kernel/linux: allow headers from full custom source tree

Accept a local tarball name as the source of the Linux kernel headers,
rather than forcing the user to use either an upstream tarball, or a
local pre-installed headers tree.

config/kernel/linux.in

@@ -83,6 +83,19 @@ config KERNEL_V_2_6_27_47
       See the original announcement by Adrian Bunk in the following mailing list
       entry: http://marc.info/?l=linux-kernel&m=122375909403298&w=2
 
+config KERNEL_LINUX_CUSTOM
+    bool
+    prompt "custom tarball"
+    help
+      Use a local tarball of a complete kernel source tree.
+
+config KERNEL_LINUX_CUSTOM_TARBALL
+    string
+    prompt "Path to custom tarball"
+    depends on KERNEL_LINUX_CUSTOM
+    help
+      Enter here the path to the tarball of your full kernel tree.
+
 endchoice
 
 config KERNEL_VERSION
@@ -144,10 +157,16 @@ endif # KERNEL_LINUX_INSTALL
 
 config KERNEL_LINUX_USE_CUSTOM_HEADERS
     bool
-    prompt "custom, and/or pre-installed, headers tree"
+    prompt "pre-installed headers tree"
     help
-      If you have some kernel headers lying around, you can enter the path
-      below.
+      If you have some pre-installed kernel headers lying around, you can
+      enter the path to these headers, below, they will be copied from
+      there, and into the toolchain's sysroot.
+      
+      Note:
+      This will *not* let you use a complete kernel tree!
+      If you want to use your own full kernel tree, then you want to
+      say 'Y' to KERNEL_LINUX_INSTALL, above, and select KERNEL_LINUX_CUSTOM.
 
 if KERNEL_LINUX_USE_CUSTOM_HEADERS
 

scripts/build/kernel/linux.sh

@@ -17,7 +17,9 @@ CT_DoKernelTupleValues() {
 
 # Download the kernel
 do_kernel_get() {
-    if [ "${CT_KERNEL_LINUX_INSTALL}" = "y" ]; then
+    if [    "${CT_KERNEL_LINUX_INSTALL}" = "y"  \
+         -a "${CT_KERNEL_LINUX_CUSTOM}" != "y"  \
+       ]; then
         CT_GetFile "linux-${CT_KERNEL_VERSION}" \
                    {ftp,http}://ftp.{de.,eu.,}kernel.org/pub/linux/kernel/v2.{6{,/testing},4,2}
     fi
@@ -25,9 +27,43 @@ do_kernel_get() {
 
 # Extract kernel
 do_kernel_extract() {
+    local tar_opt
     if [ "${CT_KERNEL_LINUX_INSTALL}" = "y" ]; then
-        CT_Extract "linux-${CT_KERNEL_VERSION}"
-        CT_Patch "linux" "${CT_KERNEL_VERSION}"
+        if [ "${CT_KERNEL_LINUX_CUSTOM}" = "y" ]; then
+            # We extract the custom linux tree into a directory with a
+            # well-known name, and strip the leading directory component
+            # of the extracted pathes. This is needed because we do not
+            # know the value for this first component, because it is a
+            # _custom_ tree.
+            # Also, we have to protect from partial extraction using the
+            # .extracting and .extracted locks (not using .patching and
+            # .patched as we are *not* patching that kernel).
+
+            if [ -e "${CT_SRC_DIR}/.linux-custom.extracted" ]; then
+                CT_DoLog DEBUG "Custom linux kernel tree already extracted"
+                return 0
+            fi
+
+            CT_TestAndAbort "Custom kernel tree partially extracted. Remove before resuming" -f "${CT_SRC_DIR}/.linux-custom.extracting"
+            CT_DoExecLog DEBUG touch "${CT_SRC_DIR}/.linux-custom.extracting"
+            CT_DoExecLog DEBUG mkdir "${CT_SRC_DIR}/linux-custom"
+
+            case "${CT_KERNEL_LINUX_CUSTOM_TARBALL}" in
+                *.tar.bz2)      tar_opt=-j;;
+                *.tar.gz|*.tgz) tar_opt=-z;;
+                *.tar)          ;;
+                *)              CT_Abort "Don't know how to handle '${CT_KERNEL_LINUX_CUSTOM_TARBALL}': unknown extension";;
+            esac
+            CT_DoLog EXTRA "Extracting custom linux kernel"
+            CT_DoExecLog ALL tar x -C "${CT_SRC_DIR}/linux-custom"      \
+                                 --strip-components 1 -v ${tar_opt}     \
+                                 -f "${CT_KERNEL_LINUX_CUSTOM_TARBALL}"
+
+            CT_DoExecLog ALL mv -v "${CT_SRC_DIR}/.linux-custom.extracting" "${CT_SRC_DIR}/.linux-custom.extracted"
+        else
+            CT_Extract "linux-${CT_KERNEL_VERSION}"
+            CT_Patch "linux" "${CT_KERNEL_VERSION}"
+        fi
     fi
 }
 
@@ -46,17 +82,22 @@ do_kernel_headers() {
 
 # Install kernel headers using headers_install from kernel sources.
 do_kernel_install() {
+    local kernel_path
+
     CT_DoLog DEBUG "Using kernel's headers_install"
 
     mkdir -p "${CT_BUILD_DIR}/build-kernel-headers"
-    cd "${CT_BUILD_DIR}/build-kernel-headers"
 
+    kernel_path="${CT_SRC_DIR}/linux-${CT_KERNEL_VERSION}"
+    if [ "${CT_KERNEL_LINUX_CUSTOM}" = "y" ]; then
+        kernel_path="${CT_SRC_DIR}/linux-custom"
+    fi
     V_OPT="V=${CT_KERNEL_LINUX_VERBOSE_LEVEL}"
 
     CT_DoLog EXTRA "Installing kernel headers"
     CT_DoExecLog ALL                                    \
-    make -C "${CT_SRC_DIR}/linux-${CT_KERNEL_VERSION}"  \
-         O=$(pwd)                                       \
+    make -C "${kernel_path}"                            \
+         O="${CT_BUILD_DIR}/build-kernel-headers"       \
          ARCH=${CT_ARCH}                                \
          INSTALL_HDR_PATH="${CT_SYSROOT_DIR}/usr"       \
          ${V_OPT}                                       \
@@ -65,8 +106,8 @@ do_kernel_install() {
     if [ "${CT_KERNEL_LINUX_INSTALL_CHECK}" = "y" ]; then
         CT_DoLog EXTRA "Checking installed headers"
         CT_DoExecLog ALL                                    \
-        make -C "${CT_SRC_DIR}/linux-${CT_KERNEL_VERSION}"  \
-             O=$(pwd)                                       \
+        make -C "${kernel_path}"                            \
+             O="${CT_BUILD_DIR}/build-kernel-headers"       \
              ARCH=${CT_ARCH}                                \
              INSTALL_HDR_PATH="${CT_SYSROOT_DIR}/usr"       \
              ${V_OPT}                                       \