/*
 * Copyright 2007 - 2018 ETH Zuerich, CISD and SIS.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include <time.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <jni.h>

/* Types of links. Keep in sync with Java enum. */
#define REGULAR_FILE 0
#define DIRECTORY 1
#define SYMLINK 2
#define OTHER 3

/* Field name for nano second precission of file stat times. */
#ifdef __MACH__
#define ST_ATIME_NANO st_atimespec.tv_nsec
#define ST_MTIME_NANO st_mtimespec.tv_nsec
#define ST_CTIME_NANO st_ctimespec.tv_nsec
#else
#define ST_ATIME_NANO st_atim.tv_nsec
#define ST_MTIME_NANO st_mtim.tv_nsec
#define ST_CTIME_NANO st_ctim.tv_nsec
#endif

#ifndef __STAT
#define __STAT stat
#endif

#ifndef __LSTAT
#define __LSTAT lstat
#endif

/* Global references. */
jclass stringClass;
jclass passwordClass;
jmethodID passwordConstructorID;
jclass groupClass;
jmethodID groupConstructorID;
jclass statClass;
jmethodID statConstructorID;
jboolean statConstructorHasNanos;

/* 
 * Error and Exception Handling 
 */
 
#define THROWEXCEPTION(className,args) {                                    \
    jclass     jc;                                                          \
    jmethodID  jm;                                                          \
    jobject    ex;                                                          \
    jc = (*env)->FindClass(env, (className));                               \
    if (jc == NULL) {                                                       \
        return JNI_FALSE;                                                   \
    }                                                                       \
    jm = (*env)->GetMethodID(env, jc, "<init>", "(Ljava/lang/String;)V");   \
    if (jm == NULL) {                                                       \
        printf("THROWEXCEPTION FATAL ERROR: GetMethodID failed\n");         \
        return JNI_FALSE;                                                   \
    }                                                                       \
    ex = (*env)->NewObjectA (env, jc, jm, (jvalue*)(args));                 \
    if (ex == NULL) {                                                       \
        printf("THROWEXCEPTION FATAL ERROR:  %s: Creation failed\n", (className)); \
        return JNI_FALSE;                                                   \
    }                                                                       \
    if ((*env)->Throw(env, (jthrowable)ex) < 0) {                           \
        printf("THROWEXCEPTION FATAL ERROR:  %s: Throw failed\n", (className));    \
        return JNI_FALSE;                                                   \
    }                                                                       \
    return JNI_TRUE;                                                        \
}

/*
 *  Routine to raise particular Java exceptions from C
 */
static jboolean
jni_error_class
    (JNIEnv *env, const char *message, const char *className)
{
    char *args[2];
    jstring str = (*env)->NewStringUTF(env, message);
    args[0] = (char *)str;
    args[1] = 0;

    THROWEXCEPTION(className, args);
} /* end jni_error_class() */

/*
 *  A NULL argument in an HDF5 call
 *  Create and throw an 'NullPointerException'
 *
 *  Note:  This routine never returns from the 'throw',
 *  and the Java native method immediately raises the
 *  exception.
 */
jboolean null_pointer_exception(JNIEnv *env, const char *functName)
{
    return jni_error_class(env, functName, "java/lang/NullPointerException");
} /* end null_pointer_exception() */

/*
 *  A fatal error in a JNI call
 *  Create and throw an 'InternalError'
 *
 *  Note:  This routine never returns from the 'throw',
 *  and the Java native method immediately raises the
 *  exception.
 */
jboolean internal_error(JNIEnv *env, const char *functName)
{
    return jni_error_class(env, functName, "java/lang/InternalError");
} /* end iternal_error() */


