machined: add OpenMachinePTY() bus call for allocating a PTY device within a container

Then, port "machinectl" over to make use of it.

4 files changed, 151 insertions, 111 deletions

diff --git a/src/machine/machine-dbus.c b/src/machine/machine-dbus.c
index f6fd9cf361..7cabe0f2ff 100644
--- a/src/machine/machine-dbus.c
+++ b/src/machine/machine-dbus.c
@@ -319,14 +319,14 @@ int bus_machine_method_get_os_release(sd_bus *bus, sd_bus_message *message, void
 
         r = namespace_open(m->leader, NULL, &mntns_fd, NULL, &root_fd);
         if (r < 0)
-                return sd_bus_error_set_errno(error, r);
+                return r;
 
         if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, pair) < 0)
-                return sd_bus_error_set_errno(error, -errno);
+                return -errno;
 
         child = fork();
         if (child < 0)
-                return sd_bus_error_set_errno(error, -errno);
+                return -errno;
 
         if (child == 0) {
                 _cleanup_close_ int fd = -1;
@@ -355,37 +355,137 @@ int bus_machine_method_get_os_release(sd_bus *bus, sd_bus_message *message, void
 
         f = fdopen(pair[0], "re");
         if (!f)
-                return sd_bus_error_set_errno(error, -errno);
+                return -errno;
 
         pair[0] = -1;
 
         r = load_env_file_pairs(f, "/etc/os-release", NULL, &l);
         if (r < 0)
-                return sd_bus_error_set_errno(error, r);
+                return r;
 
         r = wait_for_terminate(child, &si);
         if (r < 0)
-                return sd_bus_error_set_errno(error, r);
+                return r;
         if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
-                return sd_bus_error_set_errno(error, EIO);
+                return -EIO;
 
         r = sd_bus_message_new_method_return(message, &reply);
         if (r < 0)
-                return sd_bus_error_set_errno(error, r);
+                return r;
 
         r = sd_bus_message_open_container(reply, 'a', "{ss}");
         if (r < 0)
-                return sd_bus_error_set_errno(error, r);
+                return r;
 
         STRV_FOREACH_PAIR(k, v, l) {
                 r = sd_bus_message_append(reply, "{ss}", *k, *v);
                 if (r < 0)
-                        return sd_bus_error_set_errno(error, r);
+                        return r;
         }
 
         r = sd_bus_message_close_container(reply);
         if (r < 0)
-                return sd_bus_error_set_errno(error, r);
+                return r;
+
+        return sd_bus_send(bus, reply, NULL);
+}
+
+int bus_machine_method_open_pty(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, rootfd = -1;
+        _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
+        _cleanup_close_pair_ int pair[2] = { -1, -1 };
+        _cleanup_close_ int master = -1;
+        union {
+                struct cmsghdr cmsghdr;
+                uint8_t buf[CMSG_SPACE(sizeof(int))];
+        } control = {};
+        struct msghdr mh = {
+                .msg_control = &control,
+                .msg_controllen = sizeof(control),
+        };
+        Machine *m = userdata;
+        struct cmsghdr *cmsg;
+        siginfo_t si;
+        pid_t child;
+        int r;
+
+        assert(bus);
+        assert(message);
+        assert(m);
+
+        r = namespace_open(m->leader, &pidnsfd, &mntnsfd, NULL, &rootfd);
+        if (r < 0)
+                return r;
+
+        if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
+                return -errno;
+
+        child = fork();
+        if (child < 0)
+                return -errno;
+
+        if (child == 0) {
+                pair[0] = safe_close(pair[0]);
+
+                r = namespace_enter(pidnsfd, mntnsfd, -1, rootfd);
+                if (r < 0)
+                        _exit(EXIT_FAILURE);
+
+                master = posix_openpt(O_RDWR|O_NOCTTY|O_CLOEXEC);
+                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;
+
+                if (sendmsg(pair[1], &mh, MSG_NOSIGNAL) < 0)
+                        _exit(EXIT_FAILURE);
+
+                _exit(EXIT_SUCCESS);
+        }
+
+        pair[1] = safe_close(pair[1]);
+
+        r = wait_for_terminate(child, &si);
+        if (r < 0)
+                return r;
+        if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
+                return -EIO;
+
+        if (recvmsg(pair[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];
+                }
+
+        if (master < 0)
+                return -EIO;
+
+        r = sd_bus_message_new_method_return(message, &reply);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_append(reply, "hs", master, ptsname(master));
+        if (r < 0)
+                return r;
 
