IOS SDK中提供了一个现成的函数 NSSetUncaughtExceptionHandler 用来做异常处理，但功能非常有限，而引起崩溃的大多数原因如：内存访问错误，重复释放等错误捕获不到，因为这些异常抛出的是Signal，所以必须要专门做Signal处理。工具类的实现源码如下：

头文件

#import <Foundation/Foundation.h>

extern NSString *const UncaughtExceptionHandlerSignalKey;
extern NSString *const SingalExceptionHandlerAddressesKey;
extern NSString *const ExceptionHandlerAddressesKey;

@interface ExceptionHandler : NSObject
+ (void)installExceptionHandler;
+ (NSArray *)backtrace;
@end

#import "ExceptionHandler.h"
#include <libkern/OSAtomic.h>
#include <execinfo.h>

NSString *const UncaughtExceptionHandlerSignalKey = @"UncaughtExceptionHandlerSignalKey";
NSString *const SingalExceptionHandlerAddressesKey = @"SingalExceptionHandlerAddressesKey";
NSString *const ExceptionHandlerAddressesKey = @"ExceptionHandlerAddressesKey";

const int32_t _uncaughtExceptionMaximum = 20;

// 系统信号截获处理方法
void signalHandler(int signal);

// 异常截获处理方法
void exceptionHandler(NSException *exception);

void signalHandler(int signal)
{
    volatile int32_t _uncaughtExceptionCount = 0;
    int32_t exceptionCount = OSAtomicIncrement32(&_uncaughtExceptionCount);

    // 如果太多不用处理
    if (exceptionCount > _uncaughtExceptionMaximum) {
        return;
    }
    
    // 获取信息
    NSMutableDictionary *userInfo = [NSMutableDictionary dictionaryWithObject:[NSNumber numberWithInt:signal] forKey:UncaughtExceptionHandlerSignalKey];
    NSArray *callStack = [ExceptionHandler backtrace];
    [userInfo  setObject:callStack  forKey:SingalExceptionHandlerAddressesKey];

    // 现在就可以保存信息到本地［］
    
}

void exceptionHandler(NSException *exception)
{
    volatile int32_t _uncaughtExceptionCount = 0;
    int32_t exceptionCount = OSAtomicIncrement32(&_uncaughtExceptionCount);
    
    // 如果太多不用处理
    if (exceptionCount > _uncaughtExceptionMaximum) {
        return;
    }
    
    NSArray *callStack = [ExceptionHandler backtrace];
    NSMutableDictionary *userInfo =[NSMutableDictionary dictionaryWithDictionary:[exception userInfo]];
    [userInfo setObject:callStack forKey:ExceptionHandlerAddressesKey];
    NSLog(@"Exception Invoked: %@", userInfo);
    
    // 现在就可以保存信息到本地［］
    
    
}

@implementation ExceptionHandler

//获取调用堆栈
+ (NSArray *)backtrace
{
    void* callstack[128];
    int frames = backtrace(callstack, 128);
    char **strs = backtrace_symbols(callstack,frames);
    
    NSMutableArray *backtrace = [NSMutableArray arrayWithCapacity:frames];
    for (int i=0;i<frames;i++) {
        [backtrace addObject:[NSString stringWithUTF8String:strs[i]]];
    }
    free(strs);
    return backtrace;
}


// 注册崩溃拦截
+ (void)installExceptionHandler
{
    NSSetUncaughtExceptionHandler(&exceptionHandler);
    signal(SIGHUP, signalHandler);
    signal(SIGINT, signalHandler);
    signal(SIGQUIT, signalHandler);
    signal(SIGABRT, signalHandler);
    signal(SIGILL, signalHandler);
    signal(SIGSEGV, signalHandler);
    signal(SIGFPE, signalHandler);
    signal(SIGBUS, signalHandler);
    signal(SIGPIPE, signalHandler);
}

@end

iOS Crash闪退信息捕获工具类