Re: [Patch] Read CONFIG_RD_ variables for initramfs compression

[P J P]

  Hello Andrew,

+-- On Wed, 30 Oct 2013, Andrew Morton wrote --+
| Isn't there some convenient way of testing for the presence of an 
| executable in $PATH?
| 
| The shell-builtin `which' seems to dtrt:

  True. Please see an updated patch attached herein.

Thank you.
--
Prasad J Pandit / Red Hat Security Response Team
From 352781fd2846c54e92ae0c37dd972dc5fcdfb695 Mon Sep 17 00:00:00 2001
From: P J P <pra...@redhat.com>
Date: Thu, 31 Oct 2013 12:03:00 +0530
Subject: Read CONFIG_RD_ variables for initramfs compression

When expert configuration option(CONFIG_EXPERT) is enabled,
menuconfig offers a choice of compression algorithm to compress
initial ramfs image; This choice is stored into CONFIG_RD_*
variables. But usr/Makefile uses earlier INITRAMFS_COMPRESSION_*
macros to build initial ramfs file. Since none of them is defined,
resulting 'initramfs_data.cpio' file remains un-compressed.

This patch updates the Makefile to use CONFIG_RD_* variables and
adds support for LZ4 compression algorithm. Also updates the
'gen_initramfs_list.sh' script to check whether a selected
compression command is accessible or not. And fall-back to default
gzip(1) compression when it is not.

Signed-off-by: P J P <pra...@redhat.com>

diff --git a/scripts/gen_initramfs_list.sh b/scripts/gen_initramfs_list.sh
index b482f16..ef47409 100644
--- a/scripts/gen_initramfs_list.sh
+++ b/scripts/gen_initramfs_list.sh
@@ -240,12 +240,24 @@ case "$arg" in
                output_file="$1"
                cpio_list="$(mktemp ${TMPDIR:-/tmp}/cpiolist.XXXXXX)"
                output=${cpio_list}
-               echo "$output_file" | grep -q "\.gz$" && compr="gzip -n -9 -f"
-               echo "$output_file" | grep -q "\.bz2$" && compr="bzip2 -9 -f"
-               echo "$output_file" | grep -q "\.lzma$" && compr="lzma -9 -f"
-               echo "$output_file" | grep -q "\.xz$" && \
-                               compr="xz --check=crc32 --lzma2=dict=1MiB"
-               echo "$output_file" | grep -q "\.lzo$" && compr="lzop -9 -f"
+               echo "$output_file" | grep -q "\.gz$" \
+                && [ -x "`which gzip 2> /dev/null`" ] \
+                && compr="gzip -n -9 -f"
+               echo "$output_file" | grep -q "\.bz2$" \
+                && [ -x "`which bzip2 2> /dev/null`" ] \
+                && compr="bzip2 -9 -f"
+               echo "$output_file" | grep -q "\.lzma$" \
+                && [ -x "`which lzma 2> /dev/null`" ] \
+                && compr="lzma -9 -f"
+               echo "$output_file" | grep -q "\.xz$" \
+                && [ -x "`which xz 2> /dev/null`" ] \
+                && compr="xz --check=crc32 --lzma2=dict=1MiB"
+               echo "$output_file" | grep -q "\.lzo$" \
+                && [ -x "`which lzop 2> /dev/null`" ] \
+                && compr="lzop -9 -f"
+               echo "$output_file" | grep -q "\.lz4$" \
+                && [ -x "`which lz4 2> /dev/null`" ] \
+                && compr="lz4 -9 -f"
                echo "$output_file" | grep -q "\.cpio$" && compr="cat"
                shift
                ;;
diff --git a/usr/Makefile b/usr/Makefile
index 029ffe6..e767f01 100644
--- a/usr/Makefile
+++ b/usr/Makefile
@@ -6,20 +6,23 @@ klibcdirs:;
 PHONY += klibcdirs
 
 
-# Gzip
-suffix_$(CONFIG_INITRAMFS_COMPRESSION_GZIP)   = .gz
-
 # Bzip2
-suffix_$(CONFIG_INITRAMFS_COMPRESSION_BZIP2)  = .bz2
+suffix_$(CONFIG_RD_BZIP2)  = .bz2
 
 # Lzma
-suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZMA)   = .lzma
+suffix_$(CONFIG_RD_LZMA)   = .lzma
 
 # XZ
-suffix_$(CONFIG_INITRAMFS_COMPRESSION_XZ)     = .xz
+suffix_$(CONFIG_RD_XZ)     = .xz
 
 # Lzo
-suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZO)   = .lzo
+suffix_$(CONFIG_RD_LZO)    = .lzo
+
+# Lz4
+suffix_$(CONFIG_RD_LZ4)    = .lz4
+
+# Gzip
+suffix_$(CONFIG_RD_GZIP)   = .gz
 
 AFLAGS_initramfs_data.o += 
-DINITRAMFS_IMAGE="usr/initramfs_data.cpio$(suffix_y)"
 
@@ -53,7 +56,10 @@ endif
 quiet_cmd_initfs = GEN     $@
       cmd_initfs = $(initramfs) -o $@ $(ramfs-args) $(ramfs-input)
 
-targets := initramfs_data.cpio.gz initramfs_data.cpio.bz2 
initramfs_data.cpio.lzma initramfs_data.cpio.xz initramfs_data.cpio.lzo 
initramfs_data.cpio
+targets := initramfs_data.cpio.gz initramfs_data.cpio.bz2 \
+       initramfs_data.cpio.lzma initramfs_data.cpio.xz \
+       initramfs_data.cpio.lzo initramfs_data.cpio.lz4 \
+       initramfs_data.cpio
 # do not try to update files included in initramfs
 $(deps_initramfs): ;
 
@@ -66,4 +72,3 @@ $(deps_initramfs): klibcdirs
 $(obj)/initramfs_data.cpio$(suffix_y): $(obj)/gen_init_cpio $(deps_initramfs) 
klibcdirs
        $(Q)$(initramfs) -l $(ramfs-input) > $(obj)/.initramfs_data.cpio.d
        $(call if_changed,initfs)
-
-- 
1.8.3.1