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Systemd/src/libsystemd/sd-login/sd-login.c
Lennart Poettering f5aaf57562 sd-login: add new sd_pid_get_cgroup() API 
This adds a new sd_pid_get_cgroup() call to sd-login which may be used
to query the control path of a process. This is useful for programs when
making use of delegation units, in order to figure out which subtree has
been delegated.

In light of the unified control group hierarchy this is finally safe to
do, hence let's add a proper API for it, to make it easier to use this.
2015-09-05 14:56:23 +02:00

1054 lines
26 KiB
C
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2011 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/inotify.h>
#include <poll.h>
#include "util.h"
#include "cgroup-util.h"
#include "macro.h"
#include "strv.h"
#include "fileio.h"
#include "login-util.h"
#include "formats-util.h"
#include "hostname-util.h"
#include "sd-login.h"
/* Error codes:
*
* invalid input parameters → -EINVAL
* invalid fd → -EBADF
* process does not exist → -ESRCH
* cgroup does not exist → -ENOENT
* machine, session does not exist → -ENXIO
* requested metadata on object is missing → -ENODATA
*/
_public_ int sd_pid_get_session(pid_t pid, char **session) {
assert_return(pid >= 0, -EINVAL);
assert_return(session, -EINVAL);
return cg_pid_get_session(pid, session);
}
_public_ int sd_pid_get_unit(pid_t pid, char **unit) {
assert_return(pid >= 0, -EINVAL);
assert_return(unit, -EINVAL);
return cg_pid_get_unit(pid, unit);
}
_public_ int sd_pid_get_user_unit(pid_t pid, char **unit) {
assert_return(pid >= 0, -EINVAL);
assert_return(unit, -EINVAL);
return cg_pid_get_user_unit(pid, unit);
}
_public_ int sd_pid_get_machine_name(pid_t pid, char **name) {
assert_return(pid >= 0, -EINVAL);
assert_return(name, -EINVAL);
return cg_pid_get_machine_name(pid, name);
}
_public_ int sd_pid_get_slice(pid_t pid, char **slice) {
assert_return(pid >= 0, -EINVAL);
assert_return(slice, -EINVAL);
return cg_pid_get_slice(pid, slice);
}
_public_ int sd_pid_get_user_slice(pid_t pid, char **slice) {
assert_return(pid >= 0, -EINVAL);
assert_return(slice, -EINVAL);
return cg_pid_get_user_slice(pid, slice);
}
_public_ int sd_pid_get_owner_uid(pid_t pid, uid_t *uid) {
assert_return(pid >= 0, -EINVAL);
assert_return(uid, -EINVAL);
return cg_pid_get_owner_uid(pid, uid);
}
_public_ int sd_pid_get_cgroup(pid_t pid, char **cgroup) {
char *c;
int r;
assert_return(pid >= 0, -EINVAL);
assert_return(cgroup, -EINVAL);
r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &c);
if (r < 0)
return r;
/* The internal APIs return the empty string for the root
* cgroup, let's return the "/" in the public APIs instead, as
* that's easier and less ambigious for people to grok. */
if (isempty(c)) {
free(c);
c = strdup("/");
if (!c)
return -ENOMEM;
}
*cgroup = c;
return 0;
}
_public_ int sd_peer_get_session(int fd, char **session) {
struct ucred ucred = {};
int r;
assert_return(fd >= 0, -EBADF);
assert_return(session, -EINVAL);
r = getpeercred(fd, &ucred);
if (r < 0)
return r;
return cg_pid_get_session(ucred.pid, session);
}
_public_ int sd_peer_get_owner_uid(int fd, uid_t *uid) {
struct ucred ucred;
int r;
assert_return(fd >= 0, -EBADF);
assert_return(uid, -EINVAL);
r = getpeercred(fd, &ucred);
if (r < 0)
return r;
return cg_pid_get_owner_uid(ucred.pid, uid);
}
_public_ int sd_peer_get_unit(int fd, char **unit) {
struct ucred ucred;
int r;
assert_return(fd >= 0, -EBADF);
assert_return(unit, -EINVAL);
r = getpeercred(fd, &ucred);
if (r < 0)
return r;
return cg_pid_get_unit(ucred.pid, unit);
}
_public_ int sd_peer_get_user_unit(int fd, char **unit) {
struct ucred ucred;
int r;
assert_return(fd >= 0, -EBADF);
