cfprefs.m

#import <Foundation/Foundation.h>
#include <sandbox.h>
int sandbox_init_with_parameters(const char* profile,
                                 uint64_t flags,
                                 const char* const parameters[],
                                 char** errorbuf);

#define SANDBOX_PROFILE "/System/Library/Frameworks/WebKit.framework/Versions/A/Resources/com.apple.WebProcess.sb"
#define SANDBOX_NAMED_EXTERNAL 0x0003


void init_sandbox() {
    NSString *home = NSHomeDirectory();
    NSString *prefs = [home stringByAppendingString:@"Library/Preferences"];
    
    char temporaryDirectory[PATH_MAX];
    size_t temporaryDirectoryLen = confstr(_CS_DARWIN_USER_TEMP_DIR, temporaryDirectory, sizeof(temporaryDirectory));
    if (!temporaryDirectoryLen) {
        printf("failed to retrieve private temporary directory path\n");
        exit(-1);
    }
    setenv("TMPDIR", temporaryDirectory, 1);
    
    char cacheDirectory[PATH_MAX];
    size_t cacheDirectoryLen = confstr(_CS_DARWIN_USER_CACHE_DIR, cacheDirectory, PATH_MAX);
    if (!cacheDirectoryLen) {
        printf("failed to retrieve cache path\n");
        exit(-1);
    }

#define SAFARI "com.apple.WebKit.WebContent+com.apple.Safari"
    strncat(cacheDirectory, SAFARI, PATH_MAX - cacheDirectoryLen);
    strncat(temporaryDirectory, SAFARI, PATH_MAX - temporaryDirectoryLen);
    
    const char *sandbox_parameters[] = {
        "HOME_DIR",
        [home UTF8String],
        
        "WEBKIT2_FRAMEWORK_DIR",
        "/System/Library/Frameworks",
        
        "DARWIN_USER_CACHE_DIR",
        cacheDirectory,
        
        "DARWIN_USER_TEMP_DIR",
        temporaryDirectory,
        
        "HOME_LIBRARY_PREFERENCES_DIR",
        [prefs UTF8String],
        
        NULL
    };
    
    char *errorBuf;
    if (sandbox_init_with_parameters(SANDBOX_PROFILE, SANDBOX_NAMED_EXTERNAL, sandbox_parameters, &errorBuf)) {
        printf("Couldn't initialize sandbox profile, error '%s'\n", errorBuf);
    }
}

int main(int argc, char *argv[])
{
    // comment this out, the call after init_sandbox will fail
    NSLog(@"before: %@", CFPreferencesCopyAppValue(CFSTR("TALLogoutSavesState"), CFSTR("com.apple.loginwindow")));
    init_sandbox();
    NSLog(@"after: %@", CFPreferencesCopyAppValue(CFSTR("TALLogoutSavesState"), CFSTR("com.apple.loginwindow")));
    return 0;
}