/*
 * End Error and Exception Handling 
 */

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_init
  (JNIEnv *env, jclass clss)
{
    stringClass = (*env)->FindClass(env, "java/lang/String");
    if (stringClass == NULL) /* Really shouldn't happen, will throw NoClassDefFoundError. */
    {
        return -1;
    }
    stringClass = (*env)->NewGlobalRef(env, stringClass);
    passwordClass = (*env)->FindClass(env, "ch/systemsx/cisd/base/unix/Unix$Password");
    if (passwordClass == NULL) /* Really shouldn't happen, will throw NoClassDefFoundError. */
    {
        return -1;
    }
    passwordClass = (*env)->NewGlobalRef(env, passwordClass);
    passwordConstructorID = (*env)->GetMethodID(env, passwordClass, "<init>", "(Ljava/lang/String;Ljava/lang/String;IILjava/lang/String;Ljava/lang/String;Ljava/lang/String;)V");
    if (passwordConstructorID == NULL) /* Really shouldn't happen, will throw NoSuchMethodError. */
    {
        return -1;
    }
    groupClass = (*env)->FindClass(env, "ch/systemsx/cisd/base/unix/Unix$Group");
    if (groupClass == NULL) /* Really shouldn't happen, will throw NoClassDefFoundError. */
    {
        return -1;
    }
    groupClass = (*env)->NewGlobalRef(env, groupClass);
    groupConstructorID = (*env)->GetMethodID(env, groupClass, "<init>", "(Ljava/lang/String;Ljava/lang/String;I[Ljava/lang/String;)V");
    if (groupConstructorID == NULL) /* Really shouldn't happen, will throw NoSuchMethodError. */
    {
        return -1;
    }
    statClass = (*env)->FindClass(env, "ch/systemsx/cisd/base/unix/Unix$Stat");
    if (statClass == NULL) /* Really shouldn't happen, will throw NoClassDefFoundError. */
    {
        return -1;
    }
    statClass = (*env)->NewGlobalRef(env, statClass);
    statConstructorHasNanos = JNI_TRUE;
    statConstructorID = (*env)->GetMethodID(env, statClass, "<init>", "(JJSBIIIJJJJJJJJI)V");
    if (statConstructorID == NULL) /* We have an old Java class without the "microsecond constructor". */
    {
        (*env)->ExceptionClear(env);
	    statConstructorHasNanos = JNI_FALSE;
	    statConstructorID = (*env)->GetMethodID(env, statClass, "<init>", "(JJSBIIIJJJJJI)V");
	    if (statConstructorID == NULL) /* Really shouldn't happen, will throw NoSuchMethodError. */
	    {
	        return -1;
	    }
	}
    return 0;
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_link
  (JNIEnv *env, jclass clss, jstring filename, jstring linktarget)
{
    const char* pfilename;
    const char* plinktarget;
    int retval;

    pfilename = (char *)(*env)->GetStringUTFChars(env, filename, NULL);
    plinktarget = (char *)(*env)->GetStringUTFChars(env, linktarget, NULL);

    retval = link(pfilename, plinktarget);
    if (retval < 0)
    {
        retval = -errno;
    }

    (*env)->ReleaseStringUTFChars(env, filename, pfilename);
    (*env)->ReleaseStringUTFChars(env, linktarget, plinktarget);

   return retval;
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_symlink
  (JNIEnv *env, jclass clss, jstring filename, jstring linktarget)
{
    const char* pfilename;
    const char* plinktarget;
    int retval;

    pfilename = (char *)(*env)->GetStringUTFChars(env, filename, NULL);
    plinktarget = (char *)(*env)->GetStringUTFChars(env, linktarget, NULL);

    retval = symlink(pfilename, plinktarget);
    if (retval < 0)    { 
        retval = -errno; 
    }

    (*env)->ReleaseStringUTFChars(env, filename, pfilename);
    (*env)->ReleaseStringUTFChars(env, linktarget, plinktarget);

   return retval;
}

/* Function pointer for stat function calls. */
typedef int (*stat_func_ptr)(const char *path, struct __STAT *buf);

jobject call_stat(JNIEnv *env, jclass clss, jstring filename, stat_func_ptr statf)
{
    const char* pfilename;
    struct __STAT s;
    jobject result;
    int retval;
    jbyte type;

    pfilename = (char *) (*env)->GetStringUTFChars(env, filename, NULL);
    retval = statf(pfilename, &s);
    (*env)->ReleaseStringUTFChars(env, filename, pfilename);
    if (retval < 0)
    {
        return NULL;
    } else
    {
        if (S_ISLNK(s.st_mode))
        {
            type = SYMLINK;
        } else if (S_ISDIR(s.st_mode))
        {
            type = DIRECTORY;
        } else if (S_ISREG(s.st_mode))
        {
            type = REGULAR_FILE;
        } else
        {
            type = OTHER;
        }
        if (statConstructorHasNanos)
        {
            result = (*env)->NewObject(env, statClass, statConstructorID, (jlong) s.st_dev, (jlong) s.st_ino, 
                       (jshort) (s.st_mode & 07777), (jbyte) type, (jint) s.st_nlink, 
                       (jint) s.st_uid, (jint) s.st_gid, (jlong) s.st_atime, (jlong) s.ST_ATIME_NANO, 
                       (jlong) s.st_mtime, (jlong) s.ST_MTIME_NANO, (jlong) s.st_ctime, (jlong) s.ST_CTIME_NANO, 
                       (jlong) s.st_size, (jlong) s.st_blocks, (jint) s.st_blksize);
        } else
        {
            result = (*env)->NewObject(env, statClass, statConstructorID, (jlong) s.st_dev, (jlong) s.st_ino, 
                       (jshort) (s.st_mode & 07777), (jbyte) type, (jint) s.st_nlink, 
                       (jint) s.st_uid, (jint) s.st_gid, (jlong) s.st_atime, (jlong) s.st_mtime, 
                       (jlong) s.st_ctime, (jlong) s.st_size, (jlong) s.st_blocks, (jint) s.st_blksize);
        }
        return result;
    }
}

