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-rw-r--r-- | jni/iconv/doc/relocatable.texi | 62 |
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diff --git a/jni/iconv/doc/relocatable.texi b/jni/iconv/doc/relocatable.texi new file mode 100644 index 0000000..dc7a4e2 --- /dev/null +++ b/jni/iconv/doc/relocatable.texi @@ -0,0 +1,62 @@ +@node Enabling Relocatability +@section Enabling Relocatability + +It has been a pain for many users of GNU packages for a long time that +packages are not relocatable. It means a user cannot copy a program, +installed by another user on the same machine, to his home directory, +and have it work correctly (including i18n). So many users need to go +through @code{configure; make; make install} with all its +dependencies, options, and hurdles. + +Red Hat, Debian, and similar package systems solve the ``ease of +installation'' problem, but they hardwire path names, usually to +@file{/usr} or @file{/usr/local}. This means that users need root +privileges to install a binary package, and prevents installing two +different versions of the same binary package. + +A relocatable program can be moved or copied to a different location +on the filesystem. It is possible to make symlinks to the installed +and moved programs, and invoke them through the symlink. It is +possible to do the same thing with a hard link @emph{only} if the hard +link file is in the same directory as the real program. + +To configure a program to be relocatable, add +@option{--enable-relocatable} to the @command{configure} command line. + +On some OSes the executables remember the location of shared libraries +and prefer them over any other search path. Therefore, such an +executable will look for its shared libraries first in the original +installation directory and only then in the current installation +directory. Thus, for reliability, it is best to also give a +@option{--prefix} option pointing to a directory that does not exist +now and which never will be created, e.g.@: +@option{--prefix=/nonexistent}. You may use +@code{DESTDIR=@var{dest-dir}} on the @command{make} command line to +avoid installing into that directory. + +We do not recommend using a prefix writable by unprivileged users +(e.g.@: @file{/tmp/inst$$}) because such a directory can be recreated +by an unprivileged user after the original directory has been removed. +We also do not recommend prefixes that might be behind an automounter +(e.g.@: @file{$HOME/inst$$}) because of the performance impact of +directory searching. + +Here's a sample installation run that takes into account all these +recommendations: + +@example +./configure --enable-relocatable --prefix=/nonexistent +make +make install DESTDIR=/tmp/inst$$ +@end example + +Installation with @option{--enable-relocatable} will not work for +setuid or setgid executables, because such executables search only +system library paths for security reasons. Also, installation with +@option{--enable-relocatable} might not work on OpenBSD, when the +package contains shared libraries and libtool versions 1.5.xx are used. + +The runtime penalty and size penalty are negligible on GNU/Linux (just +one system call more when an executable is launched), and small on +other systems (the wrapper program just sets an environment variable +and executes the real program). |