NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | NOTES | SEE ALSO | COLOPHON

SD_PID_GET_SESSION(3)        sd_pid_get_session        SD_PID_GET_SESSION(3)

NAME         top

       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_pid_get_user_slice, sd_pid_get_cgroup, 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, sd_peer_get_user_slice,
       sd_peer_get_cgroup - Determine session, unit, owner of a session,
       container/VM or slice of a specific PID or socket peer

SYNOPSIS         top

       #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_pid_get_user_slice(pid_t pid, char **slice);

       int sd_pid_get_cgroup(pid_t pid, char **cgroup);

       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);

       int sd_peer_get_user_slice(int fd, char **slice);

       int sd_peer_get_cgroup(int fd, char **cgroup);

DESCRIPTION         top

       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 with -ENODATA. 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 or scope unit) 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 with -ENODATA. (More specifically, this call will
       not work for kernel threads.) 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 or scope unit) 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 UID (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, whereas 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 with -ENODATA.

       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. For processes not part
       of a VM or containers, this function fails with -ENODATA.

       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.

       Similarly, sd_pid_get_user_slice() returns the user slice (as managed
       by the user's systemd instance) of a process.

       sd_pid_get_cgroup() returns the control group path of the specified
       process, relative to the root of the hierarchy. Returns the path
       without trailing slash, except for processes located in the root
       control group, where "/" is returned. To find the actual control
       group path in the file system, the returned path needs to be prefixed
       with /sys/fs/cgroup/ (if the unified control group setup is used), or
       /sys/fs/cgroup/HIERARCHY/ (if the legacy multi-hierarchy control
       group setup is used).

       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(), sd_peer_get_slice(),
       sd_peer_get_user_slice() and sd_peer_get_cgroup() calls operate
       similar to their PID counterparts, but operate on a connected AF_UNIX
       socket and retrieve information about the connected peer process.
       Note that these fields are retrieved via /proc, and hence are not
       suitable for authorization purposes, as they are subject to races.

RETURN VALUE         top

       On success, these calls return 0 or a positive integer. On failure,
       these calls return a negative errno-style error code.

ERRORS         top

       Returned errors may indicate the following problems:

       -ESRCH
           The specified PID does not refer to a running process.

       -EBADF
           The specified socket file descriptor was invalid.

       -ENODATA
           The given field is not specified for the described process or
           peer.

       -EINVAL
           An input parameter was invalid (out of range, or NULL, where that
           is not accepted).

       -ENOMEM
           Memory allocation failed.

NOTES         top

       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_pid_get_user_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() and
       sd_peer_get_user_slice() interfaces are available as a shared
       library, which can be compiled and linked to with the
       libsystemd 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 ALSO         top

       systemd(1), sd-login(3), sd_session_is_active(3), getsid(2),
       systemd.slice(5), systemd-machined.service(8)

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have a bug
       report for this manual page, see 
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.  This
       page was obtained from the project's upstream Git repository 
       ⟨https://github.com/systemd/systemd.git⟩ on 2017-09-15.  If you dis‐
       cover any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

systemd 234                                            SD_PID_GET_SESSION(3)

Pages that refer to this page: sd-login(3)sd_machine_get_class(3)sd_session_is_active(3)sd_uid_get_state(3)systemd.directives(7)systemd.index(7)