diff options
| -rw-r--r-- | Makefile.am | 2 | ||||
| -rw-r--r-- | src/nspawn/nspawn.c | 136 | ||||
| -rw-r--r-- | src/shared/eventfd-util.c | 169 | ||||
| -rw-r--r-- | src/shared/eventfd-util.h | 43 |
4 files changed, 60 insertions, 290 deletions
diff --git a/Makefile.am b/Makefile.am index f0d80ba748..fe680b0d94 100644 --- a/Makefile.am +++ b/Makefile.am @@ -845,8 +845,6 @@ libsystemd_shared_la_SOURCES = \ src/shared/barrier.h \ src/shared/async.c \ src/shared/async.h \ - src/shared/eventfd-util.c \ - src/shared/eventfd-util.h \ src/shared/copy.c \ src/shared/copy.h \ src/shared/base-filesystem.c \ diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c index bad93a5e2b..e75cc28074 100644 --- a/src/nspawn/nspawn.c +++ b/src/nspawn/nspawn.c @@ -40,7 +40,6 @@ #include <sys/un.h> #include <sys/socket.h> #include <linux/netlink.h> -#include <sys/eventfd.h> #include <net/if.h> #include <linux/veth.h> #include <sys/personality.h> @@ -84,12 +83,12 @@ #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" #include "copy.h" #include "base-filesystem.h" +#include "barrier.h" #ifdef HAVE_SECCOMP #include "seccomp-util.h" @@ -3074,12 +3073,18 @@ int main(int argc, char *argv[]) { for (;;) { ContainerStatus container_status; - int eventfds[2] = { -1, -1 }; + _barrier_destroy_ Barrier barrier = { }; struct sigaction sa = { .sa_handler = nop_handler, .sa_flags = SA_NOCLDSTOP, }; + r = barrier_init(&barrier); + if (r < 0) { + log_error("Cannot initialize IPC barrier: %s", strerror(-r)); + goto finish; + } + /* 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. */ @@ -3095,9 +3100,9 @@ int main(int argc, char *argv[]) { goto finish; } - pid = clone_with_eventfd(SIGCHLD|CLONE_NEWNS| - (arg_share_system ? 0 : CLONE_NEWIPC|CLONE_NEWPID|CLONE_NEWUTS)| - (arg_private_network ? CLONE_NEWNET : 0), eventfds); + pid = syscall(__NR_clone, SIGCHLD|CLONE_NEWNS| + (arg_share_system ? 0 : CLONE_NEWIPC|CLONE_NEWPID|CLONE_NEWUTS)| + (arg_private_network ? CLONE_NEWNET : 0), NULL); 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"); @@ -3126,6 +3131,8 @@ int main(int argc, char *argv[]) { }; char **env_use; + barrier_set_role(&barrier, BARRIER_CHILD); + envp[n_env] = strv_find_prefix(environ, "TERM="); if (envp[n_env]) n_env ++; @@ -3151,26 +3158,26 @@ int main(int argc, char *argv[]) { } log_error("Failed to open console: %s", strerror(-k)); - goto child_fail; + _exit(EXIT_FAILURE); } if (dup2(STDIN_FILENO, STDOUT_FILENO) != STDOUT_FILENO || dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO) { log_error("Failed to duplicate console: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } if (setsid() < 0) { log_error("setsid() failed: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } if (reset_audit_loginuid() < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (prctl(PR_SET_PDEATHSIG, SIGKILL) < 0) { log_error("PR_SET_PDEATHSIG failed: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } /* Mark everything as slave, so that we still @@ -3178,113 +3185,109 @@ int main(int argc, char *argv[]) { * propagate mounts to the real root. */ if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0) { log_error("MS_SLAVE|MS_REC failed: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } if (mount_devices(arg_directory, root_device, root_device_rw, home_device, home_device_rw, srv_device, srv_device_rw) < 0) - goto child_fail; + _exit(EXIT_FAILURE); /* Turn directory into bind mount */ if (mount(arg_directory, arg_directory, "bind", MS_BIND|MS_REC, NULL) < 0) { log_error("Failed to make bind mount: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } r = setup_volatile(arg_directory); if (r < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (setup_volatile_state(arg_directory) < 0) - goto child_fail; + _exit(EXIT_FAILURE); r = base_filesystem_create(arg_directory); if (r < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (arg_read_only) { k = bind_remount_recursive(arg_directory, true); if (k < 0) { log_error("Failed to make tree read-only: %s", strerror(-k)); - goto child_fail; + _exit(EXIT_FAILURE); } } if (mount_all(arg_directory) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (copy_devnodes(arg_directory) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (setup_ptmx(arg_directory) < 0) - goto child_fail; + _exit(EXIT_FAILURE); dev_setup(arg_directory); if (setup_seccomp() < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (setup_dev_console(arg_directory, console) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (setup_kmsg(arg_directory, kmsg_socket_pair[1]) < 0) - goto child_fail; + _exit(EXIT_FAILURE); kmsg_socket_pair[1] = safe_close(kmsg_socket_pair[1]); if (setup_boot_id(arg_directory) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (setup_timezone(arg_directory) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (setup_resolv_conf(arg_directory) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (setup_journal(arg_directory) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (mount_binds(arg_directory, arg_bind, false) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (mount_binds(arg_directory, arg_bind_ro, true) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (mount_tmpfs(arg_directory) < 0) - goto child_fail; + _exit(EXIT_FAILURE); if (setup_kdbus(arg_directory, kdbus_domain) < 0) - goto child_fail; + _exit(EXIT_FAILURE); /* Tell the parent that we are ready, and that * it can cgroupify us to that we lack access * to certain devices and resources. */ - r = eventfd_send_state(eventfds[1], - EVENTFD_CHILD_SUCCEEDED); - eventfds[1] = safe_close(eventfds[1]); - if (r < 0) - goto child_fail; + barrier_place(&barrier); if (chdir(arg_directory) < 0) { log_error("chdir(%s) failed: %m", arg_directory); - goto child_fail; + _exit(EXIT_FAILURE); } if (mount(arg_directory, "/", NULL, MS_MOVE, NULL) < 0) { log_error("mount(MS_MOVE) failed: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } if (chroot(".") < 0) { log_error("chroot() failed: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } if (chdir("/") < 0) { log_error("chdir() failed: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } umask(0022); @@ -3294,18 +3297,18 @@ int main(int argc, char *argv[]) { if (drop_capabilities() < 0) { log_error("drop_capabilities() failed: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } r = change_uid_gid(&home); if (r < 0) - goto child_fail; + _exit(EXIT_FAILURE); if ((asprintf((char**)(envp + n_env++), "HOME=%s", home ? home: "/root") < 0) || (asprintf((char**)(envp + n_env++), "USER=%s", arg_user ? arg_user : "root") < 0) || (asprintf((char**)(envp + n_env++), "LOGNAME=%s", arg_user ? arg_user : "root") < 0)) { log_oom(); - goto child_fail; + _exit(EXIT_FAILURE); } if (!sd_id128_equal(arg_uuid, SD_ID128_NULL)) { @@ -3313,7 +3316,7 @@ int main(int argc, char *argv[]) { if (asprintf((char**)(envp + n_env++), "container_uuid=%s", id128_format_as_uuid(arg_uuid, as_uuid)) < 0) { log_oom(); - goto child_fail; + _exit(EXIT_FAILURE); } } @@ -3321,13 +3324,13 @@ int main(int argc, char *argv[]) { k = fdset_cloexec(fds, false); if (k < 0) { log_error("Failed to unset O_CLOEXEC for file descriptors."); - goto child_fail; + _exit(EXIT_FAILURE); } if ((asprintf((char **)(envp + n_env++), "LISTEN_FDS=%u", n_fd_passed) < 0) || (asprintf((char **)(envp + n_env++), "LISTEN_PID=1") < 0)) { log_oom(); - goto child_fail; + _exit(EXIT_FAILURE); } } @@ -3336,12 +3339,12 @@ int main(int argc, char *argv[]) { if (arg_personality != 0xffffffffLU) { if (personality(arg_personality) < 0) { log_error("personality() failed: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } } else