From fa467a411fcc5159c40a28ed302695e7321e6b73 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 14 Nov 2024 23:16:19 +0100 Subject: [PATCH] pid1: make clear that $WATCHDOG_USEC is set for the shutdown binary, noone else We use the $WATCHDOG_USEC variable for two very closely uses: as part of the sd_watchdog_enabled() protocol for implementing service watchdogs. And as part of the protocol between the service manager and systemd-shutdown across the PID 1 execve() transition during shutdown. Apparently some exitrds tools got confused by the latter use. Let's address that by setting $WATCHDOG_PID to 1, in accordance to the sd_watchdog_enabled() protocol to make clear this is only intended for PID 1 and nothing else. Replaces: #35135 (cherry picked from commit 4b20ae9a0e914e61d6bac095e5fc9664510ac03e) (cherry picked from commit cf7b3cc18225ef8824f9cac9c88b7ea0b0dce3cd) (cherry picked from commit cab88476b2b00693463992c051a0464f6bba7c85) --- src/core/main.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/src/core/main.c b/src/core/main.c index 8574f47767..f7d54e68b5 100644 --- a/src/core/main.c +++ b/src/core/main.c @@ -1606,6 +1606,11 @@ static int become_shutdown(int objective, int retval) { /* Tell the binary how often to ping, ignore failure */ (void) strv_extendf(&env_block, "WATCHDOG_USEC="USEC_FMT, watchdog_timer); + /* Make sure that tools that look for $WATCHDOG_USEC (and might get started by the exitrd) don't get + * confused by the variable, because the sd_watchdog_enabled() protocol uses the same variable for + * the same purposes. */ + (void) strv_extendf(&env_block, "WATCHDOG_PID=" PID_FMT, getpid_cached()); + if (arg_watchdog_device) (void) strv_extendf(&env_block, "WATCHDOG_DEVICE=%s", arg_watchdog_device);