diff --git a/HW/main.c b/HW/main.c
new file mode 100644
index 0000000..5548adb
--- /dev/null
+++ b/HW/main.c
@@ -0,0 +1,80 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#define SIZE 100
+
+void matrixMultiply(int matrix1[SIZE][SIZE], int matrix2[SIZE][SIZE], int result[SIZE][SIZE], int n) {
+    int i, j, k;
+    for (i = 0; i < n; i++) {
+        for (j = 0; j < n; j++) {
+            result[i][j] = 0;
+            for (k = 0; k < n; k++) {
+                result[i][j] += matrix1[i][k] * matrix2[k][j];
+            }
+        }
+    }
+}
+
+int main() {
+    char* file1 = "matrix1.txt";  // Имя файла для первой матрицы
+    char* file2 = "matrix2.txt";  // Имя файла для второй матрицы
+    char* fileResult = "result_matrix.txt";  // Имя файла для результирующей матрицы
+
+    int matrix1[SIZE][SIZE], matrix2[SIZE][SIZE], result[SIZE][SIZE];  // Матрицы
+
+    // Открываем файл первой матрицы
+    int fd1 = open(file1, O_RDONLY);
+    if (fd1 == -1) {
+        perror("Не удалось открыть файл для первой матрицы");
+        exit(1);
+    }
+
+    // Считываем данные первой матрицы из файла
+    int bytesRead = read(fd1, matrix1, sizeof(int) * SIZE * SIZE);
+    if (bytesRead == -1) {
+        perror("Ошибка при чтении первой матрицы");
+        exit(1);
+    }
+    close(fd1);  // Закрываем файл
+
+    // Открываем файл второй матрицы
+    int fd2 = open(file2, O_RDONLY);
+    if (fd2 == -1) {
+        perror("Не удалось открыть файл для второй матрицы");
+        exit(1);
+    }
+
+    // Считываем данные второй матрицы из файла
+    bytesRead = read(fd2, matrix2, sizeof(int) * SIZE * SIZE);
+    if (bytesRead == -1) {
+        perror("Ошибка при чтении второй матрицы");
+        exit(1);
+    }
+    close(fd2);  // Закрываем файл
+
+    int n = bytesRead / (sizeof(int) * SIZE);  // Размер матрицы
+
+    matrixMultiply(matrix1, matrix2, result, n);  // Выполняем умножение матриц
+
+    // Открываем файл для результирующей матрицы
+    int fdResult = open(fileResult, O_WRONLY | O_CREAT | O_TRUNC);
+    if (fdResult == -1) {
+        perror("Не удалось открыть файл для результирующей матрицы");
+        exit(1);
+    }
+
+    // Записываем результирующую матрицу в файл
+    int bytesWritten = write(fdResult, result, sizeof(int) * n * n);
+    if (bytesWritten == -1) {
+        perror("Ошибка при записи результирующей матрицы");
+        exit(1);
+    }
+    close(fdResult);  // Закрываем файл
+
+    printf("Результирующая матрица успешно записана в файл '%s'\n", fileResult);
+
+    return 0;
+}
diff --git a/Practice/04.10/output/mykey b/Practice/04.10/output/mykey
new file mode 100644
index 0000000..e69de29
diff --git a/Practice/04.10/output/mykey2 b/Practice/04.10/output/mykey2
new file mode 100644
index 0000000..e69de29
diff --git a/Practice/04.10/output/semget b/Practice/04.10/output/semget
new file mode 100755
index 0000000..bac4751
Binary files /dev/null and b/Practice/04.10/output/semget differ
diff --git a/Practice/04.10/semget.c b/Practice/04.10/semget.c
new file mode 100644
index 0000000..c5c71c4
--- /dev/null
+++ b/Practice/04.10/semget.c
@@ -0,0 +1,52 @@
+       #include <stdio.h>
+       #include <stdlib.h>
+       #include <sys/ipc.h>
+       #include <sys/sem.h>
+       #include <unistd.h>
+
+       static void
+       usage(const char *pname)
+       {
+           fprintf(stderr, "Usage: %s [-cx] pathname proj-id num-sems\n",
+                   pname);
+           fprintf(stderr, "    -c           Use IPC_CREAT flag\n");
+           fprintf(stderr, "    -x           Use IPC_EXCL flag\n");
+           exit(EXIT_FAILURE);
+       }
+
+       int
+       main(int argc, char *argv[])
+       {
+           int    semid, nsems, flags, opt;
+           key_t  key;
+
+           flags = 0;
+           while ((opt = getopt(argc, argv, "cx")) != -1) {
+               switch (opt) {
+               case 'c': flags |= IPC_CREAT;   break;
+               case 'x': flags |= IPC_EXCL;    break;
+               default:  usage(argv[0]);
+               }
+           }
+
+           if (argc != optind + 3)
+               usage(argv[0]);
+
+           key = ftok(argv[optind], argv[optind + 1][0]);
+           if (key == -1) {
+               perror("ftok");
+               exit(EXIT_FAILURE);
+           }
+
+           nsems = atoi(argv[optind + 2]);
+
+           semid = semget(key, nsems, flags | 0600);
+           if (semid == -1) {
+               perror("semget");
+               exit(EXIT_FAILURE);
+           }
+
+           printf("ID = %d\n", semid);
+
+           exit(EXIT_SUCCESS);
+       }
diff --git a/Practice/04.10/shmat/svshm_string.h b/Practice/04.10/shmat/svshm_string.h
new file mode 100644
index 0000000..3ee6af9
--- /dev/null
+++ b/Practice/04.10/shmat/svshm_string.h
@@ -0,0 +1,26 @@
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <sys/sem.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define errExit(msg)        \
+    do                      \
+    {                       \
+        perror(msg);        \
+        exit(EXIT_FAILURE); \
+    } while (0)
+
+union semun
+{ /* Used in calls to semctl() */
+    int val;
+    struct semid_ds *buf;
+    unsigned short *array;
+#if defined(__linux__)
+    struct seminfo *__buf;
+#endif
+};
+
+#define MEM_SIZE 4096
