init commit

2025-04-13 21:48:15 +03:00
commit 23255e9121
192 changed files with 12200 additions and 0 deletions
@@ -0,0 +1,30 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <wait.h>
+
+// cmd < file1 >> file2
+
+int
+main(int argc, char **argv)
+{
+    char *file1 = argv[2];
+    char *file2 = argv[3];
+    char *cmd = argv[1];
+
+    if (!fork()) {
+        int fin = open(file1, O_RDONLY);
+        int fout = open(file2, O_WRONLY | O_APPEND | O_CREAT, 0666);
+
+        dup2(fin, 0);
+        dup2(fout, 1);
+
+        execlp(cmd, cmd, NULL);
+        _exit(1);
+    } else {
+        wait(NULL);
+    }
+
+    return 0;
+}
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <wait.h>
+
+// cmd1 | cmd2
+
+int
+main(int argc, char **argv)
+{
+    char *cmd1 = argv[1];
+    char *cmd2 = argv[2];
+
+    int fd[2];
+    pipe(fd);
+
+    if (!fork()) {
+        dup2(fd[1], 1);
+        close(fd[0]);
+
+        execlp(cmd1, cmd1, NULL);
+        _exit(1);
+    } else if (!fork()) {
+        dup2(fd[0], 0);
+        close(fd[1]);
+
+        execlp(cmd2, cmd2, NULL);
+        _exit(1);
+    } else {
+        close(fd[0]);
+        close(fd[1]);
+    }
+
+    while (wait(NULL) != -1)
+        ;
+
+    return 0;
+}
@@ -0,0 +1,63 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <wait.h>
+
+int
+main(int argc, char **argv)
+{
+    int n = strtoll(argv[1], NULL, 10);
+
+    int fd1[2];
+    int fd2[2];
+    pipe(fd1);
+    pipe(fd2);
+
+    int tmp = 1;
+    write(fd2[1], &tmp, sizeof(tmp));
+
+    if (!fork()) {
+        int i = 0;
+        close(fd1[0]);
+        close(fd2[1]);
+
+        while (i < n) {
+            read(fd2[0], &i, sizeof(i));
+            if (i > n) {
+                break;
+            }
+            printf("Channel %d: %d\n", 1, i);
+            i++;
+            write(fd1[1], &i, sizeof(i));
+        }
+
+        return 0;
+    } else if (!fork()) {
+        int i = 0;
+        close(fd2[0]);
+        close(fd1[1]);
+
+        while (i < n) {
+            read(fd1[0], &i, sizeof(i));
+            if (i > n) {
+                break;
+            }
+            printf("Channel %d: %d\n", 2, i);
+            i++;
+            write(fd2[1], &i, sizeof(i));
+        }
+
+        return 0;
+    } else {
+        close(fd1[0]);
+        close(fd1[1]);
+        close(fd2[0]);
+        close(fd2[1]);
+    }
+
+    while (wait(NULL) != -1)
+        ;
+
+    return 0;
+}
@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+#include <sys/ipc.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv)
+{
+    key_t key = ftok("/dev/null", 0);
+
+    int semid = semget(key, 2, 0666 | IPC_CREAT);
+    int shmid = shmget(key, sizeof(int), 0666 | IPC_CREAT);
+
+    int *shm = shmat(shmid, NULL, 0);
+
+    pid_t pid = fork();
+    if (!pid) {
+        while (scanf("%d", shm) != -1) {
+            semop(semid, &(struct sembuf){.sem_num = 0, .sem_op = 1}, 1);
+
+            semop(semid, &(struct sembuf){.sem_num = 1, .sem_op = -1}, 1);
+        }
+
+        semctl(semid, 2, IPC_RMID, NULL);
+        exit(0);
+    } else if (pid == -1) {
+        exit(1);
+    }
+
+    pid = fork();
+    if (!pid) {
+        for (;;) {
+            if (semop(semid, &(struct sembuf){.sem_num = 0, .sem_op = -1}, 1) == -1) {
+                break;
