From 6fbbf006adc4830f0ed956042e54e747168fa879 Mon Sep 17 00:00:00 2001

From: Franck Bui <fbui@suse.com>

Date: Thu, 24 Nov 2016 18:52:04 +0100

Subject: [PATCH] core: make sure initrd-switch-root command survives PID1's

 killing spree (#4730)

This is a different way to implement the fix proposed by commit

a4021390fef27f4136497328f suggested by Lennart Poettering.

In this patch we instruct PID1 to not kill "systemctl switch-root" command

started by initrd-switch-root service using the "argv[0][0]='@'" trick.

See: https://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons/ for

more details.

We had to backup argv[0] because argv is modified by dispatch_verb().

(cherry picked from commit acc28e2e3037d689d6481e4664925cf31d4d087b)

---

 src/systemctl/systemctl.c           | 10 ++++++++++

 units/initrd-switch-root.service.in |  8 +-------

 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/systemctl/systemctl.c b/src/systemctl/systemctl.c

index dd3b931cd6..a2b667481d 100644

--- a/src/systemctl/systemctl.c

+++ b/src/systemctl/systemctl.c

@@ -142,6 +142,7 @@ static const char *arg_kill_who = NULL;

 static int arg_signal = SIGTERM;

 static char *arg_root = NULL;

 static usec_t arg_when = 0;

+static char *argv_cmdline = NULL;

 static enum action {

         _ACTION_INVALID,

         ACTION_SYSTEMCTL,

@@ -5584,6 +5585,13 @@ static int switch_root(int argc, char *argv[], void *userdata) {

                         init = NULL;

         }

+        /* Instruct PID1 to exclude us from its killing spree applied during

+         * the transition from the initrd to the main system otherwise we would

+         * exit with a failure status even though the switch to the new root

+         * has succeed. */

+        if (in_initrd())

+                argv_cmdline[0] = '@';

+

         r = acquire_bus(BUS_MANAGER, &bus;;

         if (r < 0)

                 return r;

@@ -8324,6 +8332,8 @@ static int logind_cancel_shutdown(void) {

 int main(int argc, char*argv[]) {

         int r;

+        argv_cmdline = argv[0];

+

         setlocale(LC_ALL, "");

         log_parse_environment();

         log_open();

diff --git a/units/initrd-switch-root.service.in b/units/initrd-switch-root.service.in

index b89f2348c7..82893dafb1 100644

--- a/units/initrd-switch-root.service.in

+++ b/units/initrd-switch-root.service.in

@@ -17,10 +17,4 @@ AllowIsolate=yes

 Type=oneshot

 # we have to use "--force" here, otherwise systemd would umount /run

 ExecStart=@rootbindir@/systemctl --no-block --force switch-root /sysroot

-

-# Just before switching to the new rootfs, systemd might send us a TERM signal

-# depending on how fast we are to execute the main command and exit. If we get

-# the SIGTERM signal that simply means that we succeed but haven't got enough

-# time to exit properly. Since systemd considers SIGTERM as a failure for

-# short-running process (aka Type=oneshot), instruct it to ignore this case.

-SuccessExitStatus=SIGTERM

+KillMode=none

-- 

2.9.3