Merge pull request #2579 from rear/jsmeix-fail-safe-400_copy_modules

Make 400_copy_modules.sh fail-safe for newer modinfo output
(in particular modinfo in kmod-27 since SLES15-SP3) because
otherwise copying builtin kernel "modules" would let "rear mkrescue"
error out with e.g. "ERROR: unix exists but no module file?".
Furthermore ensure that kernel modules that should be loaded
during recovery system startup (i.e. those in MODULES_LOAD)
get always copied into the recovery system.

usr/share/rear/build/GNU/Linux/400_copy_modules.sh

@@ -26,23 +26,42 @@ fi
 function modinfo_filename () {
     local module_name=$1
     local module_filename=""
-    local alias_module_name=$(modprobe -n -R $module_name 2>/dev/null)
+    # 'modprobe -n -R' prints all module names matching an alias so we have its output in an array
+    # and use only its first element to consider only the first printed module name:
+    local alias_module_name=( $( modprobe -n -R $module_name 2>/dev/null ) )
     # If the installed modprobe command supports resolving module aliases (-R), use that capability.
     test $alias_module_name && module_name=$alias_module_name
     # Older modinfo (e.g. the one in SLES10) does not support '-k'
     # but that old modinfo returns a zero exit code when called as 'modinfo -k ...'
     # and shows a 'modinfo: invalid option -- k ...' message on stderr and nothing on stdout
-    # so that we need to check if we got a non-empty module filename:
-    module_filename=$( modinfo -k $KERNEL_VERSION -F filename $module_name )
+    # so that we need to check if we got a non-empty module filename.
+    # Older modinfo (in particular modinfo before kmod-27 since SLES15-SP3)
+    # outputs nothing on stdout for builtin kernel "modules" and exits with exit code 1 like
+    #   # modinfo -F filename unix
+    #   modinfo: ERROR: Module unix not found.
+    # Newer modinfo (in particular modinfo in kmod-27 since SLES15-SP3)
+    # outputs on stdout for builtin kernel "modules" and exits with zero exit code like
+    #   # modinfo -F filename unix
+    #   name:           unix
+    #   (builtin)
+    # For real kernel modules the modinfo stdout is one word that is the kernel module filename like
+    #   # modinfo -F filename sg
+    #   /lib/modules/5.3.18-43-default/kernel/drivers/scsi/sg.ko.xz
+    module_filename="$( modinfo -k $KERNEL_VERSION -F filename $module_name )"
     # If 'modinfo -k ...' stdout is empty we retry without '-k' regardless why stdout is empty
     # but then we do not discard stderr so that error messages appear in the log file.
     # In this case we must additionally ensure that KERNEL_VERSION matches 'uname -r'
     # otherwise a module file for a wrong kernel version would be found:
-    if ! test $module_filename ; then
+    if ! test "$module_filename" ; then
         test "$KERNEL_VERSION" = "$( uname -r )" || Error "modinfo_filename failed because KERNEL_VERSION does not match 'uname -r'"
-        module_filename=$( modinfo -F filename $module_name )
+        module_filename="$( modinfo -F filename $module_name )"
     fi
-    test $module_filename && echo $module_filename
+    # grep for '(builtin)' in the modinfo stdout to get the builtin kernel "module" case and otherwise
+    # 'readlink -e something' shows the filename when something is one or more files and exits with zero exit code
+    # 'readlink -e something' shows the symlink target when something is a symlink and exits with zero exit code
+    # 'readlink -e something' shows nothing when something is no file or a broken symlink and exits with exit code 1
+    # 'readlink -e something' shows nothing on stdout but an error on stderr when something is empty and exits with exit code 1
+    grep -q '(builtin)' <<<"$module_filename" && echo '' || readlink -e $module_filename
 }
 