JNIEXPORT jobject JNICALL Java_ch_systemsx_cisd_base_unix_Unix_stat(JNIEnv *env, jclass clss, jstring filename)
{
    return call_stat(env, clss, filename, &__STAT);
}

JNIEXPORT jobject JNICALL Java_ch_systemsx_cisd_base_unix_Unix_lstat(JNIEnv *env, jclass clss, jstring filename)
{
    return call_stat(env, clss, filename, &__LSTAT);
}

JNIEXPORT jstring JNICALL Java_ch_systemsx_cisd_base_unix_Unix_readlink(JNIEnv *env, jclass clss, jstring linkname, jint linkvallen)
{
    const char* plinkname;
    char plinkvalue[linkvallen + 1];
    int retval;
	
    plinkname = (char *)(*env)->GetStringUTFChars(env, linkname, NULL);
    retval = readlink(plinkname, plinkvalue, linkvallen);
    (*env)->ReleaseStringUTFChars(env, linkname, plinkname);
    if (retval < 0)
    {
		    return NULL;
    } else
    {
        plinkvalue[linkvallen] = '\0';
        return (*env)->NewStringUTF(env, plinkvalue);
    }
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_chmod(JNIEnv *env, jclass clss, jstring linkname, jshort mode)
{
    const char* plinkname;
    int retval;
	
    plinkname = (char *)(*env)->GetStringUTFChars(env, linkname, NULL);
    retval = chmod(plinkname, mode);
    (*env)->ReleaseStringUTFChars(env, linkname, plinkname);
    if (retval < 0)
    {
		    return -errno;
    } else
    {
        return 0;
    }
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_chown(JNIEnv *env, jclass clss, jstring linkname, jint uid, jint gid)
{
    const char* plinkname;
    int retval;
	
    plinkname = (char *)(*env)->GetStringUTFChars(env, linkname, NULL);
    retval = chown(plinkname, uid, gid);
    (*env)->ReleaseStringUTFChars(env, linkname, plinkname);
    if (retval < 0)
    {
		    return -errno;
    } else
    {
        return 0;
    }
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_lchown(JNIEnv *env, jclass clss, jstring linkname, jint uid, jint gid)
{
    const char* plinkname;
    int retval;
	
    plinkname = (char *)(*env)->GetStringUTFChars(env, linkname, NULL);
    retval = lchown(plinkname, uid, gid);
    (*env)->ReleaseStringUTFChars(env, linkname, plinkname);
    if (retval < 0)
    {
		    return -errno;
    } else
    {
        return 0;
    }
}

JNIEXPORT jstring JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getuser(JNIEnv *env, jclass clss, jint uid)
{
    struct passwd *pw;
	
    pw = getpwuid(uid);
    if (pw == NULL)
    {
		    return NULL;
    } else
    {
        return (*env)->NewStringUTF(env, pw->pw_name);
    }
}

JNIEXPORT jstring JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getgroup(JNIEnv *env, jclass clss, jint gid)
{
    struct group *gp;
	
    gp = getgrgid(gid);
    if (gp == NULL)
    {
		    return NULL;
    } else
    {
        return (*env)->NewStringUTF(env, gp->gr_name);
    }
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getuid__(JNIEnv *env, jclass clss)
{
    return getuid();
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_geteuid(JNIEnv *env, jclass clss)
{
    return geteuid();
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getuid__Ljava_lang_String_2(JNIEnv *env, jclass clss, jstring user)
{
    const char* puser;
    struct passwd *pw;
	
    puser = (char *)(*env)->GetStringUTFChars(env, user, NULL);
    pw = getpwnam(puser);
    (*env)->ReleaseStringUTFChars(env, user, puser);
    if (pw == NULL)
    {
		    return -errno;
    } else
    {
        return pw->pw_uid;
    }
}

