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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
commit | 399644e47874bff147afb19c89228901ac39340e (patch) | |
tree | 1c4c0b733f4c16b5783b41bebb19194a9ef62ad1 /man3/login.3 | |
parent | Initial commit. (diff) | |
download | manpages-399644e47874bff147afb19c89228901ac39340e.tar.xz manpages-399644e47874bff147afb19c89228901ac39340e.zip |
Adding upstream version 6.05.01.upstream/6.05.01
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man3/login.3')
-rw-r--r-- | man3/login.3 | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/man3/login.3 b/man3/login.3 new file mode 100644 index 0000000..b6fa4ae --- /dev/null +++ b/man3/login.3 @@ -0,0 +1,151 @@ +'\" t +.\" Derived from text written by Martin Schulze (or taken from glibc.info) +.\" and text written by Paul Thompson - both copyright 2002. +.\" +.\" SPDX-License-Identifier: GPL-2.0-or-later +.\" +.TH login 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +login, logout \- write utmp and wtmp entries +.SH LIBRARY +System utilities library +.RI ( libutil ", " \-lutil ) +.SH SYNOPSIS +.nf +.B #include <utmp.h> +.PP +.BI "void login(const struct utmp *" ut ); +.BI "int logout(const char *" ut_line ); +.fi +.SH DESCRIPTION +The utmp file records who is currently using the system. +The wtmp file records all logins and logouts. +See +.BR utmp (5). +.PP +The function +.BR login () +takes the supplied +.IR "struct utmp" , +.IR ut , +and writes it to both the utmp and the wtmp file. +.PP +The function +.BR logout () +clears the entry in the utmp file again. +.SS GNU details +More precisely, +.BR login () +takes the argument +.I ut +struct, fills the field +.I ut\->ut_type +(if there is such a field) with the value +.BR USER_PROCESS , +and fills the field +.I ut\->ut_pid +(if there is such a field) with the process ID of the calling process. +Then it tries to fill the field +.IR ut\->ut_line . +It takes the first of +.IR stdin , +.IR stdout , +.I stderr +that is a terminal, and +stores the corresponding pathname minus a possible leading +.I /dev/ +into this field, and then writes the struct to the utmp file. +On the other hand, +if no terminal name was found, this field is filled with "???" +and the struct is not written to the utmp file. +After this, the struct is written to the wtmp file. +.PP +The +.BR logout () +function searches the utmp file for an entry matching the +.I ut_line +argument. +If a record is found, it is updated by zeroing out the +.I ut_name +and +.I ut_host +fields, updating the +.I ut_tv +timestamp field and setting +.I ut_type +(if there is such a field) to +.BR DEAD_PROCESS . +.SH RETURN VALUE +The +.BR logout () +function returns 1 if the entry was successfully written to the +database, or 0 if an error occurred. +.SH FILES +.TP +.I /var/run/utmp +user accounting database, configured through +.B _PATH_UTMP +in +.I <paths.h> +.TP +.I /var/log/wtmp +user accounting log file, configured through +.B _PATH_WTMP +in +.I <paths.h> +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lb lb lbx +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR login (), +.BR logout () +T} Thread safety T{ +.na +.nh +MT-Unsafe race:utent +sig:ALRM timer +T} +.TE +.sp 1 +In the above table, +.I utent +in +.I race:utent +signifies that if any of the functions +.BR setutent (3), +.BR getutent (3), +or +.BR endutent (3) +are used in parallel in different threads of a program, +then data races could occur. +.BR login () +and +.BR logout () +calls those functions, +so we use race:utent to remind users. +.SH VERSIONS +The member +.I ut_user +of +.I struct utmp +is called +.I ut_name +in BSD. +Therefore, +.I ut_name +is defined as an alias for +.I ut_user +in +.IR <utmp.h> . +.SH STANDARDS +BSD. +.SH SEE ALSO +.BR getutent (3), +.BR utmp (5) |