使用write()复制二进制文件,复制文件的大小增加

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

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

    int src_fd = open(argv[1], O_RDONLY);
    if (src_fd < 0) {
        perror("open source file");
        exit(1);
    }

    struct stat src_stat;
    if (fstat(src_fd, &src_stat) < 0) {
        perror("fstat source file");
        exit(1);
    }

    int dest_fd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, src_stat.st_mode);
    if (dest_fd < 0) {
        perror("open destination file");
        exit(1);
    }

    char buffer[4096];
    ssize_t bytes_read;
    while ((bytes_read = read(src_fd, buffer, sizeof(buffer))) > 0) {
        if (write(dest_fd, buffer, bytes_read) != bytes_read) {
            perror("write");
            exit(1);
        }
    }

    if (bytes_read < 0) {
        perror("read");
        exit(1);
    }

    close(src_fd);
    close(dest_fd);

    return 0;
}