lab3

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

int main(int argc, char* argv[]){
    struct stat sb;
    off_t len;
    char *fp;
    int fd;

    if (argc < 2){
        fprintf(stderr, "usage: %s file1 [file2...]\n", argv[0]);
        exit(1);
    }

    for (int i = 1; i < argc; ++i)
    {
        fd = open (argv[i], O_RDONLY);
        if(fd == -1){
            perror("open");
            exit(2);
        }

        if (fstat (fd, &sb) == -1){
            perror("fstat");
            exit(3);
        }

        if(!S_ISREG (sb.st_mode)){
            fprintf(stderr, "%s is not a file\n", argv[i]);
            exit(4);
        }

        fp = mmap (0, sb.st_size, PROT_READ, MAP_SHARED, fd, 0);
        if (fp == MAP_FAILED){
            perror("mmap");
            exit(5);
        }

        if (close(fd) == -1){
            perror("close");
            exit(6);
        }

        write(STDOUT_FILENO, fp, sb.st_size);
        putchar('\n');

        if(munmap (fp, sb.st_size)==-1){
            perror("munmap");
            exit(7);
        }
    }
}