How to apply patches to a package in Buildroot?

Question

I am working on an embedded system that uses buildroot as a tool for building the kernel and the root filesystem. I want to apply some patches to this kernel source tree, Can somebody tell me how buildroot apply patches?

Answer 1

some details about patch files in the buildroot project:

1. you have to

   diff -u "old_file" "new_file" > file.patch
   

while standing exactly above extracted location of your package tar.gz defined in

PACKAGE_NAME_SOURCE

it means, your path to the file must include extracted package folder name.

2. in case you wonder if the "old_file" path would be different from the original one - don't worry, the important one is the "new_file" path and name - it should match your package extracted one.

3. naming convention for the patches already used/defined in buildroot (all parts are separated with '-' sign):

   • 4 digits patch priority (starting from 0001)
   • target filename
   • reason for patching
   • .patch extention

example:

0001-configure.ac-convert-AC_TRY_COMPILE-AC_COMPILE_IFELS.patch

4. deposit patch file inside buildroot/package/"your package name"/ folder.

there is no need for configuration files to modify, all patches will be tried for application automatically.

5. in case of the failure, the reject-patch file (named similar to the file you are trying to patch but with .rej extention) will be deposited inside package extracted folder.