diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/supervision/deps-exe/s6-notifyoncheck | 5 | ||||
| -rw-r--r-- | src/supervision/s6-notifyoncheck.c | 244 |
2 files changed, 249 insertions, 0 deletions
diff --git a/src/supervision/deps-exe/s6-notifyoncheck b/src/supervision/deps-exe/s6-notifyoncheck new file mode 100644 index 0000000..7a6675b --- /dev/null +++ b/src/supervision/deps-exe/s6-notifyoncheck @@ -0,0 +1,5 @@ +${LIBS6} +-lskarnet +${SOCKET_LIB} +${TAINNOW_LIB} +${SPAWN_LIB} diff --git a/src/supervision/s6-notifyoncheck.c b/src/supervision/s6-notifyoncheck.c new file mode 100644 index 0000000..3d988de --- /dev/null +++ b/src/supervision/s6-notifyoncheck.c @@ -0,0 +1,244 @@ +/* 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 ; +} |