+            }
+
+            printf("$ %d\n", *shm);
+
+            if (semop(semid, &(struct sembuf){.sem_num = 1, .sem_op = 1}, 1) == -1) {
+                break;
+            }
+        }
+        exit(0);
+    } else if (pid == -1) {
+        exit(1);
+    }
+
+    while (wait(NULL) != -1)
+        ;
+
+    return 0;
+}
@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+#include <sys/ipc.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+int
+main(int argc, char **argv)
+{
+    key_t key = ftok("/dev/null", 0);
+
+    int semid = semget(key, 2, 0666 | IPC_CREAT);
+    int shmid = shmget(key, sizeof(int), 0666 | IPC_CREAT);
+
+    int *shm = shmat(shmid, NULL, 0);
+    semctl(semid, 0, SETVAL, 1);
+    semctl(semid, 1, SETVAL, 1);
+
+    pid_t pid = fork();
+    if (!pid) {
+        for (;;) {
+            semop(semid, &(struct sembuf){.sem_num = 0, .sem_op = -1}, 1);
+            semop(semid, &(struct sembuf){.sem_num = 1, .sem_op = -1}, 1);
+
+            int r = scanf("%d", shm);
+            if (r == -1) {
+                break;
+            }
+            semop(semid, &(struct sembuf){.sem_num = 0, .sem_op = 1}, 1);
+        }
+        semctl(semid, 2, IPC_RMID, NULL);
+        exit(0);
+    } else if (pid == -1) {
+        exit(1);
+    }
+
+    pid = fork();
+    if (!pid) {
+        for (;;) {
+            if (semop(semid, &(struct sembuf){.sem_num = 0, .sem_op = -1}, 1) == -1) {
+                break;
+            }
+
+            printf("$ %d\n", *shm);
+            if (semop(semid, &(struct sembuf){.sem_num = 0, .sem_op = 1}, 1) == -1) {
+                break;
+            }
+            if (semop(semid, &(struct sembuf){.sem_num = 1, .sem_op = 1}, 1) == -1) {
+                break;
+            }
+        }
+        exit(0);
+    } else if (pid == -1) {
+        exit(1);
+    }
+
+    while (wait(NULL) != -1)
+        ;
+
+    return 0;
+}
@@ -0,0 +1,25 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/sem.h>
+#include <sys/shm.h>
+#include <sys/ipc.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+// пинг понг для n процессов
+
+int
+main(int argc, char **argv)
+{
+    int n = (int) strtoll(argv[1], NULL, 10);
+    int max_n = (int) strtoll(argv[2], NULL, 10);
+
+    for (int i = 0; i < n; ++i) {
+    }
+
+    while (wait(NULL) != -1)
+        ;
+
+    return 0;
+}
@@ -0,0 +1,40 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+int
+main(int argc, char *argv[])
+{
+
+    char *fin = argv[1];
+    char *fout = argv[2];
+
+    // printf("fdin: %d\n", fin);
+
+    int fdin = open(fin, O_RDONLY);
+    if (fdin == -1) {
+        return 1;
+    }
+
+    int fdout = open(fout, O_WRONLY | O_CREAT | O_TRUNC, 0777);
+    for (;;) {
+        char c[1024];
+        int r = read(fdin, c, 1024);
+        if (r == -1) {
+            return 1;
+        }
+        if (r == 0) {
+            break;
+        }
+        write(fdout, c, r);
+    }
+
+    close(fdin);
+    close(fdout);
+
+    return 0;
+}
@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+int
+main(int argc, char *argv[])
+{
+    int fdin = open("in", O_RDWR);
+    if (fdin == -1) {
+        return 1;
+    }
+
+    double num1, num2;
+
+    // Read the first double
+    if (read(fdin, &num1, sizeof(double)) != sizeof(double)) {
