From: Karel Zak <kzak@redhat.com>
Date: Mon, 28 Feb 2022 10:02:04 +0000 (+0100)
Subject: Revert "unshare: Fix PDEATHSIG race for --kill-child"
X-Git-Tag: v2.38-rc2~14
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1f71f0cf2c8e157803ccd2e25bd9f21cae6c5fd3;p=thirdparty%2Futil-linux.git

Revert "unshare: Fix PDEATHSIG race for --kill-child"

This reverts commit 764bb68af8e6d1b6c10a154c1dace64c450100c0.

It seems getppid() is use-less in some cases. For more details see:
https://github.com/util-linux/util-linux/pull/1561#issuecomment-1049979795

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/sys-utils/unshare.c b/sys-utils/unshare.c
index 19357d478e..5effff6b18 100644
--- a/sys-utils/unshare.c
+++ b/sys-utils/unshare.c
@@ -763,7 +763,7 @@ int main(int argc, char *argv[])
 	const char *newroot = NULL;
 	const char *newdir = NULL;
 	pid_t pid_bind = 0, pid_idmap = 0;
-	pid_t pid = 0, pid_parent = 0;
+	pid_t pid = 0;
 	int fd_idmap, fd_bind = -1;
 	sigset_t sigset, oldsigset;
 	int status;
@@ -956,7 +956,6 @@ int main(int argc, char *argv[])
 
 		/* force child forking before mountspace binding
 		 * so pid_for_children is populated */
-		pid_parent = getpid();
 		pid = fork();
 
 		switch(pid) {
@@ -1008,17 +1007,8 @@ int main(int argc, char *argv[])
 		err(EXIT_FAILURE, _("child exit failed"));
 	}
 
-	if (kill_child_signo != 0) {
-		if (prctl(PR_SET_PDEATHSIG, kill_child_signo) < 0)
-			err(EXIT_FAILURE, "prctl failed");
-
-		if (getppid() != pid_parent) {
-			if (kill(getpid(), kill_child_signo) != 0)
-				err(EXIT_FAILURE, _("child kill failed"));
-			/* The selected kill_child_signo be blocked, or
-			 * might not cause termination. */
-		}
-	}
+	if (kill_child_signo != 0 && prctl(PR_SET_PDEATHSIG, kill_child_signo) < 0)
+		err(EXIT_FAILURE, "prctl failed");
 
         if (mapuser != (uid_t) -1 && !usermap)
 		map_id(_PATH_PROC_UIDMAP, mapuser, real_euid);