Support restore with -XX:CRaCRestoreFrom=PATH

closed/src/java.base/share/native/libjli/criuhelpers.c

@@ -0,0 +1,303 @@
+/*
+ * ===========================================================================
+ * (c) Copyright IBM Corp. 2024, 2024 All Rights Reserved
+ * ===========================================================================
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * IBM designates this particular file as subject to the "Classpath" exception
+ * as provided by IBM in the LICENSE file that accompanied this code.
+ *
+ * This code 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 General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * ===========================================================================
+ */
+
+#include "criuhelpers.h"
+
+#if defined(J9VM_OPT_CRAC_SUPPORT)
+
+#include "java.h"
+#include <ctype.h>
+#include <sys/wait.h>
+
+/**
+ * Get the value of a command line option in the array of command line arguments.
+ * @param[in] optionName The name of the command line option to search for
+ * @param[in] argc The number of command line arguments
+ * @param[in] argv The array of command line arguments
+ * @param[out] error A pointer to an integer for the error code
+ * @return A pointer to the value of the command line option if found, NULL otherwise
+ */
+static const char *
+getCommandLineOptionValue(const char *optionName, int argc, char **argv, int *error)
+{
+    const char *value = NULL;
+    int i = 0;
+    size_t optionNameLength = strlen(optionName);
+    *error = -1;
+    for (i = argc - 1; i >= 0; i--) {
+        const char *arg = argv[i];
+        if (0 == strncmp(arg, optionName, optionNameLength)) {
+            const char *equals = arg + optionNameLength;
+            if (('=' == *equals) || ('\0' == *equals)) {
+                *error = 0;
+                value = equals;
+                if ('=' == *value) {
+                    value += 1;
+                }
+                if ('\0' == *value) {
+                    value = NULL;
+                }
+                break;
+            }
+        }
+    }
+    return value;
+}
+
+/**
+ * Get the checkpoint directory from command line options.
+ * @param[in] argc The number of command line arguments
+ * @param[in] argv The array of command line arguments
+ * @param[in/out] error A pointer to an integer for the error code
+ * @return A pointer to the checkpoint directory if found, NULL otherwise
+ */
+static const char *
+getCheckpointDirectory(int argc, char **argv, int *error)
+{
+    const char *checkpointDirectory = NULL;
+    const char *checkpointDirectoryPropertyValue = getCommandLineOptionValue("-XX:CRaCRestoreFrom", argc, argv, error);
+    if (0 == *error) {
+        if (NULL != checkpointDirectoryPropertyValue) {
+            checkpointDirectory = checkpointDirectoryPropertyValue;
+        } else {
+            JLI_ReportErrorMessage("The value of the command line option -XX:CRaCRestoreFrom was not found.");
+            *error = -2;
+        }
+    }
+    return checkpointDirectory;
+}
+
+/**
+ * Get the log level specified in the command line arguments.
+ * Valid log levels are from 0 to 4, inclusive; the default is 2.
+ * @param[in] argc The number of command line arguments
+ * @param[in] argv The array of command line arguments
+ * @param[in/out] error A pointer to an integer for the error code
+ * @return The log level integer if successful, default of 2 otherwise
+ */
+static int
+getLogLevel(int argc, char **argv, int *error)
+{
+    int logLevelValue = 2; /* default */
+    const char *logLevelPropertyValue = getCommandLineOptionValue("-Dopenj9.internal.criu.logLevel", argc, argv, error);
+    if (0 == *error) {
+        const char *c = logLevelPropertyValue;
+        if (NULL == c) {
+            goto done;
+        }
+        for (; '\0' != *c; c++) {
+            if (!isdigit(*c)) {
+                goto setLogLevelOptionValueNotValidError;
+            }
+        }
+        logLevelValue = atoi(logLevelPropertyValue);
+        if ((0 <= logLevelValue) && (logLevelValue <= 4)) {
+            goto done;
+        } else {
+            goto setLogLevelOptionValueNotValidError;
+        }
+    } else if (-1 == *error) {
+        goto done;
+    }
+setLogLevelOptionValueNotValidError:
+    JLI_ReportErrorMessage(
+            "The option '-Dopenj9.internal.criu.logLevel=%s' is not valid.",
+            logLevelPropertyValue);
+    *error = -2;
+done:
+    return logLevelValue;
+}
+
+/**
+ * Check if the unprivileged mode is specified in the command line arguments.
+ * @param[in] argc The number of command line arguments
+ * @param[in] argv The array of command line arguments
+ * @param[in/out] error A pointer to an integer for the error code
+ * @return true if the unprivileged mode option is specified in the command line arguments, false otherwise
+ */
+static jboolean
+isUnprivilegedModeOn(int argc, char **argv, int *error)
+{
+    jboolean isUnprivilegedModeOn = JNI_FALSE;
+    const char *unprivilegedModePropertyValue = getCommandLineOptionValue("-Dopenj9.internal.criu.unprivilegedMode", argc, argv, error);
+    if (0 == *error) {
+        if (NULL == unprivilegedModePropertyValue) {
+            isUnprivilegedModeOn = JNI_TRUE;
+        } else {
+            JLI_ReportErrorMessage(
+                    "The option '-Dopenj9.internal.criu.unprivilegedMode=%s' does not accept a value.",
+                    unprivilegedModePropertyValue);
+            *error = -2;
+        }
+    }
+    return isUnprivilegedModeOn;
+}
+
+/**
+ * Get the log file specified in the command line arguments.
+ * @param[in] argc The number of command line arguments
