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Diffstat (limited to 'docs/manual/rebuilding-packages.txt')
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diff --git a/docs/manual/rebuilding-packages.txt b/docs/manual/rebuilding-packages.txt new file mode 100644 index 000000000..9a41a88ac --- /dev/null +++ b/docs/manual/rebuilding-packages.txt @@ -0,0 +1,62 @@ +Understanding how to rebuild packages +===================================== + +One of the most common questions asked by Buildroot users is how to +rebuild a given package or how to remove a package without rebuilding +everything from scratch. + +Removing a package is currently unsupported by Buildroot without +rebuilding from scratch. This is because Buildroot doesn't keep track +of which package installs what files in the +output/staging+ and ++output/target+ directories. However, implementing clean package +removal is on the TODO-list of Buildroot developers. + +The easiest way to rebuild a single package from scratch is to remove +its build directory in +output/build+. Buildroot will then re-extract, +re-configure, re-compile and re-install this package from scratch. + +However, if you don't want to rebuild the package completely from +scratch, a better understanding of the Buildroot internals is +needed. Internally, to keep track of which steps have been done and +which steps remain to be done, Buildroot maintains stamp files (empty +files that just tell whether this or that action has been done). The +problem is that these stamp files are not uniformly named and handled +by the different packages, so some understanding of the particular +package is needed. + +For packages relying on Buildroot packages infrastructures (see +xref:add-packages[this section] for details), the following stamp +files are relevant: + +* +output/build/packagename-version/.stamp_configured+. If removed, + Buildroot will trigger the recompilation of the package from the + configuration step (execution of +./configure+). + +* +output/build/packagename-version/.stamp_built+. If removed, + Buildroot will trigger the recompilation of the package from the + compilation step (execution of +make+). + +For other packages, an analysis of the specific 'package.mk' file is +needed. For example, the zlib Makefile used to look like this (before +it was converted to the generic package infrastructure): + +----------------- +$(ZLIB_DIR)/.configured: $(ZLIB_DIR)/.patched + (cd $(ZLIB_DIR); rm -rf config.cache; \ + [...] + ) + touch $@ + +$(ZLIB_DIR)/libz.a: $(ZLIB_DIR)/.configured + $(MAKE) -C $(ZLIB_DIR) all libz.a + touch -c $@ +----------------- + +If you want to trigger the reconfiguration, you need to remove ++output/build/zlib-version/.configured+. If you want to trigger only +the recompilation, you need to remove ++output/build/zlib-version/libz.a+. + +Note that most packages, if not all, will progressively be ported over +to the generic or autotools infrastructure, making it much easier to +rebuild individual packages. |