JNIEXPORT jobject JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getpwnam(JNIEnv *env, jclass clss, jstring user)
{
    const char* puser;
    struct passwd *pw;
    jstring passwd;
    jstring fullname;
    jstring homedir;
    jstring shell;
    jobject result;
	
    puser = (char *)(*env)->GetStringUTFChars(env, user, NULL);
    pw = getpwnam(puser);
    (*env)->ReleaseStringUTFChars(env, user, puser);
    if (pw == NULL)
    {
		    return NULL;
    } else
    {
        passwd = (*env)->NewStringUTF(env, pw->pw_passwd);
        fullname = (*env)->NewStringUTF(env, pw->pw_gecos);
        homedir = (*env)->NewStringUTF(env, pw->pw_dir);
        shell = (*env)->NewStringUTF(env, pw->pw_shell);
        result = (*env)->NewObject(env, passwordClass, passwordConstructorID, user, passwd, pw->pw_uid, pw->pw_gid, fullname, homedir, shell);
        return result;
    }
}

JNIEXPORT jobject JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getpwuid(JNIEnv *env, jclass clss, jint uid)
{
    struct passwd *pw;
    jstring user;
    jstring passwd;
    jstring fullname;
    jstring homedir;
    jstring shell;
    jobject result;
	
    pw = getpwuid(uid);
    if (pw == NULL)
    {
		    return NULL;
    } else
    {
        user = (*env)->NewStringUTF(env, pw->pw_name);
        passwd = (*env)->NewStringUTF(env, pw->pw_passwd);
        fullname = (*env)->NewStringUTF(env, pw->pw_gecos);
        homedir = (*env)->NewStringUTF(env, pw->pw_dir);
        shell = (*env)->NewStringUTF(env, pw->pw_shell);
        result = (*env)->NewObject(env, passwordClass, passwordConstructorID, user, passwd, pw->pw_uid, pw->pw_gid, fullname, homedir, shell);
        return result;
    }
}

JNIEXPORT jobjectArray JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getgrnam(JNIEnv *env, jclass clss, jstring group)
{
    const char* pgroup;
    struct group *gr;
    jstring grouppwd;
    jobject result;
    jobjectArray members;
    int i;
	
    pgroup = (char *)(*env)->GetStringUTFChars(env, group, NULL);
    gr = getgrnam(pgroup);
    (*env)->ReleaseStringUTFChars(env, group, pgroup);
    if (gr == NULL)
    {
		    return NULL;
    } else
    {
        grouppwd = (*env)->NewStringUTF(env, gr->gr_passwd);
        /* Count group members. */
        for (i = 0; (gr->gr_mem)[i] != NULL; ++i);
        members = (*env)->NewObjectArray(env, i, stringClass, NULL);
        for (i = 0; (gr->gr_mem)[i] != NULL; ++i)
        {
            (*env)->SetObjectArrayElement(env, members, i, (*env)->NewStringUTF(env, (gr->gr_mem)[i]));
        }
        result = (*env)->NewObject(env, groupClass, groupConstructorID, group, grouppwd, gr->gr_gid, members); 
        return result;
    }
}

JNIEXPORT jobjectArray JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getgrgid(JNIEnv *env, jclass clss, jint gid)
{
    struct group *gr;
    jstring group;
    jstring grouppwd;
    jobject result;
    jobjectArray members;
    int i;
	
    gr = getgrgid(gid);
    if (gr == NULL)
    {
		    return NULL;
    } else
    {
        group = (*env)->NewStringUTF(env, gr->gr_name);
        grouppwd = (*env)->NewStringUTF(env, gr->gr_passwd);
        /* Count group members. */
        for (i = 0; (gr->gr_mem)[i] != NULL; ++i);
        members = (*env)->NewObjectArray(env, i, stringClass, NULL);
        for (i = 0; (gr->gr_mem)[i] != NULL; ++i)
        {
            (*env)->SetObjectArrayElement(env, members, i, (*env)->NewStringUTF(env, (gr->gr_mem)[i]));
        }
        result = (*env)->NewObject(env, groupClass, groupConstructorID, group, grouppwd, gr->gr_gid, members); 
        return result;
    }
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getgid__(JNIEnv *env, jclass clss)
{
    return getgid();
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getegid(JNIEnv *env, jclass clss)
{
    return getegid();
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getgid__Ljava_lang_String_2(JNIEnv *env, jclass clss, jstring group)
{
    const char* pgroup;
    struct group *gr;
	
    pgroup = (char *)(*env)->GetStringUTFChars(env, group, NULL);
    gr = getgrnam(pgroup);
    (*env)->ReleaseStringUTFChars(env, group, pgroup);
    if (gr == NULL)
    {
		    return -errno;
    } else
    {
        return gr->gr_gid;
    }
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_getpid(JNIEnv *env, jclass clss)
{
    return getpid();
}

