linux下大文件的删除

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

#define DEFAULT_BLOCK_SIZE (100 * 1024 * 1024) // 默认100MB
#define DEFAULT_SLEEP_TIME 1                   // 默认1秒

void log_message(const char *message, off_t current_size) {
    time_t raw_time;
    struct tm *time_info;
    char buffer[80];

    time(&raw_time);
    time_info = localtime(&raw_time);
    strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", time_info);

    FILE *log_file = fopen("truncate_log.txt", "a");
    if (log_file != NULL) {
        fprintf(log_file, "[%s] %s Current Size: %ld bytes\n", buffer, message, current_size);
        fclose(log_file);
    }
}

int main(int argc, char *argv[]) {
    if (argc < 2 || argc > 4) {
        fprintf(stderr, "Usage: %s <file> [block_size_in_MB] [sleep_time_in_seconds]\n", argv[0]);
        return EXIT_FAILURE;
    }

    const char *filename = argv[1];
    off_t block_size = DEFAULT_BLOCK_SIZE;
    int sleep_time = DEFAULT_SLEEP_TIME;

    if (argc >= 3) {
        block_size = atol(argv[2]) * 1024 * 1024; // 将MB转换为字节
    }

    if (argc == 4) {
        sleep_time = atoi(argv[3]);
    }

    struct stat st;

    // 获取文件信息
    if (stat(filename, &st) == -1) {
        perror("Error getting file size");
        return EXIT_FAILURE;
    }

    off_t filesize = st.st_size;
    log_message("Start truncating file", filesize);

    while (filesize > 0) {
        off_t new_size = filesize - block_size;
        if (new_size < 0) {
            new_size = 0; // 如果剩余部分小于块大小，则直接设为0
        }

        // 使用truncate减小文件大小
        if (truncate(filename, new_size) == -1) {
            perror("Error truncating file");
            return EXIT_FAILURE;
        }

        log_message("File truncated", new_size);
        filesize = new_size;

        if (sleep_time > 0) {
            sleep(sleep_time); // 休眠指定的时间
        }
    }

    // 文件大小已降至0，现在删除文件
    if (unlink(filename) == -1) {
        perror("Error deleting file");
        return EXIT_FAILURE;
    }

    log_message("File deleted successfully", 0);
    printf("File deleted successfully.\n");
    return EXIT_SUCCESS;
}

gcc -o delete_large_file delete_large_file.c

./delete_large_file bigfile 10 1   

# 10表示每次truncate 10MB，1表示每次sleep 1秒。 这里便于演示设置的truncate步长比较小。
# 默认不加这2个参数则每次truncate 100MB，每次sleep1秒