From: Chris Webb <chris@arachsys.com>
Date: Mon, 15 Dec 2025 18:41:08 +0000 (+0000)
Subject: unshare: remove get_mnt_ino() check in bind_ns_files_from_child()
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=35f142d33fbb758da7787f8040258b45f324b35e;p=thirdparty%2Futil-linux.git

unshare: remove get_mnt_ino() check in bind_ns_files_from_child()

get_mnt_ino() was originally introduced in c84f2590 where it was used
in a loop to wait for the parent process to unshare the mount namespace
before binding the namespace in its child.

The parent and child processes are now synchronised with eventfd, so
remove this vestigial check and the now-unused get_mnt_ino() function.
This allows bind_ns_files_from_child() to be used even when the mount
namespace isn't amongst the namespaces being unshared.

Signed-off-by: Chris Webb <chris@arachsys.com>
---

diff --git a/sys-utils/unshare.c b/sys-utils/unshare.c
index 11aeae48e..d9c4d403f 100644
--- a/sys-utils/unshare.c
+++ b/sys-utils/unshare.c
@@ -199,18 +199,6 @@ static int bind_ns_files(pid_t pid)
 	return 0;
 }
 
-static ino_t get_mnt_ino(pid_t pid)
-{
-	struct stat st;
-	char path[PATH_MAX];
-
-	snprintf(path, sizeof(path), "/proc/%u/ns/mnt", (unsigned) pid);
-
-	if (stat(path, &st) != 0)
-		err(EXIT_FAILURE, _("stat of %s failed"), path);
-	return st.st_ino;
-}
-
 static void settime(int64_t offset, clockid_t clk_id)
 {
 	char buf[sizeof(stringify_value(ULONG_MAX)) * 3];
@@ -310,14 +298,11 @@ static pid_t fork_and_wait(int *fd)
 static pid_t bind_ns_files_from_child(int *fd)
 {
 	pid_t child, ppid = getpid();
-	ino_t ino = get_mnt_ino(ppid);
 
 	child = fork_and_wait(fd);
 	if (child)
 		return child;
 
-	if (get_mnt_ino(ppid) == ino)
-		exit(EXIT_FAILURE);
 	bind_ns_files(ppid);
 	exit(EXIT_SUCCESS);
 }