47 lines
1.9 KiB
Plaintext
47 lines
1.9 KiB
Plaintext
Hwclock is a program that runs under Linux and sets and queries the
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Hardware Clock, which is often called the Real Time Clock, RTC, or
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CMOS clock.
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Hwclock is shipped with an ELF executable built for ISA (Intel)
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machines. So there is nothing to build for those machines. Just
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install the executable file "hwclock" and the man page file
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"hwclock.8" in suitable directories (like /sbin/hwclock and
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/usr/man/man8/hwclock.8) and you're ready to go.
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hwclock accesses platform-dependent hardware, so if you have something
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other than an ISA machine, the shipped executable probably doesn't work,
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and you have to compile hwclock yourself.
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Sometimes, you need to install hwclock setuid root. If you want users
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other than the superuser to be able to display the clock value using the
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direct ISA I/O method, install it setuid root. If you have the /dev/rtc
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interface on your system or are on a non-ISA system, there's no need for
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users to use the direct ISA I/O method, so don't bother.
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To install setuid root, do something like this:
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chmod a=rx,u=s /sbin/hwclock
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In any case, hwclock will not allow you to set anything unless you have
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the superuser _real_ uid. (This is restriction is not necessary if you
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haven't installed setuid root, but it's there for now).
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You may want to preformat and/or compress the man page before installing.
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If you want to build hwclock, just cd to the source directory and invoke
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make with no parameters.
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hwclock calls option processing routines in the libsshopt library,
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which is part of Sverre H. Huseby's "shhopt" package. An ELF
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executable of this library is included in the package, but you can use
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a copy that is already on your system by altering the make file. You
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can find a more authoritative copy of this library, and its source
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code, on sunsite (ftp://sunsite.unc.edu/pub/Linux/libs/shhopt-X.Y).
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As shipped, the routines are linked in statically, so you only need the
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libsshopt.a file to build hwclock, not to run it.
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