+        close(fdin);
+        return 1;
+    }
+
+    // Read the second double
+    if (read(fdin, &num2, sizeof(double)) != sizeof(double)) {
+        close(fdin);
+        return 1;
+    }
+
+    // Move the file pointer back to the beginning
+    if (lseek(fdin, 0, SEEK_SET) == -1) {
+        close(fdin);
+        return 1;
+    }
+
+    // Write the second double first
+    if (write(fdin, &num2, sizeof(double)) != sizeof(double)) {
+        close(fdin);
+        return 1;
+    }
+
+    // Write the first double second
+    if (write(fdin, &num1, sizeof(double)) != sizeof(double)) {
+        close(fdin);
+        return 1;
+    }
+
+    close(fdin);
+
+    return 0;
+}
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+int main(int argc, char* argv[]) {
+    int fdout = open(argv[1], O_WRONLY | O_CREAT | O_TRUNC, 0600);
+    if (fdout == -1) {
+        return 1;
+    }
+
+    unsigned short x;
+
+    while (scanf("%hu", &x) == 1) {
+        unsigned char buf[2];
+        buf[0] = x >> 8;
+        buf[1] = x & 0xff;
+        write(fdout, &x, 2);
+    }
+    
+    close(fdout);
+    
+    return 0;
+}
@@ -0,0 +1,35 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+int
+main(int argc, char *argv[])
+{
+    int fdin = open(argv[1], O_RDONLY);
+    if (fdin == -1) {
+        return 1;
+    }
+
+    unsigned int res = 0, tmp;
+    unsigned char num[4]; // не пишем в int, т.к. неизвестно, какой порядок байтов
+
+    while (read(fdin, num, 4) == 4) {
+        // unsigned int tmp = (unsigned int) num << 24 | (unsigned int) num <<
+        // 16 |
+        //                    (unsigned int) num << 8 | (unsigned int) num;
+        for (int i = 0; i < 4; i++) {
+            tmp = tmp << 8 | num[i];
+        }
+        res += tmp;
+    }
+
+    printf("%u\n", res);
+
+    close(fdin);
+
+    return 0;
+}
@@ -0,0 +1 @@
+123 234
@@ -0,0 +1,51 @@
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+
+void
+premission_to_char(char *m, int n, mode_t mode)
+{
+    for (int i = 0; i < n; ++i) {
+        if (!(mode & 1)) {
+            m[n - i - 1] = '-';
+        }
+        mode >>= 1;
+    }
+}
+
+int
+main(int argc, char *argv[])
+{
+    struct stat st;
+
+    for (int i = 1; i < argc; i++) {
+        if (lstat(argv[i], &st) < 0) {
+            continue;
+        }
+
+        char type;
+        if (S_ISREG(st.st_mode)) {
+            type = '-';
+        } else if (S_ISDIR(st.st_mode)) {
+            type = 'd';
+        } else if (S_ISLNK(st.st_mode)) {
+            type = 'l';
+        } else {
+            type = '?';
+        }
+
+        char m[] = "rwxrwxrwx";
+        for (int j = 0; j < 9; j++) {
+            if (!((st.st_mode >> j) & 1)) {
+                m[8 - j] = '-';
+            }
+        }
+
+        printf("%c%s %lu %hu %lu %ld %s\n", type, m, st.st_nlink, st.st_uid, st.st_size, st.st_ctime, argv[i]);
+    }
+    return 0;
+}
@@ -0,0 +1,76 @@
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+
+int
+acs(const char *name, int mode)
+{
+    struct stat st;
+
+    if (lstat(name, &st) < 0) {
+        return -1;
+    }
+    uid_t uid = getuid();
+    if (uid == 0) {
+        return 0;
+    }
+
+    uid_t st_mode = st.st_mode;
+    if (st.st_mode == uid) {
+        st_mode >>= 6;
+    } else if (st.st_gid == getgid()) {