diff --git a/Practice/04.10/shmat/svshm_string_read.c b/Practice/04.10/shmat/svshm_string_read.c
new file mode 100644
index 0000000..ae6f182
--- /dev/null
+++ b/Practice/04.10/shmat/svshm_string_read.c
@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ipc.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+
+#include "svshm_string.h"
+
+int main(void)
+{
+    int semid, shmid;
+    char *addr;
+    union semun arg, dummy;
+    struct sembuf sop;
+
+    /* Create shared memory and semaphore set containing one
+       semaphore. */
+
+    shmid = shmget(IPC_PRIVATE, MEM_SIZE, IPC_CREAT | 0600);
+    if (shmid == -1)
+        errExit("shmget");
+
+    semid = semget(IPC_PRIVATE, 1, IPC_CREAT | 0600);
+    if (semid == -1)
+        errExit("semget");
+
+    /* Attach shared memory into our address space. */
+
+    addr = shmat(shmid, NULL, SHM_RDONLY);
+    if (addr == (void *)-1)
+        errExit("shmat");
+
+    /* Initialize semaphore 0 in set with value 1. */
+
+    arg.val = 1;
+    if (semctl(semid, 0, SETVAL, arg) == -1)
+        errExit("semctl");
+
+    printf("shmid = %d; semid = %d\n", shmid, semid);
+
+    /* Wait for semaphore value to become 0. */
+
+    sop.sem_num = 0;
+    sop.sem_op = 0;
+    sop.sem_flg = 0;
+
+    if (semop(semid, &sop, 1) == -1)
+        errExit("semop");
+
+    /* Print the string from shared memory. */
+
+    printf("%s\n", addr);
+
+    /* Remove shared memory and semaphore set. */
+
+    if (shmctl(shmid, IPC_RMID, NULL) == -1)
+        errExit("shmctl");
+    if (semctl(semid, 0, IPC_RMID, dummy) == -1)
+        errExit("semctl");
+
+    exit(EXIT_SUCCESS);
+}
diff --git a/Practice/04.10/shmat/svshm_string_write.c b/Practice/04.10/shmat/svshm_string_write.c
new file mode 100644
index 0000000..121c614
--- /dev/null
+++ b/Practice/04.10/shmat/svshm_string_write.c
@@ -0,0 +1,53 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+
+#include "svshm_string.h"
+
+int main(int argc, char *argv[])
+{
+    int semid, shmid;
+    char *addr;
+    size_t len;
+    struct sembuf sop;
+
+    if (argc != 4)
+    {
+        fprintf(stderr, "Usage: %s shmid semid string\n", argv[0]);
+        exit(EXIT_FAILURE);
+    }
+
+    len = strlen(argv[3]) + 1; /* +1 to include trailing '\0' */
+    if (len > MEM_SIZE)
+    {
+        fprintf(stderr, "String is too big!\n");
+        exit(EXIT_FAILURE);
+    }
+
+    /* Get object IDs from command-line. */
+    if((key = ftok("bin/sh", 'A')) = -1) errExit
+    shmid = atoi(argv[1]);
+    semid = atoi(argv[2]);
+
+    /* Attach shared memory into our address space and copy string
+       (including trailing null byte) into memory. */
+
+    addr = shmat(shmid, NULL, 0);
+    if (addr == (void *)-1)
+        errExit("shmat");
+
+    memcpy(addr, argv[3], len);
+
+    /* Decrement semaphore to 0. */
+
+    sop.sem_num = 0;
+    sop.sem_op = -1;
+    sop.sem_flg = 0;
+
+    if (semop(semid, &sop, 1) == -1)
+        errExit("semop");
+
+    exit(EXIT_SUCCESS);
+}
diff --git a/Practice/29.09/code.c b/Practice/29.09/code.c
new file mode 100644
index 0000000..488c0ad
--- /dev/null
+++ b/Practice/29.09/code.c
@@ -0,0 +1,147 @@
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <time.h>
+#include <signal.h>
+#include <poll.h>
+#define NUM 4
+#define errExit(msg)    do { perror(msg); _exit(EXIT_FAILURE); } while (0)
+#define errExit1(msg)    { perror(msg); _exit(EXIT_FAILURE); } 
+
+void child_handler(int sig) {
+    pid_t pid;
+    while((pid = waitpid(-1, NULL, WNOHANG)) > 0);
+}
+
+void int_handler(int sig){
+   printf("Ctrl-C pressed, do nothing...\n");
+}
+
+int main(int argc, char *argv[]) {
+
+  struct sigaction new_act, old_act;
+  sigemptyset (&new_act.sa_mask);
+  new_act.sa_flags = 0;
+  new_act.sa_flags = SA_RESTART;
+  new_act.sa_handler = child_handler;
+
+  sigaction (SIGCHLD, &new_act, &old_act);
+
+  struct sigaction nint_act, oint_act;
+  sigemptyset (&nint_act.sa_mask);
+  nint_act.sa_flags = 0;
+  nint_act.sa_flags = SA_RESTART;
+  nint_act.sa_handler = int_handler;
+
+  sigaction (SIGINT, &nint_act, &oint_act);
+
+  int pipefd[NUM][2];
+  pid_t cpid[NUM];
+
+  int nfds, num_open_fds;
+  struct pollfd *pfds;
+  int ready;
+
+  unsigned char i,tt;
+  char buf;
+  int rr;
+
+  if (argc != 2) {
+     fprintf(stderr, "Usage: %s <string>\n", argv[0]);
+     _exit(EXIT_FAILURE);
+  }
+
+  srand(time(NULL));
+
+  num_open_fds = nfds = NUM;
+  pfds = calloc(nfds, sizeof(struct pollfd));
+  if (pfds == NULL) errExit("malloc");
+
+  for (i=0;i<NUM;i++){           
+    tt=(unsigned char)rand()%9;
+    dprintf(STDOUT_FILENO,"child %d life time is %X\n",i,tt);
+           
+    if (pipe(pipefd[i]) == -1) errExit("pipe");
+    pfds[i].fd = pipefd[i][0];
+    pfds[i].events = POLLIN;
+    if ((cpid[i] = fork()) == -1) errExit("fork");
+
+    if (cpid[i] == 0) {    
+       close(pipefd[i][0]);
+       for (int j=0; j<i; j++){  
+           close(pipefd[j][0]);
+           close(pipefd[j][1]);
+       }
+       write(pipefd[i][1], argv[1], strlen(argv[1]));
+       write(pipefd[i][1], &i, 1);
+       write(pipefd[i][1], &tt, 1);
+       sleep(tt);
+       close(pipefd[i][1]);
+       _exit(EXIT_SUCCESS);
+    }  
+  }
+
+  for (int j=0; j<i; j++) close(pipefd[j][1]);
+
+  dprintf(STDOUT_FILENO,"Opened %d pipes, waiting...\n",num_open_fds);
+
+  while (num_open_fds > 0) {
+
+    do{
