#include <sys/signalfd.h>
#include <grp.h>
#include <linux/fs.h>
+#include <sys/un.h>
+#include <sys/socket.h>
#include <systemd/sd-daemon.h>
free(where);
}
- /* Fix the timezone, if possible */
- if (asprintf(&where, "%s/etc/localtime", dest) >= 0) {
+ return r;
+}
- if (mount("/etc/localtime", where, "bind", MS_BIND, NULL) >= 0)
- mount("/etc/localtime", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
+static int setup_timezone(const char *dest) {
+ char *where;
- free(where);
+ assert(dest);
+
+ /* Fix the timezone, if possible */
+ if (asprintf(&where, "%s/etc/localtime", dest) < 0) {
+ log_error("Out of memory");
+ return -ENOMEM;
}
- if (asprintf(&where, "%s/etc/timezone", dest) >= 0) {
+ if (mount("/etc/localtime", where, "bind", MS_BIND, NULL) >= 0)
+ mount("/etc/localtime", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
- if (mount("/etc/timezone", where, "bind", MS_BIND, NULL) >= 0)
- mount("/etc/timezone", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
+ free(where);
- free(where);
+ if (asprintf(&where, "%s/etc/timezone", dest) < 0) {
+ log_error("Out of memory");
+ return -ENOMEM;
}
- if (asprintf(&where, "%s/proc/kmsg", dest) >= 0) {
- mount("/dev/null", where, "bind", MS_BIND, NULL);
- free(where);
- }
+ if (mount("/etc/timezone", where, "bind", MS_BIND, NULL) >= 0)
+ mount("/etc/timezone", where, "bind", MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
- return r;
+ free(where);
+
+ return 0;
}
-static int copy_devnodes(const char *dest, const char *console) {
+static int copy_devnodes(const char *dest) {
static const char devnodes[] =
"null\0"
"urandom\0"
"tty\0"
"ptmx\0"
- "kmsg\0"
"rtc0\0";
const char *d;
- int r = 0, k;
+ int r = 0;
mode_t u;
- struct stat st;
- char *from = NULL, *to = NULL;
assert(dest);
- assert(console);
u = umask(0000);
NULSTR_FOREACH(d, devnodes) {
- from = to = NULL;
+ struct stat st;
+ char *from = NULL, *to = NULL;
asprintf(&from, "/dev/%s", d);
asprintf(&to, "%s/dev/%s", dest, d);
free(to);
}
- if (stat(console, &st) < 0) {
+ umask(u);
- log_error("Failed to stat %s: %m", console);
- if (r == 0)
- r = -errno;
+ return r;
+}
+
+static int setup_dev_console(const char *dest, const char *console) {
+ struct stat st;
+ char *to = NULL;
+ int r;
+ mode_t u;
+
+ assert(dest);
+ assert(console);
+
+ u = umask(0000);
+ if (stat(console, &st) < 0) {
+ log_error("Failed to stat %s: %m", console);
+ r = -errno;
goto finish;
} else if (!S_ISCHR(st.st_mode)) {
-
log_error("/dev/console is not a char device.");
- if (r == 0)
- r = -EIO;
+ r = -EIO;
+ goto finish;
+ }
+ r = chmod_and_chown(console, 0600, 0, 0);
+ if (r < 0) {
+ log_error("Failed to correct access mode for TTY: %s", strerror(-r));
goto finish;
}
if (asprintf(&to, "%s/dev/console", dest) < 0) {
-
log_error("Out of memory");
- if (r == 0)
- r = -ENOMEM;
-
- goto finish;
+ r = -ENOMEM;
+ goto finish;
}
/* We need to bind mount the right tty to /dev/console since
* doesn't actually matter here, since we mount it over
* anyway). */
- if (mknod(to, (st.st_mode & ~07777) | 0600, st.st_rdev) < 0)
- log_error("mknod for /dev/console failed: %m");
+ if (mknod(to, (st.st_mode & ~07777) | 0600, st.st_rdev) < 0) {
+ log_error("mknod() for /dev/console failed: %m");
+ r = -errno;
+ goto finish;
+ }
if (mount(console, to, "bind", MS_BIND, NULL) < 0) {
- log_error("bind mount for /dev/console failed: %m");
-
- if (r == 0)
- r = -errno;
+ log_error("Bind mount for /dev/console failed: %m");
+ r = -errno;
+ goto finish;
}
+finish:
free(to);
+ umask(u);
+
+ return r;
+}
+
+static int setup_kmsg(const char *dest, int kmsg_socket) {
+ char *from = NULL, *to = NULL;
+ int r, fd, k;
+ mode_t u;
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[CMSG_SPACE(sizeof(int))];
