Validate GPHDFS URL before calling execl() with it
Validate GPHDFS URL before calling execl() with it

Four characters "'", "\", "<", ">" could cause shell injection in
gphdfs. This quick fix filters out them to avoid the security issue.

Signed-off-by: Haozhou Wang <16af34017e39fc2fe11eb364c1c2ef2fa8289c41@pivotal.io>
Signed-off-by: Peifeng Qiu <5ac57522f17d595d0e5c6d4a23fb4fdcd3f0c5e9@pivotal.io>
lintzc/gpdb,xinzweb/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,edespino/gpdb,rvs/gpdb,rvs/gpdb,lisakowen/gpdb,lisakowen/gpdb,xinzweb/gpdb,jmcatamney/gpdb,50wu/gpdb,janebeckman/gpdb,adam8157/gpdb,Chibin/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,rvs/gpdb,janebeckman/gpdb,edespino/gpdb,kaknikhil/gpdb,Quikling/gpdb,lintzc/gpdb,Chibin/gpdb,lisakowen/gpdb,cjcjameson/gpdb,xinzweb/gpdb,kaknikhil/gpdb,lintzc/gpdb,janebeckman/gpdb,adam8157/gpdb,janebeckman/gpdb,Chibin/gpdb,kaknikhil/gpdb,lisakowen/gpdb,rvs/gpdb,Quikling/gpdb,greenplum-db/gpdb,kaknikhil/gpdb,lintzc/gpdb,Chibin/gpdb,Chibin/gpdb,Quikling/gpdb,edespino/gpdb,adam8157/gpdb,greenplum-db/gpdb,50wu/gpdb,yuanzhao/gpdb,Quikling/gpdb,jmcatamney/gpdb,cjcjameson/gpdb,kaknikhil/gpdb,lisakowen/gpdb,adam8157/gpdb,kaknikhil/gpdb,rvs/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,lintzc/gpdb,jmcatamney/gpdb,edespino/gpdb,kaknikhil/gpdb,lintzc/gpdb,rvs/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,cjcjameson/gpdb,adam8157/gpdb,Quikling/gpdb,Chibin/gpdb,ashwinstar/gpdb,cjcjameson/gpdb,Chibin/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,xinzweb/gpdb,50wu/gpdb,Quikling/gpdb,edespino/gpdb,xinzweb/gpdb,ashwinstar/gpdb,cjcjameson/gpdb,adam8157/gpdb,adam8157/gpdb,greenplum-db/gpdb,edespino/gpdb,ashwinstar/gpdb,Quikling/gpdb,janebeckman/gpdb,greenplum-db/gpdb,edespino/gpdb,50wu/gpdb,cjcjameson/gpdb,kaknikhil/gpdb,jmcatamney/gpdb,lintzc/gpdb,janebeckman/gpdb,Quikling/gpdb,janebeckman/gpdb,edespino/gpdb,adam8157/gpdb,xinzweb/gpdb,edespino/gpdb,cjcjameson/gpdb,lisakowen/gpdb,Quikling/gpdb,yuanzhao/gpdb,Chibin/gpdb,janebeckman/gpdb,xinzweb/gpdb,janebeckman/gpdb,50wu/gpdb,greenplum-db/gpdb,kaknikhil/gpdb,lintzc/gpdb,rvs/gpdb,lisakowen/gpdb,cjcjameson/gpdb,50wu/gpdb,Chibin/gpdb,ashwinstar/gpdb,kaknikhil/gpdb,yuanzhao/gpdb,lisakowen/gpdb,50wu/gpdb,rvs/gpdb,janebeckman/gpdb,jmcatamney/gpdb,rvs/gpdb,50wu/gpdb,yuanzhao/gpdb,cjcjameson/gpdb,xinzweb/gpdb,ashwinstar/gpdb,edespino/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,lintzc/gpdb,cjcjameson/gpdb,Chibin/gpdb,rvs/gpdb,yuanzhao/gpdb,Quikling/gpdb