Don't follow symlinks in w32notify file watches

* src/w32notify.c (add_watch): On filesystems that support
symlinks, don't follow symlinks.  (Bug#57536)
* src/w32.c (symlinks_supported): New function.
* src/w32.h (symlinks_supported): Add prototype.

1 files changed, 8 insertions, 4 deletions

diff --git a/src/w32notify.c b/src/w32notify.c
index 72e634f77c7..6b5fce9f927 100644
--- a/src/w32notify.c
+++ b/src/w32notify.c
@@ -367,6 +367,12 @@ add_watch (const char *parent_dir, const char *file, BOOL subdirs, DWORD flags)
   if (!file)
     return NULL;
 
+  /* Do not follow symlinks, so that the caller could watch symlink
+     files.  */
+  DWORD crflags = FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED;
+  if (symlinks_supported (parent_dir))
+    crflags |= FILE_FLAG_OPEN_REPARSE_POINT;
+
   if (w32_unicode_filenames)
     {
       wchar_t dir_w[MAX_PATH], file_w[MAX_PATH];
@@ -383,8 +389,7 @@ add_watch (const char *parent_dir, const char *file, BOOL subdirs, DWORD flags)
                              processes from deleting files inside
                              parent_dir.  */
                           FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE,
-                          NULL, OPEN_EXISTING,
-                          FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
+                          NULL, OPEN_EXISTING, crflags,
                           NULL);
     }
   else
@@ -400,8 +405,7 @@ add_watch (const char *parent_dir, const char *file, BOOL subdirs, DWORD flags)
       hdir = CreateFileA (dir_a,
                           FILE_LIST_DIRECTORY,
                           FILE_SHARE_READ|FILE_SHARE_WRITE|FILE_SHARE_DELETE,
-                          NULL, OPEN_EXISTING,
-                          FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
+                          NULL, OPEN_EXISTING, crflags,
                           NULL);
     }
   if (hdir == INVALID_HANDLE_VALUE)