 # Artificial 'for' clause that is run only once
@@ -74,7 +93,8 @@ for dummy in "once" ; do
     # Test all MODULES array members to make the 'loaded_modules' functionality work for
     # MODULES array contents like MODULES=( 'moduleX' 'loaded_modules' 'moduleY' ):
     if IsInArray "loaded_modules" "${MODULES[@]}" ; then
-        LogPrint "Copying only currently loaded kernel modules (MODULES contains 'loaded_modules')"
+        # Kernel modules that should be loaded during recovery system startup must be always copied into the recovery system:
+        LogPrint "Copying only currently loaded kernel modules (MODULES contains 'loaded_modules') and those in MODULES_LOAD"
         # The rescue/recovery system cannot work when its kernel modules
         # do not match the kernel that gets included in the rescue/recovery system
         # so that "rear mkrescue/mkbackup" errors out to be on the safe side
@@ -84,12 +104,20 @@ for dummy in "once" ; do
         if ! test "$KERNEL_VERSION" = "$currently_running_kernel_version" ; then
             Error "KERNEL_VERSION='$KERNEL_VERSION' does not match currently running kernel version ('uname -r' shows '$currently_running_kernel_version')"
         fi
-        loaded_modules="$( lsmod | tail -n +2 | cut -d ' ' -f 1 )"
-        # It can happen that a module is loaded but 'modinfo -F filename' cannot show its filename
-        # when it is loaded under a module alias name but the above modinfo_filename function
-        # could not resolve aliases (when the modprobe command does not support -R):
-        loaded_modules_files="$( for loaded_module in $loaded_modules ; do modinfo_filename $loaded_module || Error "$loaded_module loaded but no module file?" ; done )"
-        # $loaded_modules_files cannot be empty because modinfo_filename fails when it cannot show a module filename:
+        # Kernel modules that should be loaded during recovery system startup must be always copied into the recovery system:
+        loaded_modules="${MODULES_LOAD[@]}"
+        # The leading blank before $(...) is mandatory (otherwise the last in MODULES_LOAD is concatenated with the first of lsmod):
+        loaded_modules+=" $( lsmod | tail -n +2 | cut -d ' ' -f 1 )"
+        # It can happen that a module is loaded or should be loaded but 'modinfo -F filename' cannot show its filename
+        # when it is loaded or should be loaded under a module alias name but the above modinfo_filename function
+        # could not resolve aliases (when the modprobe command does not support -R).
+        # The 'sort -u' removes duplicates only to avoid useless stderr warnings from the subsequent 'cp'
+        # like "cp: warning: source file '/lib/modules/.../foo.ko' specified more than once"
+        # regardless that nothing goes wrong when 'cp' gets duplicate source files
+        # cf. http://blog.schlomo.schapiro.org/2015/04/warning-is-waste-of-my-time.html
+        loaded_modules_files="$( for loaded_module in $loaded_modules ; do modinfo_filename $loaded_module || Error "$loaded_module loaded or to be loaded but no module file?" ; done | sort -u )"
+        # $loaded_modules_files could be empty as extreme case because modinfo_filename outputs nothing in the builtin kernel "module" case:
+        test "$loaded_modules_files" || continue
         if ! cp $verbose -t $ROOTFS_DIR -L --preserve=all --parents $loaded_modules_files 1>&2 ; then
             Error "Failed to copy '$loaded_modules_files'"
         fi
@@ -127,8 +155,9 @@ for dummy in "once" ; do
                sr_mod ide_cd cdrom
                zlib zlib-inflate zlib-deflate
                libcrc32c crc32c crc32c-intel )
-    # Include the modules in MODULES plus their dependant modules:
-    for module in "${MODULES[@]}" ; do
+    # Include the modules in MODULES plus their dependant modules.
+    # Kernel modules that should be loaded during recovery system startup must be always copied into the recovery system:
+    for module in "${MODULES_LOAD[@]}" "${MODULES[@]}" ; do
         # Strip trailing ".o" if there:
         module=${module#.o}
         # Strip trailing ".ko" if there:
@@ -160,7 +189,8 @@ for dummy in "once" ; do
             # could not resolve aliases (when the modprobe command does not support -R):
             module_files="$( modinfo_filename $module || Error "$module exists but no module file?" )"
         fi
-        # $module_files cannot be empty because modinfo_filename fails when it cannot show a module filename:
+        # $module_files can be empty because modinfo_filename outputs nothing in the builtin kernel "module" case:
+        test "$module_files" || continue
         if ! cp $verbose -t $ROOTFS_DIR -L --preserve=all --parents $module_files 1>&2 ; then
             Error "Failed to copy '$module_files'"
         fi