utmp(5) - unix7

1UTMP(5)                       File Formats Manual                      UTMP(5)
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NAME

6       utmp, wtmp - login records
7

SYNOPSIS

9       #include <utmp.h>
10

DESCRIPTION

12       The utmp file allows one to discover information about who is currently
13       using UNIX.  The file is a  sequence  of  entries  with  the  following
14       structure declared in the include file:
15
16              /* Copyright (C) 1993, 1996-1999, 2012 Free Software Foundation, Inc.
17                 This file is part of the GNU C Library.
18
19                 The GNU C Library is free software; you can redistribute it and/or
20                 modify it under the terms of the GNU Lesser General Public
21                 License as published by the Free Software Foundation; either
22                 version 2.1 of the License, or (at your option) any later version.
23
24                 The GNU C Library is distributed in the hope that it will be useful,
25                 but WITHOUT ANY WARRANTY; without even the implied warranty of
26                 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
27                 Lesser General Public License for more details.
28
29                 You should have received a copy of the GNU Lesser General Public
30                 License along with the GNU C Library; if not, see
31                 <http://www.gnu.org/licenses/>.  */
32
33              #ifndef   _UTMP_H
34              #define   _UTMP_H   1
35
36              #include <features.h>
37
38              #include <sys/types.h>
39
40
41              __BEGIN_DECLS
42
43              /* Get system dependent values and data structures.  */
44              #include <bits/utmp.h>
45
46              /* Compatibility names for the strings of the canonical file names.  */
47              #define UTMP_FILE   _PATH_UTMP
48              #define UTMP_FILENAME    _PATH_UTMP
49              #define WTMP_FILE   _PATH_WTMP
50              #define WTMP_FILENAME    _PATH_WTMP
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52
53
54              /* Make FD be the controlling terminal, stdin, stdout, and stderr;
55                 then close FD.  Returns 0 on success, nonzero on error.  */
56              extern int login_tty (int __fd) __THROW;
57
58
59              /* Write the given entry into utmp and wtmp.  */
60              extern void login (const struct utmp *__entry) __THROW;
61
62              /* Write the utmp entry to say the user on UT_LINE has logged out.  */
63              extern int logout (const char *__ut_line) __THROW;
64
65              /* Append to wtmp an entry for the current time and the given info.  */
66              extern void logwtmp (const char *__ut_line, const char *__ut_name,
67                             const char *__ut_host) __THROW;
68
69              /* Append entry UTMP to the wtmp-like file WTMP_FILE.  */
70              extern void updwtmp (const char *__wtmp_file, const struct utmp *__utmp)
71                   __THROW;
72
73              /* Change name of the utmp file to be examined.  */
74              extern int utmpname (const char *__file) __THROW;
75
76              /* Read next entry from a utmp-like file.  */
77              extern struct utmp *getutent (void) __THROW;
78
79              /* Reset the input stream to the beginning of the file.  */
80              extern void setutent (void) __THROW;
81
82              /* Close the current open file.  */
83              extern void endutent (void) __THROW;
84
85              /* Search forward from the current point in the utmp file until the
86                 next entry with a ut_type matching ID->ut_type.  */
87              extern struct utmp *getutid (const struct utmp *__id) __THROW;
88
89              /* Search forward from the current point in the utmp file until the
90                 next entry with a ut_line matching LINE->ut_line.  */
91              extern struct utmp *getutline (const struct utmp *__line) __THROW;
92
93              /* Write out entry pointed to by UTMP_PTR into the utmp file.  */
94              extern struct utmp *pututline (const struct utmp *__utmp_ptr) __THROW;
95
96
97              #ifdef    __USE_MISC
98              /* Reentrant versions of the file for handling utmp files.  */
99              extern int getutent_r (struct utmp *__buffer, struct utmp **__result) __THROW;
100
101              extern int getutid_r (const struct utmp *__id, struct utmp *__buffer,
102                              struct utmp **__result) __THROW;
103
104              extern int getutline_r (const struct utmp *__line,
105                             struct utmp *__buffer, struct utmp **__result) __THROW;
106
107              #endif    /* Use misc.  */
108
109              __END_DECLS
110
111              #endif /* utmp.h  */
112
113       This  structure  gives the name of the special file associated with the
114       user's terminal, the user's login name, and the time of  the  login  in
115       the form of time(2).
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117       The  wtmp  file  records all logins and logouts.  Its format is exactly
118       like utmp except that a null user name indicates a logout on the  asso‐
119       ciated terminal.  Furthermore, the terminal name `~' indicates that the
120       system was rebooted at the indicated time; the adjacent pair of entries
121       with  terminal  names  `|'  and `}' indicate the system-maintained time
122       just before and just after a date command has changed the system's idea
123       of the time.
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125       Wtmp  is maintained by login(1) and init(8).  Neither of these programs
126       creates the file, so if it is removed record-keeping is turned off.  It
127       is summarized by ac(1).
128

FILES

130       /etc/utmp
131       /usr/adm/wtmp
132

NAME

SYNOPSIS

DESCRIPTION

FILES

SEE ALSO