Provided by:
fakeroot_1.9.5ubuntu1_i386 
NAMN
fakeroot - utför ett kommando i en miljö som fejkar root-privilegier
för filmanipulation
SYNOPSIS
fakeroot [-l|--lib library] [--faked faked-binary] [-i load-file] [-s
save-file] [-u|--unknown-is-real ] [-b|--fd-base ] [-h|--help ]
[-v|--version ] [--] [command]
BESKRIVNING
fakeroot runs a command in an environment wherein it appears to have
root privileges for file manipulation. This is useful for allowing
users to create archives (tar, ar, .deb etc.) with files in them with
root permissions/ownership. Without fakeroot one would need to have
root privileges to create the constituent files of the archives with
the correct permissions and ownership, and then pack them up, or one
would have to construct the archives directly, without using the
archiver.
fakeroot arbetar genom att ersätta biblioteksfunktionerna för
filrättighetsmodifiering (chmod(2), stat(2), osv) med sådana som
simulerar effekten som de riktiga biblioteksfunktionerna skulle ha haft
om användaren verkligen varit root. Dessa funktioner finns samlade i
biblioteket /usr/lib/libfakeroot.so* som laddas genom
LD_PRELOAD-mekanismen hos den dynamiska länkaren (se ld.so(8))
Om du planerar att bygga paket med hjälp av fakeroot, försök först att
bygga fakeroot-paketet: "debian/rules build"-stadiet har ett par tester
(som mestadels testar efter buggar i gamla versioner av fakeroot). Om
dessa tester misslyckas (till exempel på grund av att du har vissa
libc5-program på ditt system) så är det troligt att du också kommer att
misslyckas bygga andra paket, och det är möjligt att dessa fel blir
betydligt svårare att hitta.
Also, note that it’s best not to do the building of the binaries
themselves under fakeroot. Especially configure and friends don’t like
it when the system suddenly behaves differently from what they expect.
(or, they randomly unset some environment variables, some of which
fakeroot needs).
FLAGGOR
-l library, --lib library
Ange ett alternativt bibliotek med ersättningsfunktioner.
--faked binär
Ange en alternativ binär att använda istället för faked(1).
[--] kommando
Any command you want to be ran as fakeroot. Use ‘--’ if in the
command you have other options that may confuse fakeroot’s
option parsing.
-s save-file
Save the fakeroot environment to save-file on exit. This file
can be used to restore the environment later using -i. However,
this file will leak and fakeroot will behave in odd ways unless
you leave the files touched inside the fakeroot alone when
outside the environment. Still, this can be useful. For example,
it can be used with rsync(1) to back up and restore whole
directory trees complete with user, group and device information
without needing to be root. See
/usr/share/doc/fakeroot/README.saving for more details.
-i load-file
Load a fakeroot environment previously saved using -s from
load-file. Note that this does not implicitly save the file,
use -s as well for that behaviour. Using the same file for both
-i and -s in a single fakeroot invocation is safe.
-u, --unknown-is-real
Use the real ownership of files previously unknown to fakeroot
instead of pretending they are owned by root:root.
-b fd Specify fd base (TCP mode only). fd is the minimum file
descriptor number to use for TCP connections; this may be
important to avoid conflicts with the file descriptors used by
the programs being run under fakeroot.
-h Display help.
-v Display version.
EXEMPEL
Här är ett exempel på hur fakeroot kan användas. Notera att i den
fejkade root-miljön så lyckas filmanipulering som kräver
root-privilegier, trots att den egentligen inte utförs.
$ whoami
joost
$ fakeroot /bin/bash
# whoami
root
# mknod hda3 b 3 1
# ls -ld hda3
brw-r--r-- 1 root root 3, 1 Jul 2 22:58 hda3
# chown joost:root hda3
# ls -ld hda3
brw-r--r-- 1 joost root 3, 1 Jul 2 22:58 hda3
# ls -ld /
drwxr-xr-x 20 root root 1024 Jun 17 21:50 /
# chown joost:users /
# chmod a+w /
# ls -ld /
drwxrwxrwx 20 joost users 1024 Jun 17 21:50 /
# exit
$ ls -ld /
drwxr-xr-x 20 root root 1024 Jun 17 21:50 //
$ ls -ld hda3
-rw-r--r-- 1 joost users 0 Jul 2 22:58 hda3
Enbart de operationer som användaren joost skulle kunna ha genomfört
som sig själv utförs på riktigt.
fakeroot skrevs speciellt i syfte att ge användare möjlighet att skapa
Debian GNU/Linux-paket (i deb(5) format) utan att behöva
root-privilegier. Detta kan utföras genom kommandon såsom
dpkg-buildpackage -rfakeroot eller debuild -rfakeroot (-rfakeroot är
numera standard i debuild, så du behöver inte ens använda den
parametern).
