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machined: add new call OpenMachineLogin() that starts a getty in a container on a pty and returns the pty master fd to the client

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This is a one-stop solution for "machinectl login", and should simplify
getting logins in containers.
This commit is contained in:
Lennart Poettering 2014-12-23 19:12:49 +01:00
parent ee502e0c28
commit 5f8cc96a03
5 changed files with 189 additions and 79 deletions
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157
src/machine/machine-dbus.c
View File

@ -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(
@ -391,94 +393,19 @@ 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_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;
_cleanup_close_ int master = -1;
Machine *m = userdata;
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);
master = openpt_in_namespace(m->leader, 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;
return master;
r = ptsname_malloc(master, &pty_name);
if (r < 0)
@ -495,6 +422,78 @@ int bus_machine_method_open_pty(sd_bus *bus, sd_bus_message *message, void *user
return sd_bus_send(bus, reply, NULL);
}
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;
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;
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;
r = sd_bus_new(&container_bus);
if (r < 0)
return r;
#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;
container_bus->bus_client = true;
container_bus->trusted = false;
container_bus->is_system = true;
r = sd_bus_start(container_bus);
if (r < 0)
return r;
getty = strjoin("container-getty@", p, ".service", NULL);
if (!getty)
return -ENOMEM;
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;
r = sd_bus_message_append(reply, "hs", master, pty_name);
if (r < 0)
return r;
return sd_bus_send(bus, reply, NULL);
}
const sd_bus_vtable machine_vtable[] = {
SD_BUS_VTABLE_START(0),
SD_BUS_PROPERTY("Name", "s", NULL, offsetof(Machine, name), SD_BUS_VTABLE_PROPERTY_CONST),

1
src/machine/machine.h
View File

@ -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);

22
src/machine/machined-dbus.c
View File

@ -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

86
src/shared/util.c
View File

@ -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;
}

2
src/shared/util.h
View File

@ -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);