DL_DIR can be a very precious place for some users: they use it to store
all the downloaded archives to share across all their Buildroot (and
maybe non-Buildroot) builds.
We do not want to trash this location with our temporary downloads (e.g.
git, Hg, svn, cvs repository clones/checkouts, or wget, bzr tep tarballs).
Turns out that we already have some kind of scratchpad, the BUILD_DIR.
Although it is not really a disposable location, that's the best we have
so far.
Also, we create the temporary tarballs with mktemp using the final tarball,
as template, since we want the temporary to be on the same filesystem as
the final location, so the 'mv' is just a plain, atomic rename(2), and we
are not left with a half-copied file as the final location.
Using mktemp ensures all temp file names are unique, so it allows for
parallel downloads from different build dirs at the same time, without
cloberring each downloads.
Note: we're using neither ${TMP} nor ${TMPDIR} since they are shared
locations, sometime with little place (eg. tmpfs), and some of the
repositories we clone/checkout can be very big.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Samuel Martin <s.martin49@gmail.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Tested-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
[tested a particular scenario that used to fail: two separate builds
using a shared DL_DIR, ccache enabled, so that they run almost
synchronously. These would download the same file at the same time,
corrupting each other. With the patches in this series, all works
fine.]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Maintaining the download helpers in the Makefile has proved to be a bit
complex, so move it to a shell script.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Reviewed-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
