NAME

       sd_pid_get_session, sd_pid_get_unit, sd_pid_get_user_unit, sd_pid_get_owner_uid,
       sd_pid_get_machine_name - Determine session, service, owner of a session or container/VM
       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);

DESCRIPTION

       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_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.

       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() and sd_pid_get_machine_name() interfaces are available as shared
       library, which can be compiled and linked to with the libsystemd-loginpkg-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 ALSO

       systemd(1), sd-login(3), sd_session_is_active(3), getsid(2)