linux c实现文件打包

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

#define BLOCK_SIZE 512

void add_file_to_tar(const char *filename, int tar_fd) {
    struct stat st;
    if (stat(filename, &st) == -1) {
        perror("stat");
        return;
    }

    char header[BLOCK_SIZE];
    memset(header, 0, BLOCK_SIZE);
    snprintf(header, 100, "%s", filename);
    snprintf(header + 100, 8, "%07o", (unsigned int)st.st_mode);
    snprintf(header + 124, 12, "%011lo", (unsigned long long)st.st_size);

    write(tar_fd, header, BLOCK_SIZE);

    int file_fd = open(filename, O_RDONLY);
    if (file_fd == -1) {
        perror("open");
        return;
    }

    char buffer[BLOCK_SIZE];
    ssize_t bytes_read;
    while ((bytes_read = read(file_fd, buffer, BLOCK_SIZE)) > 0) {
        write(tar_fd, buffer, bytes_read);
    }

    close(file_fd);

    if (bytes_read == -1) {
        perror("read");
    }

    // Padding with zeros if necessary
    if (st.st_size % BLOCK_SIZE != 0) {
        char padding[BLOCK_SIZE];
        memset(padding, 0, BLOCK_SIZE);
        write(tar_fd, padding, BLOCK_SIZE - (st.st_size % BLOCK_SIZE));
    }
}

int main(int argc, char *argv[]) {
    if (argc < 3) {
        fprintf(stderr, "Usage: %s <output.tar> <file1> [file2 ...]\n", argv[0]);
        return 1;
    }

    int tar_fd = open(argv[1], O_WRONLY | O_CREAT | O_TRUNC, 0644);
    if (tar_fd == -1) {
        perror("open");
        return 1;
    }

    for (int i = 2; i < argc; i++) {
        add_file_to_tar(argv[i], tar_fd);
    }

    close(tar_fd);
    return 0;
}

gcc -o tar_creator tar_creator.c
./tar_creator output.tar file1.txt file2.txt