From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnout Vandecappelle Date: Mon, 1 Feb 2016 12:22:49 +0100 Subject: [Buildroot] [PATCH 03/16 v3] core/pkg-utils: add macro to hardlink-or-copy In-Reply-To: <56AF2FE6.1060206@lucaceresoli.net> References: <496a4dbb0c7e2bfd0be8726e3d8a2aab4f1d830d.1454004518.git.yann.morin.1998@free.fr> <56AE8E21.4020904@mind.be> <56AF2FE6.1060206@lucaceresoli.net> Message-ID: <56AF4009.1010503@mind.be> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net On 01-02-16 11:13, Luca Ceresoli wrote: > Hi, > > Arnout Vandecappelle wrote: >> On 28-01-16 19:15, Yann E. MORIN wrote: >>> This macro will try to copy a source file into a destination fdirectory, >>> by first atempting a hard-link, and falling back to a plain copy. >>> >>> In some situations, it will be necessary that the destination file is >>> named differently than the source (e.g. due to a re-numbering), so if a >>> third argument is specified, it is treated as the basename of the >>> destination file. >>> >>> Signed-off-by: "Yann E. MORIN" >>> Cc: Luca Ceresoli >>> >>> --- >>> Changes v2 -> v3; >>> - use "ln" instead of "cp -l" >>> - accept third argument, as the basename of the destination file >>> - drop reviewed-by and tested-by tags given in v2, due to the above >>> two changes >>> >>> Changes RFC -> v1: >>> - move to pkg-utils (Luca) >>> --- >>> package/pkg-utils.mk | 25 +++++++++++++++++++++++++ >>> 1 file changed, 25 insertions(+) >>> >>> diff --git a/package/pkg-utils.mk b/package/pkg-utils.mk >>> index 44bd2c9..6479cd8 100644 >>> --- a/package/pkg-utils.mk >>> +++ b/package/pkg-utils.mk >>> @@ -113,6 +113,31 @@ $$(error Package error: use $(2) instead of $(1). Please >>> fix your .mk file) >>> endif >>> endef >>> >>> +################################################################################ >>> >>> +# hardlink-copy -- hardlink source and destination if possible, otherwise >>> +# do a simple copy >>> +# >>> +# argument 1 is the source *file* >>> +# argument 2 is the destination *directory* >>> +# argument 3 is the basename of the destination file (optional, defaults to >>> +# the basename of the source file. >>> +# >>> +# examples: >>> +# $(call hardlink-copy,/path/to/source/file,/path/to/destination/dir/) >>> +# $(call >>> hardlink-copy,/path/to/source/file,/path/to/destination/dir/,new-name) >>> +# >>> +# Note: we make that a single command, so se can: >>> +# - use '$(Q)' in front of it and properly silence the whole macro, >>> +# - use '|| exit 1' after it, so we can exit on error in compound commands. >>> +################################################################################ >>> >>> +define hardlink-copy >>> + { mkdir -p $(2) && \ >>> + { ln $(1) $(2)$(if $(3),/$(strip $(3))) 2>/dev/null || \ >> >> Shouldn't this be ln -f (and maybe cp -f) to make sure it behaves the same when >> you run it a second time? > > Indeed it's true. Not an issue for 'make legal-info' since it wipes the > output dir before copying file in it, but the macro is generic so it > has to handle this case. > > This definitely applies to ln. cp normally doesn't need it, but it does > not hurt. With -f, cp will indeed only unlink if it can't write; if the target is a symlink, it will still not remove the symlink but instead it will overwrite the file pointed to. So an explicit rm -f is probably better. Regards, Arnout > -- Arnout Vandecappelle arnout at mind be Senior Embedded Software Architect +32-16-286500 Essensium/Mind http://www.mind.be G.Geenslaan 9, 3001 Leuven, Belgium BE 872 984 063 RPR Leuven LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle GPG fingerprint: 7493 020B C7E3 8618 8DEC 222C 82EB F404 F9AC 0DDF