+      dprintf(STDOUT_FILENO,"\ntry poll:\n");
+      for (i = 0; i < NUM; i++) pfds[i].revents=0;
+      ready = poll(pfds, nfds, -1);
+      if(ready == -1)
+         switch (errno) {
+           case EINTR: dprintf(STDOUT_FILENO,"\nPoll interrupted, repeat.\n"); 
+                       continue;
+           default: errExit("poll");
+         }
+    } while (ready <= 0);
+
+    for (i = 0; i < NUM; i++) {
+       if (pfds[i].revents != 0) {
+          dprintf(STDOUT_FILENO,"  fd=%d; events: %7s%8s%9s%8s%8s  ", pfds[i].fd,
+                  (pfds[i].revents & POLLIN)  ? "POLLIN "  : "",
+                  (pfds[i].revents & POLLHUP) ? "POLLHUP " : "",
+                  (pfds[i].revents & POLLNVAL) ? "POLLNVAL " : "",
+                  (pfds[i].revents & POLLPRI) ? "POLLPRI " : "",
+                  (pfds[i].revents & POLLERR) ? "POLLERR " : "");
+          if (pfds[i].revents & POLLIN) {
+
+             do {
+                rr=read(pfds[i].fd, &buf, 1);
+                if (rr < 0)
+                   switch (errno) {
+                     case EINTR: dprintf(STDOUT_FILENO,"\nRead interrupted, repeat.\n"); 
+                                 continue;
+                     default: errExit("read");
+                   }
+               if(rr == 0 ) 
+                   dprintf(STDOUT_FILENO,"\n");
+               else
+                   dprintf(STDOUT_FILENO,"[%2X]",buf);
+             } while (rr > 0);
+
+          } 
+          else 
+          if ((pfds[i].revents & (POLLHUP | ~POLLIN))) {
+             dprintf(STDOUT_FILENO,"Closing [%d], pipefd %d, pfds.fd %d\n",i,pipefd[i][0],pfds[i].fd);
+             if (close(pfds[i].fd) < 0 ) errExit("close pfds");
+             pfds[i].fd = -1;
+             pfds[i].events=0;
+             num_open_fds--;
+             dprintf(STDOUT_FILENO,"Still opened fds %d\n",num_open_fds);
+          }
+       }
+    }
+  }
+printf("Niggers");
+while (1) pause;
+  return EXIT_SUCCESS;
+}
diff --git a/Practice/matrix/Makefile b/Practice/matrix/Makefile
new file mode 100644
index 0000000..be9314c
--- /dev/null
+++ b/Practice/matrix/Makefile
@@ -0,0 +1,9 @@
+LIB = 
+
+default: run
+
+build:
+	gcc func.h func.c main.c -o matrix_app ${LIB}
+
+run: build
+		./matrix_app
diff --git a/Practice/matrix/func.c b/Practice/matrix/func.c
new file mode 100644
index 0000000..61c881b
--- /dev/null
+++ b/Practice/matrix/func.c
@@ -0,0 +1,38 @@
+
+#include "func.h"
+
+void init_matr(int c, short int mat[c][c])
+{
+    for (int i = 0; i < c; i++)
+    {
+        for (int j = 0; j < c; j++)
+        {
+            mat[i][j] = rand() % N;
+        }
+    }
+}
+void out_matr(int c, short int mat[c][c])
+{
+    for (int i = 0; i < c; i++)
+    {
+        for (int j = 0; j < c; j++)
+        {
+            printf("[%d] ", mat[i][j]);
+        }
+        printf("\n");
+    }
+}
+
+void trans(int c, short int mat[c][c])
+{
+    for (int i = 0; i < c; i++)
+    {
+        for (int j = i + 1; j < c; j++)
+        {
+            short c;
+            c = mat[i][j];
+            mat[i][j] = mat[j][i];
+            mat[j][i] = c;
+        }
+    }
+}
diff --git a/Practice/matrix/func.h b/Practice/matrix/func.h
new file mode 100644
index 0000000..033dc2c
--- /dev/null
+++ b/Practice/matrix/func.h
@@ -0,0 +1,15 @@
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <time.h>
+#define N 10
+#define n 100
+
+void init_matr(int c, short int mat[c][c]);
+void out_matr(int c, short int mat[c][c]);
+void trans(int c, short int mat[c][c]);
\ No newline at end of file
diff --git a/Practice/matrix/main.c b/Practice/matrix/main.c
new file mode 100644
index 0000000..e912db0
--- /dev/null
+++ b/Practice/matrix/main.c
@@ -0,0 +1,77 @@
+
+#include "func.h"
+
+int main(int argc, char *argv[])
+{
+    int pipefd[n][2], fd_ans;
+    caddr_t addr_ans;
+    pid_t cpid[n];
+    short mat1[n][n], mat2[n][n];
+    fd_ans = open(argv[2], O_RDWR | O_CREAT);
+    srand(time(NULL));
+    init_matr(n, mat1);
+    init_matr(n, mat2);
+    out_matr(n, mat1);
+    trans(n, mat2);
+    printf("\n");
+    out_matr(n, mat2);
+    printf("\n");
+    for (int i = 0; i < n; i++)
+    {
+        if (pipe(pipefd[i]) == -1)
+        {
+            perror("pipe");
+            exit(EXIT_FAILURE);
+        }
+        cpid[i] = fork();
+        if (cpid[i] == -1)
+        {
+            perror("fork");
+            exit(EXIT_FAILURE);
+        }
+
+        if (cpid[i] == 0)
+        {
+            int result[n];
+            close(pipefd[i][0]);
+            for (int j = 0; j < i; j++)
+            {
+                close(pipefd[j][0]);
+                close(pipefd[j][1]);
+            }
+            for (int j = 0; j < n; j++)
+            {
+                int sum = 0;
+                for (int k = 0; k < n; k++)
+                {
+                    sum += mat1[i][k] * mat2[j][k];
+                }
+                result[j] = sum;
+            }
+            write(pipefd[i][1], result, n * sizeof(int));
+            close(pipefd[i][1]);
+            exit(EXIT_SUCCESS);
+        }
+        else
+        {
+            close(pipefd[i][1]);
+        }
+    }
+
+    printf("Resulting mat\n");
+    for (int i = 0; i < n; i++)
+    {
+        waitpid(cpid[i], NULL, WNOHANG);
+        int result[n];
+        read(pipefd[i][0], result, n * sizeof(int));
