diff options
Diffstat (limited to 'doc/bitbake-user-manual/bitbake-user-manual-metadata.xml')
| -rw-r--r-- | doc/bitbake-user-manual/bitbake-user-manual-metadata.xml | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml index 61daadea9..cfa85b379 100644 --- a/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml +++ b/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml @@ -1107,10 +1107,18 @@ <title>Passing Information Into the Build Task Environment</title> <para> - When running a task, BitBake tightly controls the execution + When running a task, BitBake tightly controls the shell execution environment of the build tasks to make sure unwanted contamination from the build machine cannot influence the build. + <note> + By default, BitBake cleans the environment to include only those + things exported or listed in its whitelist to ensure that the build + environment is reproducible and consistent. + You can prevent this "cleaning" by setting the + <link linkend='var-BB_PRESERVE_ENV'><filename>BB_PRESERVE_ENV</filename></link> + variable. + </note> Consequently, if you do want something to get passed into the build task environment, you must take these two steps: <orderedlist> @@ -1118,14 +1126,16 @@ Tell BitBake to load what you want from the environment into the datastore. You can do so through the + <link linkend='var-BB_ENV_WHITELIST'><filename>BB_ENV_WHITELIST</filename></link> + and <link linkend='var-BB_ENV_EXTRAWHITE'><filename>BB_ENV_EXTRAWHITE</filename></link> - variable. + variables. For example, assume you want to prevent the build system from accessing your <filename>$HOME/.ccache</filename> directory. - The following command tells BitBake to load - <filename>CCACHE_DIR</filename> from the environment into - the datastore: + The following command "whitelists" the environment variable + <filename>CCACHE_DIR</filename> causing BitBack to allow that + variable into the datastore: <literallayout class='monospaced'> export BB_ENV_EXTRAWHITE="$BB_ENV_EXTRAWHITE CCACHE_DIR" </literallayout></para></listitem> @@ -1174,12 +1184,6 @@ The previous example returns <filename>BAR</filename> from the original execution environment. </para> - - <para> - By default, BitBake cleans the environment to include only those - things exported or listed in its whitelist to ensure that the build - environment is reproducible and consistent. - </para> </section> </section> |