pseudo: Fix problem where pseudo could kill a container init

In a heavily loaded container, the child process might not started
before the parent process had terminated.  The child process attempts to
signal the parent with SIGUSR1.  If the parent had terminated, the
parent becomes PID 1, which is generally init.  When it signaled pid 1,
it caused the docker mini-init to terminate.

This doesn't happen in a traditional system, as systemd/sysvinit is
protected to only root users can signal it.

[YOCTO #10324]

(From OE-Core rev: f6f13b049e8683d2a2af3e120ba979b58f9a7d9a)

Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/meta/recipes-devtools/pseudo/files/0001-Don-t-send-SIGUSR1-to-init.patch b/meta/recipes-devtools/pseudo/files/0001-Don-t-send-SIGUSR1-to-init.patch
new file mode 100644
index 0000000000..6c694ceb0d
--- /dev/null
+++ b/meta/recipes-devtools/pseudo/files/0001-Don-t-send-SIGUSR1-to-init.patch
@@ -0,0 +1,48 @@
+From befc6dbd6469d428c9e0830dbe51bdf7ac39d9ae Mon Sep 17 00:00:00 2001
+From: Seebs <seebs@seebs.net>
+Date: Thu, 22 Sep 2016 14:35:04 -0500
+Subject: [PATCH] Don't send SIGUSR1 to init.
+
+If the parent exits due to child process being slow, getppid() will return
+1, and we'll send SIGUSR1 to init, which can break things like dumbinit
+which aren't adequately protected against non-root processes sending them
+signals.
+
+Signed-off-by: Seebs <seebs@seebs.net>
+
+Upstream-Status: Backport (commit befc6dbd6469d428c9e0830dbe51bdf7ac39d9ae)
+
+[YOCTO #10324]
+
+This resolves an issue where a docker container running builds would die
+due to it's 'mini init' being signaled by pseudo.
+
+Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
+---
+ pseudo_server.c | 11 ++++++++---
+
+diff --git a/pseudo_server.c b/pseudo_server.c
+index 65102dd..8731d20 100644
+--- a/pseudo_server.c
++++ b/pseudo_server.c
+@@ -358,9 +358,14 @@ pseudo_server_start(int daemonize) {
+        signal(SIGTERM, quit_now);
+        /* tell parent process to stop waiting */
+        if (daemonize) {
+-               pseudo_diag("Setup complete, sending SIGUSR1 to pid %d.\n",
+-                       getppid());
+-               kill(getppid(), SIGUSR1);
++               pid_t ppid = getppid();
++               if (ppid == 1) {
++                       pseudo_diag("Setup complete, but parent is init, not sending SIGUSR1.\n");
++               } else {
++                       pseudo_diag("Setup complete, sending SIGUSR1 to pid %d.\n",
++                               ppid);
++                       kill(ppid, SIGUSR1);
++               }
+        }
+        pseudo_server_loop();
+        return 0;
+-- 
+2.5.5
+