+        for (int j = 0; j < n; j++)
+        {
+           //printf("[%d] ", result[j]);
+            addr_ans = mmap((caddr_t)0, PROT_READ | PROT_WRITE, MAP_SHARED, fd_dst, 0);
+
+        }
+        printf("\n");
+        close(pipefd[i][0]);
+    }
+    exit(EXIT_SUCCESS);
+}
diff --git a/Practice/matrix/matrix_app b/Practice/matrix/matrix_app
new file mode 100755
index 0000000..c8b2ab8
Binary files /dev/null and b/Practice/matrix/matrix_app differ
diff --git a/Practice/sock20.10.23/c3.c b/Practice/sock20.10.23/c3.c
new file mode 100644
index 0000000..06e81a1
--- /dev/null
+++ b/Practice/sock20.10.23/c3.c
@@ -0,0 +1,91 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <error.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <time.h>
+
+#define SERVER_PATH "/tmp/unix_sock.server"
+#define CLIENT_PATH "unix_sock.client"
+#define DATA "Hello from client"
+#define BUF 128
+
+int main(int argc,char *argv[]){
+
+    int client_sock, rc, len;
+    struct sockaddr_un server_sockaddr; 
+    struct sockaddr_un client_sockaddr; 
+    char buf[BUF];
+    size_t bs=BUF;
+    char cpath[22];
+
+    srand(time(NULL));
+    sprintf(cpath,"%03d-%s",rand()%1000,CLIENT_PATH); 
+    len = sizeof(client_sockaddr);
+    memset(&server_sockaddr, 0, sizeof(struct sockaddr_un));
+    memset(&client_sockaddr, 0, sizeof(struct sockaddr_un));
+     
+    client_sock = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (client_sock == -1) {
+        perror("socket");
+        exit(1);
+    }
+
+
+    client_sockaddr.sun_family = AF_UNIX;   
+    strcpy(client_sockaddr.sun_path, cpath); 
+    
+    unlink(cpath);
+    rc = bind(client_sock, (struct sockaddr *) &client_sockaddr, len);
+    if (rc == -1){
+        perror("bind");
+        close(client_sock);
+        exit(1);
+    }
+        
+    server_sockaddr.sun_family = AF_UNIX;
+    strcpy(server_sockaddr.sun_path, SERVER_PATH);
+    rc = connect(client_sock, (struct sockaddr *) &server_sockaddr, len);
+    if(rc == -1){
+        perror("connect");
+        close(client_sock);
+        exit(1);
+    }
+    
+    if (argc > 1) 
+       strcpy(buf, argv[1]);
+    else    
+       strcpy(buf, DATA);                 
+
+    printf("Sending data...\n");
+    rc = send(client_sock, buf, strlen(buf), 0);
+    if (rc == -1) {
+        perror("send");
+        close(client_sock);
+        exit(1);
+    }   
+    else {
+        printf("Data sent!\n");
+    }
+
+    printf("Waiting to recieve data...\n");
+    memset(buf, 0, sizeof(buf));
+    rc = recv(client_sock, buf, bs,0);
+    if (rc == -1) {
+        perror("recv");
+        close(client_sock);
+        exit(1);
+    }   
+    else {
+        printf("DATA RECEIVED = %s\n", buf);
+    }
+    
+    close(client_sock);
+    unlink(cpath);
+    
+    return 0;
+}
diff --git a/Practice/sock20.10.23/c4.c b/Practice/sock20.10.23/c4.c
new file mode 100644
index 0000000..010362d
--- /dev/null
+++ b/Practice/sock20.10.23/c4.c
@@ -0,0 +1,142 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <error.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <time.h>
+
+#define errExit(msg)       do { perror(msg); _exit(EXIT_FAILURE); } while (0)
+#define SerrExit(s,msg)    do { close(s); perror(msg); _exit(EXIT_FAILURE); } while (0)
+
+#define SERVER_PATH "/tmp/unix_sock.server"
+#define CLIENT_PATH "unix_sock.client"
+#define DATA "Hello from client"
+#define BUF 128
+#define FINS "exit_s"
+#define FINC "exit_c"
+//#define INFO 
+
+int rcvBuffer(int sock_fd){
+      int rcvBufferSize;
+      socklen_t sockOptSize = sizeof(rcvBufferSize);
+      getsockopt(sock_fd, SOL_SOCKET, SO_RCVBUF, &rcvBufferSize, &sockOptSize);
+#ifdef INFO
+      printf("initial socket receive buf %d\n", rcvBufferSize);
+#endif
+      return rcvBufferSize;
+}
+
+int recvCount(const void *s, int size){
+   register int count;
+   register int mark;
+   register char *p;
+   p=(char *)s;
+   count = 0;
+   mark = 0;
+   do {
+     if (*p && !(*(p+1))) count++;
+#ifdef INFO
+     printf("[%c][%X]\n",*p,*p);
+#endif
+     p++;
+     mark++;
+   } while (!((*p == '\0') && (*(p+1)=='\0')) && (mark < size));
+   return count;
+}
+
+int main(int argc,char *argv[]){
+
+    int client_sock, rc, len;
+    struct sockaddr_un server_sockaddr; 
+    struct sockaddr_un client_sockaddr; 
+    char obuf[BUF];
+    char **ibuf;
+    size_t obs=BUF,ibs;
+    char cpath[22];
+
+    sprintf(cpath,"%d-%s",getpid(),CLIENT_PATH); 
+    len = sizeof(client_sockaddr);
+    memset(&server_sockaddr, 0, sizeof(struct sockaddr_un));
+    memset(&client_sockaddr, 0, sizeof(struct sockaddr_un));
+     
+    client_sock = socket(AF_UNIX, SOCK_STREAM, 0);
+    if (client_sock == -1) {
+        perror("socket");
+        exit(1);
+    }
+
+
+    client_sockaddr.sun_family = AF_UNIX;   
+    strcpy(client_sockaddr.sun_path, cpath); 
+    
+    unlink(cpath);
+    rc = bind(client_sock, (struct sockaddr *) &client_sockaddr, len);
+    if (rc == -1) SerrExit(client_sock,"bind");
+
+    server_sockaddr.sun_family = AF_UNIX;
+    strcpy(server_sockaddr.sun_path, SERVER_PATH);
+    rc = connect(client_sock, (struct sockaddr *) &server_sockaddr, len);
+    if (rc == -1) SerrExit(client_sock,"connect");
+    
+    ibs=rcvBuffer(client_sock);
+    if ((ibuf=(char **)malloc(ibs)) == NULL ) errExit("malloc");
+
+    do {
