chiark / gitweb /
machinectl: add new command to spawn a getty inside a container
[elogind.git] / src / machine / machinectl.c
index 7500d5c1c3b416513d809c6a5c0212fd162307b1..7a252c34aab02d3b59e79f3d3cb944329175c44a 100644 (file)
 #include <getopt.h>
 #include <pwd.h>
 #include <locale.h>
+#include <socket.h>
+#include <fcntl.h>
 
 #include "sd-bus.h"
-
 #include "log.h"
 #include "util.h"
 #include "macro.h"
@@ -39,6 +40,7 @@
 #include "unit-name.h"
 #include "cgroup-show.h"
 #include "cgroup-util.h"
+#include "ptyfwd.h"
 
 static char **arg_property = NULL;
 static bool arg_all = false;
@@ -46,13 +48,9 @@ static bool arg_full = false;
 static bool arg_no_pager = false;
 static const char *arg_kill_who = NULL;
 static int arg_signal = SIGTERM;
-static enum transport {
-        TRANSPORT_NORMAL,
-        TRANSPORT_SSH,
-} arg_transport = TRANSPORT_NORMAL;
 static bool arg_ask_password = true;
+static BusTransport arg_transport = BUS_TRANSPORT_LOCAL;
 static char *arg_host = NULL;
-static char *arg_user = NULL;
 
 static void pager_open_if_enabled(void) {
 
@@ -94,9 +92,6 @@ static int list_machines(sd_bus *bus, char **args, unsigned n) {
                 goto fail;
 
         while ((r = sd_bus_message_read(reply, "(ssso)", &name, &class, &service, &object)) > 0) {
-                if (r < 0)
-                        goto fail;
-
                 printf("%-32s %-9s %-16s\n", name, class, service);
 
                 k++;
@@ -115,7 +110,7 @@ static int list_machines(sd_bus *bus, char **args, unsigned n) {
 
 fail:
         log_error("Failed to parse reply: %s", strerror(-r));
-        return -EIO;
+        return r;
 }
 
 static int show_scope_cgroup(sd_bus *bus, const char *unit, pid_t leader) {
@@ -129,30 +124,28 @@ static int show_scope_cgroup(sd_bus *bus, const char *unit, pid_t leader) {
         assert(bus);
         assert(unit);
 
-        if (arg_transport == TRANSPORT_SSH)
+        if (arg_transport == BUS_TRANSPORT_REMOTE)
                 return 0;
 
         path = unit_dbus_path_from_name(unit);
         if (!path)
                 return log_oom();
 
-        r = sd_bus_call_method(
+        r = sd_bus_get_property(
                         bus,
                         "org.freedesktop.systemd1",
                         path,
-                        "org.freedesktop.DBus.Properties",
-                        "Get",
+                        "org.freedesktop.systemd1.Scope",
+                        "ControlGroup",
                         &error,
                         &reply,
-                        "ss",
-                        "org.freedesktop.systemd1.Scope",
-                        "ControlGroup");
+                        "s");
         if (r < 0) {
                 log_error("Failed to query ControlGroup: %s", bus_error_message(&error, -r));
                 return r;
         }
 
-        r = sd_bus_message_read(reply, "v", "s", &cgroup);
+        r = sd_bus_message_read(reply, "s", &cgroup);
         if (r < 0) {
                 log_error("Failed to parse reply: %s", strerror(-r));
                 return r;
@@ -371,9 +364,6 @@ static int show_one(const char *verb, sd_bus *bus, const char *path, bool show_p
                 const char *name;
                 const char *contents;
 
-                if (r < 0)
-                        goto fail;
-
                 r = sd_bus_message_read_basic(reply, SD_BUS_TYPE_STRING, &name);
                 if (r < 0)
                         goto fail;
@@ -415,7 +405,7 @@ static int show_one(const char *verb, sd_bus *bus, const char *path, bool show_p
 
 fail:
         log_error("Failed to parse reply: %s", strerror(-r));
-        return -EIO;
+        return r;
 }
 
 static int show(sd_bus *bus, char **args, unsigned n) {
@@ -460,7 +450,7 @@ static int show(sd_bus *bus, char **args, unsigned n) {
                 r = sd_bus_message_read(reply, "o", &path);
                 if (r < 0) {
                         log_error("Failed to parse reply: %s", strerror(-r));
-                        return -EIO;
+                        return r;
                 }
 
                 r = show_one(args[0], bus, path, show_properties, &new_line);
@@ -528,26 +518,261 @@ static int terminate_machine(sd_bus *bus, char **args, unsigned n) {
         return 0;
 }
 
