rhbz#1667364 Open doc as R/O for which open(...,O_RDWR) returns EOPNOTSUPP

Map that EOPNOTSUPP to osl_File_E_NOSYS (and intercept it in
StillReadWriteInteraction, as used by MediaDescriptor::impl_openStreamWithURL in
unotools/source/misc/mediadescriptor.cxx, which will retry opening it read-only
then), instead of to osl_File_E_invalidError (which lead to the "General
input/output error" box).

Instead of "silently" opening the doc as read-only, this still pops up a box
claiming that the doc is locked by somebody else, asking whether to open it
read-only or to open a copy.  That's probably because of the

  rDescriptor.erase( utl::MediaDescriptor::PROP_READONLY() );

in TypeDetection::impl_openStream (filter/source/config/cache/typedetection.cxx)
where the comment already hints at the confusion among the different read-only
and locking concepts.  Changing that looks like it would easily cause
regressions, so is left for a follow-up commit.  (And ultimately LO wouldn't
need to treat the doc as read-only at all; it would just need to not attempt to
open it O_RDWR upfront, and save it via copy+rename, like other apps appear to
commonly do.)

Change-Id: I56e18f1864084ba222acaf0e38a604082edaf4c6
Reviewed-on: https://gerrit.libreoffice.org/66805
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/comphelper/source/misc/stillreadwriteinteraction.cxx b/comphelper/source/misc/stillreadwriteinteraction.cxx
index bf0ecc3fa3e2..0efec31b160b 100644
--- a/comphelper/source/misc/stillreadwriteinteraction.cxx
+++ b/comphelper/source/misc/stillreadwriteinteraction.cxx
@@ -96,6 +96,10 @@ ucbhelper::InterceptedInteraction::EInterceptionState StillReadWriteInteraction:
                 (exIO.Code == css::ucb::IOErrorCode_ACCESS_DENIED     )
                 || (exIO.Code == css::ucb::IOErrorCode_LOCKING_VIOLATION )
                 || (exIO.Code == css::ucb::IOErrorCode_NOT_EXISTING )
+                // At least on Linux, a request to open some fuse-mounted file O_RDWR may fail with
+                // EOPNOTSUPP (mapped to osl_File_E_NOSYS to IOErrorCode_NOT_SUPPORTED) when opening
+                // it O_RDONLY would succeed:
+                || (exIO.Code == css::ucb::IOErrorCode_NOT_SUPPORTED )
 #ifdef MACOSX
                 // this is a workaround for MAC, on this platform if the file is locked
                 // the returned error code looks to be wrong