我正在尝试使用libzbc与C库jnr-ffi进行交互。 第一个函数调用 zbc_open 工作并返回指向打开设备的指针。然后，对 zbc_get_device_info 的下一次调用会导致JVM崩溃。
原因是什么？怎么解决？ 我认为错误是在zbc或我的传递参数的界面中，但是搜索JNR的任何文档都没有在google中产生任何有用的结果。如果我省略了结构中的数组部分，崩溃也会发生。
我使用jnr-fuse项目作为起点，因为我的目标是编写一个FUSE文件系统。
C函数：
void zbc_set_log_level( char *log_level )
int zbc_open (const char *filename, int flags, struct zbc_device **dev)
void zbc_get_device_info( struct zbc_device *dev, struct zbc_device_info * info)
C结构zbc_device_info ：
enum zbc_dev_type zbd_type
enum zbc_dev_model zbd_model
char zbd_vendor_id [ZBC_DEVICE_INFO_LENGTH]
uint32_t zbd_flags
uint64_t zbd_sectors
uint32_t zbd_lblock_size
uint64_t zbd_lblocks
uint32_t zbd_pblock_size
uint64_t zbd_pblocks
uint64_t zbd_max_rw_sectors
uint32_t zbd_opt_nr_open_seq_pref
uint32_t zbd_opt_nr_non_seq_write_seq_pref
uint32_t zbd_max_nr_open_seq_req
JNR界面：
public interface zbc{
public void zbc_set_log_level(String level);
public int zbc_open(String filename,int flags, PointerByReference p);
public void zbc_get_device_info(Pointer dev,zbc_device_info info);
}
public static class zbc_device_info extends Struct {
int zbd_type;
int zbd_model;
byte zbd_vendor_id[]=new byte[32];
u_int32_t zbd_flags;
u_int64_t zbd_sectors;
u_int32_t zbd_lblock_size;
u_int64_t zbd_lblocks;
u_int32_t zbd_pblock_size;
u_int64_t zbd_pblocks;
u_int64_t zbd_max_rw_sectors;
u_int32_t zbd_opt_nr_open_seq_pref;
u_int32_t zbd_opt_nr_non_seq_write_seq_pref;
u_int32_t zbd_max_nr_open_seq_pref;
protected zbc_device_info(Runtime runtime) {
super(runtime);
}
}
主要功能：
public static void main(String[] args) {
zbc z = LibraryLoader.create(zbc.class).load("zbc");
Runtime runtime=Runtime.getRuntime(z);
z.zbc_set_log_level("debug");
PointerByReference pr = new PointerByReference();
int ret=z.zbc_open("/temp/test.img", IO_RDWR,pr);
zbc_device_info info=new zbc_device_info(runtime);
z.zbc_get_device_info(pr.getValue(),info);
}
JVM崩溃：
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00007fa794300c70, pid=29106, tid=0x00007fa7bd4a4700
#
# JRE version: OpenJDK Runtime Environment (8.0_131-b11) (build 1.8.0_131-8u131-b11-2ubuntu1.16.04.3-b11)
# Java VM: OpenJDK 64-Bit Server VM (25.131-b11 mixed mode linux-amd64 compressed oops)
# Problematic frame:
# C [jffi6917022509387828651.so+0x5c70] jffi_releaseArrays+0x60
#
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /home/mmmm/jnr-fuse/hs_err_pid29106.log
#
# If you would like to submit a bug report, please visit:
# http://bugreport.java.com/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#
答案 0 :(得分：1)
Struct的声明不正确。字段未声明。尝试使用以下声明：
package com.github.goto1134.libzbc;
import jnr.ffi.Runtime;
import jnr.ffi.Struct;
import jnr.ffi.util.EnumMapper.IntegerEnum;
public class zbc_device_info
extends Struct {
public static final int ZBC_DEVICE_INFO_LENGTH = 32;
public final Enum<zbc_dev_type> zbd_type = new Enum<>(zbc_dev_type.class);
public final Enum<zbc_dev_model> zbd_model = new Enum<>(zbc_dev_model.class);
public final UTF8String zbd_vendor_id = new UTF8String(ZBC_DEVICE_INFO_LENGTH);
public final Unsigned32 zbd_flags = new Unsigned32();
public final Unsigned64 zbd_sectors = new Unsigned64();
public final Unsigned32 zbd_lblock_size = new Unsigned32();
public final Unsigned64 zbd_lblocks = new Unsigned64();
public final Unsigned32 zbd_pblock_size = new Unsigned32();
public final Unsigned64 zbd_pblocks = new Unsigned64();
public final Unsigned64 zbd_max_rw_sectors = new Unsigned64();
public final Unsigned32 zbd_opt_nr_open_seq_pref = new Unsigned32();
public final Unsigned32 zbd_opt_nr_non_seq_write_seq_pref = new Unsigned32();
public final Unsigned32 zbd_max_nr_open_seq_req = new Unsigned32();
protected zbc_device_info(Runtime runtime) {
super(runtime);
}
public enum zbc_dev_type
implements IntegerEnum {
/**
* Unknown drive type.
*/
ZBC_DT_UNKNOWN(0x00),
/**
* Zoned block device (for kernels supporting ZBC/ZAC).
*/
ZBC_DT_BLOCK(0x01),
/**
* SCSI device.
*/
ZBC_DT_SCSI(0x02),
/**
* ATA device.
*/
ZBC_DT_ATA(0x03),
/**
* Fake device (emulation mode).
*/
ZBC_DT_FAKE(0x04);
private final int value;
zbc_dev_type(int value) {
this.value = value;
}
@Override
public int intValue() {
return value;
}
}
public enum zbc_dev_model
implements IntegerEnum {
/**
* Unknown drive model.
*/
ZBC_DM_DRIVE_UNKNOWN(0x00),
/**
* Host-aware drive model: the device type/signature is 0x00
* and the ZONED field of the block device characteristics VPD
* page B1h is 01b.
*/
ZBC_DM_HOST_AWARE(0x01),
/**
* Host-managed drive model: the device type/signature is 0x14/0xabcd.
*/
ZBC_DM_HOST_MANAGED(0x02),
/**
* Drive-managed drive model: the device type/signature is 0x00
* and the ZONED field of the block device characteristics VPD
* page B1h is 10b.
*/
ZBC_DM_DEVICE_MANAGED(0x03),
/**
* Standard block device: the device type/signature is 0x00
* and the ZONED field of the block device characteristics VPD
* page B1h is 00b.
*/
ZBC_DM_STANDARD(0x04);
private final int value;
zbc_dev_model(int value) {
this.value = value;
}
@Override
public int intValue() {
return value;
}
}
}
在hs日志中有一个调用堆栈导致程序崩溃。你能提供吗？