+ } control;
+ struct msghdr mh;
+ struct cmsghdr *cmsg;
- if ((k = chmod_and_chown(console, 0600, 0, 0)) < 0) {
- log_error("Failed to correct access mode for TTY: %s", strerror(-k));
+ assert(dest);
+ assert(kmsg_socket >= 0);
+
+ u = umask(0000);
+
+ /* We create the kmsg FIFO as /dev/kmsg, but immediately
+ * delete it after bind mounting it to /proc/kmsg. While FIFOs
+ * on the reading side behave very similar to /proc/kmsg,
+ * their writing side behaves differently from /dev/kmsg in
+ * that writing blocks when nothing is reading. In order to
+ * avoid any problems with containers deadlocking due to this
+ * we simply make /dev/kmsg unavailable to the container. */
+ if (asprintf(&from, "%s/dev/kmsg", dest) < 0) {
+ log_error("Out of memory");
+ r = -ENOMEM;
+ goto finish;
+ }
- if (r == 0)
- r = k;
+ if (asprintf(&to, "%s/proc/kmsg", dest) < 0) {
+ log_error("Out of memory");
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ if (mkfifo(from, 0600) < 0) {
+ log_error("mkfifo() for /dev/kmsg failed: %m");
+ r = -errno;
+ goto finish;
+ }
+
+ r = chmod_and_chown(from, 0600, 0, 0);
+ if (r < 0) {
+ log_error("Failed to correct access mode for /dev/kmsg: %s", strerror(-r));
+ goto finish;
+ }
+
+ if (mount(from, to, "bind", MS_BIND, NULL) < 0) {
+ log_error("Bind mount for /proc/kmsg failed: %m");
+ r = -errno;
+ goto finish;
}
+ fd = open(from, O_RDWR|O_NDELAY|O_CLOEXEC);
+ if (fd < 0) {
+ log_error("Failed to open fifo: %m");
+ r = -errno;
+ goto finish;
+ }
+
+ zero(mh);
+ zero(control);
+
+ mh.msg_control = &control;
+ mh.msg_controllen = sizeof(control);
+
+ cmsg = CMSG_FIRSTHDR(&mh);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+ memcpy(CMSG_DATA(cmsg), &fd, sizeof(int));
+
+ mh.msg_controllen = cmsg->cmsg_len;
+
+ /* Store away the fd in the socket, so that it stays open as
+ * long as we run the child */
+ k = sendmsg(kmsg_socket, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
+ close_nointr_nofail(fd);
+
+ if (k < 0) {
+ log_error("Failed to send FIFO fd: %m");
+ r = -errno;
+ goto finish;
+ }
+
+ /* And now make the FIFO unavailable as /dev/kmsg... */
+ unlink(from);
+
finish:
+ free(from);
+ free(to);
umask(u);
return r;
sigset_t mask;
bool saved_attr_valid = false;
struct winsize ws;
+ int kmsg_socket_pair[2] = { -1, -1 };
log_parse_environment();
log_open();
goto finish;
}
+ if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, kmsg_socket_pair) < 0) {
+ log_error("Failed to create kmsg socket pair");
+ goto finish;
+ }
+
assert_se(sigemptyset(&mask) == 0);
sigset_add_many(&mask, SIGCHLD, SIGWINCH, SIGTERM, SIGINT, -1);
assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
close_nointr(STDOUT_FILENO);
close_nointr(STDERR_FILENO);
- close_all_fds(NULL, 0);
+ close_all_fds(&kmsg_socket_pair[1], 1);
reset_all_signal_handlers();
if (mount_all(arg_directory) < 0)
goto child_fail;
- if (copy_devnodes(arg_directory, console) < 0)
+ if (copy_devnodes(arg_directory) < 0)
+ goto child_fail;
+
+ if (setup_dev_console(arg_directory, console) < 0)
+ goto child_fail;
+
+ if (setup_kmsg(arg_directory, kmsg_socket_pair[1]) < 0)
+ goto child_fail;
+
+ close_nointr_nofail(kmsg_socket_pair[1]);
+
+ if (setup_timezone(arg_directory) < 0)
goto child_fail;
if (chdir(arg_directory) < 0) {
dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO)
goto child_fail;
- if (mount(arg_directory, "/", "bind", MS_BIND|MS_MOVE, NULL) < 0) {
+ if (mount(arg_directory, "/", "bind", MS_BIND, NULL) < 0) {
log_error("mount(MS_MOVE) failed: %m");
goto child_fail;
}
if (master >= 0)
close_nointr_nofail(master);
+ close_pipe(kmsg_socket_pair);
+
if (oldcg)
cg_attach(SYSTEMD_CGROUP_CONTROLLER, oldcg, 0);
~ianmdlvl / elogind.git / blobdiff