/**
* finds the (k + 1)th perm and writes it in tmp
*/
void permut(int k) {
for(a = 0; a < len; a++) {
tmp = fctrl(len - 1 - a);
indx = find(k / tmp);
perm[a] = availableNums[indx];
availableNums[indx] = -1;
k %= tmp;
}
}
int main(int argc, char **argv) {
printf("This program demonstrates two algorithms: the kth permutation and the next permutation.\n");
printf("Enter the length (2 - 9): ");
scanf("%d", &len);
if ((len > 9) || (len < 2)) {
fprintf(stderr, "length should be between 2 to 9\n");
exit(1);
}
int load = fctrl(len);
printf("Enter the value of k (1 - %d): ", load);
scanf("%d", &myK);
if ((myK < 1) || (myK > load)) {
fprintf(stderr, "k should be between 1 to %d\n", load);
exit(1);
}
availableNums = (int *)calloc(len, sizeof(int));
perm = (int *)calloc(len, sizeof(int));
for (a = 0; a < len; a++)
availableNums[a] = a + 1;
printf("The %dth permutation is: ", myK);
permut(myK - 1);
process();
printf("\n");
printf("The next permutation is: ");
if (myK == load) // some cheat
printf("na");
else {
nextPermut();
process();
}
printf("\n");
free(availableNums);
free(perm);
scanf("\n");
return 0;
}
/* checkTag() also tries to lookup the socket address in the kernel and
* return it when *addr == NULL.
* This allows for better look ups when another process is also setting the same
* tag + uid. But it is not fool proof.
* Without the kernel reporting more info on who setup the socket tag, it is
* not easily verifiable from user-space.
* Returns: true if tag found.
*/
bool SockInfo::checkTag(uint64_t acct_tag, uid_t uid) {
int res;
uint64_t k_tag;
uint32_t k_uid;
long dummy_count;
pid_t dummy_pid;
std::ifstream fctrl("/proc/net/xt_qtaguid/ctrl", std::fstream::in);
if(!fctrl.is_open()) {
testPrintI("qtaguid ctrl open failed!");
}
uint64_t full_tag = acct_tag | uid;
std::string buff = android::base::StringPrintf(" tag=0x%" PRIx64 " (uid=%u)", full_tag, uid);
if (addr) {
buff = android::base::StringPrintf("sock=%" PRIxPTR, (uintptr_t)addr) + buff;
}
testPrintI("looking for '%s'", buff.c_str());
std::string ctrl_data;
std::size_t pos = std::string::npos;
while(std::getline(fctrl, ctrl_data)) {
testPrintI("<ctrl_raw_data> : %s", ctrl_data.c_str());
pos = ctrl_data.find(buff);
if (pos != std::string::npos) {
if(!addr) {
testPrintI("matched data : %s", ctrl_data.c_str());
assert(sizeof(void*) == sizeof(long int));
res = sscanf(ctrl_data.c_str(),
"sock=%" SCNxPTR " tag=0x%" SCNx64 " (uid=%" SCNu32 ") pid=%u f_count=%lu",
(uintptr_t *)&addr, &k_tag, &k_uid, &dummy_pid, &dummy_count );
if (!(res == 5 && k_tag == full_tag && k_uid == uid)) {
testPrintE("Unable to read sock addr res=%d", res);
addr = 0;
} else {
testPrintI("Got sock_addr %lx", addr);
}
}
break;
}
}
return pos != std::string::npos;
}