+        st_mode >>= 3;
+    }
+    st_mode &= 7;
+
+    // for (int i = 0; i < 3; ++i) {
+    //     if (st_mode ^ mode & 1) {
+    //         return -1;
+    //     }
+    //     st_mode >>= 1;
+    //     mode >>= 1;
+    // }
+
+    if (st_mode & mode == mode) {
+        return 0;
+    }
+
+    return -1;
+}
+
+int
+main(int argc, char *argv[])
+{
+    struct stat st;
+
+    for (int i = 1; i < argc; i++) {
+        if (lstat(argv[i], &st) < 0) {
+            continue;
+        }
+
+        char type;
+        if (S_ISREG(st.st_mode)) {
+            type = '-';
+        } else if (S_ISDIR(st.st_mode)) {
+            type = 'd';
+        } else if (S_ISLNK(st.st_mode)) {
+            type = 'l';
+        } else {
+            type = '?';
+        }
+
+        char m[] = "rwxrwxrwx";
+        for (int j = 0; j < 9; j++) {
+            if (!((st.st_mode >> j) & 1)) {
+                m[8 - j] = '-';
+            }
+        }
+
+        printf("%c%s %lu %hu %lu %ld %s\n", type, m, st.st_nlink, st.st_uid, st.st_size, st.st_ctime, argv[i]);
+    }
+    return 0;
+}
@@ -0,0 +1,39 @@
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <string.h>
+
+int
+main(int argc, char *argv[])
+{
+    struct stat st;
+
+    if (lstat(argv[1], &st) < 0) {
+        exit(1);
+    }
+
+    if (S_ISDIR(st.st_mode)) {
+        char *file = calloc(strlen(argv[1]) + 30, sizeof(char));
+
+        snprintf(file, strlen(argv[1]) + 30, "%s/%s.uid", argv[1], argv[0]);
+
+        sprintf(file, "%s/%s.uid", argv[1], argv[0]);
+
+        int fd = open(file, O_WRONLY | O_CREAT | O_TRUNC);
+        uid_t uid = getuid();
+        write(fd, &uid, sizeof(uid_t));
+
+        close(fd);
+    } else if (S_ISREG(st.st_mode)) {
+        int fd = open(argv[1], O_WRONLY | O_TRUNC);
+        write(fd, st.st_uid, sizeof(uid_t));
+
+        close(fd);
+    } else {
+        exit(1);
+    }
+}
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <string.h>
+#include <linux/limits.h>
+
+int
+main(int argc, char *argv[])
+{
+    DIR *dir = opendir(argv[1]);
+    unsigned long long sum = 0;
+    struct dirent *de;
+    while (de = readdir(dir)) {
+        char *name = calloc(PATH_MAX, sizeof(char));
+        snprintf(name, PATH_MAX, "%s/%s", argv[1], de->d_name);
+
+        struct stat st;
+        if (lstat(name, &st) < 0) {
+            continue;
+        }
+        if (S_ISREG(st.st_mode)) {
+            sum += st.st_size;
+        }
+    }
+
+    closedir(dir);
+
+    printf("%d\n", sum);
+
+    return 0;
+}
@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <string.h>
+#include <linux/limits.h>
+#include <sys/stat.h>
+
+int
+main(int argc, char *argv[])
+{
+    DIR *dir = opendir(argv[1]);
+    struct dirent *de;
+    while (de = readdir(dir)) {
+        char *name = calloc(PATH_MAX, sizeof(char));
+        snprintf(name, PATH_MAX, "%s/%s", argv[1], de->d_name);
+
+        struct stat st;
+        if (lstat(name, &st) < 0) {
+            continue;
+        }
+        if (!(S_ISREG(st.st_mode))) {
+            continue;
+        }
+
+        if (access(name, 3)) {
+            continue;
+        }
+        int len = strlen(name);
+
+        if (name[len - 1] == '~' || (len >= 4 && strcmp(name + strlen(name) - 4, ".bak") == 0)) {
+            unlink(name);
+        }
+    }
