diff options
Diffstat (limited to 'src/nspawn')
| -rw-r--r-- | src/nspawn/nspawn.c | 92 |
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); |