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authorLennart Poettering <lennart@poettering.net>2014-03-11 01:01:38 +0100
committerLennart Poettering <lennart@poettering.net>2014-03-11 01:01:38 +0100
commitd96c1ecf7bf9dae6b0cb728e41d09999ecce0b4a (patch)
tree791096d3c22e7b8ad38c887ca2cb395739ed8d06 /src/nspawn/nspawn.c
parent2ecfc64e59b5e4e96bed6f68bd36b612ef77a146 (diff)
nspawn: make sure we don't try to mount the container block device in the child after the parent added us to the device cgroup
Diffstat (limited to 'src/nspawn/nspawn.c')
-rw-r--r--src/nspawn/nspawn.c53
1 files changed, 38 insertions, 15 deletions
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index bef866a966..0903c57225 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -2222,7 +2222,7 @@ static void loop_remove(int nr, int *image_fd) {
int main(int argc, char *argv[]) {
_cleanup_free_ char *kdbus_domain = NULL, *device_path = NULL, *root_device = NULL, *home_device = NULL, *srv_device = NULL;
- _cleanup_close_ int master = -1, kdbus_fd = -1, sync_fd = -1, image_fd = -1;
+ _cleanup_close_ int master = -1, kdbus_fd = -1, image_fd = -1;
_cleanup_close_pipe_ int kmsg_socket_pair[2] = { -1, -1 };
_cleanup_fdset_free_ FDSet *fds = NULL;
int r = EXIT_FAILURE, k, n_fd_passed, loop_nr = -1;
@@ -2396,10 +2396,18 @@ int main(int argc, char *argv[]) {
assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
for (;;) {
+ int parent_ready_fd = -1, child_ready_fd = -1;
siginfo_t status;
+ eventfd_t x;
- sync_fd = eventfd(0, EFD_CLOEXEC);
- if (sync_fd < 0) {
+ parent_ready_fd = eventfd(0, EFD_CLOEXEC);
+ if (parent_ready_fd < 0) {
+ log_error("Failed to create event fd: %m");
+ goto finish;
+ }
+
+ child_ready_fd = eventfd(0, EFD_CLOEXEC);
+ if (child_ready_fd < 0) {
log_error("Failed to create event fd: %m");
goto finish;
}
@@ -2436,7 +2444,6 @@ int main(int argc, char *argv[]) {
NULL
};
char **env_use;
- eventfd_t x;
envp[n_env] = strv_find_prefix(environ, "TERM=");
if (envp[n_env])
@@ -2554,6 +2561,13 @@ int main(int argc, char *argv[]) {
if (setup_kdbus(arg_directory, kdbus_domain) < 0)
goto child_fail;
+ /* Tell the parent that we are ready, and that
+ * it can cgroupify us to that we lack access
+ * to certain devices and resources. */
+ eventfd_write(child_ready_fd, 1);
+ close_nointr_nofail(child_ready_fd);
+ child_ready_fd = -1;
+
if (chdir(arg_directory) < 0) {
log_error("chdir(%s) failed: %m", arg_directory);
goto child_fail;
@@ -2682,9 +2696,11 @@ int main(int argc, char *argv[]) {
}
}
- eventfd_read(sync_fd, &x);
- close_nointr_nofail(sync_fd);
- sync_fd = -1;
+#ifdef HAVE_SELINUX
+ if (arg_selinux_context)
+ if (setexeccon((security_context_t) arg_selinux_context) < 0)
+ log_error("setexeccon(\"%s\") failed: %m", arg_selinux_context);
+#endif
if (!strv_isempty(arg_setenv)) {
char **n;
@@ -2699,11 +2715,11 @@ int main(int argc, char *argv[]) {
} else
env_use = (char**) envp;
-#ifdef HAVE_SELINUX
- if (arg_selinux_context)
- if (setexeccon((security_context_t) arg_selinux_context) < 0)
- log_error("setexeccon(\"%s\") failed: %m", arg_selinux_context);
-#endif
+ /* Wait until the parent is ready with the setup, too... */
+ eventfd_read(parent_ready_fd, &x);
+ close_nointr_nofail(parent_ready_fd);
+ parent_ready_fd = -1;
+
if (arg_boot) {
char **a;
size_t l;
@@ -2739,6 +2755,12 @@ int main(int argc, char *argv[]) {
fdset_free(fds);
fds = NULL;
+ /* Wait until the child reported that it is ready with
+ * all it needs to do with priviliges. After we got
+ * the notification we can make the process join its
+ * cgroup which might limit what it can do */
+ eventfd_read(child_ready_fd, &x);
+
r = register_machine(pid);
if (r < 0)
goto finish;
@@ -2759,9 +2781,10 @@ int main(int argc, char *argv[]) {
if (r < 0)
goto finish;
- eventfd_write(sync_fd, 1);
- close_nointr_nofail(sync_fd);
- sync_fd = -1;
+ /* Notify the child that the parent is ready with all
+ * its setup, and thtat the child can now hand over
+ * control to the code to run inside the container. */
+ eventfd_write(parent_ready_fd, 1);
k = process_pty(master, &mask, arg_boot ? pid : 0, SIGRTMIN+3);
if (k < 0) {