
if (!r) strerr_dief1x(100, "s6-supervise not running.") ;
}
if (checkprog) childargv[2] = checkprog ;
else
{
childargv[0] = "./data/check" ;
childargv[1] = 0 ;
}
if (autodetect)
{
int r = read_uint("notification-fd", &fd) ;
if (r < 0) strerr_diefu2sys(111, "read ", "./notification-fd") ;
if (!r) strerr_dief2x(100, "invalid ", "./notification-fd") ;
}
if (fcntl(fd, F_GETFD) < 0)
strerr_dief2sys(111, "notification-fd", " sanity check failed") ;
tain_now_g() ;
tain_add_g(&globaldeadline, &globaldeadline) ;
/*
Fork, let the parent exec into the daemon, keep working in the child.
We want the child to die if the parent dies, because no need to keep
polling a dead service. And another child will be spawned next time the
service is relaunched by s6-supervise.
We could keep a pipe from the parent to the child, for death
notification, but that's an additional fd forever open in the parent,
which is not good (we need to be 100% transparent).
So we're using ftrigr to listen to a 'd' event in the servicedir's
fifodir. It's much heavier, but temporary - it doesn't use permanent
resources in the daemon - and we're polling anyway, so the user
doesn't care about being 100% lightweight.
*/
if (!ftrigr_startf_g(&a, &globaldeadline))
strerr_diefu1sys(111, "ftrigr_startf") ;
id = ftrigr_subscribe_g(&a, "event", "d", 0, &globaldeadline) ;
if (!id) strerr_diefu1sys(111, "ftrigr_subscribe to event fifodir") ;
switch (df ? doublefork() : fork())
{
case -1: strerr_diefu1sys(111, df ? "doublefork" : "fork") ;
case 0 : break ;
default:
{
close((int)fd) ;
xpathexec_run(argv[0], argv, envp) ;
}
}
x[0].fd = selfpipe_init() ;
if (x[0].fd < 0) strerr_diefu1sys(111, "selfpipe_init") ;
if (selfpipe_trap(SIGCHLD) < 0) strerr_diefu1sys(111, "trap SIGCHLD") ;
x[1].fd = ftrigr_fd(&a) ;
/* Loop around a sleep and a ./data/check invocation */
while (tries == UINT_MAX || tries--)
{
tain_t deadline = globaldeadline ;
tain_t localdeadline ;
pid_t pid ;
tain_add_g(&localdeadline, &sleeptto) ;
sleeptto = waittto ;
if (tain_less(&localdeadline, &deadline)) deadline = localdeadline ;
for (;;)
{
int r = iopause_g(x+1, 1, &deadline) ;
if (r < 0) strerr_diefu1sys(111, "iopause") ;
if (!r)
{
if (!tain_future(&globaldeadline)) return 3 ;
else break ;
}
if (handle_event(&a, id, 0)) return 2 ;
}
pid = child_spawn0(childargv[0], childargv, envp) ;
if (!pid)
{
strerr_warnwu2sys("spawn ", childargv[0]) ;
continue ;
}
deadline = globaldeadline ;
tain_add_g(&localdeadline, &localtto) ;
if (tain_less(&localdeadline, &deadline)) deadline = localdeadline ;
for (;;)
{
int r = iopause_g(x, 2, &deadline) ;
if (r < 0) strerr_diefu1sys(111, "iopause") ;
if (!r)
{
if (!tain_future(&globaldeadline))
{
kill(pid, SIGTERM) ;
return 3 ;
}
else break ;
}
if (x[0].revents & IOPAUSE_READ)
{
int wstat ;
if (handle_signals(pid, &wstat))
{
if (WIFEXITED(wstat) && !WEXITSTATUS(wstat))
{
write((int)fd, "\n", 1) ;
return 0 ;
}
else break ;
}
}
if (x[1].revents & IOPAUSE_READ && handle_event(&a, id, pid)) return 2 ;
}
}
return 1 ;
}
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