runsvdir: do not exit if we are pid 1.

diff --git a/runit/runsvdir.c b/runit/runsvdir.c
index 8099ebf..d37eaf5 100644 (file)
--- a/runit/runsvdir.c
+++ b/runit/runsvdir.c
@@ -115,10 +115,16 @@ static void runsv(int no, const char *name)
                /* child */
                if (set_pgrp)
                        setsid();
+/* man execv:
+ * Signals set to be caught by the calling process image
+ * shall be set to the default action in the new process image.
+ * Therefore, we do not need this: */
+#if 0
                bb_signals(0
-                       + (1 << SIGHUP)
-                       + (1 << SIGTERM)
+                       | (1 << SIGHUP)
+                       | (1 << SIGTERM)
                        , SIG_DFL);
+#endif
                execvp(prog[0], prog);
                fatal2_cannot("start runsv ", name);
        }
@@ -227,7 +233,19 @@ int runsvdir_main(int argc UNUSED_PARAM, char **argv)
        set_pgrp = getopt32(argv, "P");
        argv += optind;
 
-       bb_signals_recursive((1 << SIGTERM) | (1 << SIGHUP), record_signo);
+       bb_signals(0
+               | (1 << SIGTERM)
+               | (1 << SIGHUP)
+               /* For busybox's init, SIGTERM == reboot,
+                * SIGUSR1 == halt
+                * SIGUSR2 == poweroff
+                * so we need to intercept SIGUSRn too.
+                * Note that we do not implement actual reboot
+                * (killall(TERM) + umount, etc), we just pause
+                * respawing and avoid exiting (-> making kernel oops).
+                * The user is responsible for the rest. */
+               | (getpid() == 1 ? ((1 << SIGUSR1) | (1 << SIGUSR2)) : 0)
+               , record_signo);
        svdir = *argv++;
 
 #if ENABLE_FEATURE_RUNSVDIR_LOG
@@ -256,7 +274,7 @@ int runsvdir_main(int argc UNUSED_PARAM, char **argv)
                rplog = NULL;
                warnx("log service disabled");
        }
-run:
+ run:
 #endif
        curdir = open_read(".");
        if (curdir == -1)
@@ -319,8 +337,9 @@ run:
                }
                pfd[0].revents = 0;
 #endif
-               sig_block(SIGCHLD);
                deadline = (need_rescan ? 1 : 5);
+ do_sleep:
+               sig_block(SIGCHLD);
 #if ENABLE_FEATURE_RUNSVDIR_LOG
                if (rplog)
                        poll(pfd, 1, deadline*1000);
@@ -333,11 +352,11 @@ run:
                if (pfd[0].revents & POLLIN) {
                        char ch;
                        while (read(logpipe.rd, &ch, 1) > 0) {
-                               if (ch) {
-                                       for (i = 6; i < rploglen; i++)
-                                               rplog[i-1] = rplog[i];
-                                       rplog[rploglen-1] = ch;
-                               }
+                               if (ch < ' ')
+                                       ch = ' ';
+                               for (i = 6; i < rploglen; i++)
+                                       rplog[i-1] = rplog[i];
+                               rplog[rploglen-1] = ch;
                        }
                }
 #endif
@@ -346,11 +365,19 @@ run:
                        for (i = 0; i < svnum; i++)
                                if (sv[i].pid)
                                        kill(sv[i].pid, SIGTERM);
-                       // N.B. fall through
+                       /* fall through */
                case SIGTERM:
-                       _exit((SIGHUP == bb_got_signal) ? 111 : EXIT_SUCCESS);
+                       /* exit, unless we are init */
+                       if (getpid() != 1)
+                               goto ret;
+               default:
+                       /* so we are init. do not exit,
+                        * and pause respawning - we may be rebooting... */
+                       bb_got_signal = 0;
+                       deadline = 60;
+                       goto do_sleep;
                }
        }
-       /* not reached */
-       return 0;
+ ret:
+       return (SIGHUP == bb_got_signal) ? 111 : EXIT_SUCCESS;
 }