sd_session_is_active(3)

1SD_SESSION_IS_ACTIVE(3)      sd_session_is_active      SD_SESSION_IS_ACTIVE(3)
2
3
4

NAME

6       sd_session_is_active, sd_session_is_remote, sd_session_get_state,
7       sd_session_get_uid, sd_session_get_seat, sd_session_get_service,
8       sd_session_get_type, sd_session_get_class, sd_session_get_desktop,
9       sd_session_get_display, sd_session_get_tty, sd_session_get_vt,
10       sd_session_get_remote_host, sd_session_get_remote_user - Determine
11       state of a specific session
12

SYNOPSIS

14       #include <systemd/sd-login.h>
15
16       int sd_session_is_active(const char *session);
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18       int sd_session_is_remote(const char *session);
19
20       int sd_session_get_state(const char *session, char **state);
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22       int sd_session_get_uid(const char *session, uid_t *uid);
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24       int sd_session_get_seat(const char *session, char **seat);
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26       int sd_session_get_service(const char *session, char **service);
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28       int sd_session_get_type(const char *session, char **type);
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30       int sd_session_get_class(const char *session, char **class);
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32       int sd_session_get_desktop(const char *session, char **desktop);
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34       int sd_session_get_display(const char *session, char **display);
35
36       int sd_session_get_remote_host(const char *session,
37                                      char **remote_host);
38
39       int sd_session_get_remote_user(const char *session,
40                                      char **remote_user);
41
42       int sd_session_get_tty(const char *session, char **tty);
43
44       int sd_session_get_vt(const char *session, unsigned int *vt);
45

DESCRIPTION

47       sd_session_is_active() may be used to determine whether the session
48       identified by the specified session identifier is currently active
49       (i.e. currently in the foreground and available for user input) or not.
50
51       sd_session_is_remote() may be used to determine whether the session
52       identified by the specified session identifier is a remote session
53       (i.e. its remote host is known) or not.
54
55       sd_session_get_state() may be used to determine the state of the
56       session identified by the specified session identifier. The following
57       states are currently known: "online" (session logged in, but session
58       not active, i.e. not in the foreground), "active" (session logged in
59       and active, i.e. in the foreground), "closing" (session nominally
60       logged out, but some processes belonging to it are still around). In
61       the future additional states might be defined, client code should be
62       written to be robust in regards to additional state strings being
63       returned. This function is a more generic version of
64       sd_session_is_active(). The returned string needs to be freed with the
65       libc free(3) call after use.
66
67       sd_session_get_uid() may be used to determine the user identifier of
68       the Unix user the session identified by the specified session
69       identifier belongs to.
70
71       sd_session_get_seat() may be used to determine the seat identifier of
72       the seat the session identified by the specified session identifier
73       belongs to. Note that not all sessions are attached to a seat, this
74       call will fail (returning -ENODATA) for them. The returned string needs
75       to be freed with the libc free(3) call after use.
76
77       sd_session_get_service() may be used to determine the name of the
78       service (as passed during PAM session setup) that registered the
79       session identified by the specified session identifier. The returned
80       string needs to be freed with the libc free(3) call after use.
81
82       sd_session_get_type() may be used to determine the type of the session
83       identified by the specified session identifier. The returned string is
84       one of "x11", "wayland", "tty", "mir" or "unspecified" and needs to be
85       freed with the libc free(3) call after use.
86
87       sd_session_get_class() may be used to determine the class of the
88       session identified by the specified session identifier. The returned
89       string is one of "user", "greeter", "lock-screen", or "background" and
90       needs to be freed with the libc free(3) call after use.
91
92       sd_session_get_desktop() may be used to determine the brand of the
93       desktop running on the session identified by the specified session
94       identifier. This field can be set freely by desktop environments and
95       does not follow any special formatting. However, desktops are strongly
96       recommended to use the same identifiers and capitalization as for
97       $XDG_CURRENT_DESKTOP, as defined by the Desktop Entry Specification[1].
98       The returned string needs to be freed with the libc free(3) call after
99       use.
100
101       sd_session_get_display() may be used to determine the X11 display of
102       the session identified by the specified session identifier. The
103       returned string needs to be freed with the libc free(3) call after use.
104
105       sd_session_get_remote_host() may be used to determine the remote
106       hostname of the session identified by the specified session identifier.
107       The returned string needs to be freed with the libc free(3) call after
108       use.
109
110       sd_session_get_remote_user() may be used to determine the remote
111       username of the session identified by the specified session identifier.
112       The returned string needs to be freed with the libc free(3) call after
113       use. Note that this value is rarely known to the system, and even then
114       should not be relied on.
115
116       sd_session_get_tty() may be used to determine the TTY device of the
117       session identified by the specified session identifier. The returned
118       string needs to be freed with the libc free(3) call after use.
119
120       sd_session_get_vt() may be used to determine the VT number of the
121       session identified by the specified session identifier. This function
122       will return an error if the seat does not support VTs.
123
124       If the session parameter of any of these functions is passed as NULL,
125       the operation is executed for the session the calling process is a
126       member of, if there is any.
127

RETURN VALUE

129       If the test succeeds, sd_session_is_active() and sd_session_is_remote()
130       return a positive integer; if it fails, 0. On success,
131       sd_session_get_state(), sd_session_get_uid(), sd_session_get_seat(),
132       sd_session_get_service(), sd_session_get_type(),
133       sd_session_get_class(), sd_session_get_display(),
134       sd_session_get_remote_user(), sd_session_get_remote_host() and
135       sd_session_get_tty() return 0 or a positive integer. On failure, these
136       calls return a negative errno-style error code.
137
138   Errors
139       Returned errors may indicate the following problems:
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141       -ENXIO
142           The specified session does not exist.
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144       -ENODATA
145           The given field is not specified for the described session.
146
147       -EINVAL
148           An input parameter was invalid (out of range, or NULL, where that
149           is not accepted).
150
151       -ENOMEM
152           Memory allocation failed.
153

NOTES

155       These APIs are implemented as a shared library, which can be compiled
156       and linked to with the libsystemd pkg-config(1) file.
157

NOTES

162        1. Desktop Entry Specification
163           http://standards.freedesktop.org/desktop-entry-spec/latest/
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166
167systemd 245                                            SD_SESSION_IS_ACTIVE(3)

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

NOTES

SEE ALSO

NOTES