如何通过应用程序 id 在 iOS 上确定哪些应用程序是后台应用程序以及哪些应用程序是前台程序答案

【问题标题】：how to determine which apps are background and which app is foreground on iOS by application id如何通过应用程序 id 在 iOS 上确定哪些应用程序是后台应用程序以及哪些应用程序是前台程序
【发布时间】：2012-01-05 08:20:27
【问题描述】：

使用this question中描述的方法，我可以获得iOS设备上运行的应用列表。我知道 PID 并且可以访问它们的 kinfo_proc 结构。如何确定哪些是前台进程，哪些是后台（假设我的应用是后台）？

我试图通过kp_proc.p_priority 中的kinfo_proc（参见第一个链接）中的信息找出这一点，但似乎无法从优先级推断背景/前景状态。

我真的不在乎这是否适用于 AppStore Review，但我更喜欢一种无需越狱即可工作的方法（即私有 API 可以，但哪些？）。我希望它至少可以在 iOS 5 上运行

我考虑写一个简单的MobileSubstrate扩展，将它注入到所有应用程序中，然后挂钩每个人的applicationDidBecomeActive，但这需要越狱，而且侵入性太大。

【问题讨论】：

标签： ios iphone-privateapi

【解决方案1】：

这对我来说适用于所有 IOS 设备：

#define UIKITPATH "/System/Library/Framework/UIKit.framework/UIKit"
#define SBSERVPATH "/System/Library/PrivateFrameworks/SpringBoardServices.framework/SpringBoardServices"

 - (NSArray*) getActiveApps
 {
mach_port_t *p;
void *uikit = dlopen(UIKITPATH, RTLD_LAZY);
int (*SBSSpringBoardServerPort)() =
dlsym(uikit, "SBSSpringBoardServerPort");
p = (mach_port_t *)SBSSpringBoardServerPort();
dlclose(uikit);

if(self.frameWorkPath == nil || self.frameWorkPath.length == 0)
{
    self.frameWorkPath = @SBSERVPATH;
    self.frameWorkPath = [self.frameWorkPath stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];
}

const char *cString = [self.frameWorkPath cStringUsingEncoding:NSUTF8StringEncoding];
//const char *bar = [self.frameWorkPath UTF8String];
void *sbserv = dlopen(cString, RTLD_LAZY);
NSArray* (*SBSCopyApplicationDisplayIdentifiers)(mach_port_t* port, BOOL runningApps,BOOL debuggable) =
dlsym(sbserv, "SBSCopyApplicationDisplayIdentifiers");
//SBDisplayIdentifierForPID - protype assumed,verification of params done
void* (*SBDisplayIdentifierForPID)(mach_port_t* port, int pid,char * result) =
dlsym(sbserv, "SBDisplayIdentifierForPID");
//SBFrontmostApplicationDisplayIdentifier - prototype assumed,verification of params done,don't call this TOO often(every second on iPod touch 4G is 'too often,every 5 seconds is not)
void* (*SBFrontmostApplicationDisplayIdentifier)(mach_port_t* port,char * result) =
dlsym(sbserv, "SBFrontmostApplicationDisplayIdentifier");



//Get frontmost application
char frontmostAppS[512];
memset(frontmostAppS,sizeof(frontmostAppS),0);
SBFrontmostApplicationDisplayIdentifier(p,frontmostAppS);
NSString * frontmostApp=[NSString stringWithFormat:@"%s",frontmostAppS];