SÄKERHETSASPEKTER
fakeroot är ett vanligt program utan setuid. Det ger inte användaren
några extra privilegier, och minskar inte systemets säkerhet.
FILER
/usr/lib/libfakeroot/libfakeroot.so* Det delade bibliotek som
innehåller ersättningsfunktionerna.
MILJÖ
FAKEROOTKEY
The key used to communicate with the fakeroot daemon. Any
program started with the right LD_PRELOAD and a FAKEROOTKEY of a
running daemon will automatically connect to that daemon, and
have the same "fake" view of the file system’s
permissions/ownerships. (assuming the daemon and connecting
program were started by the same user).
LD_LIBRARY_PATH
LD_PRELOAD
Fakeroot is implemented by wrapping system calls. This is
accomplished by setting LD_LIBRARY_PATH=/usr/lib/fakeroot and
LD_PRELOAD=libfakeroot.so.0. That library is loaded before the
system’s C library, and so most of the library functions are
intercepted by it. If you need to set either LD_LIBRARY_PATH or
LD_PRELOAD from within a fakeroot environment, it should be set
relative to the given paths, as in
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/foo/bar/
BEGRÄNSNINGAR
Biblioteksversioner
Every command executed within fakeroot needs to be linked to the
same version of the C library as fakeroot itself.
open()/create()
fakeroot doesn’t wrap open(), create(), etc. So, if user joost
does either
touch foo
fakeroot
ls -al foo
eller omvänt,
fakeroot
touch foo
ls -al foo
fakeroot has no way of knowing that in the first case, the owner
of foo really should be joost while the second case it should
have been root. For the Debian packaging, defaulting to giving
all "unknown" files uid=gid=0, is always OK. The real way around
this is to wrap open() and create(), but that creates other
problems, as demonstrated by the libtricks package. This package
wrapped many more functions, and tried to do a lot more than
fakeroot . It turned out that a minor upgrade of libc (from one
where the stat() function didn’t use open() to one with a stat()
function that did (in some cases) use open()), would cause
unexplainable segfaults (that is, the libc6 stat() called the
wrapped open(), which would then call the libc6 stat(), etc).
Fixing them wasn’t all that easy, but once fixed, it was just a
matter of time before another function started to use open(),
never mind trying to port it to a different operating system.
Thus I decided to keep the number of functions wrapped by
fakeroot as small as possible, to limit the likelihood of
‘collisions’.
GNU configure (och liknande program)
fakeroot, in effect, is changing the way the system behaves.
Programs that probe the system like GNU configure may get
confused by this (or if they don’t, they may stress fakeroot so
much that fakeroot itself becomes confused). So, it’s advisable
not to run "configure" from within fakeroot. As configure should
be called in the "debian/rules build" target, running
"dpkg-buildpackage -rfakeroot" correctly takes care of this.
BUGGAR
It doesn’t wrap open(). This isn’t bad by itself, but if a program does
open("file", O_WRONLY, 000), writes to file "file", closes it, and then
again tries to open to read the file, then that open fails, as the mode
of the file will be 000. The bug is that if root does the same, open()
will succeed, as the file permissions aren’t checked at all for root. I
choose not to wrap open(), as open() is used by many other functions in
libc (also those that are already wrapped), thus creating loops (or
possible future loops, when the implementation of various libc
functions slightly change).
LICENS
fakeroot distribueras under GNU General Public License. (GPL 2.0 eller
senare).
FÖRFATTARE
joost witteveen
<joostje@debian.org>
Clint Adams
<schizo@debian.org>
Timo Savola
ÖVERSÄTTNING
David Weinehall <tao@kernel.org>
MANUALSIDA
mostly by J.H.M. Dassen <jdassen@debian.org> Rather a lot
mods/additions by joost and Clint.
SE ÄVEN
faked(1) dpkg-buildpackage(1), debuild(1)
/usr/share/doc/fakeroot/DEBUG