+ * @param[in] argv The array of command line arguments
+ * @param[in/out] error A pointer to an integer for the error code
+ * @return A pointer to the log file string if successful, NULL otherwise
+ */
+static const char *
+getLogFile(int argc, char **argv, int *error)
+{
+    const char *logFile = NULL;
+    const char *logFilePropertyValue = getCommandLineOptionValue("-Dopenj9.internal.criu.logFile", argc, argv, error);
+    if (0 == *error) {
+        if (NULL != logFilePropertyValue) {
+            logFile = logFilePropertyValue;
+        } else {
+            JLI_ReportErrorMessage("The option -Dopenj9.internal.criu.logFile requires a value.");
+            *error = -2;
+        }
+    }
+    return logFile;
+}
+
+/**
+ * Restore the system state from a checkpoint using the CRIU tool.
+ * @param[in] checkpointDirectory The directory containing the checkpoint data
+ * @param[in] logLevel The log level for CRIU logging
+ * @param[in] unprivilegedModeOn Indicates whether the unprivileged mode option is on
+ * @param[in] logFile The log file option for CRIU
+ * @return 0 if the execution of the 'criu restore' command succeeds, -1 otherwise
+ */
+static int
+restoreFromCheckpoint(const char *checkpointDirectory, int logLevel, jboolean unprivilegedModeOn, const char *logFile)
+{
+    int length = -1;
+    char logLevelOption[4] = { 0 };
+    char *logFileOption = NULL;
+    int argc = 0;
+    const char *argv[9] = { NULL };
+    argv[argc++] = "criu";
+    argv[argc++] = "restore";
+    argv[argc++] = "-D";
+    argv[argc++] = checkpointDirectory;
+    /* The log level is a single digit. */
+    snprintf(logLevelOption, sizeof(logLevelOption), "-v%d", logLevel);
+    argv[argc++] = logLevelOption;
+    argv[argc++] = "--shell-job";
+    if (unprivilegedModeOn) {
+        argv[argc++] = "--unprivileged";
+    }
+    if (NULL != logFile) {
+        length = strlen(logFile) + sizeof("--log-file=%s") - 1;
+        logFileOption = (char *)JLI_MemAlloc(length + 1);
+        if (NULL == logFileOption) {
+            JLI_ReportErrorMessage("Failed to allocate memory for option '--log-file=%s'.", logFile);
+            goto fail;
+        }
+        if (snprintf(logFileOption, length + 1, "--log-file=%s", logFile) < 0) {
+            JLI_ReportErrorMessage("Failed to format option '--log-file=%s'.", logFile);
+            goto fail;
+        }
+        argv[argc++] = logFileOption;
+    }
+    argv[argc] = NULL;
+    execvp(argv[0], (char * const *)argv);
+    /* If execvp returns, there was an error. */
+fail:
+    if (NULL != logFileOption) {
+        JLI_MemFree((void *)logFileOption);
+    }
+    return -1;
+}
+
+/**
+ * Handle the restoration of the system state from a checkpoint.
+ * @param[in] argc The number of command line arguments
+ * @param[in] argv The array of command line arguments
+ */
+void
+handleCRaCRestore(int argc, char **argv)
+{
+    const char *checkpointDirectory = NULL;
+    int error = 0;
+    int parentProcessExitStatus = EXIT_SUCCESS;
+    pid_t childProcessPid = 0;
+    int logLevel = 0;
+    int childProcessExitStatus = EXIT_SUCCESS;
+    jboolean unprivilegedModeOn = JNI_FALSE;
+    const char *logFile = NULL;
+    int childProcessPidStatus = 0;
+    int childProcessPidExitStatus = 0;
+    checkpointDirectory = getCheckpointDirectory(argc, argv, &error);
+    if (-1 == error) {
+        /* Option -XX:CRaCRestoreFrom not specified. */
+        return;
+    }
+    if (-2 == error) {
+        JLI_ReportErrorMessage("Failed to get the CRIU checkpoint directory.");
+        parentProcessExitStatus = EXIT_FAILURE;
+        goto doneParentProcess;
+    }
+    /*
+     * The if block will be invoked by the child process,
+     * and the else block will be invoked by the parent process.
+     */
+    childProcessPid = fork();
+    if (0 == childProcessPid) {
+        logLevel = getLogLevel(argc, argv, &error);
+        if (-2 == error) {
+            JLI_ReportErrorMessage("Failed to get the CRIU log level.");
+            childProcessExitStatus = EXIT_FAILURE;
+            goto doneChildProcess;
+        }
+        unprivilegedModeOn = isUnprivilegedModeOn(argc, argv, &error);
+        if (-2 == error) {
+            JLI_ReportErrorMessage("Failed to get the CRIU unprivileged mode.");
+            childProcessExitStatus = EXIT_FAILURE;
+            goto doneChildProcess;
+        }
+        logFile = getLogFile(argc, argv, &error);
+        if (-2 == error) {
+            JLI_ReportErrorMessage("Failed to get the CRIU log file.");
+            childProcessExitStatus = EXIT_FAILURE;
+            goto doneChildProcess;
+        }
+        childProcessExitStatus = restoreFromCheckpoint(checkpointDirectory, logLevel, unprivilegedModeOn, logFile);
+doneChildProcess:
+        exit(childProcessExitStatus);
+    } else {
+        waitpid(childProcessPid, &childProcessPidStatus, 0);
+        if (WIFEXITED(childProcessPidStatus)) {
+            childProcessPidExitStatus = WEXITSTATUS(childProcessPidStatus);
+            if (EXIT_SUCCESS == childProcessPidExitStatus) {
+                JLI_ReportMessage("Completed restore with -XX:CRaCRestoreFrom=PATH.");
+            } else {
+                JLI_ReportErrorMessage("Failed to restore from checkpoint, error=%d.", childProcessPidExitStatus);
+                parentProcessExitStatus = EXIT_FAILURE;
+            }
+        } else {
+            JLI_ReportErrorMessage("The CRIU restore child process failed.");
+            parentProcessExitStatus = EXIT_FAILURE;
+        }
+    }
+doneParentProcess:
+    exit(parentProcessExitStatus);
+}
+#endif /* defined(J9VM_OPT_CRAC_SUPPORT) */