+
+    closedir(dir);
+    return 0;
+}
@@ -0,0 +1,66 @@
+// подкаталог пустой
+// совпадают айдишники
+// есть права у остальных на запись
+// rmdir
+
+#include <stdio.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <string.h>
+#include <linux/limits.h>
+#include <sys/stat.h>
+
+int
+main(int argc, char *argv[])
+{
+    DIR *dir = opendir(argv[1]);
+    struct dirent *de;
+    while (de = readdir(dir)) {
+        if ((de->d_name[0] == '.' && strlen(de->d_name) == 1) ||
+            (strlen(de->d_name) == 2) && !strcmp(de->d_name, "..")) {
+            continue;
+        }
+        char *name = calloc(PATH_MAX, sizeof(char));
+        snprintf(name, PATH_MAX, "%s/%s", argv[1], de->d_name);
+
+        struct stat st;
+        if (lstat(name, &st) < 0) {
+            continue;
+        }
+        if (!(S_ISDIR(st.st_mode))) {
+            continue;
+        }
+
+        if (st.st_uid != getuid()) {
+            continue;
+        }
+
+        if (!(st.st_mode & 2)) {
+            continue;
+        }
+
+        int num_files = 0;
+        DIR *dirt = opendir(name);
+        while (readdir(dirt)) {
+            num_files++;
+            if (num_files > 2) {
+                break;
+            }
+        }
+
+        if (num_files > 2) {
+            continue;
+        }
+
+        closedir(dirt);
+        rmdir(name);
+    }
+
+    closedir(dir);
+    return 0;
+}
@@ -0,0 +1,50 @@
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <sys/types.h>
+#include <string.h>
+#include <dirent.h>
+#include <linux/limits.h>
+
+struct Files
+{
+    char *pathname;
+    __ino_t st_ino;
+    __dev_t st_dev;
+};
+
+int
+main(int argc, char **argv)
+{
+    struct stat st;
+    if (lstat(".", &st) == -1) {
+        printf("stat error\n");
+        return 1;
+    }
+
+    DIR *dir = opendir("..");
+    struct dirent *de;
+    while ((de = readdir(dir))) {
+        if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) {
+            continue;
+        }
+
+        struct stat sttmp;
+
+        char buf[PATH_MAX];
+        snprintf(buf, PATH_MAX, "%s/%s", "..", de->d_name);
+        if (lstat(buf, &sttmp) == -1) {
+            printf("lstat error\n");
+            return 1;
+        }
+        printf("%s\n", de->d_name);
+        if (sttmp.st_dev == st.st_dev && sttmp.st_ino == st.st_ino) {
+            printf("%s\n", de->d_name);
+        }
+    }
+
+    return 0;
+}
@@ -0,0 +1,33 @@
+#include <time.h>
+#include <stdio.h>
+
+void
+f(int *y, int *m, int *d, int offset)
+{ // offset in seconds
+    struct tm t = {0};
+    // struct tm* tptr = calloc(1, sizeof(struct tm));
+    t.tm_isdst = -1;
+    t.tm_year = *y - 1900;
+    t.tm_mon = *m - 1;
+    t.tm_mday = *d;
+    time_t time = mktime(&t);
+    time += offset;
+    localtime_r(&time, &t);
+    *y = t.tm_year + 1900;
+    *m = t.tm_mon + 1;
+    *d = t.tm_mday;
+
+    return;
+}
+
+int
+main(void)
+{
+    int y = 2021;
+    int m = 1;
+    int d = 1;
+    f(&y, &m, &d, 65 * 60 * 60 * 24);
+    printf("%d-%d-%d\n", y, m, d);
+
+    return 0;
+}
@@ -0,0 +1,45 @@
+#include <time.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+void
+str_to_ll(char *str, long long *num)
+{
+    errno = 0;
+    char *endptr;
+    *num = strtoll(str, &endptr, 10);
+
+    if (*endptr || errno || endptr == str) {
