上一篇见iOS常见Crash案例总结
iOS Crash捕获
iOS端的crash分为两类，一类是NSException异常，另外一类是Signal信号异常。这两类异常我们都可以通过注册相关函数来捕获。
Crash种类
1、对于unrecognized selector sent to instance找不到方法iOS系统抛出异常崩溃，给NSObject添加一个分类，实现消息转发的几个方法
当无实现的方法时消息转发流程.jpeg
利用runtime消息转发处理未实现的方法crash，代码如下：
#import <objc/runtime.h>
static NSString *_errorFunctionName;
void dynamicMethodIMP(id self,SEL _cmd) {}
static inline void change_method(Class _originalClass ,SEL _originalSel,Class _newClass ,SEL _newSel) {
Method methodOriginal = class_getInstanceMethod(_originalClass, _originalSel);
Method methodNew = class_getInstanceMethod(_newClass, _newSel);
method_exchangeImplementations(methodOriginal, methodNew);
}
@implementation NSObject(UnRecognized)
+ (void)load {
change_method([self class], @selector(methodSignatureForSelector:), [self class], @selector(ws_methodSignatureForSelector:));
change_method([self class], @selector(forwardInvocation:), [self class], @selector(ws_forwardInvocation:));
}
- (NSMethodSignature *)ws_methodSignatureForSelector:(SEL)aSelector {
if (![self respondsToSelector:aSelector]) {
_errorFunctionName = NSStringFromSelector(aSelector);
NSMethodSignature *methodSignature = [self ws_methodSignatureForSelector:aSelector];
if (class_addMethod([self class], aSelector, (IMP)dynamicMethodIMP, method_getTypeEncoding(class_getInstanceMethod([self class], @selector(methodSignatureForSelector:))))) {
NSLog(@"添加临时方法成功！");
}
if (!methodSignature) {
methodSignature = [self ws_methodSignatureForSelector:aSelector];
}
return methodSignature;
}else{
return [self ws_methodSignatureForSelector:aSelector];
}
}
- (void)ws_forwardInvocation:(NSInvocation *)anInvocation{
SEL selector = [anInvocation selector];
if ([self respondsToSelector:selector]) {
[anInvocation invokeWithTarget:self];
}else{
[self ws_forwardInvocation:anInvocation];
}
}
@end
2、对于signal产生的crash，创建一个crash捕获的单例，里面进行信号捕捉处理，只需要在AppDelegate中进行初始化
#import "WSCrashHandler.h"
#include <libkern/OSAtomic.h>
#include <execinfo.h>
#include <sys/signal.h>
NSString * const kSignalExceptionName = @"kSignalExceptionName";
NSString * const kSignalKey = @"kSignalKey";
NSString * const kCaughtExceptionStackInfoKey = @"kCaughtExceptionStackInfoKey";
static void HandleException(NSException *exception);
static void SignalHandler(int signal);
@interface WSCrashHandler ()
@property (nonatomic, assign) BOOL dismissed;
@end
@implementation WSCrashHandler
+ (instancetype)shared {
static WSCrashHandler *sharedHelper = nil;
static dispatch_once_t predicate;
dispatch_once(&predicate, ^{
sharedHelper = [[WSCrashHandler alloc] init];
});
return sharedHelper;
}
- (instancetype)init {
self = [super init];
if (self) {
// 1.捕获一些异常导致的崩溃
NSSetUncaughtExceptionHandler(&HandleException);
// 2.捕获非异常情况，通过signal传递出来的崩溃
//signal是一个函数，有2个参数，第一个是int类型，第二个参数是一个函数指针
//添加想要监听的signal类型，当发出相应类型的signal时，会回调SignalHandler方法
signal(SIGABRT, SignalHandler);// SIGABRT--程序中止命令中止信号
signal(SIGILL, SignalHandler);//SIGILL--程序非法指令信号
signal(SIGSEGV, SignalHandler);//SIGSEGV--程序无效内存中止信号
signal(SIGFPE, SignalHandler);//SIGFPE--程序浮点异常信号
signal(SIGBUS, SignalHandler);//SIGBUS--程序内存字节未对齐中止信号
signal(SIGPIPE, SignalHandler);//SIGPIPE--程序Socket发送失败中止信号