+      memset(obuf, 0, obs);
+       printf("> ");
+      scanf("%s",obuf);
+
+      printf("Sending data...\n");
+      rc = send(client_sock, obuf, strlen(obuf)+1, 0);
+      if (rc == -1) {
+         perror("send");
+         close(client_sock);
+         exit(1);
+      } else {
+        printf("Data sent!\n");
+      }
+
+      printf("Waiting to recieve data...\n");
+      memset(ibuf, 0, ibs);
+      rc = recv(client_sock, ibuf, ibs,0);
+      if (rc == -1) {
+         perror("recv");
+         close(client_sock);
+         exit(1);
+      } else {
+        int c = recvCount(ibuf,ibs);
+#ifdef INFO
+        char *p = (char *)ibuf;
+        printf("count: %d resieved\n",c);
+        for (int i = 0; i < 32; i++){
+           printf("[%c][%X]",*p,*p);
+           p++;
+        }
+        printf("\n");
+#endif
+#ifndef INFO
+        char p[obs];
+        char *tp = (char *)ibuf;
+//        if ((ibuf=(char **)malloc(ibs)) == NULL ) errExit("malloc");
+        for (int i = 0; i < c; i++){
+           memset(p,0,obs);
+           while (*tp) {strncat(p,tp,1);tp++;}
+           tp++;
+//           printf("DATA RECEIVED [%ld] = %s\n", strlen(ibuf[i]),ibuf[i]);
+           printf("DATA RECEIVED [%ld] = %s\n", strlen(p),p);
+//           printf("DATA RECEIVED [%ld] = %s\n", strlen(p[i]),p[i]);
+        }
+#endif
+      }
+      
+    } while (strcmp(obuf,FINC) && strcmp(obuf,FINS));
+
+    close(client_sock);
+    unlink(cpath);
+    
+    return 0;
+}
diff --git a/Practice/sock20.10.23/s3.c b/Practice/sock20.10.23/s3.c
new file mode 100644
index 0000000..e82bbd3
--- /dev/null
+++ b/Practice/sock20.10.23/s3.c
@@ -0,0 +1,106 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <error.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#define errExit(msg)    do { perror(msg); _exit(EXIT_FAILURE); } while (0)
+
+#define SOCK_PATH  "/tmp/unix_sock.server"
+#define DATA "Hello from server"
+#define BUF 128
+#define FIN "exit"
+
+int session(int client_sock, struct sockaddr_un server_sockaddr, struct sockaddr_un client_sockaddr){     
+ int rc;
+ char inbuf[BUF];
+ char outbuf[BUF];
+ int bytes_rec = 0;
+ size_t bs = BUF;
+ socklen_t len;
+   len = sizeof(client_sockaddr);
+   rc = getpeername(client_sock, (struct sockaddr *) &client_sockaddr, &len);
+   if (rc == -1){
+      close(client_sock);
+      errExit("getpeer");
+   } else {
+      printf("Client socket filepath: %s\n", client_sockaddr.sun_path);
+   }
+    
+   printf("waiting to read...\n");
+   memset(inbuf, 0, bs);                
+   bytes_rec = recv(client_sock, inbuf, bs, 0);
+   if (bytes_rec == -1){
+      close(client_sock);
+      errExit("recv");
+   } else {
+      printf("DATA RECEIVED = %s\n", inbuf);
+   }
+    
+   memset(outbuf, 0, bs);
+   strcpy(outbuf, DATA);      
+   printf("Sending data...\n");
+   rc = send(client_sock, outbuf, strlen(outbuf), 0);
+   if (rc == -1) {
+      close(client_sock);
+      errExit("send");
+   } else {
+      printf("Data sent!\n");
+   }
+   close(client_sock);
+   return strcmp(inbuf,FIN);
+}
+
+
+int main(void){
+
+ int server_sock, client_sock, rc;
+ socklen_t len;
+ struct sockaddr_un server_sockaddr;
+ struct sockaddr_un client_sockaddr;     
+ int backlog = 10;
+
+ len = sizeof(server_sockaddr);
+ memset(&server_sockaddr, 0, sizeof(struct sockaddr_un));
+ memset(&client_sockaddr, 0, sizeof(struct sockaddr_un));
+    
+ server_sock = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (server_sock == -1) errExit("socket");
+    
+ server_sockaddr.sun_family = AF_UNIX;   
+ strcpy(server_sockaddr.sun_path, SOCK_PATH); 
+    
+ unlink(SOCK_PATH);
+ rc = bind(server_sock, (struct sockaddr *) &server_sockaddr, len);
+ if (rc == -1){
+    close(server_sock);
+    errExit("bind");
+ }
+    
+ rc = listen(server_sock, backlog);
+ if (rc == -1){
+    close(server_sock);
+    errExit("listen");
+ }
+
+ printf("socket listening...\n");
+
+ do {
+   client_sock = accept(server_sock, (struct sockaddr *) &client_sockaddr, &len);
+   if (client_sock == -1){
+      close(server_sock);
+      close(client_sock);
+      errExit("accept");
+   }
+ } while (session(client_sock,server_sockaddr,client_sockaddr));
+   
+
+ close(server_sock);
+ unlink(SOCK_PATH);
+    
+ return 0;
+}
diff --git a/Practice/sock20.10.23/s4.c b/Practice/sock20.10.23/s4.c
new file mode 100644
index 0000000..48b2e3f
--- /dev/null
+++ b/Practice/sock20.10.23/s4.c
@@ -0,0 +1,142 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <error.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+
+#define errExit(msg)    do { perror(msg); _exit(EXIT_FAILURE); } while (0)
+
+#define SOCK_PATH  "/tmp/unix_sock.server"
+#define DATA "Hello from server"
+#define BUF 128
+#define FINS "exit_s"
+#define FINC "exit_c"
+
+void child_handler(int sig) {
+    pid_t pid;
+    while((pid = waitpid(-1, NULL, WNOHANG)) > 0);
+}
+
+void session(int client_sock, struct sockaddr_un server_sockaddr, struct sockaddr_un client_sockaddr){     
+ int rc;
+ char inbuf[BUF];
+ char outbuf[BUF];
+ int bytes_rec = 0;
+ size_t bs = BUF;
+ socklen_t len;
+ pid_t ppid, pid;
+
+ ppid=getppid();
+ pid=getpid();
+
+   len = sizeof(client_sockaddr);
+   rc = getpeername(client_sock, (struct sockaddr *) &client_sockaddr, &len);
+   if (rc == -1){
+      close(client_sock);
+      errExit("getpeer");
