1 files changed, 44 insertions, 0 deletions
diff --git a/util/tmpmount.c b/util/tmpmount.c
new file mode 100644
index 0000000..75e225d
--- /dev/null
+++ b/util/tmpmount.c
@@ -0,0 +1,44 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/mount.h>
+#include <sched.h>
+#include <libsimple.h>
+#include <libsimple-arg.h>
+
+NUSAGE(125, "mountpoint utility [argument] ...");
+
+
+int
+main(int argc, char *argv[])
+{
+	const char *mountpoint;
+
+	libsimple_default_failure_exit = 125;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc < 2)
+		usage();
+
+	mountpoint = *argv++;
+	argc--;
+
+	if (unshare(CLONE_NEWNS))
+		eprintf("unshare CLONE_NEWNS:");
+	if (mount("none", "/", NULL, MS_REC | MS_SLAVE, NULL))
+		eprintf("mount none / NULL MS_REC|MS_SLAVE NULL:");
+
+	if (mount("tmpfs", mountpoint, "tmpfs", 0, NULL))
+		eprintf("mount tmpfs %s tmpfs 0 NULL:", mountpoint);
+
+	if (setegid(getgid()))
+		eprintf("setegid <real group>:");
+	if (seteuid(getuid()))
+		eprintf("seteuid <real user>:");
+
+	execvp(argv[0], argv);
+	enprintf(errno == ENOENT ? 127 : 126, "execvp %s:", argv[0]);
+	return 0;
+}