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Diffstat (limited to 'src/nspawn/nspawn.c')
-rw-r--r--src/nspawn/nspawn.c92
1 files changed, 67 insertions, 25 deletions
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 0cd476cd9e..a1d77244f8 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -84,6 +84,7 @@
#include "def.h"
#include "rtnl-util.h"
#include "udev-util.h"
+#include "eventfd-util.h"
#include "blkid-util.h"
#include "gpt.h"
#include "siphash24.h"
@@ -2642,6 +2643,8 @@ static int wait_for_container(pid_t pid, ContainerStatus *container) {
return r;
}
+static void nop_handler(int sig) {}
+
int main(int argc, char *argv[]) {
_cleanup_free_ char *kdbus_domain = NULL, *device_path = NULL, *root_device = NULL, *home_device = NULL, *srv_device = NULL;
@@ -2653,8 +2656,8 @@ int main(int argc, char *argv[]) {
const char *console = NULL;
char veth_name[IFNAMSIZ];
bool secondary = false;
+ sigset_t mask, mask_chld;
pid_t pid = 0;
- sigset_t mask;
log_parse_environment();
log_open();
@@ -2816,36 +2819,44 @@ int main(int argc, char *argv[]) {
sd_notify(0, "READY=1");
assert_se(sigemptyset(&mask) == 0);
+ assert_se(sigemptyset(&mask_chld) == 0);
+ sigaddset(&mask_chld, SIGCHLD);
sigset_add_many(&mask, SIGCHLD, SIGWINCH, SIGTERM, SIGINT, -1);
assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
for (;;) {
ContainerStatus container_status;
- int parent_ready_fd = -1, child_ready_fd = -1;
- eventfd_t x;
-
- parent_ready_fd = eventfd(0, EFD_CLOEXEC);
- if (parent_ready_fd < 0) {
- log_error("Failed to create event fd: %m");
+ int eventfds[2] = { -1, -1 };
+ struct sigaction sa = {
+ .sa_handler = nop_handler,
+ .sa_flags = SA_NOCLDSTOP,
+ };
+
+ /* Child can be killed before execv(), so handle SIGCHLD
+ * in order to interrupt parent's blocking calls and
+ * give it a chance to call wait() and terminate. */
+ r = sigprocmask(SIG_UNBLOCK, &mask_chld, NULL);
+ if (r < 0) {
+ log_error("Failed to change the signal mask: %m");
goto finish;
}
- child_ready_fd = eventfd(0, EFD_CLOEXEC);
- if (child_ready_fd < 0) {
- log_error("Failed to create event fd: %m");
+ r = sigaction(SIGCHLD, &sa, NULL);
+ if (r < 0) {
+ log_error("Failed to install SIGCHLD handler: %m");
goto finish;
}
- pid = syscall(__NR_clone,
- SIGCHLD|CLONE_NEWNS|
- (arg_share_system ? 0 : CLONE_NEWIPC|CLONE_NEWPID|CLONE_NEWUTS)|
- (arg_private_network ? CLONE_NEWNET : 0), NULL);
+ pid = clone_with_eventfd(SIGCHLD|CLONE_NEWNS|
+ (arg_share_system ? 0 : CLONE_NEWIPC|CLONE_NEWPID|CLONE_NEWUTS)|
+ (arg_private_network ? CLONE_NEWNET : 0), eventfds);
if (pid < 0) {
if (errno == EINVAL)
log_error("clone() failed, do you have namespace support enabled in your kernel? (You need UTS, IPC, PID and NET namespacing built in): %m");
else
log_error("clone() failed: %m");
+ r = pid;
goto finish;
}
@@ -2986,8 +2997,11 @@ int main(int argc, char *argv[]) {
/* 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);
- child_ready_fd = safe_close(child_ready_fd);
+ r = eventfd_send_state(eventfds[1],
+ EVENTFD_CHILD_SUCCEEDED);
+ eventfds[1] = safe_close(eventfds[1]);
+ if (r < 0)
+ goto child_fail;
if (chdir(arg_directory) < 0) {
log_error("chdir(%s) failed: %m", arg_directory);
@@ -3089,8 +3103,10 @@ int main(int argc, char *argv[]) {
env_use = (char**) envp;
/* Wait until the parent is ready with the setup, too... */
- eventfd_read(parent_ready_fd, &x);
- parent_ready_fd = safe_close(parent_ready_fd);
+ r = eventfd_parent_succeeded(eventfds[0]);
+ eventfds[0] = safe_close(eventfds[0]);
+ if (r < 0)
+ goto child_fail;
if (arg_boot) {
char **a;
@@ -3121,17 +3137,27 @@ int main(int argc, char *argv[]) {
log_error("execv() failed: %m");
child_fail:
+ /* Tell the parent that the setup failed, so he
+ * can clean up resources and terminate. */
+ if (eventfds[1] != -1)
+ eventfd_send_state(eventfds[1],
+ EVENTFD_CHILD_FAILED);
_exit(EXIT_FAILURE);
}
fdset_free(fds);
fds = NULL;
- /* Wait until the child reported that it is ready with
- * all it needs to do with privileges. 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);
+ /* Wait for the child event:
+ * If EVENTFD_CHILD_FAILED, the child will terminate soon.
+ * If EVENTFD_CHILD_SUCCEEDED, the child is reporting 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 */
+ r = eventfd_child_succeeded(eventfds[1]);
+ eventfds[1] = safe_close(eventfds[1]);
+ if (r < 0)
+ goto check_container_status;
r = register_machine(pid);
if (r < 0)
@@ -3153,10 +3179,25 @@ int main(int argc, char *argv[]) {
if (r < 0)
goto finish;
+ /* Block SIGCHLD here, before notifying child.
+ * process_pty() will handle it with the other signals. */
+ r = sigprocmask(SIG_BLOCK, &mask_chld, NULL);
+ if (r < 0)
+ goto finish;
+
+ /* Reset signal to default */
+ r = default_signals(SIGCHLD, -1);
+ if (r < 0)
+ goto finish;
+
/* Notify the child that the parent is ready with all
- * its setup, and thtat the child can now hand over
+ * its setup, and that the child can now hand over
* control to the code to run inside the container. */
- eventfd_write(parent_ready_fd, 1);
+ r = eventfd_send_state(eventfds[0],
+ EVENTFD_PARENT_SUCCEEDED);
+ eventfds[0] = safe_close(eventfds[0]);
+ if (r < 0)
+ goto finish;
k = process_pty(master, &mask, arg_boot ? pid : 0, SIGRTMIN+3);
if (k < 0) {
@@ -3170,6 +3211,7 @@ int main(int argc, char *argv[]) {
/* Kill if it is not dead yet anyway */
terminate_machine(pid);
+check_container_status:
/* Redundant, but better safe than sorry */
kill(pid, SIGKILL);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-07-23 12:34:51 +0000