From 3ce142861d88c357864d3a3bef7ec453826d737d Mon Sep 17 00:00:00 2001

From: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>

Date: Wed, 4 Nov 2015 11:31:10 +0900

Subject: [PATCH] lsinitrd: Suppress "cat: write error: Broken pipe"

On systemd, SIGPIPE is ignored by default; see man 5 systemd.exec for

IgnoreSIGPIPE=. As a result, lsinitrd.sh under a systemd service

outputs "cat: write error: Broken pipe" in the processing of

determining a compression format of a given initramfs file using cat

command in the write part of a pipeline processing.

For example, this is a log message of kdump.service in RHEL7.1,

    -- Logs begin at Wed 2015-11-04 09:57:33 JST, end at Wed 2015-11-04 09:58:28 JST. --

    Nov 04 09:57:33 localhost systemd[1]: Stopping Crash recovery kernel arming...

    Nov 04 09:57:33 localhost kdumpctl[22545]: kexec: unloaded kdump kernel

    Nov 04 09:57:33 localhost kdumpctl[22545]: Stopping kdump: [OK]

    Nov 04 09:57:33 localhost systemd[1]: Starting Crash recovery kernel arming...

    Nov 04 09:57:36 localhost kdumpctl[22553]: Detected change(s) in the following file(s):

    Nov 04 09:57:36 localhost kdumpctl[22553]: /etc/kdump.conf

    Nov 04 09:57:36 localhost kdumpctl[22553]: Rebuilding /boot/initramfs-3.10.0-229.el7.x86_64kdump.img

    Nov 04 09:57:40 localhost dracut[24914]: Executing: /usr/sbin/dracut --hostonly --hostonly-cmdline -o "plymouth dash resume" -f /boot/initramfs-3.10.0-229.el7.x86_64kdump.img 3.10.0-229.el7.x86_64

    ...<cut>...

    Nov 04 09:58:12 localhost dracut[24914]: *** Creating image file done ***

    Nov 04 09:58:12 localhost dracut[24914]: Image: /boot/initramfs-3.10.0-229.el7.x86_64kdump.img: 18M

    Nov 04 09:58:12 localhost kdumpctl[22553]: cat: write error: Broken pipe

    Nov 04 09:58:12 localhost dracut[24914]: ========================================================================

    Nov 04 09:58:12 localhost dracut[24914]: Version: dracut-033-240.el7

    Nov 04 09:58:12 localhost dracut[24914]:

    Nov 04 09:58:12 localhost dracut[24914]: Arguments: --hostonly --hostonly-cmdline -o 'plymouth dash resume' -f

    Nov 04 09:58:13 localhost dracut[24914]:

    Nov 04 09:58:13 localhost dracut[24914]: dracut modules:

    Nov 04 09:58:13 localhost dracut[24914]: bash

kdump.service builds and loads an initramfs for kdump kernel using

kdumpctl command which uses dracut command and so lsinitrd command,

too.

Although there's no actual harm except for the error message, there

has been several inquiries from customers about this message so

far. We should suppress this message to reduce needless

communications.

To suppress the message, this commit cleans up the processing of

reading the first 6 bytes of a given initramfs file without cat

command.

---

 lsinitrd.sh | 59 ++++++++++++++++++++++++++++-------------------------------

 1 file changed, 28 insertions(+), 31 deletions(-)

diff --git a/lsinitrd.sh b/lsinitrd.sh

index d2ddd76..441fb92 100755

--- a/lsinitrd.sh

+++ b/lsinitrd.sh

@@ -176,38 +176,35 @@ case $bin in

         ;;

 esac

-CAT=$({

-        if [[ $SKIP ]]; then

-            $SKIP "$image"

+if [[ $SKIP ]] ; then

+    bin="$($SKIP "$image" | { read -N 6 bin && echo "$bin" ; })"

+else

+    read -N 6 bin < "$image"

+fi

+case $bin in

+    $'\x1f\x8b'*)

+        CAT="zcat --"

+        ;;

+    BZh*)

+        CAT="bzcat --"

+        ;;

+    $'\x71\xc7'*|070701)

+        CAT="cat --"

+        ;;

+    $'\x02\x21'*)

+        CAT="lz4 -d -c"

+        ;;

+    $'\x89'LZO$'\0'*)

+        CAT="lzop -d -c"

+        ;;

+    *)

+        if echo "test"|xz|xzcat --single-stream >/dev/null 2>&1; then

+            CAT="xzcat --single-stream --"

         else

-            cat "$image"

-        fi } | {

-        read -N 6 bin

-        case $bin in

-            $'\x1f\x8b'*)

-                echo "zcat --"

-                ;;

-            BZh*)

-                echo "bzcat --"

-                ;;

-            $'\x71\xc7'*|070701)

-                echo "cat --"

-                ;;

-            $'\x02\x21'*)

-                echo "lz4 -d -c"

-                ;;

-            $'\x89'LZO$'\0'*)

-                echo "lzop -d -c"

-                ;;

-            *)

-                if echo "test"|xz|xzcat --single-stream >/dev/null 2>&1; then

-                    echo "xzcat --single-stream --"

-                else

-                    echo "xzcat --"

-                fi

-                ;;

-        esac

-    })

+            CAT="xzcat --"

+        fi

+        ;;

+esac

 skipcpio()

 {