if([self iOsMajorVersion] >= 7){
    NSNumber *topmost = [NSNumber numberWithBool:YES];
    NSMutableDictionary * dict = [[NSMutableDictionary alloc] init];
    NSMutableArray  * splitted = [frontmostApp componentsSeparatedByString:@"."];
    if(frontmostApp.length > 0 && splitted != nil && splitted.count > 1 && topmost.boolValue == YES){
        NSString *appname = [splitted lastObject];
        [dict setObject:[appname capitalizedString] forKey:@"ProcessName"];
        [dict setObject:frontmostApp forKey:@"ProcessID"];
        [dict setObject:frontmostApp forKey:@"AppID"];
        [dict setObject:topmost forKey:@"isFrontmost"];
        NSLog(@"Running TOPMOST App %@",dict);
        return @[dict];
    }
    else{
        return nil;
    }
}
//NSLog(@"Frontmost app is %@",frontmostApp);
//get list of running apps from SpringBoard
NSArray *allApplications = SBSCopyApplicationDisplayIdentifiers(p,NO, NO);
//Really returns ACTIVE applications(from multitasking bar)
   NSLog(@"Active applications:");
 for(NSString *identifier in allApplications) {
     // NSString * locName=SBSCopyLocalizedApplicationNameForDisplayIdentifier(p,identifier);
     NSLog(@"Active Application:%@",identifier);
 }


//get list of all apps from kernel
int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0};
size_t miblen = 4;

size_t size;
int st = sysctl(mib, miblen, NULL, &size, NULL, 0);

struct kinfo_proc * process = NULL;
struct kinfo_proc * newprocess = NULL;

do {

    size += size / 10;
    newprocess = realloc(process, size);

    if (!newprocess){

        if (process){
            free(process);
        }

        return nil;
    }

    process = newprocess;
    st = sysctl(mib, miblen, process, &size, NULL, 0);

} while (st == -1 && errno == ENOMEM);

if (st == 0){

    if (size % sizeof(struct kinfo_proc) == 0){
        int nprocess = size / sizeof(struct kinfo_proc);

        if (nprocess){

            NSMutableArray * array = [[NSMutableArray alloc] init];

            for (int i = nprocess - 1; i >= 0; i--){

                int ruid=process[i].kp_eproc.e_pcred.p_ruid;
                int uid=process[i].kp_eproc.e_ucred.cr_uid;
                //short int nice=process[i].kp_proc.p_nice;
                //short int u_prio=process[i].kp_proc.p_usrpri;
                short int prio=process[i].kp_proc.p_priority;
                NSString * processID = [[NSString alloc] initWithFormat:@"%d", process[i].kp_proc.p_pid];
                NSString * processName = [[NSString alloc] initWithFormat:@"%s", process[i].kp_proc.p_comm];


                BOOL systemProcess=YES;
                if (ruid==501){
                    systemProcess=NO;
                }


                char * appid[256];
                memset(appid,sizeof(appid),0);
                int intID,intID2;
                intID=process[i].kp_proc.p_pid,appid;
                SBDisplayIdentifierForPID(p,intID,appid);

                NSString * appId=[NSString stringWithFormat:@"%s",appid];

                if (systemProcess==NO)
                {
                    if ([appId isEqualToString:@""])
                    {
                        //final check.if no appid this is not springboard app
                        //NSLog(@"(potentially system)Found process with PID:%@ name %@,isSystem:%d,Priority:%d",processID,processName,systemProcess,prio);
                    }
                    else
                    {

                        BOOL isFrontmost=NO;
                        if ([frontmostApp isEqualToString:appId])
                        {
                            isFrontmost=YES;
                        }
                        NSNumber *isFrontmostN=[NSNumber numberWithBool:isFrontmost];
                        NSDictionary * dict = [[NSDictionary alloc] initWithObjects:[NSArray arrayWithObjects:processID, processName,appId,isFrontmostN, nil] 
                                                                            forKeys:[NSArray arrayWithObjects:@"ProcessID", @"ProcessName",@"AppID",@"isFrontmost", nil]];
                        NSLog(@"PID:%@, name: %@, AppID:%@,isFrontmost:%d",processID,processName,appId,isFrontmost);
                        [array addObject:dict];
                    }
                }
            }

            free(process);
            return array;
        }
    }
}

dlclose(sbserv);
 }

【讨论】：

所有 iOS 设备是什么意思？这适用于 iOS >= 8

【解决方案2】：

很好的答案！但是您的代码中有一个小错字，应该是：

首先确保定义了 SBSERVPATH 并且包含了正确的头文件：

#import <sys/sysctl.h>
#import <dlfcn.h>

#define SBSERVPATH "/System/Library/PrivateFrameworks/SpringBoardServices.framework/SpringBoardServices"