+        fprintf(stderr, "Invalid number: %s\n", str);
+        exit(1); // TODO: по-хорошему заменить на внешний обработчик ошибок
+    }
+
+    return;
+}
+
+int
+main(int argc, char **argv)
+{
+    long long year, day, dw, res = 0;
+    str_to_ll(argv[1], &year);
+    str_to_ll(argv[2], &day);
+    str_to_ll(argv[3], &dw);
+
+    struct tm t = {0};
+    t.tm_isdst = -1;
+    t.tm_mday = 1;
+    t.tm_year = year - 1900;
+
+    while (t.tm_year == year - 1900) {
+        mktime(&t);
+        if (t.tm_mday == day && dw == t.tm_wday) {
+            res++;
+        }
+        t.tm_mday++;
+    }
+
+    printf("%d\n", (int) res);
+
+    return 0;
+}
@@ -0,0 +1,47 @@
+#include <time.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+void
+str_to_ll(char *str, long long *num)
+{
+    errno = 0;
+    char *endptr;
+    *num = strtoll(str, &endptr, 10);
+
+    if (*endptr || errno || endptr == str) {
+        fprintf(stderr, "Invalid number: %s\n", str);
+        exit(1); // TODO: по-хорошему заменить на внешний обработчик ошибок
+    }
+
+    return;
+}
+
+int
+main(int argc, char **argv)
+{
+    long long year, mth, res = 0;
+    str_to_ll(argv[1], &year);
+    str_to_ll(argv[2], &mth);
+
+    struct tm t = {0};
+    t.tm_isdst = -1;
+    t.tm_mday = 1;
+    t.tm_mon = mth - 1;
+    t.tm_year = year - 1900;
+
+    while (t.tm_mon == mth - 1) {
+        if (t.tm_wday > 0 && t.tm_wday < 5) {
+            res += 8;
+        } else if (t.tm_wday == 5) {
+            res += 6;
+        }
+        t.tm_mday++;
+        mktime(&t);
+    }
+
+    printf("%d\n", (int) res);
+
+    return 0;
+}
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+int
+main(int argc, char *argv[])
+{
+    int fd = open(argv[1], O_RDWR | O_CREAT, 0666);
+
+    struct stat st;
+    lseek(fd, 0, SEEK_END);
+    stat(argv[1], &st);
+    char *addr = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+
+    for (int i = 0; i < st.st_size / 2; i++) {
+        char tmp = addr[i];
+        addr[i] = addr[st.st_size - i - 1];
+        addr[st.st_size - i - 1] = tmp;
+    }
+
+    close(fd);
+    munmap(addr, st.st_size);
+
+    return 0;
+}
@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main(int argc, char *argv[])
+{
+    int fdin = open(argv[1], O_RDONLY);
+    int fdout = open(argv[2], O_RDWR | O_CREAT, 0666);
+
+    off_t len = lseek(fdin, 0, SEEK_END);
+    char *fin = mmap(NULL, len, PROT_READ, MAP_SHARED, fdin, 0);
+
+    ftruncate(fdout, len);
+    char *fout = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fdout, 0);
+
+    memcpy(fout, fin, len);
+
+    close(fdin);
+    close(fdout);
+    munmap(fin, len);
+    munmap(fout, len);
+
+    return 0;
+}
@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <sys/wait.h>
+
+void
+str_to_ll(char *str, long long *num)
+{
+    errno = 0;
+    char *endptr;
+    *num = strtoll(str, &endptr, 10);
+
+    if (*endptr || errno || endptr == str) {
+        fprintf(stderr, "Invalid number: %s\n", str);
+        exit(1); // TODO: по-хорошему заменить на внешний обработчик ошибок
+    }
+
+    return;
+}
+
+int
+main(int argc, char *argv[])
+{
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s <deepth>\n", argv[0]);
+        return 1;
+    }
+
+    long long deepth;
+    str_to_ll(argv[1], &deepth);
