runsvdir: do not exit if we are pid 1.

1 files changed, 41 insertions, 14 deletions

diff --git a/runit/runsvdir.c b/runit/runsvdir.c
index 8099ebf5c..d37eaf548 100644
--- 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;
 }