Work around macOS faccessat bug

* src/fileio.c (file_accessible_directory_p): Append an
extra "/" to work around macOS bug in faccessat (Bug#30350).

1 files changed, 8 insertions, 5 deletions

diff --git a/src/fileio.c b/src/fileio.c
index be29e60fc0a..b0ef3d4e91f 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -2811,12 +2811,15 @@ file_accessible_directory_p (Lisp_Object file)
     dir = data;
   else
     {
-      /* Just check for trailing '/' when deciding whether to append '/'.
-         That's simpler than testing the two special cases "/" and "//",
-         and it's a safe optimization here.  */
-      char *buf = SAFE_ALLOCA (len + 3);
+      /* Just check for trailing '/' when deciding whether append '/'
+         before appending '.'.  That's simpler than testing the two
+         special cases "/" and "//", and it's a safe optimization
+         here.  After appending '.', append another '/' to work around
+         a macOS bug (Bug#30350).  */
+      static char const appended[] = "/./";
+      char *buf = SAFE_ALLOCA (len + sizeof appended);
       memcpy (buf, data, len);
-      strcpy (buf + len, &"/."[data[len - 1] == '/']);
+      strcpy (buf + len, &appended[data[len - 1] == '/']);
       dir = buf;
     }