Use exclusive lock under /dev/, silence expected errors in installer

resolvd(8), slaacd(8) and dhcpleased(8) are different from other daemons
in that there must only be a single instance.

resolvd already does this, adjust slaacd and dhcpleased accordingly while
moving the lockfile paths under /dev/ such that they work early on boot and
don't run into races should /var be (un)mounted between daemon starts.

Locking is especially required in the installer where all three daemons are
started every time the "(I)nstall, (U)pgrade, (A)utoinstall or (S)hell? "
prompt is entered, i.e. restarting installation or dropping into a shell
and back into the prompt again would start multiple instances.

To avoid expected lockfile error messages in between installer prompts,
discard standard error when starting the autoconf daemons;  none of them
has other potential failure cases in installer mode before daemon(3)izing.

Input sthen deraadt
OK deraadt

diff --git a/distrib/miniroot/dot.profile b/distrib/miniroot/dot.profile
index 0baba16..93e6f58 100644 (file)
--- a/distrib/miniroot/dot.profile
+++ b/distrib/miniroot/dot.profile
@@ -1,4 +1,4 @@
-#      $OpenBSD: dot.profile,v 1.45 2021/07/16 15:24:44 florian Exp $
+#      $OpenBSD: dot.profile,v 1.46 2021/07/21 03:53:50 kn Exp $
 #      $NetBSD: dot.profile,v 1.1 1995/12/18 22:54:43 pk Exp $
 #
 # Copyright (c) 2009 Kenneth R. Westerback
@@ -58,9 +58,10 @@ if [[ -z $DONEPROFILE ]]; then
        mkdir -m u=rwx,go=rx -p /tmp/{ai,i}
 
        # Start autoconfiguration daemons.
-       [[ -x /sbin/resolvd ]] && /sbin/resolvd
-       [[ -x /sbin/dhcpleased ]] && /sbin/dhcpleased
-       [[ -x /sbin/slaacd ]] && /sbin/slaacd
+       # Hide legit "already running" errors when reentering the installer.
+       [[ -x /sbin/resolvd ]] && /sbin/resolvd 2>/dev/null
+       [[ -x /sbin/dhcpleased ]] && /sbin/dhcpleased 2>/dev/null
+       [[ -x /sbin/slaacd ]] && /sbin/slaacd 2>/dev/null
 
        # Set up some sane tty defaults.
        echo 'erase ^?, werase ^W, kill ^U, intr ^C, status ^T'

diff --git a/sbin/dhcpleased/dhcpleased.c b/sbin/dhcpleased/dhcpleased.c
index 2157406..8fc6069 100644 (file)
--- a/sbin/dhcpleased/dhcpleased.c
+++ b/sbin/dhcpleased/dhcpleased.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: dhcpleased.c,v 1.14 2021/07/12 15:09:18 beck Exp $    */
+/*     $OpenBSD: dhcpleased.c,v 1.15 2021/07/21 03:53:50 kn Exp $      */
 
 /*
  * Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org>
@@ -131,7 +131,7 @@ main(int argc, char *argv[])
        char                    *saved_argv0;
        int                      pipe_main2frontend[2];
        int                      pipe_main2engine[2];
-       int                      frontend_routesock, rtfilter;
+       int                      frontend_routesock, rtfilter, lockfd;
        int                      rtable_any = RTABLE_ANY;
        char                    *csock = _PATH_DHCPLEASED_SOCKET;
 #ifndef SMALL
@@ -181,6 +181,10 @@ main(int argc, char *argv[])
        if (geteuid())
                errx(1, "need root privileges");
 
+       lockfd = open(_PATH_LOCKFILE, O_CREAT|O_RDWR|O_EXLOCK|O_NONBLOCK, 0600);
+       if (lockfd == -1)
+               errx(1, "already running");
+
        /* Check for assigned daemon user */
        if (getpwnam(DHCPLEASED_USER) == NULL)
                errx(1, "unknown user %s", DHCPLEASED_USER);

diff --git a/sbin/dhcpleased/dhcpleased.h b/sbin/dhcpleased/dhcpleased.h
index 2654293..ae81baa 100644 (file)
--- a/sbin/dhcpleased/dhcpleased.h
+++ b/sbin/dhcpleased/dhcpleased.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: dhcpleased.h,v 1.6 2021/06/20 08:31:45 florian Exp $  */
+/*     $OpenBSD: dhcpleased.h,v 1.7 2021/07/21 03:53:50 kn Exp $       */
 
