sd_pid_get_session, sd_pid_get_unit, sd_pid_get_user_unit, sd_pid_get_owner_uid, sd_pid_get_machine_name, sd_pid_get_slice, sd_peer_get_session, sd_peer_get_unit, sd_peer_get_user_unit, sd_peer_get_owner_uid, sd_peer_get_machine_name, sd_peer_get_slice — Determine session, service, owner of a session, container/VM or slice of a specific PID or socket peer
#include <systemd/sd-login.h>
int sd_pid_get_session( | pid_t pid, |
char **session); |
int sd_pid_get_unit( | pid_t pid, |
char **unit); |
int sd_pid_get_user_unit( | pid_t pid, |
char **unit); |
int sd_pid_get_owner_uid( | pid_t pid, |
uid_t *uid); |
int sd_pid_get_machine_name( | pid_t pid, |
char **name); |
int sd_pid_get_slice( | pid_t pid, |
char **slice); |
int sd_peer_get_session( | int fd, |
char **session); |
int sd_peer_get_unit( | int fd, |
char **unit); |
int sd_peer_get_user_unit( | int fd, |
char **unit); |
int sd_peer_get_owner_uid( | int fd, |
uid_t *uid); |
int sd_peer_get_machine_name( | int fd, |
char **name); |
int sd_peer_get_slice( | int fd, |
char **slice); |
sd_pid_get_session() may be used to
determine the login session identifier of a process identified by
the specified process identifier. The session identifier is a
short string, suitable for usage in file system paths. Note that
not all processes are part of a login session (e.g. system service
processes, user processes that are shared between multiple
sessions of the same user, or kernel threads). For processes not
being part of a login session this function will fail. The
returned string needs to be freed with the libc
free(3)
call after use.
sd_pid_get_unit() may be used to
determine the systemd system unit (i.e. system service) identifier
of a process identified by the specified PID. The unit name is a
short string, suitable for usage in file system paths. Note that
not all processes are part of a system unit/service (e.g. user
processes, or kernel threads). For processes not being part of a
systemd system unit this function will fail. (More specifically:
this call will not work for processes that are part of user units,
use sd_pid_get_user_unit() for that.) The
returned string needs to be freed with the libc
free(3)
call after use.
sd_pid_get_user_unit() may be used to
determine the systemd user unit (i.e. user service) identifier of
a process identified by the specified PID. This is similar to
sd_pid_get_unit() but applies to user units
instead of system units.
sd_pid_get_owner_uid() may be used to
determine the Unix user identifier of the owner of the session of
a process identified the specified PID. Note that this function
will succeed for user processes which are shared between multiple
login sessions of the same user, where
sd_pid_get_session() will fail. For processes
not being part of a login session and not being a shared process
of a user this function will fail.
sd_pid_get_machine_name() may be used
to determine the name of the VM or container is a member of. The
machine name is a short string, suitable for usage in file system
paths. The returned string needs to be freed with the libc
free(3)
call after use.
sd_pid_get_slice() may be used to
determine the slice unit the process is a member of. See
systemd.slice(5)
for details about slices. The returned string needs to be freed
with the libc
free(3)
call after use.
If the pid parameter of any of these
functions is passed as 0, the operation is executed for the
calling process.
The sd_peer_get_session(),
sd_peer_get_unit(),
sd_peer_get_user_unit(),
sd_peer_get_owner_uid(),
sd_peer_get_machine_name() and
sd_peer_get_slice() calls operate similar to
their PID counterparts, but operate on a connected AF_UNIX socket
and retrieve information about the connected peer process.
On success, these calls return 0 or a positive integer. On failure, these calls return a negative errno-style error code.
The sd_pid_get_session(),
sd_pid_get_unit(),
sd_pid_get_user_unit(),
sd_pid_get_owner_uid(),
sd_pid_get_machine_name(),
sd_pid_get_slice(),
sd_peer_get_session(),
sd_peer_get_unit(),
sd_peer_get_user_unit(),
sd_peer_get_owner_uid(),
sd_peer_get_machine_name() and
sd_peer_get_slice() interfaces are
available as a shared library, which can be compiled
and linked to with the
libelogind pkg-config(1)
file.
Note that the login session identifier as
returned by sd_pid_get_session()
is completely unrelated to the process session
identifier as returned by
getsid(2).