From 5f8cc96a0301c1177b11dd2e89370ef0b2ef577b Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Tue, 23 Dec 2014 19:12:49 +0100 Subject: [PATCH] machined: add new call OpenMachineLogin() that starts a getty in a container on a pty and returns the pty master fd to the client This is a one-stop solution for "machinectl login", and should simplify getting logins in containers. --- src/machine/machine-dbus.c | 125 ++++++++++++++++++------------------ src/machine/machine.h | 1 + src/machine/machined-dbus.c | 22 +++++++ src/shared/util.c | 86 +++++++++++++++++++++++++ src/shared/util.h | 2 + 5 files changed, 173 insertions(+), 63 deletions(-) diff --git a/src/machine/machine-dbus.c b/src/machine/machine-dbus.c index 76c5dcf73..600d42f19 100644 --- a/src/machine/machine-dbus.c +++ b/src/machine/machine-dbus.c @@ -32,6 +32,8 @@ #include "fileio.h" #include "in-addr-util.h" #include "local-addresses.h" +#include "path-util.h" +#include "bus-internal.h" #include "machine.h" static int property_get_id( @@ -391,99 +393,96 @@ int bus_machine_method_get_os_release(sd_bus *bus, sd_bus_message *message, void } 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_free_ char *pty_name = NULL; _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; - _cleanup_free_ char *pty_name = NULL; - 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); + master = openpt_in_namespace(m->leader, O_RDWR|O_NOCTTY|O_CLOEXEC); + if (master < 0) + return master; + + r = ptsname_malloc(master, &pty_name); 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)); + r = sd_bus_message_new_method_return(message, &reply); + if (r < 0) + return r; - mh.msg_controllen = cmsg->cmsg_len; + r = sd_bus_message_append(reply, "hs", master, pty_name); + if (r < 0) + return r; - if (sendmsg(pair[1], &mh, MSG_NOSIGNAL) < 0) - _exit(EXIT_FAILURE); + return sd_bus_send(bus, reply, NULL); +} - _exit(EXIT_SUCCESS); - } +int bus_machine_method_open_login(sd_bus *bus, sd_bus_message *message, void *userdata, sd_bus_error *error) { + _cleanup_bus_message_unref_ sd_bus_message *reply = NULL; + _cleanup_free_ char *pty_name = NULL, *getty = NULL; + _cleanup_bus_unref_ sd_bus *container_bus = NULL; + _cleanup_close_ int master = -1; + Machine *m = userdata; + const char *p; + int r; - pair[1] = safe_close(pair[1]); + master = openpt_in_namespace(m->leader, O_RDWR|O_NOCTTY|O_CLOEXEC); + if (master < 0) + return master; - r = wait_for_terminate(child, &si); + r = ptsname_malloc(master, &pty_name); 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) + p = path_startswith(pty_name, "/dev/pts/"); + if (!p) + return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "PTS name %s is invalid", pty_name); + + if (unlockpt(master) < 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; + r = sd_bus_new(&container_bus); + if (r < 0) + return r; - fds = (int*) CMSG_DATA(cmsg); - n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); +#ifdef ENABLE_KDBUS + asprintf(&container_bus->address, "x-container-kernel:pid=" PID_FMT ";x-container-unix:pid=" PID_FMT, m->leader, m->leader); +#else + asprintf(&container_bus->address, "x-container-kernel:pid=" PID_FMT, m->leader); +#endif + if (!container_bus->address) + return -ENOMEM; - if (n_fds != 1) { - close_many(fds, n_fds); - return -EIO; - } + container_bus->bus_client = true; + container_bus->trusted = false; + container_bus->is_system = true; - master = fds[0]; - } + r = sd_bus_start(container_bus); + if (r < 0) + return r; - if (master < 0) - return -EIO; + getty = strjoin("container-getty@", p, ".service", NULL); + if (!getty) + return -ENOMEM; - r = ptsname_malloc(master, &pty_name); + r = sd_bus_call_method( + container_bus, + "org.freedesktop.systemd1", + "/org/freedesktop/systemd1", + "org.freedesktop.systemd1.Manager", + "StartUnit", + error, NULL, + "ss", getty, "replace"); if (r < 0) return r; + container_bus = sd_bus_unref(container_bus); + r = sd_bus_message_new_method_return(message, &reply); if (r < 0) return r; diff --git a/src/machine/machine.h b/src/machine/machine.h index e1094c265..3a78ab448 100644 --- a/src/machine/machine.h +++ b/src/machine/machine.h @@ -105,6 +105,7 @@ int bus_machine_method_kill(sd_bus *bus, sd_bus_message *message, void *userdata 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 bus_machine_method_open_login(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/machined-dbus.c b/src/machine/machined-dbus.c index 370d04a9a..5ce091bf2 100644 --- a/src/machine/machined-dbus.c +++ b/src/machine/machined-dbus.c @@ -536,6 +536,27 @@ static int method_open_machine_pty(sd_bus *bus, sd_bus_message *message, void *u return bus_machine_method_open_pty(bus, message, machine, error); } +static int method_open_machine_login(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_login(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), @@ -552,6 +573,7 @@ const sd_bus_vtable manager_vtable[] = { 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_METHOD("OpenMachineLogin", "s", "hs", method_open_machine_login, 0), SD_BUS_SIGNAL("MachineNew", "so", 0), SD_BUS_SIGNAL("MachineRemoved", "so", 0), SD_BUS_VTABLE_END diff --git a/src/shared/util.c b/src/shared/util.c index 6bd278e79..97ff320bc 100644 --- a/src/shared/util.c +++ b/src/shared/util.c @@ -7473,3 +7473,89 @@ int ptsname_malloc(int fd, char **ret) { l *= 2; } } + +int openpt_in_namespace(pid_t pid, int flags) { + _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, rootfd = -1; + _cleanup_close_pair_ int pair[2] = { -1, -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; + siginfo_t si; + pid_t child; + int r; + + 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) { + int master; + + 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; + } + + return fds[0]; + } + + return -EIO; +} diff --git a/src/shared/util.h b/src/shared/util.h index d3e78e43c..ec0a6639c 100644 --- a/src/shared/util.h +++ b/src/shared/util.h @@ -1054,3 +1054,5 @@ int sethostname_idempotent(const char *s); #define laccess(path, mode) faccessat(AT_FDCWD, (path), (mode), AT_SYMLINK_NOFOLLOW) int ptsname_malloc(int fd, char **ret); + +int openpt_in_namespace(pid_t pid, int flags); -- 2.30.2