LP#1098377: sanitize savepoint names

When invoking open-ils.{cstore,pcrud,rstore}.savepoint.*, the
caller supplies a name for the savepoint.  However, the savepoint
names could be constructed so that the caller could execute
arbitrary SQL.  This patch sanitizes the name so that it contains
only alphanumeric and underscore characters.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Dan Scott <dscott@laurentian.ca>
Protect against overly long savepoint names

Per http://postgresql.org/docs/9.1/static/sql-syntax-lexical.html#SQL-SYNTAX-IDENTIFIERS,
the maximum identifier length works out to being 63 bytes (+1 for the
null terminator), so to avoid potential memory pressure by a 10GB string
somehow being passed in as the savepoint name, malloc no more than 64
bytes and copy no more than 63 bytes from the incoming name to the
escaped name.

Signed-off-by: Dan Scott <dscott@laurentian.ca>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Verify savepoint name is non-null

Before we attempt to mangle the name, let's ensure that it's non-null.
Otherwise, segfaults ensue.

Signed-off-by: Bill Erickson <berick@esilibrary.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>
LP#1098377: protect against even more cstore segfaults

Following up on the preceding patch, passing null
as the savepoint name to savepoint.release and
savepoint.rollback would also segfault cstore.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Bill Erickson <berick@esilibrary.com>