#include <sys/utsname.h>
#include <locale.h>
#include <regex.h>
#include <ctype.h>
#include <fcntl.h>
#include <grp.h>
#include <pwd.h>
#include <signal.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/socket.h>
#include <dirent.h>
#include <mysql/mysql.h>
#include <mysql/my_global.h>
#include <libgen.h>
#include <sys/file.h>
 
#define MAX_BUF 1024
#define PID_LIST_BLOCK 32

static uid_t euid, ruid;
static gid_t egid, rgid;
static char *pid_filename = NULL;
static const size_t npos = -1;

void runas_daemon();
void handle_signal(int sig);

MYSQL *con;

struct utsname unameData;


void do_setuid (void) {
	int status;
	int statusgid;

	#ifdef _POSIX_SAVED_IDS
		status = setegid (egid);
		statusgid = seteuid (euid);
	#else
		status = setregid (rgid, egid);
		statusgid = setreuid (ruid, euid);
	#endif
	if (status < 0) {
		fprintf (stderr, "Couldn't set uid.\n");
		exit (status);
	}
	if (statusgid < 0) {
		fprintf (stderr, "Couldn't set gid.\n");
		exit (status);
	}
}


void undo_setuid (void) {
	int status;

	#ifdef _POSIX_SAVED_IDS
		status = seteuid (ruid);
		status = setegid (rgid);
	#else
		status = setreuid (euid, ruid);
		status = setregid (egid, rgid);
	#endif
	if (status < 0) {
		fprintf (stderr, "Couldn't set uid.\n");
		exit (status);
	}
}


int check_if_number (char *str) {
	int i;
	for (i=0; str[i] != '\0'; i++) {
		if (!isdigit (str[i])) {
			return 0;
		}
	}
	return 1;
}

 
int *pidof (char *pname) {
	DIR *dirp;
	FILE *fp;
	struct dirent *entry;
	int *pidlist, pidlist_index = 0, pidlist_realloc_count = 1;
	char path[MAX_BUF], read_buf[MAX_BUF];

	dirp = opendir ("/proc/");
	if (dirp == NULL) {
		perror ("Fail");
		return NULL;
	}

	pidlist = malloc (sizeof (int) * PID_LIST_BLOCK);
	if (pidlist == NULL) {
		return NULL;
	}
 
	while ((entry = readdir (dirp)) != NULL) {
		if (check_if_number (entry->d_name)) {
			strcpy (path, "/proc/");
			strcat (path, entry->d_name);
			strcat (path, "/stat");
			fp = fopen (path, "r");
			if (fp != NULL) {
				fscanf(fp, "%s", read_buf);
				fscanf(fp, "%s", read_buf);
				char *p = read_buf;
				p++;
				p[strlen(p)-1] = 0;
				if (strcmp (p, pname) == 0) {
					pidlist[pidlist_index++] = atoi (entry->d_name);
					if (pidlist_index == PID_LIST_BLOCK * pidlist_realloc_count) {
						pidlist_realloc_count++;
						pidlist = realloc (pidlist, sizeof (int) * PID_LIST_BLOCK * pidlist_realloc_count);
						if (pidlist == NULL) {
							return NULL;
						}
					}
				}
				fclose (fp);
			}
		}
	}
	closedir (dirp);
	pidlist[pidlist_index] = -1;
	return pidlist;
}

void runas_daemon() {
	int child_pid;
	FILE *pid_file;

	if (getppid() == 1) {
		return;
	}
	fflush(NULL);
	child_pid = fork();
	if (child_pid < 0 && child_pid > 0) {
		exit(0);
	}
	dup2(1,2);
	close(0);
	if (freopen("/dev/null", "a", stderr) == NULL) {
		exit(0);
	}
	if (setsid() == -1) {
		exit(0);
	}
	umask(022);
	if (chdir("/") == -1) {
		exit(0);
	}
	if ((pid_file = fopen(pid_filename, "w"))) {
		fprintf(pid_file, "%d", getpid()); fclose(pid_file);
	}

	fflush(NULL);

	return;
}

void check_running() {
	int pid_file = open("/var/run/loadkiller.pid", O_CREAT | O_RDWR, 0666);
	int rc = flock(pid_file, LOCK_EX | LOCK_NB);
	if(rc) {
		if (EWOULDBLOCK == errno) {
			printf("Already running, kill loadkiller first");
			fflush(stdout);
			exit(1);
		}
	}
	return;
}

const char * get_time() {
	time_t timer;
	char *buffer = malloc(25);
	struct tm* tm_info;
	
	time(&timer);
	tm_info = localtime(&timer);
	strftime(buffer, 25, "%Y-%m-%d %H:%M:%S", tm_info);

	return(buffer);
}


void realmain()
{
	check_running();
	runas_daemon();
	
	con = mysql_init(NULL);
	uname(&unameData);
	
