Re: [Bug-tar] tar -vf /dev/stdout produces corrupted archives

[Jim Meyering]

Radek Brich <address@hidden> wrote:
> On Tue 11. of December 2007 13:55:53 you wrote:
>> Radek Brich <address@hidden> ha escrit:
>> > Although it'd need some cleaning, I'd like to hear what
>> > you think about the idea?
>>
>> Generally speaking, looks nice, except that fstat may fail (e.g. if
>> stdout is closed) in which case st_stdout would contain garbage.
...
> +  struct stat st_buf;
> +  ino_t stdout_ino = fstat(STDOUT_FILENO, &st_buf) == -1 ?
> +                     0 : st_buf.st_ino;
> +  ino_t archive_ino = stat(archive_name_array[0], &st_buf) == -1 ?
> +                     0 : st_buf.st_ino;
> +  bool archive_is_stdout = (archive_ino != 0 && archive_ino == stdout_ino);

You'll want to compare st_dev, as well.
Otherwise, there's a small risk of a false positive with
a file on a different partition, but with the same inode number.

You can use the SAME_INODE macro from gnulib's lib/same-inode.h,
since tar already has that file.