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diff --git a/login/README.utmpd b/login/README.utmpd deleted file mode 100644 index b691c36f27..0000000000 --- a/login/README.utmpd +++ /dev/null @@ -1,175 +0,0 @@ -With the introduction of version 2 of the GNU C Library the format of -the UTMP and WTMP files changed for some configurations (see Q&A `Why -does getlogin() always return NULL on my Linux box?' of the FAQ). -This version of the GNU C Library contains a solution for the problems -this may cause, by providing an UTMP daemon `utmpd'. - -Do I need it? -============= - -If your configuration is one of the following: - - i[3456]86-*-linux-gnu Linux-2.0 on Intel - m68k-*-linux-gnu Linux-2.0 on Motorola 680x0 - -you might need it, so please read on. If it is not, please read the -section titled `Programming' at the end of this text. - -In principle, you only need the daemon if you want to keep using old -programs linked against the previous version of the Linux C Library -(libc5). In addition you will need the daemon if you are running -Linux on Intel, and you are planning to use iBCS (Intel Binary -Compatibility Standard). If you have no libc5 programs left on your -system and you are not using iBCS, it is probably better not to -install the daemon since it uses (a small amount of) memory and CPU -time. But apart from that it shouldn't hurt to install `utmpd', so -when in doubt install it anyway. - - -Installation -============ - -The installation process (`make install') already places the `utmpd' -binary in $(sbindir). The only thing you have to do is modifying your -startup scripts to start the daemon. Unfortunately this is a bit of a -hassle, since the layout of these scripts is not standardized. You -should try to find the command that creates the file `/var/run/utmp'. -This is usually done in a script named `/etc/rc', `/etc/init.d/boot' -(Debian) or `/etc/rc.d/rc.S' (Slackware). You could try: - - grep utmp /etc/* /etc/init.d/* /etc/rc.d/* - -to find the right script. The creation of `/var/run/utmp' is usually -done with a command like: - - : > /var/run/utmp - -or - - cat /dev/null > /var/run/utmp - -Now add a line before this command to create the file `/var/run/utmpx' -e.g. - - : > /var/run/utmpx - -or - - cat /dev/null > /var/run/utmpx - -whatever you prefer, and after this command, add a line to start the -daemon - - utmpd - -The entire fragment could look something like - - # Clean up /var/run and create /var/run/utmp so that we can login. - ( cd /var/run && find . ! -type d -exec rm -f -- {} \; ) - : > /var/run/utmpx - : > /var/run/utmp - utmpd - -If the file `/var/log/wtmp' exists on your system, you will probably -want to create the file `/var/log/wtmpx'. Programs linked against the -GNU C Library will now write to `/var/log/wtmpx', while programs -linked against the old library will continue to write to -`/var/log/wtmp'. Of course this means that the information gets -spread over two files. We hope to provide a better solution in the -future. - -After a reboot, user accounting should be working again. If not, -please refer to the section titled `Troubleshooting' below before -submitting a bug report. - - -What is `utmpd' doing? -====================== - -After installation there will be two files that store the user -accounting information: `/var/run/utmp' and `/var/run/utmpx'. The -file `/var/run/utmp' will be in the old format so libc5 programs will -continue to work (even if they are broken and do not use the library -functions to access the user accounting database). And on Intel, you -can safely link `/var/run/utmp' to `/etc/utmp' for iBCS programs. -Programs linked against the new GNU C Library (glibc2) will contact -the daemon for all user accounting database access. The daemon will -store its information in `/var/run/utmpx' and keeps this file in sync -with `/var/run/utmp'. Entries added to `/var/run/utmpx' will be -converted to the old format and will be added to `/var/run/utmp' and -vice versa. This way both libc5 and glibc2 see the same information -in the same fields of `struct utmp'. Of course libc5 programs see only -part of the information that glibc2 programs see because not all -members of the glibc2 `struct utmp' are present in the libc5 `struct -utmp'. For the same reason libc5 will see a truncated version of -those fields where the length of the glibc2 field is larger than the -corresponding libc5 field (ut_user, ut_line, ut_host). - - -Troubleshooting -=============== - -If user accounting is not working on your system, e.g. programs like -`who' or `logname' return rubbish, or you cannot login, make -sure that: - -* The file `/var/run/utmpx' exists. - -* The file `/var/log/wtmpx' exists. - -* No program linked against the GNU C Library (libc6) is accessing - `/var/run/utmp' directly (see the section on `Programming' below). - -If that does not solve your problems, please use the `glibcbug' script -to report the problem to <bugs@gnu.org>. - -The `utmpd' daemon uses `syslogd' to report problems. It uses the -`daemon' facility and `warning' and `error' levels. Alternatively you -could use the following option to ease debugging: - -`--debug' - Use this option if you want the daemon to output its warnings and - error messages to the terminal instead of sending them to the - system logger (`syslogd'). When using this option the daemon does - not auto-background itself. - -To use this option you should first kill the daemon that is already -running, and start a fresh one with the desired option: - - kill `cat /var/run/utmpd.pid` - utmpd --debug - -Please include any warnings or error messages from `utmpd' in your -bug reports. - - -Programming -=========== - -In order for the `utmpd' approach to work it is essential that NO -program EVER accesses the UTMP and WTMP files directly. Instead, a -program should use ONLY the available library functions: - - * utmpname() Select the database used (UTMP, WTMP, ...). - * setutent() Open the database. - * getutent() Read the next entry from the database. - * getutid() Search for the next entry with a specific ID. - * getutline() Search for the next entry for a specific line. - * pututline() Write an entry to the database. - * endutent() Close the database. - * updwtmp() Add an entry to a database (WTMP, ...). - -For details, please refer to `The GNU C Library Reference Manual', -which also contains information about some additional functions -derived from BSD and XPG that may be of interest. The command - - info libc "User Accounting Database" - -should point you at the right location. - -If you encounter a program that reads from or, even worse, writes to -the UTMP and WTMP files directly, please report this as a bug to the -author of that program. Note that the files referred to by the macros -`_PATH_UTMP' and `_PATH_WTMP' might even disappear in the future, so -please do not use these, except in a call to `utmpname()' or -`updwtmp()', not even to check their existence. |