svn commit: r241205 - stable/9/libexec/save-entropy

[Doug Barton]

Author: dougb
Date: Thu Oct  4 22:23:40 2012
New Revision: 241205
URL: http://svn.freebsd.org/changeset/base/241205

Log:
  MFC r240090:
  
  Improve file rotation

Modified:
  stable/9/libexec/save-entropy/save-entropy.sh
Directory Properties:
  stable/9/libexec/save-entropy/   (props changed)

Modified: stable/9/libexec/save-entropy/save-entropy.sh
==============================================================================
--- stable/9/libexec/save-entropy/save-entropy.sh	Thu Oct  4 22:16:58 2012	(r241204)
+++ stable/9/libexec/save-entropy/save-entropy.sh	Thu Oct  4 22:23:40 2012	(r241205)
@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# Copyright (c) 2001-2006 Douglas Barton, DougB at FreeBSD.org
+# Copyright (c) 2001-2006,2012 Douglas Barton, dougb at FreeBSD.org
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -29,7 +29,7 @@
 # This script is called by cron to store bits of randomness which are
 # then used to seed /dev/random on boot.
 
-# Originally developed by Doug Barton, DougB at FreeBSD.org
+# Originally developed by Doug Barton, dougb at FreeBSD.org
 
 PATH=/bin:/usr/bin
 
@@ -55,38 +55,36 @@ entropy_save_sz=${entropy_save_sz:-2048}
 entropy_save_num=${entropy_save_num:-8}
 
 if [ ! -d "${entropy_dir}" ]; then
-	umask 077
-	mkdir "${entropy_dir}" || {
-	    logger -is -t "$0" The entropy directory "${entropy_dir}" does not \
-exist, and cannot be created.  Therefore no entropy can be saved. ;
-	    exit 1;}
-	/usr/sbin/chown operator:operator "${entropy_dir}"
-	chmod 0700 "${entropy_dir}"
+	install -d -o operator -g operator -m 0700 "${entropy_dir}" || {
+		logger -is -t "$0" The entropy directory "${entropy_dir}" does \
+		    not exist, and cannot be created. Therefore no entropy can \
+		    be saved.; exit 1; }
 fi
 
+cd "${entropy_dir}" || {
+	logger -is -t "$0" Cannot cd to the entropy directory: "${entropy_dir}". \
+	    Entropy file rotation is aborted.; exit 1; }
+
+for f in saved-entropy.*; do
+	case "${f}" in saved-entropy.\*) continue ;; esac	# No files match
+	[ ${f#saved-entropy\.} -ge ${entropy_save_num} ] && unlink ${f}
+done
+
 umask 377
 
-esn_m1=$(( ${entropy_save_num} - 1 ))
-for file_num in `jot $esn_m1 $esn_m1 1`; do
-	if [ -e "${entropy_dir}/saved-entropy.${file_num}" ]; then
-		if [ -f "${entropy_dir}/saved-entropy.${file_num}" ]; then
-			new_file=saved-entropy.$(( $file_num + 1 ))
-			if [ -e "${entropy_dir}/${new_file}" ]; then
-				unlink ${entropy_dir}/${new_file}
-			fi
-			mv "${entropy_dir}/saved-entropy.${file_num}" \
-			    "${entropy_dir}/${new_file}"
-		else
-			logger -is -t "$0" \
-"${entropy_dir}/saved-entropy.${file_num} is not a regular file, and therefore \
-it will not be rotated. Entropy file harvesting is aborted."
-			exit 1
-		fi
+n=$(( ${entropy_save_num} - 1 ))
+while [ ${n} -ge 1 ]; do
+	if [ -f "saved-entropy.${n}" ]; then
+		mv "saved-entropy.${n}" "saved-entropy.$(( ${n} + 1 ))"
+	elif [ -e "saved-entropy.${n}" -o -L "saved-entropy.${n}" ]; then
+		logger -is -t "$0" \
+	"${entropy_dir}/saved-entropy.${n}" is not a regular file, and so \
+	    it will not be rotated. Entropy file rotation is aborted.
+		exit 1
 	fi
+	n=$(( ${n} - 1 ))
 done
 
-dd if=/dev/random of="${entropy_dir}/saved-entropy.1" \
-    bs="$entropy_save_sz" count=1 2> /dev/null
+dd if=/dev/random of=saved-entropy.1 bs=${entropy_save_sz} count=1 2>/dev/null
 
 exit 0
-