+ if (r != -ENOENT)
+ return log_debug_errno(r, "Failed to read /run/systemd/container: %m");
+
+ /* Fallback for cases where PID 1 was not systemd (for example, cases where init=/bin/sh is used. */
+ r = getenv_for_pid(1, "container", &m);
+ if (r > 0) {
+ e = m;
+ goto translate_name;
+ }
+ if (r < 0) /* This only works if we have CAP_SYS_PTRACE, hence let's better ignore failures here */
+ log_debug_errno(r, "Failed to read $container of PID 1, ignoring: %m");
+
+ /* Interestingly /proc/1/sched actually shows the host's PID for what we see as PID 1. Hence, if the PID shown
+ * there is not 1, we know we are in a PID namespace. and hence a container. */
+ r = read_one_line_file("/proc/1/sched", &m);
+ if (r >= 0) {
+ const char *t;
+
+ t = strrchr(m, '(');
+ if (!t)
+ return -EIO;
+
+ if (!startswith(t, "(1,")) {
+ r = VIRTUALIZATION_CONTAINER_OTHER;
+ goto finish;
+ }
+ } else if (r != -ENOENT)
+ return r;
+
+ /* If that didn't work, give up, assume no container manager. */
+ r = VIRTUALIZATION_NONE;
+ goto finish;