[SystemZ][z/OS] Fix handling of dirs with filesystem tests

[muiez]

Summary

The aim of this patch is to fix the post processing that is happening on the temporary test directories upon scope exit. In particular, ~scoped_test_env aims to chmod and remove the temporary directories; however,

• bad symlinks are followed and we get "No such file or directory". FIX: use find as alternative to chmod and avoid -follow option.
• Attempting to remove read-only files on z/OS prompts a message asking for confirmation. FIX: use the -f option to delete read-only files immediately without asking for confirmation.
• Some libcxx tests such as libcxx/test/std/input.output/filesystems/cl ass.directory_entry/directory_entry.cons/path.pass.cpp set the dir permissions to none. In turn, recursively doing chmod (-R) does not set the file permissions needed to be able to remove the dir on z/OS only. FIX: use find as alternative to chmod -R, which does not run into this issue on z/OS.

[muiez]

No change. Uploaded diff with full context

[ldionne]

Also, you're submitting a patch for a platform that isn't supported. I very much want to support it, but in order to do so properly, I need something very simple: a build bot. Would it be possible to add one?

libcxx/test/support/filesystem_test_helper.h

145

Can we unconditionally make this change?

152

Why add f?

[muiez]

libcxx/test/support/filesystem_test_helper.h

145

I tried the following test on macOS and find doesn't work for dir's with no permission, so restricting the change to z/OS could be the way to go.

// macOS

> mkdir -m 0 dir 
> find dir -exec chmod 777 {} \;  
find: dir: Permission denied

152

Attempting to remove read-only files on z/OS prompts a message asking for confirmation. The -f option is to delete read-only files immediately without asking for confirmation.

[muiez]

In D108326#2963250, @ldionne wrote:

Also, you're submitting a patch for a platform that isn't supported. I very much want to support it, but in order to do so properly, I need something very simple: a build bot. Would it be possible to add one?

I understand; however, it seems like support for a z/OS buildbot is not in IBM's plan now. I will try to push for this and update if anything changes.

[muiez]

Ping :)

[muiez]

Any feedback @ldionne? The comments have been addressed.

[muiez]

Ping :)

[muiez]

Ping

[• Quuxplusone]

FWIW, I think this is fine (all parts being scoped to __MVS__ and/or harmless). @ldionne +1?

[nilayvaish]

Looks fine to me.

libcxx/test/support/filesystem_test_helper.h

#endif
         test_root = fs::canonical(test_root);
     }
 
     ~scoped_test_env() {
 #ifdef _WIN32
         std::string cmd = "rmdir /s /q " + test_root.string();
         int ret = std::system(cmd.c_str());
         assert(ret == 0);
-#else
+#else 
+#if defined(__MVS__)
+        // The behaviour of chmod -R on z/OS prevents recursive 
+        // permission change for directories that do not have read permission.
+        std::string cmd = "find  " + test_root.string() + " -exec chmod 777 {} \\;";
+#else
         std::string cmd = "chmod -R 777 " + test_root.string();
+#endif // defined(__MVS__)
         int ret = std::system(cmd.c_str());
         assert(ret == 0);
 
-        cmd = "rm -r " + test_root.string();
+        cmd = "rm -rf " + test_root.string();
         ret = std::system(cmd.c_str());
         assert(ret == 0);
 #endif
     }
 
     scoped_test_env(scoped_test_env const &) = delete;
     scoped_test_env & operator=(scoped_test_env const &) = delete;