}
return self;
}
//NSException异常是OC代码导致的crash
void HandleException(NSException *exception) {
NSString *message = [NSString stringWithFormat:@"崩溃原因如下:\n%@\n%@",
[exception reason],
[[exception userInfo] objectForKey:kCaughtExceptionStackInfoKey]];
NSLog(@"%@",message);
// 获取NSException异常的堆栈信息
NSArray *callStack = [exception callStackSymbols];
NSMutableDictionary *userInfo = [NSMutableDictionary dictionaryWithDictionary:[exception userInfo]];
[userInfo setObject:callStack forKey:kCaughtExceptionStackInfoKey];
WSCrashHandler *crashObject = [WSCrashHandler shared];
NSException *customException = [NSException exceptionWithName:[exception name] reason:[exception reason] userInfo:userInfo];
[crashObject performSelectorOnMainThread:@selector(handleException:) withObject:customException waitUntilDone:YES];
}
//signal信号抛出的异常处理
void SignalHandler(int signal) {
NSArray *callStack = [WSCrashHandler backtrace];
NSLog(@"signal信号捕获崩溃，堆栈信息：%@",callStack);
WSCrashHandler *crashObject = [WSCrashHandler shared];
NSException *customException = [NSException exceptionWithName:kSignalExceptionName
reason:[NSString stringWithFormat:NSLocalizedString(@"Signal %d was raised.", nil),signal]
userInfo:@{kSignalKey:[NSNumber numberWithInt:signal]}];
[crashObject performSelectorOnMainThread:@selector(handleException:) withObject:customException waitUntilDone:YES];
}
- (void)handleException:(NSException *)exception {
// 打印或弹出框
// TODO :
#ifdef DEBUG
NSString *message = [NSString stringWithFormat:@"抱歉，APP发生了异常，点击屏幕继续并自动复制错误信息到剪切板。\n\n异常报告:\n异常名称：%@\n异常原因：%@\n", [exception name], [exception reason]];
NSLog(@"%@",message);
[self showCrashToastWithMessage:message];
CFRunLoopRef runLoop = CFRunLoopGetCurrent();
CFArrayRef allModes = CFRunLoopCopyAllModes(runLoop);
while (!self.dismissed) {
for (NSString *mode in (__bridge NSArray *)allModes) {
//为阻止线程退出，使用 CFRunLoopRunInMode(model, 0.001, false)等待系统消息，false表示RunLoop没有超时时间
CFRunLoopRunInMode((CFStringRef)mode, 0.001, false);
}
}
CFRelease(allModes);
#endif
// 本地保存exception异常信息并上传服务器
// TODO :
// 下面等同于清空之前设置的
NSSetUncaughtExceptionHandler(NULL);
signal(SIGABRT, SIG_DFL);
signal(SIGILL, SIG_DFL);
signal(SIGSEGV, SIG_DFL);
signal(SIGFPE, SIG_DFL);
signal(SIGBUS, SIG_DFL);
signal(SIGPIPE, SIG_DFL);
// 杀死 或 唤起
if ([[exception name] isEqual:kSignalExceptionName]) {
kill(getpid(), [[[exception userInfo] objectForKey:kSignalKey] intValue]);
} else {
[exception raise];
}
}
//该函数用来获取当前线程调用堆栈的信息，并且转化为字符串数组。
+ (NSArray *)backtrace {
void *callStack[128];//堆栈方法数组
int frames = backtrace(callStack, 128);//获取错误堆栈方法指针数组，返回数目
char **strs = backtrace_symbols(callStack, frames);//符号化
NSMutableArray *backtrace = [NSMutableArray arrayWithCapacity:frames]; //函数调用信息依照顺序存在NSMutableArray backtrace
for (int i = 0; i < frames; i++) {
[backtrace addObject:[NSString stringWithUTF8String:strs[i]]];
}
free(strs);
return backtrace;
}
- (void)showCrashToastWithMessage:(NSString *)message {
UILabel *crashLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 64, [UIApplication sharedApplication].keyWindow.bounds.size.width, [UIApplication sharedApplication].keyWindow.bounds.size.height - 64)];
