[r.zharkov@postgrespro.ru]

On 2022-08-06 08:02, Thomas Munro wrote:
> 
> Pushed.
> 
> Hmm, this stuff could *really* use a little test framework that's run
> by check-world, that exercises these various replacement operations.
> But I also suspect that problems in this area are likely to be due to
> concurrency.  It's hard to make a simple test that simulates the case
> where a file is unlinked between system calls within stat() and hits
> the STATUS_DELETE_PENDING case.  That check is code I cargo-culted in
> this patch.  So much of the stuff we've had in the tree relating to
> that area has been wrong in the past...

Hello, hackers!

initdb on my windows 10 system stopped working after the commit
c5cb8f3b: "Provide lstat() for Windows."
The error message is: creating directory C:/HOME/data ... initdb:
error: could not create directory "C:/HOME": File exists

"C:/HOME" is the junction point to the second volume on my hard drive -
"\??\Volume{GUID}\" which name pgreadlink() erroneously strips here:
https://github.com/postgres/postgres/blob/7e29a79a46d30dc236d097825ab849158929d977/src/port/dirmod.c....
So initdb could not stat the file with name "Volume{GUID}", tried to
create it and failed.
With the attached patch initdb works fine again.

-- 
regards,

Roman

Attachments:

dirmod.c.patch (text/x-diff, 514B) download
diff --git a/src/port/dirmod.c b/src/port/dirmod.c
index 2818bfd2e95..9d73620a6ba 100644
--- a/src/port/dirmod.c
+++ b/src/port/dirmod.c
@@ -354,7 +354,8 @@ pgreadlink(const char *path, char *buf, size_t size)
 	 * If the path starts with "\??\", which it will do in most (all?) cases,
 	 * strip those out.
 	 */
-	if (r > 4 && strncmp(buf, "\\??\\", 4) == 0)
+	if (r > 4 && strncmp(buf, "\\??\\", 4) == 0 &&
+		strncmp(buf, "\\??\\Volume", 10) != 0)
 	{
 		memmove(buf, buf + 4, strlen(buf + 4) + 1);
 		r -= 4;