[yocto] understanding what's in an image

[Jim Abernathy]

On 01/10/2012 09:57 AM, Gary Thomas wrote:
> On 2012-01-10 07:48, Jim Abernathy wrote:
>> On 01/09/2012 09:07 PM, Christopher Larson wrote:
>>> Read layer.conf in each layer. See the BBFILES variable.
>>> -- 
>>> Christopher Larson
>>>
>>> On Monday, January 9, 2012 at 5:51 PM, James Abernathy wrote:
>>>
>>>> I'm trying to understand how bitbake parses the poky directory tree 
>>>> a little better.
>>>>
>>>> The best I can figure all .bb files are NOT included. Just some of 
>>>> them are. I'm guessing that the .bb in the meta/recipe-sato named 
>>>> core-image-sato.bb is the one that is used
>>>> to start the parsing if bitbake core-image-sato is executed.
>>>> I originally thought all subdirectories of a path included in 
>>>> BBLAYER were parsed looking for .bb files, but now I know that is 
>>>> not true, but not sure why.
>>>>
>>>> For example, it does not appear that webkit is included in the 
>>>> core-image-sato even though the recipe-sato directory includes the 
>>>> webkit subdirectory with it's recipe. What
>>>> would be the proper way of adding the webkit to core-image-sato??
>>>>
>>>> Jim A
>>>>
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>>>
>> the layer.conf in meta/conf includes and covers  all .bb files under 
>> it like receipe-sato, which includes web-webkit.  So does this say 
>> that the web-webkit get's built by bitbake,
>> but the images does not contain web-webkit until you put in the 
>> IMAGE_INSTALL += "web-webit"???
>
> No, only packages which are needed to satisfy the needs of
> the given image are built.  So, if your image does not include
> web-webkit, it won't be built even though there is a recipe
> for it.
>
> When building an image, bitbake looks at the image recipe and
> figures out what packages are needed (these are listed explicitly).
> Then any additional packages which are needed (DEPENDS, RDEPENDS, etc)
> will be added to the list.  This process continues until all
> dependencies are met, yielding the final package set.  Out of
> the 1000 or so possible recipes, you may end up only building
> a few hundred and many of these are support - i.e. only used
> for the build process itself.
>
This makes sense now, thanks.  I did this via hob this morning and it 
become more obvious because hob approaches this process as all about the 
package.

Jim A