/*

 * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 2015, 2018, SAP SE. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle 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, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include "jni_util.h"

#include <sys/socket.h>

#include <sys/stat.h>

#include <sys/types.h>

#include <sys/un.h>

#include <errno.h>

#include <signal.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include "sun_tools_attach_VirtualMachineImpl.h"

#define RESTARTABLE(_cmd, _result) do { \

  do { \

    _result = _cmd; \

  } while((_result == -1) && (errno == EINTR)); \

} while(0)

#define ROOT_UID 0

/*

 * Class:     sun_tools_attach_VirtualMachineImpl

 * Method:    socket

 * Signature: ()I

 */

JNIEXPORT jint JNICALL Java_sun_tools_attach_VirtualMachineImpl_socket

  (JNIEnv *env, jclass cls)

{

    int fd = socket(PF_UNIX, SOCK_STREAM, 0);

    if (fd == -1) {

        JNU_ThrowIOExceptionWithLastError(env, "socket");

    }

    return (jint)fd;

}

/*

 * Class:     sun_tools_attach_VirtualMachineImpl

 * Method:    connect

 * Signature: (ILjava/lang/String;)I

 */

JNIEXPORT void JNICALL Java_sun_tools_attach_VirtualMachineImpl_connect

  (JNIEnv *env, jclass cls, jint fd, jstring path)

{

    jboolean isCopy;

    const char* p = GetStringPlatformChars(env, path, &isCopy);

    if (p != NULL) {

        struct sockaddr_un addr;

        int err = 0;

        memset(&addr, 0, sizeof(addr));

        addr.sun_family = AF_UNIX;

        /* strncpy is safe because addr.sun_path was zero-initialized before. */

        strncpy(addr.sun_path, p, sizeof(addr.sun_path) - 1);

        /* We must call bind with the actual socketaddr length. This is obligatory for AS400. */

        if (connect(fd, (struct sockaddr*)&addr, SUN_LEN(&addr)) == -1) {

            err = errno;

        }

        if (isCopy) {

            JNU_ReleaseStringPlatformChars(env, path, p);

        }

        /*

         * If the connect failed then we throw the appropriate exception

         * here (can't throw it before releasing the string as can't call

         * JNI with pending exception)

         */

        if (err != 0) {

            if (err == ENOENT) {

                JNU_ThrowByName(env, "java/io/FileNotFoundException", NULL);

            } else {

                char* msg = strdup(strerror(err));

                JNU_ThrowIOException(env, msg);

                if (msg != NULL) {

                    free(msg);

                }

            }

        }

    }

}

/*

 * Class:     sun_tools_attach_VirtualMachineImpl

 * Method:    sendQuitTo

 * Signature: (I)V

 */

JNIEXPORT void JNICALL Java_sun_tools_attach_VirtualMachineImpl_sendQuitTo

  (JNIEnv *env, jclass cls, jint pid)

{

    if (kill((pid_t)pid, SIGQUIT)) {

        JNU_ThrowIOExceptionWithLastError(env, "kill");

    }

}

/*

 * Class:     sun_tools_attach_VirtualMachineImpl

 * Method:    checkPermissions

 * Signature: (Ljava/lang/String;)V

 */

JNIEXPORT void JNICALL Java_sun_tools_attach_VirtualMachineImpl_checkPermissions

  (JNIEnv *env, jclass cls, jstring path)

{

    jboolean isCopy;

    const char* p = GetStringPlatformChars(env, path, &isCopy);

    if (p != NULL) {

        struct stat64 sb;

        uid_t uid, gid;

        int res;

        memset(&sb, 0, sizeof(struct stat64));

        /*

         * Check that the path is owned by the effective uid/gid of this

         * process. Also check that group/other access is not allowed.

         */

        uid = geteuid();

        gid = getegid();

        res = stat64(p, &sb);

        if (res != 0) {

            /* save errno */

            res = errno;

        }

        if (res == 0) {

            char msg[100];

            jboolean isError = JNI_FALSE;

            if (sb.st_uid != uid && uid != ROOT_UID) {

                snprintf(msg, sizeof(msg),

                    "file should be owned by the current user (which is %d) but is owned by %d", uid, sb.st_uid);

                isError = JNI_TRUE;

            } else if (sb.st_gid != gid && uid != ROOT_UID) {

                snprintf(msg, sizeof(msg),

                    "file's group should be the current group (which is %d) but the group is %d", gid, sb.st_gid);

                isError = JNI_TRUE;

            } else if ((sb.st_mode & (S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)) != 0) {

                snprintf(msg, sizeof(msg),

                    "file should only be readable and writable by the owner but has 0%03o access", sb.st_mode & 0777);

                isError = JNI_TRUE;

            }

            if (isError) {

                char buf[256];

                snprintf(buf, sizeof(buf), "well-known file %s is not secure: %s", p, msg);

                JNU_ThrowIOException(env, buf);

            }

        } else {

            char* msg = strdup(strerror(res));

            JNU_ThrowIOException(env, msg);

            if (msg != NULL) {

                free(msg);

            }

        }

        if (isCopy) {

            JNU_ReleaseStringPlatformChars(env, path, p);

        }

    }

}

/*

 * Class:     sun_tools_attach_VirtualMachineImpl

 * Method:    close

 * Signature: (I)V

 */

JNIEXPORT void JNICALL Java_sun_tools_attach_VirtualMachineImpl_close

  (JNIEnv *env, jclass cls, jint fd)

{

    int res;

    shutdown(fd, SHUT_RDWR);

    RESTARTABLE(close(fd), res);

}

/*

 * Class:     sun_tools_attach_VirtualMachineImpl

 * Method:    read

 * Signature: (I[BI)I

 */

JNIEXPORT jint JNICALL Java_sun_tools_attach_VirtualMachineImpl_read

  (JNIEnv *env, jclass cls, jint fd, jbyteArray ba, jint off, jint baLen)

{

    unsigned char buf[128];

    size_t len = sizeof(buf);

    ssize_t n;

    size_t remaining = (size_t)(baLen - off);

    if (len > remaining) {

        len = remaining;

    }

    RESTARTABLE(read(fd, buf, len), n);

    if (n == -1) {

        JNU_ThrowIOExceptionWithLastError(env, "read");

    } else {

        if (n == 0) {

            n = -1;     // EOF

        } else {

            (*env)->SetByteArrayRegion(env, ba, off, (jint)n, (jbyte *)(buf));

        }

    }

    return n;

}

/*

 * Class:     sun_tools_attach_VirtualMachineImpl

 * Method:    write

 * Signature: (I[B)V

 */

JNIEXPORT void JNICALL Java_sun_tools_attach_VirtualMachineImpl_write

  (JNIEnv *env, jclass cls, jint fd, jbyteArray ba, jint off, jint bufLen)

{

    size_t remaining = bufLen;

    do {

        unsigned char buf[128];

        size_t len = sizeof(buf);

        int n;

        if (len > remaining) {

            len = remaining;

        }

        (*env)->GetByteArrayRegion(env, ba, off, len, (jbyte *)buf);

        RESTARTABLE(write(fd, buf, len), n);

        if (n > 0) {

            off += n;

            remaining -= n;

        } else {

            JNU_ThrowIOExceptionWithLastError(env, "write");

            return;

        }

    } while (remaining > 0);

}