Provided by: libelogind-dev-doc_239.3+20190131-1+debian1_all bug


       sd_pid_get_owner_uid, sd_pid_get_session, sd_pid_get_user_unit, sd_pid_get_unit,
       sd_pid_get_machine_name, sd_pid_get_slice, sd_pid_get_user_slice, sd_pid_get_cgroup,
       sd_peer_get_owner_uid, sd_peer_get_session, sd_peer_get_user_unit, sd_peer_get_unit,
       sd_peer_get_machine_name, sd_peer_get_slice, sd_peer_get_user_slice, sd_peer_get_cgroup -
       Determine the owner uid of the user unit or session, or the session, user unit, system
       unit, container/VM or slice that a specific PID or socket peer belongs to.


       #include <elogind/sd-login.h>

       int sd_pid_get_owner_uid(pid_t pid, uid_t *uid);

       int sd_pid_get_session(pid_t pid, char **session);

       int sd_pid_get_user_unit(pid_t pid, char **unit);

       int sd_pid_get_unit(pid_t pid, char **unit);

       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_owner_uid(int fd, uid_t *uid);

       int sd_peer_get_session(int fd, char **session);

       int sd_peer_get_user_unit(int fd, char **unit);

       int sd_peer_get_unit(int fd, char **unit);

       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);


       sd_pid_get_owner_uid() may be used to determine the Unix UID (user identifier) which owns
       the login session of a process identified by the specified PID. For processes which are
       not part of a login session and not managed by a user manager, this function will fail
       with -ENODATA.

       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. For processes which are not 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_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_owner_uid(), sd_peer_get_session(), sd_peer_get_user_unit(),
       sd_peer_get_unit(), 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.


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


       Returned errors may indicate the following problems:

           The specified PID does not refer to a running process.

           The specified socket file descriptor was invalid.

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

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

           Memory allocation failed.


       These APIs are implemented 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).



       sd-login(3), sd_session_is_active(3),