然后先找到正确的SB口：

mach_port_t *port;
void *lib = dlopen(SBSERVPATH, RTLD_LAZY);
int (*SBSSpringBoardServerPort)() = 
dlsym(lib, "SBSSpringBoardServerPort");
port = (mach_port_t *)SBSSpringBoardServerPort(); 
dlclose(lib);

然后找到激活的应用：

mach_port_t * port = [self getSpringBoardPort];
// open springboard lib
void *lib = dlopen(SBSERVPATH, RTLD_LAZY);

// retrieve function SBFrontmostApplicationDisplayIdentifier
void *(*SBFrontmostApplicationDisplayIdentifier)(mach_port_t *port, char *result) =
dlsym(lib, "SBFrontmostApplicationDisplayIdentifier");

// reserve memory for name
char appId[256];
memset(appId, 0, sizeof(appId));

// retrieve front app name
SBFrontmostApplicationDisplayIdentifier(port, appId);

// close dynlib
dlclose(lib);

【讨论】：

有一个更简单的方法：extern NSString * SBSCopyFrontmostApplicationDisplayIdentifier();
在 iOS 6 和 iOS 7 中使用了上面的代码，它工作正常。但是它在 iOS 8 中不起作用。发现苹果已经改进了 iOS8 中的安全性来防止这种情况。有没有其他方法可以绕过这个。链接：cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4361
据我所知，绝对没有办法再这样做了 :)

【解决方案3】：

好吧，看起来在模拟器中的 SpringBoardServices 二进制文件中使用 nm 和 IDA 对我有所帮助。以下代码适用于在 iPod Touch 4、iPhone 4 和 iPad1 WiFi（所有非 JB）上运行的 iOS 5.0.1 当然，您永远不应该尝试将其提交到 AppStore

- (NSArray*) getActiveApps
{
mach_port_t *p;
void *uikit = dlopen(UIKITPATH, RTLD_LAZY);
int (*SBSSpringBoardServerPort)() = 
dlsym(uikit, "SBSSpringBoardServerPort");
p = (mach_port_t *)SBSSpringBoardServerPort(); 
dlclose(uikit);

void *sbserv = dlopen(SBSERVPATH, RTLD_LAZY);
NSArray* (*SBSCopyApplicationDisplayIdentifiers)(mach_port_t* port, BOOL runningApps,BOOL debuggable) = 
dlsym(sbserv, "SBSCopyApplicationDisplayIdentifiers");
//SBDisplayIdentifierForPID - protype assumed,verification of params done
void* (*SBDisplayIdentifierForPID)(mach_port_t* port, int pid,char * result) = 
dlsym(sbserv, "SBDisplayIdentifierForPID");
//SBFrontmostApplicationDisplayIdentifier - prototype assumed,verification of params done,don't call this TOO often(every second on iPod touch 4G is 'too often,every 5 seconds is not)
void* (*SBFrontmostApplicationDisplayIdentifier)(mach_port_t* port,char * result) = 
dlsym(sbserv, "SBFrontmostApplicationDisplayIdentifier");



//Get frontmost application
char frontmostAppS[256];
memset(frontmostAppS,sizeof(frontmostAppS),0);
SBFrontmostApplicationDisplayIdentifier(p,frontmostAppS);
NSString * frontmostApp=[NSString stringWithFormat:@"%s",frontmostAppS];
//NSLog(@"Frontmost app is %@",frontmostApp);
//get list of running apps from SpringBoard
NSArray *allApplications = SBSCopyApplicationDisplayIdentifiers(p,NO, NO);
//Really returns ACTIVE applications(from multitasking bar)
/*   NSLog(@"Active applications:");
 for(NSString *identifier in allApplications) {
 // NSString * locName=SBSCopyLocalizedApplicationNameForDisplayIdentifier(p,identifier);
 NSLog(@"Active Application:%@",identifier);
 }
 */ 

