source: trunk/packages/xen-3.1/xen-3.1/tools/examples/vtpm-common.sh @ 34

#
# Copyright (c) 2005 IBM Corporation
# Copyright (c) 2005 XenSource Ltd.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of version 2.1 of the GNU Lesser General Public
# License as published by the Free Software Foundation.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

dir=$(dirname "$0")
. "$dir/logging.sh"
. "$dir/locking.sh"

VTPMDB="/etc/xen/vtpm.db"

#In the vtpm-impl file some commands should be defined:
#      vtpm_create, vtpm_setup, vtpm_start, etc. (see below)
if [ -r "$dir/vtpm-impl.alt" ]; then
        . "$dir/vtpm-impl.alt"
elif [ -r "$dir/vtpm-impl" ]; then
        . "$dir/vtpm-impl"
else
        function vtpm_create () {
                true
        }
        function vtpm_setup() {
                true
        }
        function vtpm_start() {
                true
        }
        function vtpm_suspend() {
                true
        }
        function vtpm_resume() {
                true
        }
        function vtpm_delete() {
                true
        }
        function vtpm_migrate() {
                echo "Error: vTPM migration accross machines not implemented."
        }
        function vtpm_migrate_local() {
                echo "Error: local vTPM migration not supported"
        }
        function vtpm_migrate_recover() {
                true
        }
fi


#Find the instance number for the vtpm given the name of the domain
# Parameters
# - vmname : the name of the vm
# Return value
#  Returns '0' if instance number could not be found, otherwise
#  it returns the instance number in the variable 'instance'
function vtpmdb_find_instance () {
        local vmname ret instance
        vmname=$1
        ret=0

        instance=$(cat $VTPMDB |                   \
                  awk -vvmname=$vmname             \
                  '{                               \
                     if ( 1 != index($1,"#")) {    \
                       if ( $1 == vmname ) {       \
                         print $2;                 \
                         exit;                     \
                       }                           \
                     }                             \
                   }')
        if [ "$instance" != "" ]; then
                ret=$instance
        fi
        echo "$ret"
}


# Check whether a particular instance number is still available
# returns "0" if it is not available, "1" otherwise.
function vtpmdb_is_free_instancenum () {
        local instance instances avail i
        instance=$1
        avail=1
        #Allowed instance number range: 1-255
        if [ $instance -eq 0 -o $instance -gt 255 ]; then
                avail=0
        else
                instances=$(cat $VTPMDB |                \
                           gawk                          \
                           '{                            \
                               if (1 != index($1,"#")) { \
                                 printf("%s ",$2);       \
                               }                         \
                            }')
                for i in $instances; do
                        if [ $i -eq $instance ]; then
                                avail=0
                                break
                        fi
                done
        fi
        echo "$avail"
}


# Get an available instance number given the database
# Returns an unused instance number
function vtpmdb_get_free_instancenum () {
        local ctr instances don found
        instances=$(cat $VTPMDB |                \
                   gawk                          \
                   '{                            \
                       if (1 != index($1,"#")) { \
                         printf("%s ",$2);       \
                       }                         \
                    }')
        ctr=1
        don=0
        while [ $don -eq 0 ]; do
                found=0
                for i in $instances; do
                        if [ $i -eq $ctr ]; then
                                found=1;
                                break;
                        fi
                done

                if [ $found -eq 0 ]; then
                        don=1
                        break
                fi
                let ctr=ctr+1
        done
        echo "$ctr"
}


# Add a domain name and instance number to the DB file
function vtpmdb_add_instance () {
        local res vmname inst
        vmname=$1
        inst=$2

        if [ ! -f $VTPMDB ]; then
                echo "#Database for VM to vTPM association" > $VTPMDB
                echo "#1st column: domain name" >> $VTPMDB
                echo "#2nd column: TPM instance number" >> $VTPMDB
        fi
        res=$(vtpmdb_validate_entry $vmname $inst)
        if [ $res -eq 0 ]; then
                echo "$vmname $inst" >> $VTPMDB
        fi
}


#Validate whether an entry is the same as passed to this
#function
function vtpmdb_validate_entry () {
        local res rc vmname inst
        rc=0
        vmname=$1
        inst=$2

        res=$(cat $VTPMDB |            \
             gawk -vvmname=$vmname     \
                  -vinst=$inst         \
             '{                        \
                 if ( 1 == index($1,"#")) {\
                 } else                \
                 if ( $1 == vmname &&  \
                      $2 == inst) {    \
                    printf("1");       \
                    exit;              \
                 } else                \
                 if ( $1 == vmname ||  \
                      $2 == inst) {    \
                    printf("2");       \
                    exit;              \
                 }                     \
             }')

        if [ "$res" == "1" ]; then
                rc=1
        elif [ "$res" == "2" ]; then
                rc=2
        fi
        echo "$rc"
}


#Remove an entry from the vTPM database given its domain name
#and instance number
function vtpmdb_remove_entry () {
        local vmname instance VTPMDB_TMP
        vmname=$1
        instance=$2
        VTPMDB_TMP="$VTPMDB".tmp

        $(cat $VTPMDB |            \
         gawk -vvmname=$vmname     \
         '{                        \
            if ( $1 != vmname ) {  \
              print $0;            \
            }                      \
         '} > $VTPMDB_TMP)
        if [ -e $VTPMDB_TMP ]; then
                mv -f $VTPMDB_TMP $VTPMDB
                vtpm_delete $instance
        else
                log err "Error creating temporary file '$VTPMDB_TMP'."
        fi
}