closed/src/java.base/share/native/libjli/criuhelpers.h

@@ -0,0 +1,34 @@
+/*
+ * ===========================================================================
+ * (c) Copyright IBM Corp. 2024, 2024 All Rights Reserved
+ * ===========================================================================
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * IBM designates this particular file as subject to the "Classpath" exception
+ * as provided by IBM in the LICENSE file that accompanied this code.
+ *
+ * This code 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 General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * ===========================================================================
+ */
+
+#ifndef CRIUHELPERS_H
+#define CRIUHELPERS_H
+
+#include "j9cfg.h"
+
+#if defined(J9VM_OPT_CRAC_SUPPORT)
+void handleCRaCRestore(int argc, char **argv);
+#endif /* defined(J9VM_OPT_CRAC_SUPPORT) */
+
+#endif /* CRIUHELPERS_H */

src/java.base/share/native/libjli/java.c

@@ -25,7 +25,7 @@
 
 /*
  * ===========================================================================
- * (c) Copyright IBM Corp. 2022, 2023 All Rights Reserved
+ * (c) Copyright IBM Corp. 2022, 2024 All Rights Reserved
  * ===========================================================================
  */
 
@@ -59,6 +59,7 @@
 
 #include <assert.h>
 
+#include "criuhelpers.h"
 #include "java.h"
 #include "jni.h"
 
@@ -547,6 +548,10 @@ JavaMain(void* _args)
     jfieldID noArgMainField;
     jboolean noArgMain;
 
+#if defined(J9VM_OPT_CRAC_SUPPORT)
+    handleCRaCRestore(argc, argv);
+#endif /* defined(J9VM_OPT_CRAC_SUPPORT) */
+
     RegisterThread();
 
     /* Initialize the virtual machine */