If linkat(2) is called with AT_EMPTY_PATH on an AF_LOCAL or
AF_UNIX socket that is not a socket file, the current code calls
fhandler_disk_file::link in most cases. The latter expects to be
operating on a disk file and uses the socket's io_handle, which
is not a file handle.
Fix this by calling fhandler_disk_file::link only if the
fhandler_socket object is a file (determined by testing
dev().isfs()).
Also fix the case of a socket file opened with O_PATH by setting
the fhandler_disk_file's io_handle.
---
winsup/cygwin/fhandler_socket_local.cc | 7 ++++++-
winsup/cygwin/fhandler_socket_unix.cc | 9 ++++++---
2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/winsup/cygwin/fhandler_socket_local.cc
b/winsup/cygwin/fhandler_socket_local.cc
index 22586c0dd..ad7dd0a98 100644
--- a/winsup/cygwin/fhandler_socket_local.cc
+++ b/winsup/cygwin/fhandler_socket_local.cc
@@ -750,9 +750,14 @@ fhandler_socket_local::facl (int cmd, int nentries,
aclent_t *aclbufp)
int
fhandler_socket_local::link (const char *newpath)
{
- if (get_sun_path () && get_sun_path ()[0] == '\0')
+ if (!dev ().isfs ())
+ /* linkat w/ AT_EMPTY_PATH called on a socket not opened w/ O_PATH. */
return fhandler_socket_wsock::link (newpath);
+ /* link on a socket file or linkat w/ AT_EMPTY_PATH called on a
+ socket opened w/ O_PATH. */
fhandler_disk_file fh (pc);
+ if (get_flags () & O_PATH)
+ fh.set_handle (get_handle ());
return fh.link (newpath);
}
diff --git a/winsup/cygwin/fhandler_socket_unix.cc
b/winsup/cygwin/fhandler_socket_unix.cc
index fae07367d..252bcd9a9 100644
--- a/winsup/cygwin/fhandler_socket_unix.cc
+++ b/winsup/cygwin/fhandler_socket_unix.cc
@@ -2421,11 +2421,14 @@ fhandler_socket_unix::facl (int cmd, int nentries,
aclent_t *aclbufp)
int
fhandler_socket_unix::link (const char *newpath)
{
- if (sun_path ()
- && (sun_path ()->un_len <= (socklen_t) sizeof (sa_family_t)
- || sun_path ()->un.sun_path[0] == '\0'))
+ if (!dev ().isfs ())
+ /* linkat w/ AT_EMPTY_PATH called on a socket not opened w/ O_PATH. */
return fhandler_socket::link (newpath);
+ /* link on a socket file or linkat w/ AT_EMPTY_PATH called on a
+ socket opened w/ O_PATH. */
fhandler_disk_file fh (pc);
+ if (get_flags () & O_PATH)
+ fh.set_handle (get_handle ());
return fh.link (newpath);
}
--
2.30.0