 /*
  * Copyright (c) 2017, 2021 Florian Obser <florian@openbsd.org>
@@ -18,6 +18,7 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#define        _PATH_LOCKFILE          "/dev/dhcpleased.lock"
 #define        _PATH_DHCPLEASED_SOCKET "/dev/dhcpleased.sock"
 #define        DHCPLEASED_USER         "_dhcp"
 #define        DHCPLEASED_RTA_LABEL    "dhcpleased"

diff --git a/sbin/resolvd/resolvd.c b/sbin/resolvd/resolvd.c
index a7d6bf2..915a8a5 100644 (file)
--- a/sbin/resolvd/resolvd.c
+++ b/sbin/resolvd/resolvd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: resolvd.c,v 1.15 2021/07/18 15:18:49 deraadt Exp $    */
+/*     $OpenBSD: resolvd.c,v 1.16 2021/07/21 03:53:50 kn Exp $ */
 /*
  * Copyright (c) 2021 Florian Obser <florian@openbsd.org>
  * Copyright (c) 2021 Theo de Raadt <deraadt@openbsd.org>
@@ -42,10 +42,10 @@
 
 #define        ROUTE_SOCKET_BUF_SIZE   16384
 #define        ASR_MAXNS               10
+#define        _PATH_LOCKFILE          "/dev/resolvd.lock"
 #define        _PATH_UNWIND_SOCKET     "/dev/unwind.sock"
 #define        _PATH_RESCONF           "/etc/resolv.conf"
 #define        _PATH_RESCONF_NEW       "/etc/resolv.conf.new"
-#define _PATH_LOCKFILE         "/var/run/resolvd.lock"
 
 #ifndef nitems
 #define        nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
@@ -193,7 +193,7 @@ main(int argc, char *argv[])
 
        lockfd = open(_PATH_LOCKFILE, O_CREAT|O_RDWR|O_EXLOCK|O_NONBLOCK, 0600);
        if (lockfd == -1)
-               errx(1, "already running, " _PATH_LOCKFILE);
+               errx(1, "already running");
 
        if (!debug)
                daemon(0, 0);

diff --git a/sbin/slaacd/slaacd.c b/sbin/slaacd/slaacd.c
index 44a754b..dbd06d6 100644 (file)
--- a/sbin/slaacd/slaacd.c
+++ b/sbin/slaacd/slaacd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: slaacd.c,v 1.60 2021/05/01 11:53:24 florian Exp $     */
+/*     $OpenBSD: slaacd.c,v 1.61 2021/07/21 03:53:50 kn Exp $  */
 
 /*
  * Copyright (c) 2017 Florian Obser <florian@openbsd.org>
@@ -129,7 +129,7 @@ main(int argc, char *argv[])
        char                    *saved_argv0;
        int                      pipe_main2frontend[2];
        int                      pipe_main2engine[2];
-       int                      frontend_routesock, rtfilter;
+       int                      frontend_routesock, rtfilter, lockfd;
        int                      rtable_any = RTABLE_ANY;
        char                    *csock = _PATH_SLAACD_SOCKET;
 #ifndef SMALL
@@ -180,6 +180,10 @@ main(int argc, char *argv[])
        if (geteuid())
                errx(1, "need root privileges");
 
+       lockfd = open(_PATH_LOCKFILE, O_CREAT|O_RDWR|O_EXLOCK|O_NONBLOCK, 0600);
+       if (lockfd == -1)
+               errx(1, "already running");
+
        /* Check for assigned daemon user */
        if (getpwnam(SLAACD_USER) == NULL)
                errx(1, "unknown user %s", SLAACD_USER);

diff --git a/sbin/slaacd/slaacd.h b/sbin/slaacd/slaacd.h
index 0bad116..7a53a29 100644 (file)
--- a/sbin/slaacd/slaacd.h
+++ b/sbin/slaacd/slaacd.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: slaacd.h,v 1.33 2021/03/21 18:25:24 florian Exp $     */
+/*     $OpenBSD: slaacd.h,v 1.34 2021/07/21 03:53:50 kn Exp $  */
 
 /*
  * Copyright (c) 2017 Florian Obser <florian@openbsd.org>
@@ -18,6 +18,7 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#define        _PATH_LOCKFILE          "/dev/slaacd.lock"
 #define        _PATH_SLAACD_SOCKET     "/dev/slaacd.sock"
 #define SLAACD_USER            "_slaacd"
 #define SLAACD_RTA_LABEL       "slaacd"