assert_return(unit, -EINVAL);
r = getpeercred(fd, &ucred);
if (r < 0)
return r;
return cg_pid_get_user_unit(ucred.pid, unit);
}
_public_ int sd_peer_get_machine_name(int fd, char **machine) {
struct ucred ucred;
int r;
assert_return(fd >= 0, -EBADF);
assert_return(machine, -EINVAL);
r = getpeercred(fd, &ucred);
if (r < 0)
return r;
return cg_pid_get_machine_name(ucred.pid, machine);
}
_public_ int sd_peer_get_slice(int fd, char **slice) {
struct ucred ucred;
int r;
assert_return(fd >= 0, -EBADF);
assert_return(slice, -EINVAL);
r = getpeercred(fd, &ucred);
if (r < 0)
return r;
return cg_pid_get_slice(ucred.pid, slice);
}
_public_ int sd_peer_get_user_slice(int fd, char **slice) {
struct ucred ucred;
int r;
assert_return(fd >= 0, -EBADF);
assert_return(slice, -EINVAL);
r = getpeercred(fd, &ucred);
if (r < 0)
return r;
return cg_pid_get_user_slice(ucred.pid, slice);
}
_public_ int sd_peer_get_cgroup(int fd, char **cgroup) {
struct ucred ucred;
int r;
assert_return(fd >= 0, -EBADF);
assert_return(cgroup, -EINVAL);
r = getpeercred(fd, &ucred);
if (r < 0)
return r;
return sd_pid_get_cgroup(ucred.pid, cgroup);
}
static int file_of_uid(uid_t uid, char **p) {
assert_return(uid_is_valid(uid), -EINVAL);
assert(p);
if (asprintf(p, "/run/systemd/users/" UID_FMT, uid) < 0)
return -ENOMEM;
return 0;
}
_public_ int sd_uid_get_state(uid_t uid, char**state) {
_cleanup_free_ char *p = NULL;
char *s = NULL;
int r;
assert_return(state, -EINVAL);
r = file_of_uid(uid, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE, "STATE", &s, NULL);
if (r == -ENOENT) {
free(s);
s = strdup("offline");
if (!s)
return -ENOMEM;
}
if (r < 0) {
free(s);
return r;
}
if (isempty(s)) {
free(s);
return -EIO;
}
*state = s;
return 0;
}
_public_ int sd_uid_get_display(uid_t uid, char **session) {
_cleanup_free_ char *p = NULL, *s = NULL;
int r;
assert_return(session, -EINVAL);
r = file_of_uid(uid, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE, "DISPLAY", &s, NULL);
if (r == -ENOENT)
return -ENODATA;
if (r < 0)
return r;
if (isempty(s))
return -ENODATA;
*session = s;
s = NULL;
return 0;
}
static int file_of_seat(const char *seat, char **_p) {
char *p;
int r;
assert(_p);
if (seat) {
if (!filename_is_valid(seat))
return -EINVAL;
p = strappend("/run/systemd/seats/", seat);
} else {
_cleanup_free_ char *buf = NULL;
r = sd_session_get_seat(NULL, &buf);
if (r < 0)
return r;
p = strappend("/run/systemd/seats/", buf);
}
if (!p)
return -ENOMEM;
*_p = p;
p = NULL;
return 0;
}
_public_ int sd_uid_is_on_seat(uid_t uid, int require_active, const char *seat) {
_cleanup_free_ char *t = NULL, *s = NULL, *p = NULL;
size_t l;
int r;
const char *word, *variable, *state;
assert_return(uid_is_valid(uid), -EINVAL);
r = file_of_seat(seat, &p);
if (r < 0)
return r;
variable = require_active ? "ACTIVE_UID" : "UIDS";
r = parse_env_file(p, NEWLINE, variable, &s, NULL);
if (r == -ENOENT)
return 0;
if (r < 0)
return r;
if (isempty(s))
return 0;
if (asprintf(&t, UID_FMT, uid) < 0)
return -ENOMEM;
FOREACH_WORD(word, l, s, state)
if (strneq(t, word, l))
return 1;
return 0;
}
static int uid_get_array(uid_t uid, const char *variable, char ***array) {
_cleanup_free_ char *p = NULL, *s = NULL;
char **a;
int r;
assert(variable);
r = file_of_uid(uid, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE, variable, &s, NULL);
if (r == -ENOENT || (r >= 0 && isempty(s))) {
if (array)
*array = NULL;
return 0;
}
if (r < 0)
return r;
a = strv_split(s, " ");
if (!a)
return -ENOMEM;
strv_uniq(a);
r = strv_length(a);
if (array)
*array = a;
else
strv_free(a);
return r;
}
_public_ int sd_uid_get_sessions(uid_t uid, int require_active, char ***sessions) {
return uid_get_array(
uid,