+static int openpt_in_namespace(pid_t pid, int flags) {
+        _cleanup_close_ int nsfd = -1, rootfd = -1;
+        _cleanup_free_ char *ns = NULL, *root = NULL;
+        _cleanup_close_pipe_ int sock[2] = { -1, -1 };
+        struct msghdr mh;
+        union {
+                struct cmsghdr cmsghdr;
+                uint8_t buf[CMSG_SPACE(sizeof(int))];
+        } control;
+        struct cmsghdr *cmsg;
+        int master, r;
+        pid_t child;
+        siginfo_t si;
+
+        r = asprintf(&ns, "/proc/%lu/ns/mnt", (unsigned long) pid);
+        if (r < 0)
+                return -ENOMEM;
+
+        nsfd = open(ns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+        if (nsfd < 0)
+                return -errno;
+
+        r = asprintf(&root, "/proc/%lu/root", (unsigned long) pid);
+        if (r < 0)
+                return -ENOMEM;
+
+        rootfd = open(root, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+        if (rootfd < 0)
+                return -errno;
+
+        if (socketpair(AF_UNIX, SOCK_DGRAM, 0, sock) < 0)
+                return -errno;
+
+        zero(control);
+        zero(mh);
+        mh.msg_control = &control;
+        mh.msg_controllen = sizeof(control);
+
+        child = fork();
+        if (child < 0)
+                return -errno;
+
+        if (child == 0) {
+                close_nointr_nofail(sock[0]);
+                sock[0] = -1;
+
+                r = setns(nsfd, CLONE_NEWNS);
+                if (r < 0)
+                        _exit(EXIT_FAILURE);
+
+                if (fchdir(rootfd) < 0)
+                        _exit(EXIT_FAILURE);
+
+                if (chroot(".") < 0)
+                        _exit(EXIT_FAILURE);
+
+                master = posix_openpt(flags);
+                if (master < 0)
+                        _exit(EXIT_FAILURE);
+
+                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), &master, sizeof(int));
+
+                mh.msg_controllen = cmsg->cmsg_len;
+
+                r = sendmsg(sock[1], &mh, MSG_NOSIGNAL);
+                close_nointr_nofail(master);
+                if (r < 0)
+                        _exit(EXIT_FAILURE);
+
+                _exit(EXIT_SUCCESS);
+        }
+
+        close_nointr_nofail(sock[1]);
+        sock[1] = -1;
+
+        if (recvmsg(sock[0], &mh, MSG_NOSIGNAL|MSG_CMSG_CLOEXEC) < 0)
+                return -errno;
+
+        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg))
+                if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
+                        int *fds;
+                        unsigned n_fds;
+
+                        fds = (int*) CMSG_DATA(cmsg);
+                        n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+
+                        if (n_fds != 1) {
+                                close_many(fds, n_fds);
+                                return -EIO;
+                        }
+
+                        master = fds[0];
+                }
+
+        r = wait_for_terminate(child, &si);
+        if (r < 0 || si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS || master < 0) {
+
+                if (master >= 0)
+                        close_nointr_nofail(master);
+
+                return r < 0 ? r : -EIO;
+        }
+
+        return master;
+}
+
+static int login_machine(sd_bus *bus, char **args, unsigned n) {
+        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL, *reply2 = NULL, *reply3 = NULL;
+        _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_bus_unref_ sd_bus *container_bus = NULL;
+        _cleanup_close_ int master = -1;
+        _cleanup_free_ char *getty = NULL;
+        const char *path, *pty, *p;
+        uint32_t leader;
+        sigset_t mask;
+        int r;
+
+        assert(bus);
+        assert(args);
+
+        if (arg_transport != BUS_TRANSPORT_LOCAL) {
+                log_error("Login only support on local machines.");
+                return -ENOTSUP;
+        }
+
+        r = sd_bus_call_method(
+                        bus,
+                        "org.freedesktop.machine1",
+                        "/org/freedesktop/machine1",
+                        "org.freedesktop.machine1.Manager",
+                        "GetMachine",
+                        &error,
+                        &reply,
+                        "s", args[1]);
+        if (r < 0) {
+                log_error("Could not get path to machine: %s", bus_error_message(&error, -r));
+                return r;
+        }
+
+        r = sd_bus_message_read(reply, "o", &path);
+        if (r < 0) {
+                log_error("Failed to parse reply: %s", strerror(-r));
+                return r;
+        }
+
+        r = sd_bus_get_property(
+                        bus,
+                        "org.freedesktop.machine1",
+                        path,
+                        "org.freedesktop.machine1.Machine",
+                        "Leader",
+                        &error,
+                        &reply2,
+                        "u");
+        if (r < 0) {
+                log_error("Failed to retrieve PID of leader: %s", strerror(-r));
+                return r;
+        }
+
+        r = sd_bus_message_read(reply2, "u", &leader);
+        if (r < 0) {
+                log_error("Failed to parse reply: %s", strerror(-r));
+                return r;
+        }
+
+        master = openpt_in_namespace(leader, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NDELAY);
+        if (master < 0) {
+                log_error("Failed to acquire pseudo tty: %s", strerror(-master));
+                return master;
+        }
+
+        pty = ptsname(master);
+        if (!pty) {
+                log_error("Failed to get pty name: %m");
+                return -errno;
+        }
+
+        p = startswith(pty, "/dev/pts/");
+        if (!p) {
+                log_error("Invalid pty name %s.", pty);
+                return -EIO;
+        }
+
+        r = sd_bus_open_system_container(args[1], &container_bus);
+        if (r < 0) {
+                log_error("Failed to get container bus: %s", strerror(-r));
+                return r;
+        }
+
+        getty = strjoin("container-getty@", p, ".service", NULL);
+        if (!getty)
+                return log_oom();
+
+        if (unlockpt(master) < 0) {
+                log_error("Failed to unlock tty: %m");
+                return -errno;
+        }
+
+        r = sd_bus_call_method(container_bus,
+                               "org.freedesktop.systemd1",
+                               "/org/freedesktop/systemd1",
+                               "org.freedesktop.systemd1.Manager",
+                               "StartUnit",
+                               &error, &reply3,
+                               "ss", getty, "replace");
+        if (r < 0) {
+                log_error("Failed to start getty service: %s", bus_error_message(&error, r));
+                return r;
+        }
+
+        assert_se(sigemptyset(&mask) == 0);
+        sigset_add_many(&mask, SIGWINCH, SIGTERM, SIGINT, -1);
+        assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
+
+        log_info("Connected to container %s. Press ^] three times within 1s to exit session.", args[1]);
+
+        r = process_pty(master, &mask, 0, 0);
+        if (r < 0) {
+                log_error("Failed to process pseudo tty: %s", strerror(-r));
+                return r;
+        }
+
+        fputc('\n', stdout);
+
+        log_info("Connection to container %s terminated.", args[1]);
+
+        return 0;
+}
+
 static int help(void) {
 