crashLabel.textColor = [UIColor redColor];
crashLabel.font = [UIFont systemFontOfSize:15];
crashLabel.text = message;
crashLabel.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.7];
crashLabel.numberOfLines = 0;
[[UIApplication sharedApplication].keyWindow addSubview:crashLabel];
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(crashToastTapAction:)];
crashLabel.userInteractionEnabled = YES;
[crashLabel addGestureRecognizer:tap];
}
- (void)crashToastTapAction:(UITapGestureRecognizer *)tap {
UILabel *crashLabel = (UILabel *)tap.view;
[UIPasteboard generalPasteboard].string = crashLabel.text;
self.dismissed = YES;
}
@end
3、实例测试：
关键点：SignalHandler不要在debug环境下测试。因为系统的debug会优先去拦截。先在run的切换Release状态,运行安装后，再手动点击启动app去测试。
搞成relese模式.png
实例测试代码如下：
#import "ViewController.h"
@interface ViewController ()
@end
typedef struct Test {
int a;
int b;
}Test;
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor = [UIColor whiteColor];
// Do any additional setup after loading the view.
UIButton *crashExcButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 44, self.view.bounds.size.width, 50)];
crashExcButton.backgroundColor = [UIColor redColor];
[crashExcButton setTitle:@"Exception" forState:UIControlStateNormal];
[crashExcButton addTarget:self action:@selector(crashExcClick) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:crashExcButton];
UIButton *crashSignalEGVButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 60+44, self.view.bounds.size.width, 50)];
crashSignalEGVButton.backgroundColor = [UIColor redColor];
[crashSignalEGVButton setTitle:@"Signal(EGV)" forState:UIControlStateNormal];
[crashSignalEGVButton addTarget:self action:@selector(crashSignalEGVClick) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:crashSignalEGVButton];
UIButton *crashSignalBRTButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 120+44, self.view.bounds.size.width, 50)];
crashSignalBRTButton.backgroundColor = [UIColor redColor];
[crashSignalBRTButton setTitle:@"Signal(ABRT)" forState:UIControlStateNormal];
[crashSignalBRTButton addTarget:self action:@selector(crashSignalBRTClick) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:crashSignalBRTButton];
UIButton *crashSignalBUSButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 180+44, self.view.bounds.size.width, 50)];
crashSignalBUSButton.backgroundColor = [UIColor redColor];
[crashSignalBUSButton setTitle:@"Signal(BUS)" forState:UIControlStateNormal];
[crashSignalBUSButton addTarget:self action:@selector(crashSignalBUSClick) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:crashSignalBUSButton];
}
- (void)crashSignalEGVClick {
UIView *view = [[UIView alloc] init];
[view performSelector:NSSelectorFromString(@"release")];//导致SIGSEGV的错误，一般会导致进程流产
view.backgroundColor = [UIColor whiteColor];
}
- (void)crashSignalBRTClick {
Test *pTest = {1,2};
free(pTest);//导致SIGABRT的错误，因为内存中根本就没有这个空间，哪来的free，就在栈中的对象而已
pTest->a = 5;
}
- (void)crashSignalBUSClick {
//SIGBUS，内存地址未对齐
//EXC_BAD_ACCESS(code=1,address=0x1000dba58)
char *s = "hello world";
*s = 'H';
}
- (void)crashExcClick {
[self performSelector:@selector(aaaa)];
}
@end
