Write to `/var/lib/kdump` if $KDUMP_BOOTDIR not writable

The `/boot` directory on some operating systems might be read-only.
If we cannot write to `$KDUMP_BOOTDIR` when generating the kdump
initrd, attempt to place the generated initrd at `/var/lib/kdump`
instead.

Signed-off by: Kelvin Fan <kelvinfan001@gmail.com>
Acked-by: Kairui Song <kasong@redhat.com>

60-kdump.install

@@ -2,17 +2,23 @@
 
 COMMAND="$1"
 KERNEL_VERSION="$2"
-BOOT_DIR_ABS="$3"
+KDUMP_INITRD_DIR_ABS="$3"
 KERNEL_IMAGE="$4"
 
 if ! [[ ${KERNEL_INSTALL_MACHINE_ID-x} ]]; then
     exit 0
 fi
 
-if [[ -d "$BOOT_DIR_ABS" ]]; then
+if [[ -d "$KDUMP_INITRD_DIR_ABS" ]]; then
     KDUMP_INITRD="initrdkdump"
 else
-    BOOT_DIR_ABS="/boot"
+    # If `KDUMP_BOOTDIR` is not writable, then the kdump
+    # initrd must have been placed at `/var/lib/kdump`
+    if [[ ! -w "/boot" ]]; then
+        KDUMP_INITRD_DIR_ABS="/var/lib/kdump"
+    else
+        KDUMP_INITRD_DIR_ABS="/boot"
+    fi
     KDUMP_INITRD="initramfs-${KERNEL_VERSION}kdump.img"
 fi
 
@@ -23,7 +29,7 @@ case "$COMMAND" in
         # and managed by kdump service
         ;;
     remove)
-        rm -f -- "$BOOT_DIR_ABS/$KDUMP_INITRD"
+        rm -f -- "$KDUMP_INITRD_DIR_ABS/$KDUMP_INITRD"
         ret=$?
         ;;
 esac

kdump-lib.sh

@@ -733,20 +733,30 @@ prepare_kdump_bootinfo()
     boot_initrdlist="initramfs-$KDUMP_KERNELVER.img initrd"
     for initrd in $boot_initrdlist; do
         if [ -f "$KDUMP_BOOTDIR/$initrd" ]; then
-            DEFAULT_INITRD="$KDUMP_BOOTDIR/$initrd"
+            defaut_initrd_base="$initrd"
+            DEFAULT_INITRD="$KDUMP_BOOTDIR/$defaut_initrd_base"
             break
         fi
     done
 
-    # Get kdump initrd from default initrd filename
+    # Create kdump initrd basename from default initrd basename
     # initramfs-5.7.9-200.fc32.x86_64.img => initramfs-5.7.9-200.fc32.x86_64kdump.img
     # initrd => initrdkdump
-    if [[ -z "$DEFAULT_INITRD" ]]; then
-        KDUMP_INITRD=${KDUMP_BOOTDIR}/initramfs-${KDUMP_KERNELVER}kdump.img
-    elif [[ $(basename $DEFAULT_INITRD) == *.* ]]; then
-        KDUMP_INITRD=${DEFAULT_INITRD%.*}kdump.${DEFAULT_INITRD##*.}
+    if [[ -z "$defaut_initrd_base" ]]; then
+        kdump_initrd_base=initramfs-${KDUMP_KERNELVER}kdump.img
+    elif [[ $defaut_initrd_base == *.* ]]; then
+        kdump_initrd_base=${defaut_initrd_base%.*}kdump.${DEFAULT_INITRD##*.}
     else
-        KDUMP_INITRD=${DEFAULT_INITRD}kdump
+        kdump_initrd_base=${defaut_initrd_base}kdump
+    fi
+
+    # Place kdump initrd in `/var/lib/kdump` if `KDUMP_BOOTDIR` not writable
+    if [[ ! -w "$KDUMP_BOOTDIR" ]];then
+        var_target_initrd_dir="/var/lib/kdump"
+        mkdir -p "$var_target_initrd_dir"
+        KDUMP_INITRD="$var_target_initrd_dir/$kdump_initrd_base"
+    else
+        KDUMP_INITRD="$KDUMP_BOOTDIR/$kdump_initrd_base"
     fi
 }
 

kdumpctl

@@ -151,8 +151,8 @@ rebuild_kdump_initrd()
 
 rebuild_initrd()
 {
-	if [[ ! -w "$KDUMP_BOOTDIR" ]];then
-		derror "$KDUMP_BOOTDIR does not have write permission. Can not rebuild $TARGET_INITRD"
+	if [[ ! -w $(dirname $TARGET_INITRD) ]];then
+		derror "$(dirname $TARGET_INITRD) does not have write permission. Cannot rebuild $TARGET_INITRD"
 		return 1
 	fi
 

kexec-tools.spec

@@ -169,6 +169,7 @@ mkdir -p $RPM_BUILD_ROOT%{_unitdir}
 mkdir -p -m755 $RPM_BUILD_ROOT%{_bindir}
 mkdir -p -m755 $RPM_BUILD_ROOT%{_libdir}
 mkdir -p -m755 $RPM_BUILD_ROOT%{_prefix}/lib/kdump
+mkdir -p -m755 $RPM_BUILD_ROOT%{_sharedstatedir}/kdump
 install -m 755 %{SOURCE1} $RPM_BUILD_ROOT%{_bindir}/kdumpctl
 
 install -m 755 build/sbin/kexec $RPM_BUILD_ROOT/usr/sbin/kexec
@@ -334,6 +335,7 @@ done
 %dir %{_sysconfdir}/kdump
 %dir %{_sysconfdir}/kdump/pre.d
 %dir %{_sysconfdir}/kdump/post.d
+%dir %{_sharedstatedir}/kdump
 %{_mandir}/man8/kdumpctl.8.gz
 %{_mandir}/man8/kexec.8.gz
 %ifarch %{ix86} x86_64 ppc64 s390x ppc64le aarch64