android/local2root/runner.c
#include <jni.h>
#include <android/log.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <dirent.h>
#include <pwd.h>

#define LOG(x)  printf(x)

unsigned long crc32_table[256] = {
  0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
  0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005, 
  0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 
  0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 
  0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 
  0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
  0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 
  0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd, 
  0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 
  0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 
  0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
  0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d, 
  0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 
  0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95, 
  0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 
  0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
  0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 
  0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072, 
  0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 
  0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 
  0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
  0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, 
  0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 
  0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba, 
  0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 
  0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
  0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 
  0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a, 
  0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 
  0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 
  0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
  0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a, 
  0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 
  0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 
  0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 
  0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
  0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 
  0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b, 
  0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 
  0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 
  0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
  0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b, 
  0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 
  0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3, 
  0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 
  0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
  0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 
  0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3, 
  0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 
  0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 
  0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
  0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, 
  0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 
  0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec, 
  0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 
  0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
  0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 
  0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c, 
  0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 
  0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 
  0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
  0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c, 
  0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 
  0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4 
};

// "sum" -> previous CRC
// "c" -> content byte
int crc32(int sum, int c) {
	char k1, k2, k3, k4;
	
	k1 = (char)((c & 0xFF000000) >> 24);
	k2 = (char)((c & 0x00FF0000) >> 16);
	k3 = (char)((c & 0x0000FF00) >> 8);
	k4 = (char)(c & 0x000000FF);
	
	sum = crc32_table[(sum >> 24) ^ k1] ^ (sum << 8);
	sum = crc32_table[(sum >> 24) ^ k2] ^ (sum << 8);
	sum = crc32_table[(sum >> 24) ^ k3] ^ (sum << 8);
	sum = crc32_table[(sum >> 24) ^ k4] ^ (sum << 8);

	return sum;
}

JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM* vm, void* reserved) {
	JNIEnv *env;

    //__android_log_print(ANDROID_LOG_DEBUG, "QZ", "JNI_OnLoad c'e'");  

	return JNI_VERSION_1_6;
}

// Get Process PID
JNIEXPORT jint JNICALL Java_com_android_networking_listener_BroadcastMonitorProcess_gp (JNIEnv *env, jobject obj, jstring process) {
    //__android_log_print(ANDROID_LOG_DEBUG, "QZ", "getpid");

	DIR *d;
	struct dirent *de;
	char statline[256], *ptr;
	int fd, r, zygotePid = -1;
	
	const char *processName = (*env)->GetStringUTFChars(env, process, 0); 
	
    d = opendir("/proc");
	
    if (d == 0 || processName == NULL)
		return -1;
	
    while ((de = readdir(d)) != 0) {
        if (isdigit(de->d_name[0]) ==  0)
            continue;
		
		int pid = atoi(de->d_name);
		
		if (snprintf(statline, sizeof(statline), "/proc/%s/stat", de->d_name) < 0)
			continue;
		
		// Open "/proc/<PID>/stat"
		fd = open(statline, O_RDONLY);
		
		if (fd < 0)
			continue;
		
		memset(statline, 0x00, sizeof(statline));
		
		// Read process stat 
		r = read(fd, statline, sizeof(statline) - 1);
		
		close(fd);
		
		if (r < 0)
			continue;
			
		statline[r] = 0;

		ptr = strrchr(statline, ')'); // Skip to *last* occurence of ")"
		*ptr = 0; // Remove the ")"
		
		// Look for "("
		ptr = strchr(statline, '(');
		
		if (ptr == NULL)
			continue;
		
		// Skip after the "("
		ptr++;
		
		// ptr now contains the process name
		if (strncasecmp(processName, ptr, strlen(ptr)) == 0) {
			zygotePid = pid;
			break;
		}
    }
  
	(*env)->ReleaseStringUTFChars(env, process, processName);
	closedir(d);
	
	return zygotePid;
}

// Get Process List CRC, "p" is the ppid (we look for Zygote's children)
JNIEXPORT jint JNICALL Java_com_android_networking_listener_BroadcastMonitorProcess_gc (JNIEnv *env, jobject obj, jint p) {
    //__android_log_print(ANDROID_LOG_DEBUG, "QZ", "gc");  

	DIR *d;
	struct dirent *de;
	char dst[256], *ppid, *ptr;
	char statline[256];
	int fd, parentPid, crc = 0, r;
	
    d = opendir("/proc");
	
    if (d == 0) 
		return -1;

	// Read /proc and look for PIDs
    while ((de = readdir(d)) != 0) {
        if (isdigit(de->d_name[0]) ==  0) {
            continue;
        }
		
		int pid = atoi(de->d_name);
		
		if (snprintf(dst, sizeof(dst), "/proc/%s/stat", de->d_name) < 0) {
			continue;
		}
		
		// Open /proc/PID/stat
		fd = open(dst, O_RDONLY);
		
		if (fd < 0)
			continue;
		
		memset(dst, 0x00, sizeof(dst));
		parentPid = -1;
		
		// Look for the PPid
		r = read(fd, statline, sizeof(statline) - 1);
		
		close(fd);
		
		if (r < 0)
			continue;
		
		statline[r] = 0;
		ppid = strrchr(statline, ')'); // Skip to *last* occurence of ")"
		ppid += 4; // Skip ") X "
		
		// Look for ' ' after PPid
		ptr = strchr(ppid, ' ');
		
		if (ptr == NULL)
			continue;
		
		// Null terminate the PPid
		*ptr = 0;
		
		parentPid = atoi(ppid);
		
		// Check to see if the PPid equals the pid passed from Java (should be Zygote's PID)
		if (parentPid != p)
			continue;
		
		// Add this PID to the CRC
		crc = crc32(crc, pid);
    }
 
	closedir(d);
	return crc;
}