         return sd_bus_send(bus, reply, NULL);
 }
@@ -407,6 +507,7 @@ const sd_bus_vtable machine_vtable[] = {
         SD_BUS_METHOD("Kill", "si", NULL, bus_machine_method_kill, SD_BUS_VTABLE_CAPABILITY(CAP_KILL)),
         SD_BUS_METHOD("GetAddresses", NULL, "a(iay)", bus_machine_method_get_addresses, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("GetOSRelease", NULL, "a{ss}", bus_machine_method_get_os_release, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("OpenPTY", NULL, "hs", bus_machine_method_open_pty, 0),
         SD_BUS_VTABLE_END
 };
 
diff --git a/src/machine/machine.h b/src/machine/machine.h
index 5c6366554a..e1094c2653 100644
--- a/src/machine/machine.h
+++ b/src/machine/machine.h
@@ -104,6 +104,7 @@ int bus_machine_method_terminate(sd_bus *bus, sd_bus_message *message, void *use
 int bus_machine_method_kill(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error);
 int bus_machine_method_get_addresses(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error);
 int bus_machine_method_get_os_release(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error);
+int bus_machine_method_open_pty(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error);
 
 int machine_send_signal(Machine *m, bool new_machine);
 int machine_send_create_reply(Machine *m, sd_bus_error *error);
diff --git a/src/machine/machinectl.c b/src/machine/machinectl.c
index f5b87a23d2..ccee16f2a8 100644
--- a/src/machine/machinectl.c
+++ b/src/machine/machinectl.c
@@ -1010,106 +1010,17 @@ finish:
         return r;
 }
 
-static int openpt_in_namespace(pid_t pid, int flags) {
-        _cleanup_close_pair_ int pair[2] = { -1, -1 };
-        _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, rootfd = -1;
-        union {
-                struct cmsghdr cmsghdr;
-                uint8_t buf[CMSG_SPACE(sizeof(int))];
-        } control = {};
-        struct msghdr mh = {
-                .msg_control = &control,
-                .msg_controllen = sizeof(control),
-        };
-        struct cmsghdr *cmsg;
-        int master = -1, r;
-        pid_t child;
-        siginfo_t si;
-
-        assert(pid > 0);
-
-        r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &rootfd);
-        if (r < 0)
-                return r;
-
-        if (socketpair(AF_UNIX, SOCK_DGRAM, 0, pair) < 0)
-                return -errno;
-
-        child = fork();
-        if (child < 0)
-                return -errno;
-
-        if (child == 0) {
-                pair[0] = safe_close(pair[0]);
-
-                r = namespace_enter(pidnsfd, mntnsfd, -1, rootfd);
-                if (r < 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;
-
-                if (sendmsg(pair[1], &mh, MSG_NOSIGNAL) < 0)
-                        _exit(EXIT_FAILURE);
-
-                _exit(EXIT_SUCCESS);
-        }
-
-        pair[1] = safe_close(pair[1]);
-
-        r = wait_for_terminate(child, &si);
-        if (r < 0)
-                return r;
-        if (si.si_code != CLD_EXITED || si.si_status != EXIT_SUCCESS)
-                return -EIO;
-
-        if (recvmsg(pair[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];
-                }
-
-        if (master < 0)
-                return -EIO;
-
-        return master;
-}
-
 static int login_machine(int argc, char *argv[], void *userdata) {
         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         _cleanup_bus_message_unref_ sd_bus_message *reply = NULL;
         _cleanup_bus_close_unref_ sd_bus *container_bus = NULL;
         _cleanup_(pty_forward_freep) PTYForward *forward = NULL;
         _cleanup_event_unref_ sd_event *event = NULL;
-        _cleanup_close_ int master = -1;
         _cleanup_free_ char *getty = NULL;
+        int master = -1, r, ret = 0;
         sd_bus *bus = userdata;
         const char *pty, *p;
-        pid_t leader;
         sigset_t mask;
-        int r, ret = 0;
         char last_char = 0;
 