require_active == 0 ? "ONLINE_SESSIONS" :
require_active > 0 ? "ACTIVE_SESSIONS" :
"SESSIONS",
sessions);
}
_public_ int sd_uid_get_seats(uid_t uid, int require_active, char ***seats) {
return uid_get_array(
uid,
require_active == 0 ? "ONLINE_SEATS" :
require_active > 0 ? "ACTIVE_SEATS" :
"SEATS",
seats);
}
static int file_of_session(const char *session, char **_p) {
char *p;
int r;
assert(_p);
if (session) {
if (!session_id_valid(session))
return -EINVAL;
p = strappend("/run/systemd/sessions/", session);
} else {
_cleanup_free_ char *buf = NULL;
r = sd_pid_get_session(0, &buf);
if (r < 0)
return r;
p = strappend("/run/systemd/sessions/", buf);
}
if (!p)
return -ENOMEM;
*_p = p;
return 0;
}
_public_ int sd_session_is_active(const char *session) {
_cleanup_free_ char *p = NULL, *s = NULL;
int r;
r = file_of_session(session, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE, "ACTIVE", &s, NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (isempty(s))
return -EIO;
return parse_boolean(s);
}
_public_ int sd_session_is_remote(const char *session) {
_cleanup_free_ char *p = NULL, *s = NULL;
int r;
r = file_of_session(session, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE, "REMOTE", &s, NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (isempty(s))
return -ENODATA;
return parse_boolean(s);
}
_public_ int sd_session_get_state(const char *session, char **state) {
_cleanup_free_ char *p = NULL, *s = NULL;
int r;
assert_return(state, -EINVAL);
r = file_of_session(session, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE, "STATE", &s, NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (isempty(s))
return -EIO;
*state = s;
s = NULL;
return 0;
}
_public_ int sd_session_get_uid(const char *session, uid_t *uid) {
int r;
_cleanup_free_ char *p = NULL, *s = NULL;
assert_return(uid, -EINVAL);
r = file_of_session(session, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE, "UID", &s, NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (isempty(s))
return -EIO;
return parse_uid(s, uid);
}
static int session_get_string(const char *session, const char *field, char **value) {
_cleanup_free_ char *p = NULL, *s = NULL;
int r;
assert_return(value, -EINVAL);
assert(field);
r = file_of_session(session, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE, field, &s, NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (isempty(s))
return -ENODATA;
*value = s;
s = NULL;
return 0;
}
_public_ int sd_session_get_seat(const char *session, char **seat) {
return session_get_string(session, "SEAT", seat);
}
_public_ int sd_session_get_tty(const char *session, char **tty) {
return session_get_string(session, "TTY", tty);
}
_public_ int sd_session_get_vt(const char *session, unsigned *vtnr) {
_cleanup_free_ char *vtnr_string = NULL;
unsigned u;
int r;
assert_return(vtnr, -EINVAL);
r = session_get_string(session, "VTNR", &vtnr_string);
if (r < 0)
return r;
r = safe_atou(vtnr_string, &u);
if (r < 0)
return r;
*vtnr = u;
return 0;
}
_public_ int sd_session_get_service(const char *session, char **service) {
return session_get_string(session, "SERVICE", service);
}
_public_ int sd_session_get_type(const char *session, char **type) {
return session_get_string(session, "TYPE", type);
}
_public_ int sd_session_get_class(const char *session, char **class) {
return session_get_string(session, "CLASS", class);
}
_public_ int sd_session_get_desktop(const char *session, char **desktop) {
_cleanup_free_ char *escaped = NULL;
char *t;
int r;
assert_return(desktop, -EINVAL);
r = session_get_string(session, "DESKTOP", &escaped);
if (r < 0)
return r;
r = cunescape(escaped, 0, &t);
if (r < 0)
return r;
*desktop = t;
return 0;
}
