请帮我进行系统调用编程 ，要求如下使用系统调用open read write,完成一个C语言程序：该程序接收两个参数，参数1作为要读写的文件，参数2作为标志位，标识是读还是写。功能完成对参数1所示文件的读写，该文件的内容为 “学号 MYFILE”，其中学号填为自己的学号。 改造上面的程序，使用semaphore，并利用该程序生成2个进程，这两个进程写同一个文件，要求：a.互斥写，即只有一个进程写完后，才能让另一个进程写; b. 一个进程写入内容：“自己学号的后3位PROC1 MYFILE1”；另一个进程写入内容：“自己学号的后3位PROC2 MYFILE2” 请提交代码截图和运行结果截图

好的，首先是第一个要求的程序实现：

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

int main(int argc, char* argv[]) {
    if (argc != 3) {
        printf("Usage: %s filename flag\n", argv[0]);
        exit(1);
    }

    int fd;
    if (strcmp(argv[2], "r") == 0) {
        fd = open(argv[1], O_RDONLY);
    } else if (strcmp(argv[2], "w") == 0) {
        fd = open(argv[1], O_WRONLY);
    } else {
        printf("Invalid flag: %s\n", argv[2]);
        exit(1);
    }

    if (fd == -1) {
        perror("open");
        exit(1);
    }

    char buf[20];
    if (read(fd, buf, 20) == -1) {
        perror("read");
        exit(1);
    }

    if (strcmp(argv[2], "r") == 0) {
        printf("Content of file %s: %s\n", argv[1], buf);
    } else {
        char* my_file = malloc(sizeof(char) * 10);
        sprintf(my_file, "MYFILE%d", atoi(argv[1]+6));
        sprintf(buf, "%sPROC%d", argv[1]+7, getpid()%2+1);
        if (write(fd, buf, strlen(buf)) == -1) {
            perror("write");
            exit(1);
        }
        printf("Content written to file %s: %s\n", my_file, buf);
        free(my_file);
    }

    if (close(fd) == -1) {
        perror("close");
        exit(1);
    }

    return 0;
}

然后是使用 semaphore 实现的程序：

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <semaphore.h>
#include <sys/mman.h>
#include <string.h>

int main(int argc, char* argv[]) {
    if (argc != 2) {
        printf("Usage: %s filename\n", argv[0]);
        exit(1);
    }

    sem_t* sem_write;
    sem_t* sem_read;
    sem_t* sem_mutex;
    int fd;
    char* buf;
    char* my_file;

    sem_write = sem_open("write", O_CREAT, 0644, 1);
    sem_read = sem_open("read", O_CREAT, 0644, 0);
    sem_mutex = sem_open("mutex", O_CREAT, 0644, 1);

    if (sem_write == SEM_FAILED || sem_read == SEM_FAILED || sem_mutex == SEM_FAILED) {
        perror("sem_open");
        exit(1);
    }

    fd = open(argv[1], O_RDWR | O_CREAT | O_TRUNC, 0644);
    if (fd == -1) {
        perror("open");
        exit(1);
    }
    if (ftruncate(fd, 40) == -1) {
        perror("ftruncate");
        exit(1);
    }

    buf = mmap(NULL, 40, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (buf == MAP_FAILED) {
        perror("mmap");
        exit(1);
    }

    my_file = malloc(sizeof(char) * 10);
    sprintf(my_file, "MYFILE%d", getpid()%2+1);

    int pid = fork();
    if (pid == -1) {
        perror("fork");
        exit(1);
    } else if (pid == 0) {
        // child process
        while (1) {
            sem_wait(sem_write);
            sem_wait(sem_mutex);

            sprintf(buf, "%sPROC1", argv[0]+7);
            memcpy(buf+10, "      ", 6);
            memcpy(buf+16, my_file, strlen(my_file));
            if (write(fd, buf, strlen(buf)) == -1) {
                perror("write");
                exit(1);
            }
            printf("Content written to file %s by child process: %s\n", my_file, buf);

            sem_post(sem_mutex);
            sem_post(sem_read);
        }
    } else {
        // parent process
        int i;
        for (i = 0; i < 10; i++) {
            sem_wait(sem_read);
            sem_wait(sem_mutex);

            sprintf(buf, "%sPROC2", argv[0]+7);
            memcpy(buf+10, "      ", 6);
            memcpy(buf+16, my_file, strlen(my_file));
            if (write(fd, buf, strlen(buf)) == -1) {
                perror("write");
                exit(1);
            }
            printf("Content written to file %s by parent process: %s\n", my_file, buf);

            sem_post(sem_mutex);
            sem_post(sem_write);
        }

        if (waitpid(pid, NULL, 0) == -1) {
            perror("waitpid");
            exit(1);
        }
    }

    if (munmap(buf, 40) == -1) {
        perror("munmap");
        exit(1);
    }
    if (close(fd) == -1) {
        perror("close");
        exit(1);
    }
    if (sem_close(sem_write) == -1 || sem_close(sem_read) == -1 || sem_close(sem_mutex) == -1) {
        perror("sem_close");
        exit(1);
    }
    if (sem_unlink("write") == -1 || sem_unlink("read") == -1 || sem_unlink("mutex") == -1) {
        perror("sem_unlink");
        exit(1);
    }
    free(my_file);

    return 0;
}

注意到以上程序需要在 Linux 系统上运行，且需要安装 GCC 编译器。如果你不确定自己的操作系统和环境，可以先询问一下。