[PATCH] D83834: Add test utility 'split-file'

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added a comment.

In D83834#2208107 <https://reviews.llvm.org/D83834#2208107>, @ro wrote:

> In D83834#2208059 <https://reviews.llvm.org/D83834#2208059>, @MaskRay wrote:
>
>> 
>
>
>
>> @ro Can you set a breakpoint while running split-file, checking whether split-file can delete an existing file and replace it with a directory on Solaris?
>> This behavior is intentionally added to support changing `%t` from a file to a directory. It appears to work well on macOS, Linux and Windows.
>
> Here's what I found: the failing call to `split-file` is like this:
>
>   ./bin/split-file --no-leading-lines /vol/llvm/src/llvm-project/local/llvm/test/tools/split-file/empty.test /var/llvm/local-sparcv9-A/test/tools/split-file/Output/empty.test.tmp
>
> Running under `truss` shows
>
>   19028:  fstatat(AT_FDCWD, "/var/llvm/local-sparcv9-A/test/tools/split-file/Output/empty.test.tmp", 0xFFFFFFFF7FFFE380, AT_SYMLINK_NOFOLLOW) = 0
>   19028:      d=0x0000010600010012 i=212407 m=0042750 l=2  u=2110  g=4620  sz=3
>   19028:          at = Aug 10 11:21:41 MEST 2020  [ 1597051301.681593645 ]
>   19028:          mt = Aug 10 01:46:42 MEST 2020  [ 1597016802.271083280 ]
>   19028:          ct = Aug 10 01:46:42 MEST 2020  [ 1597016802.271083280 ]
>   19028:      bsz=512   blks=3     fs=zfs
>   19028:  unlinkat(AT_FDCWD, "/var/llvm/local-sparcv9-A/test/tools/split-file/Output/empty.test.tmp", AT_REMOVEDIR) Err#17 EEXIST
>
> i.e. it tries to remove a directory.  However, this cannot work since the directory in question isn't empty:
>
>   $ ls -la /var/llvm/local-sparcv9-A/test/tools/split-file/Output/empty.test.tmp
>   total 4
>   drwxr-s--- 2 ro gcc  3 Aug 10 01:46 ./
>   drwxr-sr-x 5 ro gcc 11 Aug 10 18:32 ../
>   -rw-r--r-- 1 ro gcc  0 Aug 10 01:46 empty
>
> When I run `split-file` in `gdb` with a breakpoint in `rmdir`, I get
>
>   #0  0xffffffff7eeb7388 in rmdir () from /lib/64/libc.so.1
>   #1  0xffffffff7ee2c47c in remove () from /lib/64/libc.so.1
>   #2  0x000000010025069c in llvm::sys::fs::remove (path=..., 
>       IgnoreNonExisting=true)
>       at /vol/llvm/src/llvm-project/local/llvm/lib/Support/Unix/Path.inc:442
>   #3  0x00000001001821ac in main (argc=4, argv=0xffffffff7fffeb38)
>       at /vol/llvm/src/llvm-project/local/llvm/tools/split-file/split-file.cpp:168
>
> So `llvm::sys::fs::remove` tries to call `::remove` on a non-empty directory, while the man page clearly states:
>
>   The  remove() function causes the file or empty directory whose name is
>   the string pointed to by path to be no longer accessible by that  name.
>   A  subsequent  attempt  to  open  that  file using that name will fail,
>   unless the file is created anew.
>   
>   For files, remove() is identical to unlink(). For directories, remove()
>   is identical to rmdir().
>
> and in turn `rmdir(2)` says
>
>   The  rmdir()  function  removes  the  directory  named by the path name
>   pointed to by path. The directory must not have any entries other  than
>   "." and "..".
>
> This just cannot work!

std::errc::directory_not_empty is intentionally excluded. What error code is it on Solaris?

  if (std::error_code ec = sys::fs::remove(output, /*IgnoreNonExisting=*/true))
    if (ec.value() != static_cast<int>(std::errc::directory_not_empty))
      fatal(output, ec.message());


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