13 Using a Development Shell

When debugging certain commands or even when just editing packages, devshell can be a useful tool. When you invoke devshell, all tasks up to and including do_patch are run for the specified target. Then, a new terminal is opened and you are placed in ${S}, the source directory. In the new terminal, all the OpenEmbedded build-related environment variables are still defined so you can use commands such as configure and make. The commands execute just as if the OpenEmbedded build system were executing them. Consequently, working this way can be helpful when debugging a build or preparing software to be used with the OpenEmbedded build system.

Following is an example that uses devshell on a target named matchbox-desktop:

$ bitbake matchbox-desktop -c devshell

This command spawns a terminal with a shell prompt within the OpenEmbedded build environment. The OE_TERMINAL variable controls what type of shell is opened.

For spawned terminals, the following occurs:

  • The PATH variable includes the cross-toolchain.

  • The pkgconfig variables find the correct .pc files.

  • The configure command finds the Yocto Project site files as well as any other necessary files.

Within this environment, you can run configure or compile commands as if they were being run by the OpenEmbedded build system itself. As noted earlier, the working directory also automatically changes to the Source Directory (S).

To manually run a specific task using devshell, run the corresponding run.* script in the ${WORKDIR}/temp directory (e.g., run.do_configure.pid). If a task’s script does not exist, which would be the case if the task was skipped by way of the sstate cache, you can create the task by first running it outside of the devshell:

$ bitbake -c task

Note

  • Execution of a task’s run.* script and BitBake’s execution of a task are identical. In other words, running the script re-runs the task just as it would be run using the bitbake -c command.

  • Any run.* file that does not have a .pid extension is a symbolic link (symlink) to the most recent version of that file.

Remember, that the devshell is a mechanism that allows you to get into the BitBake task execution environment. And as such, all commands must be called just as BitBake would call them. That means you need to provide the appropriate options for cross-compilation and so forth as applicable.

When you are finished using devshell, exit the shell or close the terminal window.

Note

  • It is worth remembering that when using devshell you need to use the full compiler name such as arm-poky-linux-gnueabi-gcc instead of just using gcc. The same applies to other applications such as binutils, libtool and so forth. BitBake sets up environment variables such as CC to assist applications, such as make to find the correct tools.

  • It is also worth noting that devshell still works over X11 forwarding and similar situations.