我从一个客户端收到了一个.so android库,我必须将其集成到我的Xamarin Forms项目中。该库帮助应用程序连接到物联网设备。由于库方法具有以下签名,我决定编写一个java包装器来简化参数并创建一个aar文件。之后,我原生地绑定了aar,并将其用作我的项目中的dll。
需要注意的是,Xamarin中的问题仅在编译目标>10.否则,效果很好。我的猜测是,最新的非SDK接口更新破坏了应用程序。
库头:
public static native int ReadParams(String token, StringBuilder serial, StringBuilder ssid, StringBuilder password, StringBuilder sensor, Integer keepAlive);
问题是:当从本地android应用程序中调用该方法时,该方法运行良好,但由于Xamarin Forms的以下错误而崩溃。崩溃发生在Java包装器的下面一行。
崩溃线:
StringBuilder strSerial = new StringBuilder();
StringBuilder strssid = new StringBuilder();
StringBuilder strpassword = new StringBuilder();
StringBuilder strsensor = new StringBuilder();
Integer keepAlive = new Integer(0);
//Crash on below line
int response = EPM002Lib.ReadParams(token, strSerial, strssid, strpassword, strsensor, keepAlive);
堆叠竞赛:
---托管Java.Lang.IncompatibleClassChangeError堆栈跟踪结束---Java.Lang.NoSuchFieldError:no"我"字段";值";在课堂上";Ljava/lang/Integer"或其超类com.esong.lib.EPM002Lib.ReadParams(本机方法)com.sensorwa.config.configdemo.SquareSdkhelper.ReadParams(SquareSdkhelper.java:32)
我知道更多关于EPM002Lib.ReadParams参数内部功能的信息会有所帮助,然而,该库似乎可以与本机android应用程序一起使用(即使是针对android 10编译的)。请随时询问更多信息或提供建议。感谢的帮助
我使用Android Aarch64编译器编译了这个文件:
#include <jni.h>
int access_field(JNIEnv *env, jobject obj) {
jclass cls_Integer = (*env)->FindClass(env, "Ljava/lang/Integer;");
jfieldID fid_Integer_value = (*env)->GetFieldID(env, cls_Integer, "value", "I");
return (*env)->GetIntField(env, obj, fid_Integer_value);
}
int access_method(JNIEnv *env, jobject obj) {
jclass cls_Integer = (*env)->FindClass(env, "Ljava/lang/Integer;");
jmethodID mid_Integer_value = (*env)->GetMethodID(env, cls_Integer, "intValue", "()I");
return (*env)->CallIntMethod(env, obj, mid_Integer_value);
}
这导致access_field
的以下代码:
int access_field(JNIEnv *env, jobject obj) {
0: d10103ff sub sp, sp, #0x40
4: a9037bfd stp x29, x30, [sp,#48]
8: 9100c3fd add x29, sp, #0x30
c: 90000008 adrp x8, 0 <access_field>
10: 91000108 add x8, x8, #0x0
14: 90000002 adrp x2, 0 <access_field>
18: 91000042 add x2, x2, #0x0
1c: 90000003 adrp x3, 0 <access_field>
20: 91000063 add x3, x3, #0x0
24: f81f83a0 stur x0, [x29,#-8]
28: f81f03a1 stur x1, [x29,#-16]
jclass cls_Integer = (*env)->FindClass(env, "Ljava/lang/Integer;");
2c: f85f83a9 ldur x9, [x29,#-8]
30: f9400129 ldr x9, [x9]
34: f9401929 ldr x9, [x9,#48]
38: f85f83a0 ldur x0, [x29,#-8]
3c: aa0803e1 mov x1, x8
40: f90007e2 str x2, [sp,#8]
44: f90003e3 str x3, [sp]
48: d63f0120 blr x9
4c: f9000fe0 str x0, [sp,#24]
jfieldID fid_Integer_value = (*env)->GetFieldID(env, cls_Integer, "value", "I");
