hotspot/src/share/vm/runtime/commandLineFlagConstraintsRuntime.cpp
author gziemski
Thu, 18 Jun 2015 14:39:38 -0500
changeset 31371 311143309e73
child 32351 1da9b960b3d4
permissions -rw-r--r--
8122937: [JEP 245] Validate JVM Command-Line Flag Arguments. Summary: Validate the arguments to all JVM command-line flags so as to avoid crashes, and ensure that appropriate error messages are displayed when they are invalid. Reviewed-by: ddmitriev, dholmes, kbarrett, drwhite, brutisso, coleenp

/*
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#include "precompiled.hpp"
#include "runtime/arguments.hpp"
#include "runtime/commandLineFlagConstraintsRuntime.hpp"
#include "runtime/globals.hpp"
#include "utilities/defaultStream.hpp"

Flag::Error ObjectAlignmentInBytesConstraintFunc(bool verbose, intx* value) {
  if (!is_power_of_2(*value)) {
    if (verbose == true) {
      jio_fprintf(defaultStream::error_stream(),
                "ObjectAlignmentInBytes=" INTX_FORMAT " must be power of 2\n",
                *value);
    }
    return Flag::VIOLATES_CONSTRAINT;
  }
  // In case page size is very small.
  if (*value >= (intx)os::vm_page_size()) {
    if (verbose == true) {
      jio_fprintf(defaultStream::error_stream(),
                "ObjectAlignmentInBytes=" INTX_FORMAT " must be less than page size " INTX_FORMAT "\n",
                *value, (intx)os::vm_page_size());
    }
    return Flag::VIOLATES_CONSTRAINT;
  }
  return Flag::SUCCESS;
}

// Need to enforce the padding not to break the existing field alignments.
// It is sufficient to check against the largest type size.
Flag::Error ContendedPaddingWidthConstraintFunc(bool verbose, intx* value) {
  if ((*value != 0) && ((*value % BytesPerLong) != 0)) {
    if (verbose == true) {
      jio_fprintf(defaultStream::error_stream(),
                "ContendedPaddingWidth=" INTX_FORMAT " must be a multiple of %d\n",
                *value, BytesPerLong);
    }
    return Flag::VIOLATES_CONSTRAINT;
  } else {
    return Flag::SUCCESS;
  }
}