         printf("%s [OPTIONS...] {COMMAND} ...\n\n"
                "Send control commands to or query the virtual machine and container registration manager.\n\n"
                "  -h --help              Show this help\n"
                "     --version           Show package version\n"
+               "     --no-pager          Do not pipe output into a pager\n"
+               "     --no-ask-password   Don't prompt for password\n"
+               "  -H --host=[USER@]HOST  Operate on remote host\n"
+               "  -M --machine=CONTAINER Operate on local container\n"
                "  -p --property=NAME     Show only properties by this name\n"
                "  -a --all               Show all properties, including empty ones\n"
-               "     --kill-who=WHO      Who to send signal to\n"
                "  -l --full              Do not ellipsize output\n"
-               "  -s --signal=SIGNAL     Which signal to send\n"
-               "     --no-ask-password   Don't prompt for password\n"
-               "  -H --host=[USER@]HOST  Show information for remote host\n"
-               "     --no-pager          Do not pipe output into a pager\n\n"
+               "     --kill-who=WHO      Who to send signal to\n"
+               "  -s --signal=SIGNAL     Which signal to send\n\n"
                "Commands:\n"
                "  list                   List running VMs and containers\n"
                "  status [NAME...]       Show VM/container status\n"
                "  show [NAME...]         Show properties of one or more VMs/containers\n"
                "  terminate [NAME...]    Terminate one or more VMs/containers\n"
-               "  kill [NAME...]         Send signal to processes of a VM/container\n",
+               "  kill [NAME...]         Send signal to processes of a VM/container\n"
+               "  login [NAME]           Get a login prompt on a container\n",
                program_invocation_short_name);
 
         return 0;
@@ -572,17 +797,17 @@ static int parse_argv(int argc, char *argv[]) {
                 { "kill-who",        required_argument, NULL, ARG_KILL_WHO        },
                 { "signal",          required_argument, NULL, 's'                 },
                 { "host",            required_argument, NULL, 'H'                 },
-                { "privileged",      no_argument,       NULL, 'P'                 },
+                { "machine",         required_argument, NULL, 'M'                 },
                 { "no-ask-password", no_argument,       NULL, ARG_NO_ASK_PASSWORD },
                 { NULL,              0,                 NULL, 0                   }
         };
 