         assert(bus);
@@ -1127,17 +1038,22 @@ static int login_machine(int argc, char *argv[], void *userdata) {
         if (r < 0)
                 return log_error_errno(r, "Failed to attach bus to event loop: %m");
 
-        r = machine_get_leader(bus, argv[1], &leader);
-        if (r < 0)
+        r = sd_bus_call_method(bus,
+                               "org.freedesktop.machine1",
+                               "/org/freedesktop/machine1",
+                               "org.freedesktop.machine1.Manager",
+                               "OpenMachinePTY",
+                               &error,
+                               &reply,
+                               "s", argv[1]);
+        if (r < 0) {
+                log_error("Failed to get machine PTY: %s", bus_error_message(&error, -r));
                 return r;
+        }
 
-        master = openpt_in_namespace(leader, O_RDWR|O_NOCTTY|O_CLOEXEC|O_NDELAY);
-        if (master < 0)
-                return log_error_errno(master, "Failed to acquire pseudo tty: %m");
-
-        pty = ptsname(master);
-        if (!pty)
-                return log_error_errno(errno, "Failed to get pty name: %m");
+        r = sd_bus_message_read(reply, "hs", &master, &pty);
+        if (r < 0)
+                return r;
 
         p = startswith(pty, "/dev/pts/");
         if (!p) {
@@ -1161,7 +1077,7 @@ static int login_machine(int argc, char *argv[], void *userdata) {
                                "/org/freedesktop/systemd1",
                                "org.freedesktop.systemd1.Manager",
                                "StartUnit",
-                               &error, &reply,
+                               &error, NULL,
                                "ss", getty, "replace");
         if (r < 0) {
                 log_error("Failed to start getty service: %s", bus_error_message(&error, r));
diff --git a/src/machine/machined-dbus.c b/src/machine/machined-dbus.c
index 0229564234..370d04a9a5 100644
--- a/src/machine/machined-dbus.c
+++ b/src/machine/machined-dbus.c
@@ -515,6 +515,27 @@ static int method_list_images(sd_bus *bus, sd_bus_message *message, void *userda
         return sd_bus_send(bus, reply, NULL);
 }
 
+static int method_open_machine_pty(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+        Machine *machine;
+        const char *name;
+        int r;
+
+        assert(bus);
+        assert(message);
+        assert(m);
+
+        r = sd_bus_message_read(message, "s", &name);
+        if (r < 0)
+                return sd_bus_error_set_errno(error, r);
+
+        machine = hashmap_get(m->machines, name);
+        if (!machine)
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_MACHINE, "No machine '%s' known", name);
+
+        return bus_machine_method_open_pty(bus, message, machine, error);
+}
+
 const sd_bus_vtable manager_vtable[] = {
         SD_BUS_VTABLE_START(0),
         SD_BUS_METHOD("GetMachine", "s", "o", method_get_machine, SD_BUS_VTABLE_UNPRIVILEGED),
@@ -530,6 +551,7 @@ const sd_bus_vtable manager_vtable[] = {
         SD_BUS_METHOD("TerminateMachine", "s", NULL, method_terminate_machine, SD_BUS_VTABLE_CAPABILITY(CAP_KILL)),
         SD_BUS_METHOD("GetMachineAddresses", "s", "a(iay)", method_get_machine_addresses, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("GetMachineOSRelease", "s", "a{ss}", method_get_machine_os_release, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("OpenMachinePTY", "s", "hs", method_open_machine_pty, 0),
         SD_BUS_SIGNAL("MachineNew", "so", 0),
         SD_BUS_SIGNAL("MachineRemoved", "so", 0),
         SD_BUS_VTABLE_END