+   } else {
+      printf("[%d] Client socket filepath: %s\n", pid, client_sockaddr.sun_path);
+   }
+   do { 
+     printf("waiting for %s...\n",client_sockaddr.sun_path);
+     memset(inbuf, 0, bs);                
+     bytes_rec = recv(client_sock, inbuf, bs, 0);
+     if (bytes_rec == -1){
+        close(client_sock);
+        errExit("recv");
+     } else {
+      printf("[%s]:  %s\n", client_sockaddr.sun_path, inbuf);
+     }
+    
+     memset(outbuf, 0, bs);
+     strcpy(outbuf, DATA);      
+     printf("Sending data...\n");
+     rc = send(client_sock, outbuf, strlen(outbuf)+1, 0);
+     if (rc == -1) {
+        close(client_sock);
+        errExit("send");
+     } else {
+        printf("Data sent!\n");
+     }
+     if (strcmp(inbuf,FINS) == 0 ) {kill(ppid,SIGTERM);break;}
+   } while (strcmp(inbuf,FINC));
+   memset(outbuf, 0, bs);
+   sprintf(outbuf,"Exit %d\n",pid);      
+   rc = send(client_sock, outbuf, strlen(outbuf)+1, 0);
+   if (rc == -1) {
+      close(client_sock);
+      errExit("send");
+   } 
+   close(client_sock);
+   exit(0);
+}
+
+int main(void){
+
+ int server_sock, client_sock, rc;
+ socklen_t len;
+ struct sockaddr_un server_sockaddr;
+ struct sockaddr_un client_sockaddr;     
+ int backlog = 10;
+ pid_t pid;
+
+ struct sigaction new_act, old_act;
+ sigemptyset (&new_act.sa_mask);
+ new_act.sa_flags = SA_RESTART;
+ new_act.sa_handler = child_handler;
+ sigaction (SIGCHLD, &new_act, &old_act);
+
+ len = sizeof(server_sockaddr);
+ memset(&server_sockaddr, 0, sizeof(struct sockaddr_un));
+ memset(&client_sockaddr, 0, sizeof(struct sockaddr_un));
+    
+ server_sock = socket(AF_UNIX, SOCK_STREAM, 0);
+ if (server_sock == -1) errExit("socket");
+    
+ server_sockaddr.sun_family = AF_UNIX;   
+ strcpy(server_sockaddr.sun_path, SOCK_PATH); 
+    
+ unlink(SOCK_PATH);
+ rc = bind(server_sock, (struct sockaddr *) &server_sockaddr, len);
+ if (rc == -1){
+    close(server_sock);
+    errExit("bind");
+ }
+    
+ rc = listen(server_sock, backlog);
+ if (rc == -1){
+    close(server_sock);
+    errExit("listen");
+ }
+
+ printf("socket listening...\n");
+
+ do {
+   client_sock = accept(server_sock, (struct sockaddr *) &client_sockaddr, &len);
+   if (client_sock == -1){
+      close(server_sock);
+      close(client_sock);
+      errExit("accept");
+   }
+   if ((pid = fork()) == -1 ) {
+      close(server_sock);
+      close(client_sock);
+      errExit("fork");
+   }
+   if (pid == 0) session(client_sock,server_sockaddr,client_sockaddr);
+   close(client_sock);
+ } while (1);
+   
+
+ close(server_sock);
+ unlink(SOCK_PATH);
+    
+ return 0;
+}
diff --git a/Practice/trash/app b/Practice/trash/app
new file mode 100755
index 0000000..e287e7b
Binary files /dev/null and b/Practice/trash/app differ
diff --git a/Practice/trash/app_poll b/Practice/trash/app_poll
new file mode 100755
index 0000000..8384509
Binary files /dev/null and b/Practice/trash/app_poll differ
diff --git a/Practice/trash/child.c b/Practice/trash/child.c
new file mode 100644
index 0000000..c14b1fd
--- /dev/null
+++ b/Practice/trash/child.c
@@ -0,0 +1,86 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <time.h>
+#define DATA 20
+#define NUM 4
+
+struct Data {
+    char s[DATA + 1];
+    pid_t cpid;
+    unsigned char i, t;
+};
+
+int main(int argc, char *argv[]){
+    int pipefd[4][2];
+    pid_t cpid[4];
+    unsigned char i, tt;
+    int rr, wt;
+
+if (argc != 2){
+    fprintf(stderr, "Usage: %s <string>\n", argv[0]);
+    exit(EXIT_FAILURE);
+}
+
+srand(time(NULL));
+
+for(i = 0; i < NUM; i++){
+    if (pipe(pipefd[i]) == -1){
+        perror("Pipe");
+        exit(EXIT_FAILURE);
+    }
+    tt = (unsigned char)rand()%8;
+    dprintf(STDOUT_FILENO, "Time[%X]\n", tt);
+
+    cpid[i] = fork();
+    if (cpid[i] == -1){
+        perror("Fork");
+        exit(EXIT_FAILURE);
+    }
+
+    if (cpid[i] == 0){
+        struct Data data;
+        close(pipefd[i][0]);
+        for(int j = 0; j < i; j++){
+            close(pipefd[j][0]);
+            close(pipefd[j][1]);
+        }
+        data.cpid = getpid();
+        data.i = i;
+        data.t = tt;
+        strncpy(data.s, argv[1], DATA);
+        write(pipefd[i][1], &data, sizeof(struct Data));
+        close(pipefd[i][1]);
+        sleep(tt);
+        _exit(EXIT_FAILURE);
+    } else {
+        dprintf(STDOUT_FILENO, "Start [%d]\n", cpid[i]);
+        close(pipefd[i][1]);
+    }
+}
+
+printf("Waiting...\n");
+
+while((wt = waitpid(-1, NULL, WNOHANG)) > -1){
+    if (wt > 0) for(i = 0; i < NUM; i++){
+        if (cpid[i] == wt){
+            struct Data data;
+            while((rr = read(pipefd[i][0], &data, sizeof(struct Data))) > 0){
+                dprintf(STDOUT_FILENO, "[%d] num = %d, time = %d [%s]\n", data.cpid, data.i, data.t, data.s);
+            }
+            if (rr == 0) close(pipefd[i][0]);
+        }
+    }
+    usleep(3000000);
+}
+if (errno == ECHILD)
+    perror("Finish:");
+else
+    perror("Wait error:");
+    exit(EXIT_SUCCESS);
+}
\ No newline at end of file
diff --git a/Practice/trash/done b/Practice/trash/done
new file mode 100644
index 0000000..7e045a0
--- /dev/null
+++ b/Practice/trash/done
@@ -0,0 +1,2 @@
+be be be be
+aaaaaaaaaaa
\ No newline at end of file
diff --git a/Practice/trash/lect.c b/Practice/trash/lect.c
new file mode 100644
