objective-c - 如何打印 HFS 卷标头

Question

任何人请给出如何打印 HFS+ 磁盘卷标头的代码片段。

Answer 1

我编写了一个小程序（基于hfs-183.1），它打印在struct HFSPlusVolumeHeader. 该程序必须运行为root- 例如，通过sudo(8)：

#include <fcntl.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <hfs/hfs_format.h>
#include <libkern/OSByteOrder.h>

int main(void) {
    int fd;
    struct stat stat_buf;
    struct HFSPlusVolumeHeader vheader;

    const char *vname = "/dev/rdisk0s2";

    if (lstat(vname, &stat_buf) == -1) {
        fprintf(stderr, "Couldn't stat %s\n", vname);
        perror(NULL);
        exit(1);
    }

    if ((stat_buf.st_mode & S_IFMT) != S_IFCHR) {
        fprintf(stderr, "%s is not a raw char device\n", vname);
        perror(NULL);
        exit(2);
    }

    fd = open(vname, O_RDONLY);
    if (fd == -1) {
        fprintf(stderr, "%s couldn't be opened for reading\n", vname);
        perror(NULL);
        exit(3);
    }

    // The volume header starts at offset 1024

    if (pread(fd, &vheader, sizeof vheader, 1024) != sizeof vheader) {
        fprintf(stderr, "couldn't read %s's volume header\n", vname);
        perror(NULL);
        exit(4);
    }

    printf("fileCount   = %u\n"
           "folderCount = %u\n"
           "blockSize   = %u\n"
           "totalBlocks = %u\n"
           "freeBlocks  = %u\n",
           OSSwapBigToHostInt32(vheader.fileCount),
           OSSwapBigToHostInt32(vheader.folderCount),
           OSSwapBigToHostInt32(vheader.blockSize),
           OSSwapBigToHostInt32(vheader.totalBlocks),
           OSSwapBigToHostInt32(vheader.freeBlocks));

    close(fd);

    return 0;
}

头文件<hfs/hfs_format.h>声明struct HFSPlusVolumeHeader. 有关 HFS+ 卷标头内的完整字段列表，请参阅此文件。

Answer 2

系统调用getattrlist()可能会为您提供所需的信息。