+
+    // long long i = 1;
+
+    // while (deepth > 0) {
+    //     printf("Deepth: %lld\n", i++);
+
+    //     if (deepth == 1) {
+    //         break;
+    //     }
+
+    //     if (!fork()) {
+    //         deepth--;
+    //     } else {
+    //         wait(NULL);
+
+    //         break;
+    //     }
+    // }
+
+    for (int i = 1; i <= deepth; i++) {
+        if (i == deepth || fork() > 0) {
+            wait(NULL);
+            printf("Deepth: %d\n", i);
+
+            break;
+        }
+    }
+
+    return 0;
+}
@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <errno.h>
+
+void
+str_to_ll(char *str, long long *num)
+{
+    errno = 0;
+    char *endptr;
+    *num = strtoll(str, &endptr, 10);
+
+    if (*endptr || errno || endptr == str) {
+        fprintf(stderr, "Invalid number: %s\n", str);
+        exit(1); // TODO: по-хорошему заменить на внешний обработчик ошибок
+    }
+
+    return;
+}
+
+void
+make_proc(int deepth, int max_deepth)
+{
+    if (deepth == max_deepth) {
+        return;
+    }
+
+    printf("Deepth: %d\n", deepth);
+
+    pid_t pid = fork();
+    if (pid < 0) {
+        fprintf(stderr, "Fork failed\n");
+        exit(1);
+    } else if (pid == 0) {
+        make_proc(deepth + 1, max_deepth);
+        exit(0);
+    } else {
+        wait(NULL);
+    }
+
+    return;
+}
+
+int
+main(int argc, char *argv[])
+{
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s <deepth>\n", argv[0]);
+        return 1;
+    }
+
+    long long deepth;
+    str_to_ll(argv[1], &deepth);
+    make_proc(0, deepth);
+
+    return 0;
+}
@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+#include <string.h>
+#include <linux/limits.h>
+#include <sys/mman.h>
+
+void
+str_to_ll(char *str, long long *num)
+{
+    errno = 0;
+    char *endptr;
+    *num = strtoll(str, &endptr, 10);
+
+    if (*endptr || errno || endptr == str) {
+        fprintf(stderr, "Invalid number: %s\n", str);
+        exit(1); // TODO: по-хорошему заменить на внешний обработчик ошибок
+    }
+
+    return;
+}
+
+int
+main(int argc, char *argv[])
+{
+    if (argc != 3) {
+        fprintf(stderr, "Usage: %s <deepth> <file>\n", argv[0]);
+        return 1;
+    }
+
+    long long deepth;
+    str_to_ll(argv[1], &deepth);
+
+    for (int i = 1; i <= deepth; i++) {
+        if (fork() == 0) {
+            int fd = open(argv[2], O_CREAT | O_WRONLY, 0666);
+
+            lseek(fd, (deepth - i) * sizeof(int), SEEK_SET);
+            write(fd, &i, sizeof(int));
+
+            close(fd);
+
+            return 0;
+        }
+    }
+
+    return 0;
+}
@@ -0,0 +1,61 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <fcntl.h>
+#include <string.h>
+#include <linux/limits.h>
+#include <sys/mman.h>
+#include <stdint.h>
+
+void
+str_to_ll(char *str, long long *num)
+{
+    errno = 0;
+    char *endptr;
+    *num = strtoll(str, &endptr, 10);
+
+    if (*endptr || errno || endptr == str) {
+        fprintf(stderr, "Invalid number: %s\n", str);
+        exit(1); // TODO: по-хорошему заменить на внешний обработчик ошибок
+    }
+
+    return;
+}
+
+int
+main(int argc, char *argv[])
+{
+    if (argc != 3) {
+        fprintf(stderr, "Usage: %s <deepth> <file>\n", argv[0]);
+        return 1;
+    }
+
+    long long deepth;
+    str_to_ll(argv[1], &deepth);
+
