[Bug testsuite/29726] [gdb] FAIL: gdb.server/connect-with-no-symbol-file.exp: sysroot=: action=delete: connection to GDBserver succeeded

["vries at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=29726

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |luis.machado at arm dot com

--- Comment #5 from Tom de Vries <vries at gcc dot gnu.org> ---
(In reply to Tom de Vries from comment #0)
> This doesn't look like a gdb bug, but I have no idea yet what it could be.

I think I understand what's going on.

We're using remote_spawn instead of remote_exec to do chmod 000, and never wait
for it.

So, we know for sure that the chmod 000 has started, but we don't know when it
actually will have effect, which explains the failure I saw: it could have
lingered until after the copy that was supposed to restore the permission.

So, the non-intrusive way to fix this is to wait for the chmod 000 pid before
moving on to the next scenario.

OTOH, it's possible that using remote_spawn is a mistake, and remote_exec was
meant.

In the original submission (
https://sourceware.org/pipermail/gdb-patches/2016-February/131420.html ) we
had:
...
+if {[file exists $binfile]} {
+    system "chmod 000 $binfile"
+}
...
but after a review comment "Seems like this won't work with remote-host
testing?" it was changed to:
...
+       } elseif { $action == "permission" } {
+         remote_spawn target "chmod 000 $binfile"
+       }
...
which was committed.

Then there was a patch to fix behaviour with remote-gdbserver-on-localhost,
which would have gone with remote_exec:
...
+proc make_inaccessible { file } {
+    remote_exec host "chmod 000 $file"
+    remote_exec target "chmod 000 $file"
+}
...

Taking all this into account, I think the use of remote_spawn was a mistake.

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