How to find the purple port for the front most application in IOS 5 and above?

Question

I am trying to write an app that runs in the background and injects touches to the springboard or other apps. I understand that I will be using private APIs and structures.

Answer 1

UPDATE: I haven't tested this on ios7.

I happen to work on the exact same requirement before.

To get the purple port, you can use GSCopyPurpleNamedPort() with the bundle Id as an argument.

If you need to simulate touch on SpringBoard, use GSGetPurpleSystemEventPort.

With this below code, you should be able to get the port and use it to inject touch system wide.

#import <dlfcn.h>
// Framework Paths
#define SBSERVPATH  "/System/Library/PrivateFrameworks/SpringBoardServices.framework/SpringBoardServices"
-(mach_port_t)getFrontMostAppPort
{
    bool locked;
    bool passcode;
    mach_port_t *port;
    void *lib = dlopen(SBSERVPATH, RTLD_LAZY);
    int (*SBSSpringBoardServerPort)() = dlsym(lib, "SBSSpringBoardServerPort");
    void* (*SBGetScreenLockStatus)(mach_port_t* port, bool *lockStatus, bool *passcodeEnabled) = dlsym(lib, "SBGetScreenLockStatus");
    port = (mach_port_t *)SBSSpringBoardServerPort();
    dlclose(lib);
    SBGetScreenLockStatus(port, &locked, &passcode);
    void *(*SBFrontmostApplicationDisplayIdentifier)(mach_port_t *port, char *result) = dlsym(lib, "SBFrontmostApplicationDisplayIdentifier");
    char appId[256];
    memset(appId, 0, sizeof(appId));
    SBFrontmostApplicationDisplayIdentifier(port, appId);
    NSString * frontmostApp=[NSString stringWithFormat:@"%s",appId];
    if([frontmostApp length] == 0 || locked)
        return GSGetPurpleSystemEventPort();
    else
        return GSCopyPurpleNamedPort(appId);
}

I've tested...this works fine on iOS 5 and 6. You might not need the lock part if you don't inject when the lock screen shows up. Hope this helps.