[hurd,commited] hurd: Support AT_EMPTY_PATH

[Samuel Thibault]

        * hurd/lookup-at.c (__file_name_lookup_at): When at_flags contains
        AT_EMPTY_PATH, call __dir_lookup and __hurd_file_name_lookup_retry
        directly instead of __hurd_file_name_lookup.
---
 ChangeLog        |  3 +++
 hurd/lookup-at.c | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 8bffe5035b..fed239cf3c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,9 @@
 
        * sysdeps/mach/hurd/faccessat.c (__faccessat_common): Check for errors
        returned by __hurd_at_flags.
+       * hurd/lookup-at.c (__file_name_lookup_at): When at_flags contains
+       AT_EMPTY_PATH, call __dir_lookup and __hurd_file_name_lookup_retry
+       directly instead of __hurd_file_name_lookup.
 
 2019-01-21  Joseph Myers  <address@hidden>
 
diff --git a/hurd/lookup-at.c b/hurd/lookup-at.c
index 813ebee8e5..3e6980f949 100644
--- a/hurd/lookup-at.c
+++ b/hurd/lookup-at.c
@@ -28,6 +28,9 @@ __file_name_lookup_at (int fd, int at_flags,
 {
   error_t err;
   file_t result;
+  int empty = at_flags & AT_EMPTY_PATH;
+
+  at_flags &= ~AT_EMPTY_PATH;
 
   err = __hurd_at_flags (&at_flags, &flags);
   if (err)
@@ -36,6 +39,23 @@ __file_name_lookup_at (int fd, int at_flags,
   if (fd == AT_FDCWD || file_name[0] == '/')
     return __file_name_lookup (file_name, flags, mode);
 
+  if (empty != 0 && file_name[0] == '\0')
+    {
+      enum retry_type doretry;
+      char retryname[1024];    /* XXX string_t LOSES! */
+
+      err = HURD_DPORT_USE (fd, __dir_lookup (port, "", flags, mode,
+                                             &doretry, retryname,
+                                             &result));
+
+      if (! err)
+       err = __hurd_file_name_lookup_retry (&_hurd_ports_use, &__getdport,
+                                            NULL, doretry, retryname,
+                                            flags, mode, &result);
+
+      return err ? (__hurd_dfail (fd, err), MACH_PORT_NULL) : result;
+    }
+
   file_t startdir;
   error_t use_init_port (int which, error_t (*operate) (mach_port_t))
     {
-- 
2.20.1