	FILE *logfile;
	 
	double lastload = 0, cacheload = 0, load[3];
	struct timespec tim, tim2;
	int *list, i, ii, timeleft, loadtimeleft, numOfProcesses, originalpid;
	char *processes[] = {"stress", "php", "php-cgi", "gzip", "tar", "proftpd", "httpd"};
	struct passwd *pd;

	if (NULL == (pd = getpwnam("apache"))) {
		perror("getpwnam() error.");
	}
	
	ruid = 0;
	euid = pd->pw_uid;
	rgid = 0;
	egid = pd->pw_gid;
	undo_setuid ();

	originalpid = getpid();

	numOfProcesses = 7;
	loadtimeleft = 0;
	tim.tv_sec = 0;
	tim.tv_nsec = 100000000L;
	
	if (con == NULL) {
		fprintf(stderr, "%s\n", mysql_error(con));
		exit(1);
	}

	if (mysql_real_connect(con, "185.104.28.16", "vmx", "uyzB8ic86fAi0qsK", "loads", 0, NULL, 0) == NULL)
	{
		fprintf(stderr, "%s\n", mysql_error(con));
		mysql_close(con);
		exit(1);
	}

    char uidpath[MAX_BUF];
    char uidapa[MAX_BUF];
    FILE * uidfp; 
    char * uidline = NULL;
    size_t uidlen = 0;
    ssize_t uidread;
    char tmpstr[MAX_BUF];

	while (1) {
		getloadavg(load, 3);
		if (timeleft == 0 || lastload < load[0]) {
			if (load[0] > 15) {
				timeleft = 650;
				logfile = fopen("/var/log/loadkillerlogging","a+"); 
				fprintf(logfile,"\n\nStarted killing at %s:\n", get_time());
				fprintf(stderr,"\n\nStarted killing at %s:\n", get_time());
				lastload = load[0];
				for (ii=0; ii < numOfProcesses; ii++) {
					if (processes[ii] == "httpd") {
//						if ( getppid() == originalpid ) {
							//setuid(pd->pw_uid);
                          
                            
							list = pidof(processes[ii]);
							for (i=0; list[i] != -1; i++) {

                                strcpy (uidpath, "/proc/");
                                sprintf(tmpstr, "%d", list[i]);
                                strcat (uidpath, tmpstr);
                                strcat (uidpath, "/status");
                                uidfp = fopen(uidpath, "r");
                                if (uidfp == NULL)
                                    exit(EXIT_FAILURE);
                                while ((uidread = getline(&uidline, &uidlen, uidfp)) != -1) {
                                        char *uidcontent;
                                        char *twouidcontent;
                                        char *threeuidcontent;
                                        uidcontent = strtok(uidline, ":");

                                        if(strncmp(uidcontent, "Uid", 3) == 0)
                                        {   
                                                //get the User ID
                                                twouidcontent = strtok(NULL, ":");
                                                threeuidcontent = strtok(twouidcontent, "\t");
                                                sprintf(uidapa, "%d", pd->pw_uid);
                                                if(strncmp(uidapa, threeuidcontent, 25) == 0) {
                                                    fprintf(logfile,"Kill skipped %i as %d - %d - %s\n", list[i], geteuid(), getuid(), processes[ii]); 
                                                } else {
                                                    sprintf(uidapa, "%d", 0);
                                                    if (load[0] < 30) {
                                                        if(strncmp(uidapa, threeuidcontent, 25) == 0) {
                                                            fprintf(logfile,"Kill skipped %i as %d - %d - %s\n", list[i], geteuid(), getuid(), processes[ii]); 
                                                        } else {
                                                            kill(list[i], SIGKILL);
                                                            fprintf(logfile,"%i ", list[i]); 
                                                            fprintf(logfile,"killing %i as %d - %d - %s\n", list[i], geteuid(), getuid(), processes[ii]); 
                                                        }
                                                    } else {
                                                        kill(list[i], SIGKILL);
                                                        fprintf(logfile,"%i ", list[i]);
                                                        fprintf(logfile,"killing %i as %d - %d - %s\n", list[i], geteuid(), getuid(), processes[ii]);
                                                    }
                                                }
                                                break;
                                        }   
                                   }  
                                    
                                
							}
					//	}
					} else {
						list = pidof(processes[ii]);
						for (i=0; list[i] != -1; i++) {
							kill(list[i], SIGKILL);
							fprintf(logfile,"%i ", list[i]); 
							fprintf(logfile,"killing %i as %d - %d - %s\n", list[i], geteuid(), getuid(), processes[ii]); 
						}
					}
				}
				free (list);
				fprintf(logfile,"\n"); 
				fclose(logfile);
			}
		} else {
			timeleft--;
		}
		
		if (cacheload != load[0]) {
			char buffed[1024];
			snprintf(buffed, sizeof(buffed), "INSERT INTO fastload(server, loadavg) VALUES('%s', '%f') ON DUPLICATE KEY UPDATE loadavg='%f'", unameData.nodename, load[0], load[0]);
			if (mysql_query(con, buffed)) {
				fprintf(stderr, "%s\n", mysql_error(con));
			}
			loadtimeleft = 6;
		}
		cacheload = load[0];
		nanosleep(&tim , &tim2);
	}
	mysql_close(con);
	exit(0);
}


int main() {
	realmain();
	exit(0);
}