SD_PID_GET_SESSION(3)sd_pid_get_sessionSD_PID_GET_SESSION(3)NAME
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 -
Determine session, service, owner of a session, container/VM or slice
of a specific PID
SYNOPSIS
#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);
DESCRIPTIONsd_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.
RETURN VALUE
On success, these calls return 0 or a positive integer. On failure,
these calls return a negative errno-style error code.
NOTES
The sd_pid_get_session(), sd_pid_get_unit(), sd_pid_get_user_unit(),
sd_pid_get_owner_uid(), sd_pid_get_machine_name() and
sd_pid_get_slice() interfaces are available as a shared library, which
can be compiled and linked to with the libsystemd-login 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).
SEE ALSOsystemd(1), sd-login(3), sd_session_is_active(3), getsid(2),
systemd.slice(5)systemd 208SD_PID_GET_SESSION(3)