if (secondary) { if (personality(PER_LINUX32) < 0) { log_error("personality() failed: %m"); - goto child_fail; + _exit(EXIT_FAILURE); } } @@ -3349,7 +3352,7 @@ int main(int argc, char *argv[]) { if (arg_selinux_context) if (setexeccon((security_context_t) arg_selinux_context) < 0) { log_error("setexeccon(\"%s\") failed: %m", arg_selinux_context); - goto child_fail; + _exit(EXIT_FAILURE); } #endif @@ -3359,7 +3362,7 @@ int main(int argc, char *argv[]) { n = strv_env_merge(2, envp, arg_setenv); if (!n) { log_oom(); - goto child_fail; + _exit(EXIT_FAILURE); } env_use = n; @@ -3367,10 +3370,8 @@ int main(int argc, char *argv[]) { env_use = (char**) envp; /* Wait until the parent is ready with the setup, too... */ - r = eventfd_parent_succeeded(eventfds[0]); - eventfds[0] = safe_close(eventfds[0]); - if (r < 0) - goto child_fail; + if (!barrier_place_and_sync(&barrier)) + _exit(EXIT_FAILURE); if (arg_boot) { char **a; @@ -3399,29 +3400,15 @@ 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); } + barrier_set_role(&barrier, BARRIER_PARENT); fdset_free(fds); fds = NULL; - /* 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) { + /* wait for child-setup to be done */ + if (barrier_place_and_sync(&barrier)) { int ifi = 0; r = move_network_interfaces(pid); @@ -3458,10 +3445,7 @@ int main(int argc, char *argv[]) { /* Notify the child that the parent is ready with all * its setup, and that the child can now hand over * control to the code to run inside the container. */ - r = eventfd_send_state(eventfds[0], EVENTFD_PARENT_SUCCEEDED); - eventfds[0] = safe_close(eventfds[0]); - if (r < 0) - goto finish; + barrier_place(&barrier); k = process_pty(master, &mask, arg_boot ? pid : 0, SIGRTMIN+3); if (k < 0) { diff --git a/src/shared/eventfd-util.c b/src/shared/eventfd-util.c deleted file mode 100644 index 27b7cf788f..0000000000 --- a/src/shared/eventfd-util.c +++ /dev/null @@ -1,169 +0,0 @@ -/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ - -/*** - This file is part of systemd. - - Copyright 2014 Djalal Harouni - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. -***/ - -#include <assert.h> -#include <errno.h> -#include <unistd.h> -#include <sys/eventfd.h> -#include <sys/syscall.h> - -#include "eventfd-util.h" -#include "util.h" - - -/* - * Use this to create processes that need to setup a full context - * and sync it with their parents using cheap mechanisms. - * - * This will create two blocking eventfd(s). A pair for the parent and - * the other for the child so they can be used as a notify mechanism. - * Each process will gets its copy of the parent and child eventfds. - * - * This is useful in case: - * 1) If the parent fails or dies, the child must die. - * 2) Child will install PR_SET_PDEATHSIG as soon as possible. - * 3) Parent and child need to sync using less resources. - * 4) If parent is not able to install a SIGCHLD handler: - * parent will wait using a blocking eventfd_read() or - * eventfd_child_succeeded() call on the child eventfd. - * - * * If the child setup succeeded, child should notify with an - * EVENTFD_CHILD_SUCCEEDED, parent will continue. - * * If the child setup failed, child should notify with an - * EVENTFD_CHILD_FAILED before any _exit(). This avoids blocking - * the parent. - * - * 5) If parent is able to install a SIGCHLD handler: - * An empty signal handler without SA_RESTART will do it, since the - * blocking eventfd_read() or eventfd_parent_succeeded() of the - * parent will be interrupted by SIGCHLD and the call will fail with - * EINTR. This is useful in case the child dies abnormaly and did - * not have a chance to notify its parent using EVENTFD_CHILD_FAILED. - * - * 6) Call wait*() in the main instead of the signal handler in order - * to: 1) reduce side effects and 