index 0000000..81ed6cd
--- /dev/null
+++ b/Practice/trash/lect.c
@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+
+int main(int argc, char *argv[]){
+    int fd_src, fd_dst;
+    caddr_t addr_src, addr_dst;
+    struct stat filestat;
+    fd_src = open(argv[1], O_RDONLY);
+    fd_dst = open(argv[2], O_RDWR | O_CREAT);
+    fstat(fd_src, &filestat);
+    lseek(fd_dst, filestat.st_size - 1, SEEK_SET);
+    write(fd_dst, "", 1);
+    addr_src = mmap((caddr_t)0, filestat.st_size, PROT_READ, MAP_SHARED, fd_src, 0);
+    addr_dst = mmap((caddr_t)0, filestat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd_dst, 0);
+    memcpy(addr_dst, addr_src, filestat.st_size);
+    exit(0);
+}
\ No newline at end of file
diff --git a/Practice/trash/pin.c b/Practice/trash/pin.c
new file mode 100644
index 0000000..f99b0de
--- /dev/null
+++ b/Practice/trash/pin.c
@@ -0,0 +1,74 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <time.h>
+#define NUM 4
+
+int main(int argc, char *argv[]){
+    int pipefd[4][2];
+    pid_t cpid[4];
+    unsigned char i, tt;
+    char buf;
+    int rr, wt;
+
+if (argc != 2){
+    fprintf(stderr, "Usage: %s <string>\n", argv[0]);
+    exit(EXIT_FAILURE);
+}
+
+srand(time(NULL));
+
+for(i = 0; i < NUM; i++){
+    if (pipe(pipefd[i]) == -1){
+        perror("Pipe");
+        exit(EXIT_FAILURE);
+    }
+    tt = (unsigned char)rand()%8;
+    dprintf(STDOUT_FILENO, "Time[%X]\n", tt);
+
+    cpid[i] = fork();
+    if (cpid[i] == -1){
+        perror("Fork");
+        exit(EXIT_FAILURE);
+    }
+
+    if (cpid[i] == 0){
+        close(pipefd[i][0]);
+        write(pipefd[i][1], argv[1], strlen(argv[1]));
+        write(pipefd[i][1], &i, 1);
+        write(pipefd[i][1], &tt, 1);
+        close(pipefd[i][1]);
+        sleep(tt);
+        _exit(EXIT_FAILURE);
+    } else {
+        close(pipefd[i][1]);
+    }
+}
+
+printf("Waiting...\n");
+
+while((wt = waitpid(-1, NULL, WNOHANG)) > -1){
+    if (wt > 0) for(i = 0; i < NUM; i++){
+        if (cpid[i] == wt){
+            while((rr = read(pipefd[i][0], &buf, 1)) > 0){
+                write(STDOUT_FILENO, &buf, 1);
+                dprintf(STDOUT_FILENO, "[%X]", buf);
+            }
+            if (rr == 0){
+                write(STDOUT_FILENO, "\n", 1);
+                close(pipefd[i][0]);
+            }
+        }
+    }
+}
+if (errno == ECHILD)
+    perror("Finish:");
+else
+    perror("Wait error:");
+    exit(EXIT_SUCCESS);
+}
\ No newline at end of file
diff --git a/Practice/trash/poll.c b/Practice/trash/poll.c
new file mode 100644
index 0000000..9c8ce94
--- /dev/null
+++ b/Practice/trash/poll.c
@@ -0,0 +1,133 @@
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <time.h>
+#include <signal.h>
+#include <poll.h>
+#define NUM 4
+#define errExit(msg)    do { perror(msg); _exit(EXIT_FAILURE); } while (0)
+#define errExit1(msg)    { perror(msg); _exit(EXIT_FAILURE); } 
+
+void child_handler(int sig) {
+    pid_t pid;
+    while((pid = waitpid(-1, NULL, WNOHANG)) > 0);
+}
+
+int main(int argc, char *argv[]) {
+
+  struct sigaction new_act, old_act;
+  sigemptyset (&new_act.sa_mask);
+  new_act.sa_flags = 0;
+  new_act.sa_handler = child_handler;
+
+  sigaction (SIGCHLD, &new_act, &old_act);
+
+  int pipefd[NUM][2];
+  pid_t cpid[NUM];
+
+  int nfds, num_open_fds;
+  struct pollfd *pfds;
+  int ready;
+
+  unsigned char i,tt;
+  char buf;
+  int rr;
+
+  if (argc != 2) {
+     fprintf(stderr, "Usage: %s <string>\n", argv[0]);
+     _exit(EXIT_FAILURE);
+  }
+
+  srand(time(NULL));
+
+  num_open_fds = nfds = NUM;
+  pfds = calloc(nfds, sizeof(struct pollfd));
+  if (pfds == NULL) errExit("malloc");
+
+  for (i=0;i<NUM;i++){           
+    tt=(unsigned char)rand()%9;
+    dprintf(STDOUT_FILENO,"child %d life time is %X\n",i,tt);
+           
+    if (pipe(pipefd[i]) == -1) errExit("pipe");
+    pfds[i].fd = pipefd[i][0];
+    pfds[i].events = POLLIN;
+    if ((cpid[i] = fork()) == -1) errExit("fork");
+
+    if (cpid[i] == 0) {    
+       close(pipefd[i][0]);
+       for (int j=0; j<i; j++){  
+           close(pipefd[j][0]);
+           close(pipefd[j][1]);
+       }
+       write(pipefd[i][1], argv[1], strlen(argv[1]));
+       write(pipefd[i][1], &i, 1);
+       write(pipefd[i][1], &tt, 1);
+       sleep(tt);
+       close(pipefd[i][1]);
+       _exit(EXIT_SUCCESS);
+    }  
+  }
+
+  for (int j=0; j<i; j++) close(pipefd[j][1]);
+
+  dprintf(STDOUT_FILENO,"Opened %d pipes, waiting...\n",num_open_fds);
+
+  while (num_open_fds > 0) {
+
+    do{
+      dprintf(STDOUT_FILENO,"\ntry poll:\n");
+      for (i = 0; i < NUM; i++) pfds[i].revents=0;
+      ready = poll(pfds, nfds, -1);
+      if(ready == -1)
+         switch (errno) {
+           case EINTR: dprintf(STDOUT_FILENO,"\nPoll interrupted, repeat.\n"); 
+                       continue;
+           default: errExit("poll");
+         }
+    } while (ready <= 0);
+
+    for (i = 0; i < NUM; i++) {
+       if (pfds[i].revents != 0) {
+          dprintf(STDOUT_FILENO,"  fd=%d; events: %7s%8s%9s%8s%8s  ", pfds[i].fd,
+                  (pfds[i].revents & POLLIN)  ? "POLLIN "  : "",
+                  (pfds[i].revents & POLLHUP) ? "POLLHUP " : "",
+                  (pfds[i].revents & POLLNVAL) ? "POLLNVAL " : "",
+                  (pfds[i].revents & POLLPRI) ? "POLLPRI " : "",