_public_ int sd_session_get_display(const char *session, char **display) {
return session_get_string(session, "DISPLAY", display);
}
_public_ int sd_session_get_remote_user(const char *session, char **remote_user) {
return session_get_string(session, "REMOTE_USER", remote_user);
}
_public_ int sd_session_get_remote_host(const char *session, char **remote_host) {
return session_get_string(session, "REMOTE_HOST", remote_host);
}
_public_ int sd_seat_get_active(const char *seat, char **session, uid_t *uid) {
_cleanup_free_ char *p = NULL, *s = NULL, *t = NULL;
int r;
assert_return(session || uid, -EINVAL);
r = file_of_seat(seat, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE,
"ACTIVE", &s,
"ACTIVE_UID", &t,
NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (session && !s)
return -ENOENT;
if (uid && !t)
return -ENOENT;
if (uid && t) {
r = parse_uid(t, uid);
if (r < 0)
return r;
}
if (session && s) {
*session = s;
s = NULL;
}
return 0;
}
_public_ int sd_seat_get_sessions(const char *seat, char ***sessions, uid_t **uids, unsigned *n_uids) {
_cleanup_free_ char *p = NULL, *s = NULL, *t = NULL;
_cleanup_strv_free_ char **a = NULL;
_cleanup_free_ uid_t *b = NULL;
unsigned n = 0;
int r;
r = file_of_seat(seat, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE,
"SESSIONS", &s,
"ACTIVE_SESSIONS", &t,
NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (s) {
a = strv_split(s, " ");
if (!a)
return -ENOMEM;
}
if (uids && t) {
const char *word, *state;
size_t l;
FOREACH_WORD(word, l, t, state)
n++;
if (n > 0) {
unsigned i = 0;
b = new(uid_t, n);
if (!b)
return -ENOMEM;
FOREACH_WORD(word, l, t, state) {
_cleanup_free_ char *k = NULL;
k = strndup(word, l);
if (!k)
return -ENOMEM;
r = parse_uid(k, b + i);
if (r < 0)
continue;
i++;
}
}
}
r = strv_length(a);
if (sessions) {
*sessions = a;
a = NULL;
}
if (uids) {
*uids = b;
b = NULL;
}
if (n_uids)
*n_uids = n;
return r;
}
static int seat_get_can(const char *seat, const char *variable) {
_cleanup_free_ char *p = NULL, *s = NULL;
int r;
assert(variable);
r = file_of_seat(seat, &p);
if (r < 0)
return r;
r = parse_env_file(p, NEWLINE,
variable, &s,
NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (isempty(s))
return -ENODATA;
return parse_boolean(s);
}
_public_ int sd_seat_can_multi_session(const char *seat) {
return seat_get_can(seat, "CAN_MULTI_SESSION");
}
_public_ int sd_seat_can_tty(const char *seat) {
return seat_get_can(seat, "CAN_TTY");
}
_public_ int sd_seat_can_graphical(const char *seat) {
return seat_get_can(seat, "CAN_GRAPHICAL");
}
_public_ int sd_get_seats(char ***seats) {
return get_files_in_directory("/run/systemd/seats/", seats);
}
_public_ int sd_get_sessions(char ***sessions) {
return get_files_in_directory("/run/systemd/sessions/", sessions);
}
_public_ int sd_get_uids(uid_t **users) {
_cleanup_closedir_ DIR *d;
int r = 0;
unsigned n = 0;
_cleanup_free_ uid_t *l = NULL;
d = opendir("/run/systemd/users/");
if (!d)
return -errno;
for (;;) {
struct dirent *de;
int k;
uid_t uid;
errno = 0;
de = readdir(d);
if (!de && errno != 0)
return -errno;
if (!de)
break;
dirent_ensure_type(d, de);
if (!dirent_is_file(de))
continue;
k = parse_uid(de->d_name, &uid);
if (k < 0)
continue;
if (users) {
if ((unsigned) r >= n) {
uid_t *t;
n = MAX(16, 2*r);
t = realloc(l, sizeof(uid_t) * n);
if (!t)
return -ENOMEM;
l = t;
}
assert((unsigned) r < n);
l[r++] = uid;
} else
r++;
}
if (users) {
*users = l;
l = NULL;
}
return r;
}
_public_ int sd_get_machine_names(char ***machines) {
char **l = NULL, **a, **b;
int r;
assert_return(machines, -EINVAL);
r = get_files_in_directory("/run/systemd/machines/", &l);
if (r < 0)
return r;
if (l) {
r = 0;
/* Filter out the unit: symlinks */
for (a = l, b = l; *a; a++) {