50: f85f83a8 ldur x8, [x29,#-8]
54: f9400108 ldr x8, [x8]
58: f9417908 ldr x8, [x8,#752]
5c: f85f83a0 ldur x0, [x29,#-8]
60: f9400fe1 ldr x1, [sp,#24]
64: f94007e2 ldr x2, [sp,#8]
68: f94003e3 ldr x3, [sp]
6c: d63f0100 blr x8
70: f9000be0 str x0, [sp,#16]
return (*env)->GetIntField(env, obj, fid_Integer_value);
74: f85f83a8 ldur x8, [x29,#-8]
78: f9400108 ldr x8, [x8]
7c: f9419108 ldr x8, [x8,#800]
80: f85f83a0 ldur x0, [x29,#-8]
84: f85f03a1 ldur x1, [x29,#-16]
88: f9400be2 ldr x2, [sp,#16]
8c: d63f0100 blr x8
90: a9437bfd ldp x29, x30, [sp,#48]
94: 910103ff add sp, sp, #0x40
98: d65f03c0 ret
}
对于access_method
:
int access_method(JNIEnv *env, jobject obj) {
9c: d10103ff sub sp, sp, #0x40
a0: a9037bfd stp x29, x30, [sp,#48]
a4: 9100c3fd add x29, sp, #0x30
a8: 90000008 adrp x8, 0 <access_field>
ac: 91000108 add x8, x8, #0x0
b0: 90000002 adrp x2, 0 <access_field>
b4: 91000042 add x2, x2, #0x0
b8: 90000003 adrp x3, 0 <access_field>
bc: 91000063 add x3, x3, #0x0
c0: f81f83a0 stur x0, [x29,#-8]
c4: f81f03a1 stur x1, [x29,#-16]
jclass cls_Integer = (*env)->FindClass(env, "Ljava/lang/Integer;");
c8: f85f83a9 ldur x9, [x29,#-8]
cc: f9400129 ldr x9, [x9]
d0: f9401929 ldr x9, [x9,#48]
d4: f85f83a0 ldur x0, [x29,#-8]
d8: aa0803e1 mov x1, x8
dc: f90007e2 str x2, [sp,#8]
e0: f90003e3 str x3, [sp]
e4: d63f0120 blr x9
e8: f9000fe0 str x0, [sp,#24]
jmethodID mid_Integer_value = (*env)->GetMethodID(env, cls_Integer, "intValue", "()I");
ec: f85f83a8 ldur x8, [x29,#-8]
f0: f9400108 ldr x8, [x8]
f4: f9408508 ldr x8, [x8,#264]
f8: f85f83a0 ldur x0, [x29,#-8]
fc: f9400fe1 ldr x1, [sp,#24]
100: f94007e2 ldr x2, [sp,#8]
104: f94003e3 ldr x3, [sp]
108: d63f0100 blr x8
10c: f9000be0 str x0, [sp,#16]
return (*env)->CallIntMethod(env, obj, mid_Integer_value);
110: f85f83a8 ldur x8, [x29,#-8]
114: f9400108 ldr x8, [x8]
118: f940c508 ldr x8, [x8,#392]
11c: f85f83a0 ldur x0, [x29,#-8]
120: f85f03a1 ldur x1, [x29,#-16]
124: f9400be2 ldr x2, [sp,#16]
128: d63f0100 blr x8
12c: a9437bfd ldp x29, x30, [sp,#48]
130: 910103ff add sp, sp, #0x40
134: d65f03c0 ret
主要区别在于ldr x8
调用中使用的偏移量。这些是JNIEnv
内部函数指针表的偏移量,更具体地说:
GetFieldID
位于偏移752处GetIntField
处于偏移800GetMethodID
处于偏移264- CCD_ 8处于偏移392处
另一个区别是传递给GetIntField
或GetMethodID
的签名,在链接器时注入。我转储的对象文件还没有链接,所以那里有伪指令。它是第四个自变量,因此它在寄存器x3
中传递。
因此,总结一下,您需要执行以下操作:
- 在库中的某个位置查找字符串
"()I"
的地址或将其添加到字符串表中 - 您需要找到访问
java.lang.Integer#value
的所有位置 - 在
blr x8
调用之前替换ldr x8
中的两个函数指针偏移量(752->264;800->392) - 查找更改
x3
的代码,并使其指向"()I"
祝你好运!
您所依赖的是本不应该依赖的实现细节。
现在它坏了,你可以保留两块。