91 lines
3.5 KiB
Bash
Executable File
91 lines
3.5 KiB
Bash
Executable File
#!/bin/sh
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# Break the process if there are any errors
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set -e
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# Import common variables and functions
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. ../../common.sh
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# By convention the overlay bundles have "source" folder, where the source
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# code is downloaded. If the source is downloaded from internet, this allows
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# the download to proceed if the process has been interrupted. In our simple
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# use case we will copy the file "hello.c" and in this way we will simulate
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# (kind of) that it has been downloaded.
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#
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# The main overlay source folder is "minimal/src/source/overlay" and the bundle
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# source artifact will be "minimal/src/source/overlay/hello.c".
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cp $SRC_DIR/hello.c \
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$OVERLAY_SOURCE_DIR
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# The next step is to prepare the source code that we have downloaded in the
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# previous step. Usually this means to extract it. By convention each overlay
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# bundle has its own root folder where all the build magic happens. In our
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# simple use case we will "extract" the source code by copying it from the
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# source folder to the main bundle folder.
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#
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# The main overlay folder is "minimal/src/work/overlay" and the bundle overlay
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# folder will be "minimal/src/work/overlay/hello_mll".
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mkdir $OVERLAY_WORK_DIR/$BUNDLE_NAME
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cp $OVERLAY_SOURCE_DIR/hello.c \
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$OVERLAY_WORK_DIR/$BUNDLE_NAME
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# Each overlay bundle also has a special directory where all build artifacts
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# are put in a structure which represents the final OS folder structure. This
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# folder is "minimal/src/work/overlay/hello_mll/hello_mll_installed".
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# First we create the "destination" folder.
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mkdir $DEST_DIR
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# We want our "hello" executable to reside in the "/bin" folder, so we create
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# subfolder "bin" in "$DEST_DIR".
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mkdir $DEST_DIR/bin
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# Now we can compile "$OVERLAY_WORK_DIR/$BUNDLE_NAME/hello.c" and place it in
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# "$DEST_DIR/bin" as executable binary "hello".
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gcc -o $DEST_DIR/bin/hello $OVERLAY_WORK_DIR/$BUNDLE_NAME/hello.c
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# Optionally, we can reduce the size of the generated overlay bundle artifacts.
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# We use the special function "reduce_size" and we pass as argument the file or
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# folder where our generated artifacts are located.
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reduce_size $DEST_DIR/bin/hello
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# No matter what you do with your bundles, no matter how you compile and/or
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# prepare them, in the end all your bundle artifacts must end up in the folder
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# "$OVERLAY_ROOTFS". This special folder represents the final OS structure
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# where all overlay bundles place their final artifacts. In our simple use case
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# we have already prepared appropriate OS folder structure in "$DEST_DIR", so
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# we will simply copy it in "$OVERLAY_ROOTFS".
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#
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# The overlay root filesystem folder is "minimal/src/work/overlay_rootfs".
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# We use the special function "install_to_overlay" which works in three modes:
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#
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# Mode 1 - install everything from "$DEST_DIR" in "OVERLAY_ROOTFS":
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#
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# install_to_overlay (no arguments provided)
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#
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# Mode 2 - install specific file/folder from "$DEST_DIR", e.g. "$DEST_DIR/bin"
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# directly in "$OVERLAY_ROOTFS":
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#
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# install_to_overlay bin
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#
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# Mode 3 - install specific file/folder from "$DEST_DIR", e.g. "$DEST_DIR/bin"
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# as specific file/folder in "$OVERLAY_ROOTFS", e.g. "$OVERLAY_ROOTFS/bin"
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#
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# install_to_overlay bin bin
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#
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# All of the above examples have the same final effect. In our simple use case
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# we use the first mode (i.e. we provide no arguments).
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install_to_overlay
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# In the end we print message that our bundle has been installed and we return
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# to the overlay source folder.
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echo "Bundle '$BUNDLE_NAME' has been installed."
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cd $SRC_DIR
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# That's it. Add the overlay bundle in the main ".config" file, rebuild MLL
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# (i.e. run "repackage.sh") and when the OS starts, type "hello".
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