diff options
Diffstat (limited to 'man5/utmp.5')
| -rw-r--r-- | man5/utmp.5 | 42 |
1 files changed, 21 insertions, 21 deletions
diff --git a/man5/utmp.5 b/man5/utmp.5 index 4a02964..48f300e 100644 --- a/man5/utmp.5 +++ b/man5/utmp.5 @@ -8,7 +8,7 @@ .\" Modified 1996-07-20 by Michael Haardt .\" Modified 1997-07-02 by Nicolás Lichtmaier <nick@debian.org> .\" Modified 2004-10-31 by aeb, following Gwenole Beauchesne -.TH utmp 5 2023-05-03 "Linux man-pages 6.05.01" +.TH utmp 5 2023-10-31 "Linux man-pages 6.7" .SH NAME utmp, wtmp \- login records .SH SYNOPSIS @@ -22,7 +22,7 @@ file allows one to discover information about who is currently using the system. There may be more users currently using the system, because not all programs use utmp logging. -.PP +.P .B Warning: .I utmp must not be writable by the user class "other", @@ -32,7 +32,7 @@ You risk faked system logfiles and modifications of system files if you leave .I utmp writable to any user other than the owner and group owner of the file. -.PP +.P The file is a sequence of .I utmp structures, @@ -40,7 +40,7 @@ declared as follows in .I <utmp.h> (note that this is only one of several definitions around; details depend on the version of libc): -.PP +.P .in +4n .EX /* Values for ut_type field, below */ @@ -112,7 +112,7 @@ struct utmp { #define ut_addr ut_addr_v6[0] .EE .in -.PP +.P This structure gives the name of the special file associated with the user's terminal, the user's login name, and the time of login in the form of @@ -120,7 +120,7 @@ of String fields are terminated by a null byte (\[aq]\e0\[aq]) if they are shorter than the size of the field. -.PP +.P The first entries ever created result from .BR init (1) processing @@ -137,7 +137,7 @@ with the needed \fIut_id\fP can be found, creates a new one. It sets \fIut_id\fP from the inittab, \fIut_pid\fP and \fIut_time\fP to the current values, and \fIut_type\fP to \fBINIT_PROCESS\fP. -.PP +.P .BR mingetty (8) (or .BR agetty (8)) @@ -156,7 +156,7 @@ and .BR login (1), records may be located by \fIut_line\fP instead of the preferable \fIut_pid\fP. -.PP +.P When .BR init (1) finds that a process has exited, it locates its utmp entry by @@ -171,7 +171,7 @@ and clears and .I ut_time with null bytes. -.PP +.P .BR xterm (1) and other terminal emulators directly create a \fBUSER_PROCESS\fP record and generate the \fIut_id\fP by using the @@ -184,7 +184,7 @@ If they can, they will mark it as \fBDEAD_PROCESS\fP on exiting and it is advised that they null \fIut_line\fP, \fIut_time\fP, \fIut_user\fP, and \fIut_host\fP as well. -.PP +.P .BR telnetd (8) sets up a \fBLOGIN_PROCESS\fP entry and leaves the rest to .BR login (1) @@ -192,7 +192,7 @@ as usual. After the telnet session ends, .BR telnetd (8) cleans up utmp in the described way. -.PP +.P The \fIwtmp\fP file records all logins and logouts. Its format is exactly like \fIutmp\fP except that a null username indicates a logout @@ -237,7 +237,7 @@ POSIX.1 does not specify the lengths of the and .I ut_user fields. -.PP +.P Linux defines the .I utmpx structure to be the same as the @@ -248,14 +248,14 @@ Linux. .SH HISTORY Linux utmp entries conform neither to v7/BSD nor to System V; they are a mix of the two. -.PP +.P v7/BSD has fewer fields; most importantly it lacks \fIut_type\fP, which causes native v7/BSD-like programs to display (for example) dead or login entries. Further, there is no configuration file which allocates slots to sessions. BSD does so because it lacks \fIut_id\fP fields. -.PP +.P In Linux (as in System V), the \fIut_id\fP field of a record will never change once it has been set, which reserves that slot without needing a configuration file. @@ -267,7 +267,7 @@ with null bytes is not required by System V semantics, but makes it possible to run many programs which assume BSD semantics and which do not modify utmp. Linux uses the BSD conventions for line contents, as documented above. -.PP +.P .\" mtk: What is the referrent of "them" in the following sentence? .\" System V only uses the type field to mark them and logs .\" informative messages such as \fB"new time"\fP in the line field. @@ -279,10 +279,10 @@ must always exist on Linux. If you want to disable .BR who (1), then do not make utmp world readable. -.PP +.P The file format is machine-dependent, so it is recommended that it be processed only on the machine architecture where it was created. -.PP +.P Note that on \fIbiarch\fP platforms, that is, systems which can run both 32-bit and 64-bit applications (x86-64, ppc64, s390x, etc.), \fIut_tv\fP is the same size in 32-bit mode as in 64-bit mode. @@ -303,15 +303,15 @@ and .IR tv_usec . Since \fIut_tv\fP may not be the same as \fIstruct timeval\fP, then instead of the call: -.PP +.P .in +4n .EX gettimeofday((struct timeval *) &ut.ut_tv, NULL); .EE .in -.PP +.P the following method of setting this field is recommended: -.PP +.P .in +4n .EX struct utmp ut; @@ -322,7 +322,7 @@ ut.ut_tv.tv_sec = tv.tv_sec; ut.ut_tv.tv_usec = tv.tv_usec; .EE .in -.\" .PP +.\" .P .\" Note that the \fIutmp\fP struct from libc5 has changed in libc6. .\" Because of this, .\" binaries using the old libc5 struct will corrupt |