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Yann E. MORIN 514d7cab61 infra: do not append an empty LD_LIBRARY_PATH
When we set LD_LIBRARY_PATH when building our host tools, we append any
pre-existing value to our custom path:
        LD_LIBRARY_PATH="$(HOST_DIR)/usr/lib:$(LD_LIBRARY_PATH)"

But then if LD_LIBRARY_PATH was previously empty, we end up with an
LD_LIBRARY_PATH that ends with a colon.

Also, when we check that an existing LD_LIBRARY_PATH does not contain
CWD, we previously did not look for a zero-length prefix.

Since 'man ld.so' says of LD_LIBRARY_PATH:
    A colon-separated list of directories in which to search for ELF
    libraries at execution-time. Similar to the PATH environment
    variable.

And POSIX states about PATH:
    A zero-length prefix is a legacy feature that indicates the current
    working directory.

And bash also recognises a zero-length prefix to search in CWD:
    A zero-length (null) directory name in the value of PATH indicates
    the current directory.

We may thus end up on a system where a zero-length prefix in
LD_LIBRARY_PATH is interpreted as CWD.

Do not append the previous LD_LIBRARY_PATH if it was empty, and check
for a zero-length prefix when checking dependencies.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Peter Korsgaard <jacmet@uclibc.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
2014-11-30 23:56:14 +01:00
arch arch/Config.in.x86: drop BR2_x86_generic 2014-11-07 19:51:06 +01:00
board configs/apf9328: bump to a modern kernel 2014-11-11 23:00:58 +01:00
boot barebox: bump to version 2014.11.0 2014-11-06 09:13:28 +01:00
configs configs/apf9328: bump to a modern kernel 2014-11-11 23:00:58 +01:00
docs Update for 2014.11-rc3 2014-11-28 13:23:38 +01:00
fs package: indentation cleanup 2014-10-26 05:47:05 +01:00
linux linux: bump default version to 3.17.4 2014-11-21 21:45:38 +01:00
package infra: do not append an empty LD_LIBRARY_PATH 2014-11-30 23:56:14 +01:00
support infra: do not append an empty LD_LIBRARY_PATH 2014-11-30 23:56:14 +01:00
system system/permissions: /etc/random-seed must be mode 600 2014-11-25 22:37:43 +01:00
toolchain toolchain/external: fix building the wrapper on MIPS 2014-11-27 22:47:08 +01:00
.defconfig buildroot: get rid of s390 support 2009-01-12 14:36:14 +00:00
.gitignore update gitignore 2013-05-04 12:41:55 +02:00
CHANGES Update for 2014.11-rc3 2014-11-28 13:23:38 +01:00
COPYING clarify license and fix website license link 2009-05-08 09:29:41 +02:00
Config.in Config.in: remove BR2_DEBIAN_MIRROR completely 2014-10-25 11:26:45 +02:00
Config.in.legacy Config.in.legacy: fix typo 2014-11-09 08:54:47 +01:00
Makefile Update for 2014.11-rc3 2014-11-28 13:23:38 +01:00
Makefile.legacy Makefile.legacy: fix recursive invocation with BUILDROOT_DL_DIR and _CONFIG 2014-02-11 08:14:57 +01:00
README docs: Move README file to root 2014-03-03 21:28:39 +01:00

README

To build and use the buildroot stuff, do the following:

1) run 'make menuconfig'
2) select the packages you wish to compile
3) run 'make'
4) wait while it compiles
5) Use your shiny new root filesystem. Depending on which sort of
    root filesystem you selected, you may want to loop mount it,
    chroot into it, nfs mount it on your target device, burn it
    to flash, or whatever is appropriate for your target system.

You do not need to be root to build or run buildroot.  Have fun!

Offline build:
==============

In order to do an offline-build (not connected to the net), fetch all
selected source by issuing a
$ make source

before you disconnect.
If your build-host is never connected, then you have to copy buildroot
and your toplevel .config to a machine that has an internet-connection
and issue "make source" there, then copy the content of your dl/ dir to
the build-host.

Building out-of-tree:
=====================

Buildroot supports building out of tree with a syntax similar
to the Linux kernel. To use it, add O=<directory> to the
make command line, E.G.:

$ make O=/tmp/build

And all the output files (including .config) will be located under /tmp/build.

More finegrained configuration:
===============================

You can specify a config-file for uClibc:
$ make UCLIBC_CONFIG_FILE=/my/uClibc.config

And you can specify a config-file for busybox:
$ make BUSYBOX_CONFIG_FILE=/my/busybox.config

To use a non-standard host-compiler (if you do not have 'gcc'),
make sure that the compiler is in your PATH and that the library paths are
setup properly, if your compiler is built dynamically:
$ make HOSTCC=gcc-4.3.orig HOSTCXX=gcc-4.3-mine

Depending on your configuration, there are some targets you can use to
use menuconfig of certain packages. This includes:
$ make HOSTCC=gcc-4.3 linux-menuconfig
$ make HOSTCC=gcc-4.3 uclibc-menuconfig
$ make HOSTCC=gcc-4.3 busybox-menuconfig

Please feed suggestions, bug reports, insults, and bribes back to the
buildroot mailing list: buildroot@buildroot.org