if (startswith(*a, "unit:") || !machine_name_is_valid(*a))
free(*a);
else {
*b = *a;
b++;
r++;
}
}
*b = NULL;
}
*machines = l;
return r;
}
_public_ int sd_machine_get_class(const char *machine, char **class) {
_cleanup_free_ char *c = NULL;
const char *p;
int r;
assert_return(machine_name_is_valid(machine), -EINVAL);
assert_return(class, -EINVAL);
p = strjoina("/run/systemd/machines/", machine);
r = parse_env_file(p, NEWLINE, "CLASS", &c, NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (!c)
return -EIO;
*class = c;
c = NULL;
return 0;
}
_public_ int sd_machine_get_ifindices(const char *machine, int **ifindices) {
_cleanup_free_ char *netif = NULL;
size_t l, allocated = 0, nr = 0;
int *ni = NULL;
const char *p, *word, *state;
int r;
assert_return(machine_name_is_valid(machine), -EINVAL);
assert_return(ifindices, -EINVAL);
p = strjoina("/run/systemd/machines/", machine);
r = parse_env_file(p, NEWLINE, "NETIF", &netif, NULL);
if (r == -ENOENT)
return -ENXIO;
if (r < 0)
return r;
if (!netif) {
*ifindices = NULL;
return 0;
}
FOREACH_WORD(word, l, netif, state) {
char buf[l+1];
int ifi;
*(char*) (mempcpy(buf, word, l)) = 0;
if (safe_atoi(buf, &ifi) < 0)
continue;
if (ifi <= 0)
continue;
if (!GREEDY_REALLOC(ni, allocated, nr+1)) {
free(ni);
return -ENOMEM;
}
ni[nr++] = ifi;
}
*ifindices = ni;
return nr;
}
static inline int MONITOR_TO_FD(sd_login_monitor *m) {
return (int) (unsigned long) m - 1;
}
static inline sd_login_monitor* FD_TO_MONITOR(int fd) {
return (sd_login_monitor*) (unsigned long) (fd + 1);
}
_public_ int sd_login_monitor_new(const char *category, sd_login_monitor **m) {
int fd, k;
bool good = false;
assert_return(m, -EINVAL);
fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
if (fd < 0)
return -errno;
if (!category || streq(category, "seat")) {
k = inotify_add_watch(fd, "/run/systemd/seats/", IN_MOVED_TO|IN_DELETE);
if (k < 0) {
safe_close(fd);
return -errno;
}
good = true;
}
if (!category || streq(category, "session")) {
k = inotify_add_watch(fd, "/run/systemd/sessions/", IN_MOVED_TO|IN_DELETE);
if (k < 0) {
safe_close(fd);
return -errno;
}
good = true;
}
if (!category || streq(category, "uid")) {
k = inotify_add_watch(fd, "/run/systemd/users/", IN_MOVED_TO|IN_DELETE);
if (k < 0) {
safe_close(fd);
return -errno;
}
good = true;
}
if (!category || streq(category, "machine")) {
k = inotify_add_watch(fd, "/run/systemd/machines/", IN_MOVED_TO|IN_DELETE);
if (k < 0) {
safe_close(fd);
return -errno;
}
good = true;
}
if (!good) {
close_nointr(fd);
return -EINVAL;
}
*m = FD_TO_MONITOR(fd);
return 0;
}
_public_ sd_login_monitor* sd_login_monitor_unref(sd_login_monitor *m) {
int fd;
assert_return(m, NULL);
fd = MONITOR_TO_FD(m);
close_nointr(fd);
return NULL;
}
_public_ int sd_login_monitor_flush(sd_login_monitor *m) {
assert_return(m, -EINVAL);
return flush_fd(MONITOR_TO_FD(m));
}
_public_ int sd_login_monitor_get_fd(sd_login_monitor *m) {
assert_return(m, -EINVAL);
return MONITOR_TO_FD(m);
}
_public_ int sd_login_monitor_get_events(sd_login_monitor *m) {
assert_return(m, -EINVAL);
/* For now we will only return POLLIN here, since we don't
* need anything else ever for inotify. However, let's have
* this API to keep our options open should we later on need
* it. */
return POLLIN;
}
_public_ int sd_login_monitor_get_timeout(sd_login_monitor *m, uint64_t *timeout_usec) {
assert_return(m, -EINVAL);
assert_return(timeout_usec, -EINVAL);
/* For now we will only return (uint64_t) -1, since we don't
* need any timeout. However, let's have this API to keep our
* options open should we later on need it. */
*timeout_usec = (uint64_t) -1;
return 0;
}
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