+                  (pfds[i].revents & POLLERR) ? "POLLERR " : "");
+          if (pfds[i].revents & POLLIN) {
+
+             do {
+                rr=read(pfds[i].fd, &buf, 1);
+                if (rr < 0)
+                   switch (errno) {
+                     case EINTR: dprintf(STDOUT_FILENO,"\nRead interrupted, repeat.\n"); 
+                                 continue;
+                     default: errExit("read");
+                   }
+               if(rr == 0 ) 
+                   dprintf(STDOUT_FILENO,"\n");
+               else
+                   dprintf(STDOUT_FILENO,"[%2X]",buf);
+             } while (rr > 0);
+
+          } 
+          else 
+          if ((pfds[i].revents & (POLLHUP | ~POLLIN))) {
+             dprintf(STDOUT_FILENO,"Closing [%d], pipefd %d, pfds.fd %d\n",i,pipefd[i][0],pfds[i].fd);
+             if (close(pfds[i].fd) < 0 ) errExit("close pfds");
+             pfds[i].fd = -1;
+             pfds[i].events=0;
+             num_open_fds--;
+             dprintf(STDOUT_FILENO,"Still opened fds %d\n",num_open_fds);
+          }
+       }
+    }
+  }
+
+  return EXIT_SUCCESS;
+}
diff --git a/Practice/trash/poll2.c b/Practice/trash/poll2.c
new file mode 100644
index 0000000..660a080
--- /dev/null
+++ b/Practice/trash/poll2.c
@@ -0,0 +1,142 @@
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <time.h>
+#include <signal.h>
+#include <poll.h>
+
+#define NUM 4
+#define errExit(msg) do { perror(msg); _exit(EXIT_FAILURE); } while (0)
+#define errExit1(msg) { perror(msg); _exit(EXIT_FAILURE); }
+
+struct Child {
+unsigned char lifetime;
+char* message;
+};
+
+void child_handler(int sig) {
+pid_t pid;
+while((pid = waitpid(-1, NULL, WNOHANG)) > 0);
+}
+
+int main(int argc, char *argv[]) {
+
+struct sigaction new_act, old_act;
+sigemptyset (&new_act.sa_mask);
+new_act.sa_flags = 0;
+new_act.sa_handler = child_handler;
+
+sigaction (SIGCHLD, &new_act, &old_act);
+
+int pipefd[NUM][2];
+pid_t cpid[NUM];
+
+int nfds, num_open_fds;
+struct pollfd *pfds;
+int ready;
+
+unsigned char i,tt;
+char buf;
+int rr;
+
+struct Child children[NUM];
+
+if (argc != 2) {
+fprintf(stderr, "Usage: %s <string>\n", argv[0]);
+_exit(EXIT_FAILURE);
+}
+
+srand(time(NULL));
+
+num_open_fds = nfds = NUM;
+pfds = calloc(nfds, sizeof(struct pollfd));
+if (pfds == NULL) errExit("malloc");
+
+for (i=0;i<NUM;i++){
+tt=(unsigned char)rand()%9;
+dprintf(STDOUT_FILENO,"child %d life time is %X\n",i,tt);
+
+children[i].lifetime = tt;
+children[i].message = argv[1];
+
+if (pipe(pipefd[i]) == -1) errExit("pipe");
+pfds[i].fd = pipefd[i][0];
+pfds[i].events = POLLIN;
+if ((cpid[i] = fork()) == -1) errExit("fork");
+
+if (cpid[i] == 0) {
+close(pipefd[i][0]);
+for (int j=0; j<i; j++){
+close(pipefd[j][0]);
+close(pipefd[j][1]);
+}
+write(pipefd[i][1], children + i, sizeof(struct Child));
+sleep(tt);
+close(pipefd[i][1]);
+_exit(EXIT_SUCCESS);
+}
+}
+
+for (int j=0; j<i; j++) close(pipefd[j][1]);
+
+dprintf(STDOUT_FILENO,"Opened %d pipes, waiting...\n",num_open_fds);
+
+while (num_open_fds > 0) {
+
+do{
+dprintf(STDOUT_FILENO,"\ntry poll:\n");
+for (i = 0; i < NUM; i++) pfds[i].revents=0;
+ready = poll(pfds, nfds, -1);
+if(ready == -1)
+switch (errno) {
+case EINTR: dprintf(STDOUT_FILENO,"\nPoll interrupted, repeat.\n");
+continue;
+default: errExit("poll");
+}
+} while (ready <= 0);
+
+for (i = 0; i < NUM; i++) {
+if (pfds[i].revents != 0) {
+dprintf(STDOUT_FILENO," fd=%d; events: %7s%8s%9s%8s%8s ", pfds[i].fd,
+(pfds[i].revents & POLLIN) ? "POLLIN " : "",
+(pfds[i].revents & POLLHUP) ? "POLLHUP " : "",
+(pfds[i].revents & POLLNVAL) ? "POLLNVAL " : "",
+(pfds[i].revents & POLLPRI) ? "POLLPRI " : "",
+(pfds[i].revents & POLLERR) ? "POLLERR " : "");
+if (pfds[i].revents & POLLIN) {
+
+do {
+rr=read(pfds[i].fd, &buf, 1);
+if (rr < 0)
+switch (errno) {
+case EINTR: dprintf(STDOUT_FILENO,"\nRead interrupted, repeat.\n");
+continue;
+default: errExit("read");
+}
+if(rr == 0 )
+dprintf(STDOUT_FILENO,"\n");
+else
+dprintf(STDOUT_FILENO,"[%2X]",buf);
+} while (rr > 0);
+
+}
+else
+if ((pfds[i].revents & (POLLHUP | ~POLLIN))) {
+dprintf(STDOUT_FILENO,"Closing [%d], pipefd %d, pfds.fd %d\n",i,pipefd[i][0],pfds[i].fd);
+if (close(pfds[i].fd) < 0 ) errExit("close pfds");
+pfds[i].fd = -1;
+pfds[i].events=0;
+num_open_fds--;
+dprintf(STDOUT_FILENO,"Still opened fds %d\n",num_open_fds);
+}
+}
+}
+}
+
+return EXIT_SUCCESS;
+}
\ No newline at end of file
diff --git a/Practice/trash/prog1 b/Practice/trash/prog1
new file mode 100644
index 0000000..42d46a3
--- /dev/null
+++ b/Practice/trash/prog1
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <error.h>
+
+
+int mtx(int *m, int s){
+    srand(time(NULL));
+    for(int i = 0; i < s; i++)
+        *m++ = rand()%0xffff;
+    return 0;
+}
+
+int main(int argc, char *argv[]){
+    int fd;
+    int n,s;
+    size_t ms;
+    int *m;
+    int *fa;
+    
+    if (argc < 3){
+        printf("Usage: a.out size filename\n");
+    }
+    s = n*n;
+    ms = s*sizeof(int);
+
+    if((fd = open(argv[2], O_RDWR | O_CREAT | O_TRUNC, 0664)) == -1){
+        perror("open: ");
+        exit(errno);
+
+    }
+}
\ No newline at end of file
diff --git a/Practice/trash/text b/Practice/trash/text
new file mode 100644
index 0000000..7e045a0
--- /dev/null
+++ b/Practice/trash/text
@@ -0,0 +1,2 @@
+be be be be
+aaaaaaaaaaa
\ No newline at end of file