-        int c;
+        int c, r;
 
         assert(argc >= 0);
         assert(argv);
 
-        while ((c = getopt_long(argc, argv, "hp:als:H:P", options, NULL)) >= 0) {
+        while ((c = getopt_long(argc, argv, "hp:als:H:M:", options, NULL)) >= 0) {
 
                 switch (c) {
 
@@ -595,22 +820,16 @@ static int parse_argv(int argc, char *argv[]) {
                         puts(SYSTEMD_FEATURES);
                         return 0;
 
-                case 'p': {
-                        char **l;
-
-                        l = strv_append(arg_property, optarg);
-                        if (!l)
-                                return -ENOMEM;
-
-                        strv_free(arg_property);
-                        arg_property = l;
+                case 'p':
+                        r = strv_extend(&arg_property, optarg);
+                        if (r < 0)
+                                return log_oom();
 
                         /* If the user asked for a particular
                          * property, show it to him, even if it is
                          * empty. */
                         arg_all = true;
                         break;
-                }
 
                 case 'a':
                         arg_all = true;
@@ -641,8 +860,13 @@ static int parse_argv(int argc, char *argv[]) {
                         break;
 
                 case 'H':
-                        arg_transport = TRANSPORT_SSH;
-                        parse_user_at_host(optarg, &arg_user, &arg_host);
+                        arg_transport = BUS_TRANSPORT_REMOTE;
+                        arg_host = optarg;
+                        break;
+
+                case 'M':
+                        arg_transport = BUS_TRANSPORT_CONTAINER;
+                        arg_host = optarg;
                         break;
 
                 case '?':
@@ -657,7 +881,7 @@ static int parse_argv(int argc, char *argv[]) {
         return 1;
 }
 
-static int machinectl_main(sd_bus *bus, int argc, char *argv[], const int r) {
+static int machinectl_main(sd_bus *bus, int argc, char *argv[]) {
 
         static const struct {
                 const char* verb;
@@ -674,6 +898,7 @@ static int machinectl_main(sd_bus *bus, int argc, char *argv[], const int r) {
                 { "show",                  MORE,   1, show              },
                 { "terminate",             MORE,   2, terminate_machine },
                 { "kill",                  MORE,   2, kill_machine      },
+                { "login",                 MORE,   2, login_machine     },
         };
 
         int left;
@@ -733,16 +958,11 @@ static int machinectl_main(sd_bus *bus, int argc, char *argv[], const int r) {
                 assert_not_reached("Unknown comparison operator.");
         }
 
-        if (r < 0) {
-                log_error("Failed to get D-Bus connection: %s", strerror(-r));
-                return -EIO;
-        }
-
         return verbs[i].dispatch(bus, argv + optind, left);
 }
 
 int main(int argc, char*argv[]) {
-        int r, retval = EXIT_FAILURE;
+        int r, ret = EXIT_FAILURE;
         _cleanup_bus_unref_ sd_bus *bus = NULL;
 
         setlocale(LC_ALL, "");
@@ -753,28 +973,24 @@ int main(int argc, char*argv[]) {
         if (r < 0)
                 goto finish;
         else if (r == 0) {
-                retval = EXIT_SUCCESS;
+                ret = EXIT_SUCCESS;
                 goto finish;
         }
 
-        if (arg_transport == TRANSPORT_NORMAL)
-                r = sd_bus_open_system(&bus);
-        else if (arg_transport == TRANSPORT_SSH)
-                r = bus_connect_system_ssh(arg_host, &bus);
-        else
-                assert_not_reached("Uh, invalid transport...");
+        r = bus_open_transport(arg_transport, arg_host, false, &bus);
         if (r < 0) {
-                retval = EXIT_FAILURE;
+                log_error("Failed to create bus connection: %s", strerror(-r));
+                ret = EXIT_FAILURE;
                 goto finish;
         }
 
-        r = machinectl_main(bus, argc, argv, r);
-        retval = r < 0 ? EXIT_FAILURE : r;
+        r = machinectl_main(bus, argc, argv);
+        ret = r < 0 ? EXIT_FAILURE : r;
 
 finish:
         strv_free(arg_property);
 
         pager_close();
 
-        return retval;
+        return ret;
 }