//get list of all apps from kernel
int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_ALL, 0};
size_t miblen = 4;

size_t size;
int st = sysctl(mib, miblen, NULL, &size, NULL, 0);

struct kinfo_proc * process = NULL;
struct kinfo_proc * newprocess = NULL;

do {

    size += size / 10;
    newprocess = realloc(process, size);

    if (!newprocess){

        if (process){
            free(process);
        }

        return nil;
    }

    process = newprocess;
    st = sysctl(mib, miblen, process, &size, NULL, 0);

} while (st == -1 && errno == ENOMEM);

if (st == 0){

    if (size % sizeof(struct kinfo_proc) == 0){
        int nprocess = size / sizeof(struct kinfo_proc);

        if (nprocess){

            NSMutableArray * array = [[NSMutableArray alloc] init];

            for (int i = nprocess - 1; i >= 0; i--){

                int ruid=process[i].kp_eproc.e_pcred.p_ruid;
                int uid=process[i].kp_eproc.e_ucred.cr_uid;
                //short int nice=process[i].kp_proc.p_nice;
                //short int u_prio=process[i].kp_proc.p_usrpri;
                short int prio=process[i].kp_proc.p_priority;
                NSString * processID = [[NSString alloc] initWithFormat:@"%d", process[i].kp_proc.p_pid];
                NSString * processName = [[NSString alloc] initWithFormat:@"%s", process[i].kp_proc.p_comm];


                BOOL systemProcess=YES;
                if (ruid==501)
                    systemProcess=NO;



                char * appid[256];
                memset(appid,sizeof(appid),0);
                int intID,intID2;
                intID=process[i].kp_proc.p_pid,appid;
                SBDisplayIdentifierForPID(p,intID,appid);/

                NSString * appId=[NSString stringWithFormat:@"%s",appid];

                if (systemProcess==NO)
                {
                    if ([appId isEqualToString:@""])
                    {
                        //final check.if no appid this is not springboard app
                        NSLog(@"(potentially system)Found process with PID:%@ name %@,isSystem:%d,Priority:%d",processID,processName,systemProcess,prio);
                    }
                    else
                    {

                        BOOL isFrontmost=NO;
                        if ([frontmostApp isEqualToString:appId])
                        {
                            isFrontmost=YES;
                        }
                        NSNumber *isFrontmostN=[NSNumber numberWithBool:isFrontmost];
                        NSDictionary * dict = [[NSDictionary alloc] initWithObjects:[NSArray arrayWithObjects:processID, processName,appId,isFrontmostN, nil] 
                                                                            forKeys:[NSArray arrayWithObjects:@"ProcessID", @"ProcessName",@"AppID",@"isFrontmost", nil]];

                        NSLog(@"PID:%@, name: %@, AppID:%@,isFrontmost:%d",processID,processName,appId,isFrontmost);
                        [array addObject:dict];
                    }
                }
            }

            free(process);
            return array;
        }
    }
  }

    dlclose(sbserv);
}

当然，第二个循环不是绝对必要的，但我也需要非本地化名称和 PID。

【讨论】：

我相信这个解决方案存在一个问题。至少，我在我的 iPad 1（使用 iOS 5.1）上尝试过。 SBFrontmostApplicationDisplayIdentifier 返回最后一个非 Springboard 应用程序。也就是说，如果你输入了Mail，后来又存在到Springboard，它仍然会报告Mail是最重要的应用程序。我不确定这是针对此 API 的设计还是 iPad 1 或 isOS 5.1 的特定问题
好吧，对我来说它有效。 iPhone4、iPad1、iPad3 上的 iOS 5.1 和 iPhone4 上的 6.0beta2（尚未在 beta3 上检查）
这里的工作太多了。只需将 YES 传递给 SBSCopyApplicationDisplayIdentifiers 以获得第二个参数，您不需要任何其他代码，因为该参数意味着获取活动应用程序。
@VikartiAnatra 在 iOS 6 和 iOS 7 中使用了上面的代码，它工作正常。但是它在 iOS 8 中不起作用。发现苹果已经改进了 iOS8 中的安全性来防止这种情况。有没有其他方法可以绕过这个。链接：cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-4361
@Avinash 你有没有为 ios 8.0 找到任何绕过解决方案或替代方案？