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Yann E. MORIN 9bb7d10eea pkg-download: check hashes for locally cached files
In some cases, upstream just update their releases in-place, without
renaming them. When that package is updated in Buildroot, a new hash to
match the new upstream release is included in the corresponding .hash

As a consequence, users who previously downloaded that package's tarball
with an older version of Buildroot, will get stuck with an old archive
for that package, and after updating their Buildroot copy, will be greeted
with a failed download, due to the local file not matching the new

Also, an upstream would sometime serve us HTML garbage instead of the
actual tarball we requested, like SourceForge does from time for as-yet
unknown reasons.

So, to avoid this situation, check the hashes prior to doing the
download. If the hashes match, consider the locally cached file genuine,
and do not download it. However, if the locally cached file does not
match the known hashes we have for it, it is promptly removed, and a
download is re-attempted.

Note: this does not add any overhead compared to the previous situation,
because we were already checking hashes of locally cached files. It just
changes the order in which we do the checks. For the records, here is the
overhead of hashing a 231MiB file (qt-everywhere-opensource-src-4.8.6.tar.gz)
on a core-i5 @2.5GHz:

            cache-cold  cache-hot
    sha1      1.914s      0.762s
    sha256    2.109s      1.270s

But again, this overhead already existed before this patch.

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>
Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2014-12-11 23:59:41 +01:00
arch arch: remove superfluous arch dependencies on BR2_BINFMT_FLAT_* 2014-12-11 22:51:12 +01:00
board configs/qemu: update to the latest kernel/headers versions 2014-12-09 14:30:37 +01:00
boot barebox: bump to version 2014.12.0 2014-12-10 20:01:26 +01:00
configs configs/qemu: update to the latest kernel/headers versions 2014-12-09 14:30:37 +01:00
docs Rename BR2_PREFER_STATIC_LIB to BR2_STATIC_LIBS 2014-12-11 22:48:13 +01:00
fs package: indentation cleanup 2014-12-10 21:53:30 +01:00
linux linux: bump default to version 3.18 2014-12-08 13:11:45 +01:00
package pkg-download: verify the hashes from the download wrapper 2014-12-11 23:59:25 +01:00
support pkg-download: check hashes for locally cached files 2014-12-11 23:59:41 +01:00
system Rename BR2_PREFER_STATIC_LIB to BR2_STATIC_LIBS 2014-12-11 22:48:13 +01:00
toolchain Rename BR2_PREFER_STATIC_LIB to BR2_STATIC_LIBS 2014-12-11 22:48:13 +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 2014-12-01 10:19:00 +01:00
COPYING clarify license and fix website license link 2009-05-08 09:29:41 +02:00
Config.in Rename BR2_PREFER_STATIC_LIB to BR2_STATIC_LIBS 2014-12-11 22:48:13 +01:00
Config.in.legacy Rename BR2_PREFER_STATIC_LIB to BR2_STATIC_LIBS 2014-12-11 22:48:13 +01:00
Makefile Merge branch 'next' 2014-12-01 11:16:42 +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


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