+    truncate(argv[2], sizeof(int) * deepth);
+    int fd = open(argv[2], O_CREAT | O_RDWR, 0666);
+    int *addr = mmap(NULL, sizeof(int) * deepth, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+
+    for (int i = 1; i <= deepth; i++) {
+        if (fork() == 0) {
+            addr[deepth - i] = i;
+
+            return 0;
+        }
+    }
+
+    // for (int i = 1; i <= deepth; i++) {
+    //     wait(NULL);
+    // }
+
+    while (wait(NULL) != -1)
+        ;
+
+    munmap(addr, sizeof(int) * argc);
+
+    return 0;
+}
@@ -0,0 +1,52 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <wait.h>
+#include <errno.h>
+
+void
+str_to_ll(char *str, long long *num)
+{
+    errno = 0;
+    char *endptr;
+    *num = strtoll(str, &endptr, 10);
+
+    if (*endptr || errno || endptr == str) {
+        fprintf(stderr, "Invalid number: %s\n", str);
+        exit(1); // TODO: по-хорошему заменить на внешний обработчик ошибок
+    }
+
+    return;
+}
+
+int
+main(int argc, char *argv[])
+{
+    for (int i = 0; i < 3; ++i) {
+        pid_t pid = fork();
+
+        if (pid == -1) {
+            return 1;
+        }
+        if (pid == 0) {
+            char buf[8] = {0};
+            read(0, buf, 7);
+
+            // long long t;
+            // str_to_ll(buf, &t);
+
+            int t = (int) strtol(buf, NULL, 10);
+
+            printf("%d\n", t * t);
+            return 0;
+        } else {
+            continue;
+        }
+    }
+
+    while (wait(NULL) != -1)
+        ;
+
+    return 0;
+}
@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <wait.h>
+#include <errno.h>
+
+// 8-ми сегментная таблица сегментов
+// 32-х разрядная система
+
+typedef struct
+{
+    int size;
+    int base;
+} segment;
+
+unsigned int
+f(segment *segtable, unsigned int VAdr)
+{
+    int bit = 3;
+    unsigned int segnum = VAdr >> (32 - bit);
+    unsigned int segoff = VAdr & ((1 << (32 - bit)) - 1);
+
+    int addr = segtable[segnum].base + segoff;
+    int size = segtable[segnum].size;
+
+    if (segoff >= size) {
+        return 25;
+        // exit(1);
+    }
+
+    return addr;
+}
+
+int
+main(int argc, char *argv[])
+{
+    segment segtable[8] = {};
+
+    return 0;
+}
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <wait.h>
+#include <errno.h>
+
+// инвертированная сегментная таблица сегментов
+// 32-х разрядная система
+
+typedef struct
+{
+    pid_t pid;
+    unsigned int VirtNum;
+} page_record;
+
+unsigned int
+f(page_record *pagetable, unsigned int VAdr, int size_segtable)
+{
+    pid_t pid = getpid();
+
+    unsigned int pagenum = VAdr >> (12); // 12 - размер страницы
+
+    for (int i = 0; i < size_segtable; i++) {
+        if (pagetable[i].VirtNum == pagenum && pagetable[i].pid == pid) {
+            return i << (32 - 12) + (VAdr << 20 >> 20);
+        }
+    }
+
+    return -1;
+}
+
+int
+main(int argc, char *argv[])
+{
+    return 0;
+}
@@ -0,0 +1,16 @@
+
+// по номеру начального размер блока и указатель на таблицу файлов
+// вывести размер файла
+
+unsigned int
+f(unsigned int n, unsigned int *table)
+{
+    unsigned int size = 0;
+    int first_block = table[n];
+    while (first_block) {
+        size++; // размер блока
+        first_block = table[first_block];
+    }
+
+    return size;
+}
@@ -0,0 +1,3 @@
+000007
+000010
+000009