Fix insert-file-contents with pipes and /dev/stdin

* src/fileio.c (Finsert_file_contents): Restore logic of
non-regular but seekable files.  (Bug#65156)

1 files changed, 2 insertions, 2 deletions

diff --git a/src/fileio.c b/src/fileio.c
index 995e4142f58..55132f1ec38 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -4581,7 +4581,7 @@ by calling `format-decode', which see.  */)
       goto handled;
     }
 
-  if (seekable || !NILP (end))
+  if ((seekable && regular) || !NILP (end))
     total = end_offset - beg_offset;
   else
     /* For a special file, all we can do is guess.  */
@@ -4678,7 +4678,7 @@ by calling `format-decode', which see.  */)
            For a special file, where TOTAL is just a buffer size,
            so don't bother counting in HOW_MUCH.
            (INSERTED is where we count the number of characters inserted.)  */
-        if (seekable || !NILP (end))
+        if ((seekable && regular) || !NILP (end))
           how_much += this;
         inserted += this;
       }