From e82670759e7eea3fb9faec99fcd94ad9f2fe03b6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Mon, 15 Nov 2021 23:15:07 +0000
Subject: [PATCH] copy: avoid SEEK_DATA on macOS

* src/copy.c (infer_scantype): Don't probe for SEEK_DATA support
on __APPLE__ systems, as SEEK_DATA was seen to return ENXIO
inappropriately there.
* init.cfg (seek_data_capable_): Return failure on Darwin systems.
Addresses https://bugs.gnu.org/51857
---
 init.cfg   | 6 ++++++
 src/copy.c | 2 +-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/init.cfg b/init.cfg
index b92f717f5..2ab607cf3 100644
--- a/init.cfg
+++ b/init.cfg
@@ -533,6 +533,12 @@ require_kill_group_()
 # which SEEK_DATA support exists.
 seek_data_capable_()
 {
+  # The SEEK_DATA implementation on macOS is not supported
+  if test "$(uname)" = Darwin; then
+    warn_ 'seek_data_capable_: Darwin detected: assuming not SEEK_DATA capable'
+    return 1
+  fi
+
   { python3 < /dev/null && PYTHON_=python3; } ||
   { python  < /dev/null && PYTHON_=python; }
 
diff --git a/src/copy.c b/src/copy.c
index f88bf3ed3..ecb37a02c 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -1100,7 +1100,7 @@ infer_scantype (int fd, struct stat const *sb,
          && ST_NBLOCKS (*sb) < sb->st_size / ST_NBLOCKSIZE))
     return PLAIN_SCANTYPE;
 
-#ifdef SEEK_HOLE
+#if defined SEEK_HOLE && !defined __APPLE__
   scan_inference->ext_start = lseek (fd, 0, SEEK_DATA);
   if (0 <= scan_inference->ext_start || errno == ENXIO)
     return LSEEK_SCANTYPE;
-- 
2.26.2