diff options
Diffstat (limited to 'runit/runsv.c')
| -rw-r--r-- | runit/runsv.c | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/runit/runsv.c b/runit/runsv.c index 61ea240..7fad563 100644 --- a/runit/runsv.c +++ b/runit/runsv.c @@ -149,11 +149,15 @@ static void warn_cannot(const char *m) warn2_cannot(m, ""); } +/* SIGCHLD/TERM handlers are reentrancy-safe because they are unmasked + * only over poll() call, not over memory allocations + * or printouts. Do not need to save/restore errno either, + * as poll() error is not checked there. + */ static void s_child(int sig_no UNUSED_PARAM) { write(selfpipe.wr, "", 1); } - static void s_term(int sig_no UNUSED_PARAM) { sigterm = 1; @@ -380,14 +384,14 @@ static void startservice(struct svdir *s) xdup2(logpipe.wr, 1); } } - /* Non-ignored signals revert to SIG_DFL on exec anyway. - * But we can get signals BEFORE execl(), this is unlikely - * but wouldn't be good... + /* Non-ignored signals revert to SIG_DFL on exec. + * But we can get signals BEFORE execl(), unlikely as that may be. + * SIGCHLD is safe (would merely write to selfpipe), + * but SIGTERM would set sigterm = 1 (with vfork, we affect parent). + * Avoid that. */ - /*bb_signals(0 - + (1 << SIGCHLD) - + (1 << SIGTERM) - , SIG_DFL);*/ + /*signal(SIGCHLD, SIG_DFL);*/ + signal(SIGTERM, SIG_DFL); sig_unblock(SIGCHLD); sig_unblock(SIGTERM); execv(arg[0], (char**) arg); @@ -514,9 +518,13 @@ int runsv_main(int argc UNUSED_PARAM, char **argv) ndelay_on(selfpipe.wr); sig_block(SIGCHLD); - bb_signals_recursive_norestart(1 << SIGCHLD, s_child); sig_block(SIGTERM); - bb_signals_recursive_norestart(1 << SIGTERM, s_term); + /* No particular reason why we don't set SA_RESTART + * (poll() wouldn't restart regardless of that flag), + * we just follow what runit-2.1.2 does: + */ + bb_signals_norestart(1 << SIGCHLD, s_child); + bb_signals_norestart(1 << SIGTERM, s_term); xchdir(dir); /* bss: svd[0].pid = 0; */ @@ -628,6 +636,7 @@ int runsv_main(int argc UNUSED_PARAM, char **argv) sig_unblock(SIGTERM); sig_unblock(SIGCHLD); poll(x, 2 + haslog, 3600*1000); + /* NB: signal handlers can trash errno of poll() */ sig_block(SIGTERM); sig_block(SIGCHLD); |