2) have a better handling for - * child termination in order to reduce various race conditions. - * - * - * The return value of clone_with_eventfd() is the same of clone(). - * On success the eventfds[] will contain the two eventfd(s). These - * file descriptors can be closed later with safe_close(). On failure, - * a negative value is returned in the caller's context, and errno will - * be set appropriately. - * - * Extra preliminary work: - * 1) Child can wait before starting its setup by using the - * eventfd_recv_start() call on the parent eventfd, in that case the - * parent must notify with EVENTFD_START, after doing any preliminary - * work. - * - * Note: this function depends on systemd internal functions - * safe_close() and it should be used only by direct binaries, no - * libraries. - */ -pid_t clone_with_eventfd(int flags, int eventfds[2]) { - pid_t pid; - - assert(eventfds); - - eventfds[0] = eventfd(EVENTFD_INIT, EFD_CLOEXEC); - if (eventfds[0] < 0) - return -1; - - eventfds[1] = eventfd(EVENTFD_INIT, EFD_CLOEXEC); - if (eventfds[1] < 0) - goto err_eventfd0; - - pid = syscall(__NR_clone, flags, NULL); - if (pid < 0) - goto err_eventfd1; - - return pid; - -err_eventfd1: - eventfds[1] = safe_close(eventfds[1]); -err_eventfd0: - eventfds[0] = safe_close(eventfds[0]); - return -1; -} - -int eventfd_send_state(int efd, eventfd_t s) { - return eventfd_write(efd, s); -} - -/* - * Receive an eventfd state on the eventfd file descriptor. - * - * If the third argument is set to a value other than zero, then this - * function will compare the received value with this argument and set - * the return value. - * - * On success return 0. On error, -1 will be returned, and errno will - * be set appropriately. - */ -int eventfd_recv_state(int efd, eventfd_t *e, eventfd_t s) { - int ret; - - ret = eventfd_read(efd, e); - if (ret < 0) - return ret; - else if (s != 0 && *e != s) { - errno = EINVAL; - return -1; - } - - return 0; -} - -/* - * Receive the EVENTFD_START state on the eventfd file descriptor. - * - * On Success return 0. On error, -1 will be returned, and errno will - * be set appropriately. - */ -int eventfd_recv_start(int efd) { - eventfd_t e = EVENTFD_INIT; - return eventfd_recv_state(efd, &e, EVENTFD_START); -} - -/* - * Receive the EVENTFD_PARENT_SUCCEEDED state on the eventfd file - * descriptor. - * - * On Success return 0. On error, -1 will be returned, and errno will - * be set appropriately. - */ -int eventfd_parent_succeeded(int efd) { - eventfd_t e = EVENTFD_INIT; - return eventfd_recv_state(efd, &e, EVENTFD_PARENT_SUCCEEDED); -} - -/* - * Receive the EVENTFD_CHILD_SUCCEEDED state on the eventfd file - * descriptor. - * - * On Success return 0. On error, -1 will be returned, and errno will - * be set appropriately. - */ -int eventfd_child_succeeded(int efd) { - eventfd_t e = EVENTFD_INIT; - return eventfd_recv_state(efd, &e, EVENTFD_CHILD_SUCCEEDED); -} diff --git a/src/shared/eventfd-util.h b/src/shared/eventfd-util.h deleted file mode 100644 index 0120f0409e..0000000000 --- a/src/shared/eventfd-util.h +++ /dev/null @@ -1,43 +0,0 @@ -/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ - -#pragma once - -/*** - This file is part of systemd. - - Copyright 2014 Djalal Harouni - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. -***/ - -#include <sys/types.h> -#include <sys/eventfd.h> - -enum { - EVENTFD_INIT, - EVENTFD_START, - EVENTFD_PARENT_SUCCEEDED, - EVENTFD_PARENT_FAILED, - EVENTFD_CHILD_SUCCEEDED, - EVENTFD_CHILD_FAILED, -}; - -pid_t clone_with_eventfd(int flags, int eventfds[2]); - -int eventfd_send_state(int efd, eventfd_t s); -int eventfd_recv_state(int efd, eventfd_t *e, eventfd_t s); - -int eventfd_recv_start(int efd); -int eventfd_parent_succeeded(int efd); -int eventfd_child_succeeded(int efd); |