# Find the reason for the creation of this device:
# Returns 'resume' or 'create'
function vtpm_get_create_reason () {
        local resume
        resume=$(xenstore_read $XENBUS_PATH/resume)
        if [ "$resume" == "True" ]; then
                echo "resume"
        else
                echo "create"
        fi
}


#Create a vTPM instance
# If no entry in the TPM database is found, the instance is
# created and an entry added to the database.
function vtpm_create_instance () {
        local res instance domname reason
        domname=$(xenstore_read "$XENBUS_PATH"/domain)
        reason=$(vtpm_get_create_reason)

        claim_lock vtpmdb
        instance=$(vtpmdb_find_instance $domname)

        if [ "$instance" == "0" -a "$reason" != "create" ]; then
                release_lock vtpmdb
                return
        fi

        if [ "$instance" == "0" ]; then
                #Try to give the preferred instance to the domain
                instance=$(xenstore_read "$XENBUS_PATH"/pref_instance)
                if [ "$instance" != "" ]; then
                        res=$(vtpmdb_is_free_instancenum $instance)
                        if [ $res -eq 0 ]; then
                                instance=$(vtpmdb_get_free_instancenum)
                        fi
                else
                        instance=$(vtpmdb_get_free_instancenum)
                fi

                vtpm_create $instance

                if [ $vtpm_fatal_error -eq 0 ]; then
                        vtpmdb_add_instance $domname $instance
                fi
        else
                if [ "$reason" == "resume" ]; then
                        vtpm_resume $instance
                else
                        vtpm_start $instance
                fi
        fi

        release_lock vtpmdb

        xenstore_write $XENBUS_PATH/instance $instance
}


#Remove an instance when a VM is terminating or suspending.
#Since it is assumed that the VM will appear again, the
#entry is kept in the VTPMDB file.
function vtpm_remove_instance () {
        local instance reason domname
        #Stop script execution quietly if path does not exist (anymore)
        xenstore-exists "$XENBUS_PATH"/domain
        domname=$(xenstore_read "$XENBUS_PATH"/domain)

        if [ "$domname" != "" ]; then
                claim_lock vtpmdb

                instance=$(vtpmdb_find_instance $domname)

                if [ "$instance" != "0" ]; then
                        vtpm_suspend $instance
                fi

                release_lock vtpmdb
        fi
}


#Remove an entry in the VTPMDB file given the domain's name
#1st parameter: The name of the domain
function vtpm_delete_instance () {
        local instance

        claim_lock vtpmdb

        instance=$(vtpmdb_find_instance $1)
        if [ "$instance" != "0" ]; then
                vtpmdb_remove_entry $1 $instance
        fi

        release_lock vtpmdb
}

# Determine whether the given address is local to this machine
# Return values:
#  "-1" : the given machine name is invalid
#  "0"  : this is not an address of this machine
#  "1"  : this is an address local to this machine
function vtpm_isLocalAddress() {
        local addr res
        addr=$(ping $1 -c 1 |  \
               gawk '{ print substr($3,2,length($3)-2); exit }')
        if [ "$addr" == "" ]; then
                echo "-1"
                return
        fi
        res=$(ifconfig | grep "inet addr" |  \
             gawk -vaddr=$addr               \
             '{                              \
                if ( addr == substr($2, 6)) {\
                  print "1";                 \
                }                            \
             }'                              \
            )
        if [ "$res" == "" ]; then
                echo "0"
                return
        fi
        echo "1"
}

# Perform a migration step. This function differentiates between migration
# to the local host or to a remote machine.
# Parameters:
# 1st: destination host to migrate to
# 2nd: name of the domain to migrate
# 3rd: the migration step to perform
function vtpm_migration_step() {
        local res=$(vtpm_isLocalAddress $1)
        if [ "$res" == "0" ]; then
                vtpm_migrate $1 $2 $3
        else
                vtpm_migrate_local
        fi
}

# Recover from migration due to an error. This function differentiates
# between migration to the local host or to a remote machine.
# Parameters:
# 1st: destination host the migration was going to
# 2nd: name of the domain that was to be migrated
# 3rd: the last successful migration step that was done
function vtpm_recover() {
        local res
        res=$(vtpm_isLocalAddress $1)
        if [ "$res" == "0" ]; then
                vtpm_migrate_recover $1 $2 $3
        fi
}


#Determine the domain id given a domain's name.
#1st parameter: name of the domain
#return value: domain id  or -1 if domain id could not be determined
function vtpm_domid_from_name () {
        local id name ids
        ids=$(xenstore-list /local/domain)
        for id in $ids; do
                name=$(xenstore_read /local/domain/$id/name)
                if [ "$name" == "$1" ]; then
                        echo "$id"
                        return
                fi
        done
        echo "-1"
}


#Add a virtual TPM instance number and its associated domain name
#to the VTPMDB file and activate usage of this virtual TPM instance
#by writing the instance number into the xenstore
#1st parm: name of virtual machine
#2nd parm: instance of assoicate virtual TPM
function vtpm_add_and_activate() {
        local domid=$(vtpm_domid_from_name $1)
        if [ "$domid" != "-1" ]; then
                vtpmdb_add_instance $1 $2
                xenstore-write backend/vtpm/$domid/0/instance $2
        fi
}