JNIEXPORT jstring JNICALL Java_ch_systemsx_cisd_base_unix_Unix_strerror__I(JNIEnv *env, jclass clss, jint errnum)
{
    return (*env)->NewStringUTF(env, strerror(errnum < 0 ? -errnum : errnum));
}

JNIEXPORT jstring JNICALL Java_ch_systemsx_cisd_base_unix_Unix_strerror__(JNIEnv *env, jclass clss)
{
    return (*env)->NewStringUTF(env, strerror(errno));
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_lutimes
  (JNIEnv *env, jclass clss, jstring filename, jlong accessTimeSecs, jlong accessTimeMicroSecs, jlong modificationTimeSecs, jlong modificationTimeMicroSecs)
{
    const char* pfilename;
    struct timeval times[2];
    int retval;

    pfilename = (char *)(*env)->GetStringUTFChars(env, filename, NULL);
    times[0].tv_sec = accessTimeSecs;
    times[0].tv_usec = accessTimeMicroSecs;
    times[1].tv_sec = modificationTimeSecs;
    times[1].tv_usec = modificationTimeMicroSecs;

    retval = lutimes(pfilename, times);
    if (retval < 0)
    {
        retval = -errno;
    }

    (*env)->ReleaseStringUTFChars(env, filename, pfilename);

   return retval;
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_utimes
  (JNIEnv *env, jclass clss, jstring filename, jlong accessTimeSecs, jlong accessTimeMicroSecs, jlong modificationTimeSecs, jlong modificationTimeMicroSecs)
{
    const char* pfilename;
    struct timeval times[2];
    int retval;

    pfilename = (char *)(*env)->GetStringUTFChars(env, filename, NULL);
    times[0].tv_sec = accessTimeSecs;
    times[0].tv_usec = accessTimeMicroSecs;
    times[1].tv_sec = modificationTimeSecs;
    times[1].tv_usec = modificationTimeMicroSecs;

    retval = utimes(pfilename, times);
    if (retval < 0)
    {
        retval = -errno;
    }

    (*env)->ReleaseStringUTFChars(env, filename, pfilename);

   return retval;
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_clock_1gettime
  (JNIEnv *env, jclass clss, jlongArray time)
{
    struct timespec spec;
    jlong   *timeP;
    jboolean isCopy;
    int retval;
    
    if (time == NULL) 
    {
        null_pointer_exception(env, "clock_gettime: time is NULL");
    } /* end if */
    timeP = (jlong*)(*env)->GetPrimitiveArrayCritical(env, time, &isCopy);
    if (timeP == NULL) 
    {
        internal_error(env, "clock_gettime: time not pinned");
    } /* end if */


    retval = clock_gettime(CLOCK_REALTIME, &spec);
    if (retval < 0)
    {
        retval = -errno;
    } else
    {
	    timeP[0] = spec.tv_sec;
	    timeP[1] = spec.tv_nsec;
	}

    (*env)->ReleasePrimitiveArrayCritical(env, time, timeP, 0);    
    
    return retval;
}

int clock_gettime2(int clk_id, struct timespec* t) {
    struct timeval now;
    
    int rv = gettimeofday(&now, NULL);
    if (rv) 
    {
        return rv;
    }
    t->tv_sec  = now.tv_sec;
    t->tv_nsec = now.tv_usec * 1000;
    
    return 0;
}

JNIEXPORT jint JNICALL Java_ch_systemsx_cisd_base_unix_Unix_clock_1gettime2
  (JNIEnv *env, jclass clss, jlongArray time)
{
    struct timespec spec;
    jlong   *timeP;
    jboolean isCopy;
    int retval;
    
    if (time == NULL) 
    {
        null_pointer_exception(env, "clock_gettime: time is NULL");
    } /* end if */
    timeP = (jlong*)(*env)->GetPrimitiveArrayCritical(env, time, &isCopy);
    if (timeP == NULL) 
    {
        internal_error(env, "clock_gettime: time not pinned");
    } /* end if */


    retval = clock_gettime2(CLOCK_REALTIME, &spec);
    if (retval < 0)
    {
        retval = -errno;
    } else
    {
	    timeP[0] = spec.tv_sec;
	    timeP[1] = spec.tv_nsec;
	}

    (*env)->ReleasePrimitiveArrayCritical(env, time, timeP, 0);    
    
    return retval;
}