From 0af3c2f5092cb52ee0ea0b4ab2b1285237441a85 Mon Sep 17 00:00:00 2001
From: Maxime Devos <maximedevos@telenet.be>
Date: Tue, 16 Nov 2021 11:06:34 +0000
Subject: =?UTF-8?q?Define=20a=20Scheme=20binding=20to=20=E2=80=98fchownat?=
 =?UTF-8?q?=E2=80=99=20when=20it=20exists.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

* configure.ac: Detect whether ‘fchownat’ is available.
* libguile/filesys.c (scm_chownat): Define a Scheme binding to
  ‘fchownat’ when available.
* libguile/filesys.h (scm_chownat): Make it part of the API.
* doc/ref/posix.texi (File System): Document it.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>
---
 libguile/filesys.c | 35 +++++++++++++++++++++++++++++++++++
 libguile/filesys.h |  1 +
 2 files changed, 36 insertions(+)

(limited to 'libguile')

diff --git a/libguile/filesys.c b/libguile/filesys.c
index ee7fc5bfa..af00a98d4 100644
--- a/libguile/filesys.c
+++ b/libguile/filesys.c
@@ -180,6 +180,41 @@ SCM_DEFINE (scm_chown, "chown", 3, 0, 0,
 #undef FUNC_NAME
 #endif /* HAVE_CHOWN */
 
+#ifdef HAVE_FCHOWNAT
+SCM_DEFINE (scm_chownat, "chown-at", 4, 1, 0,
+            (SCM dir, SCM name, SCM owner, SCM group, SCM flags),
+            "Like @code{chown}, but modify the owner and/or group of\n"
+            "the file named @var{name} in the directory referred to\n"
+            "by the file port @var{dir} instead.  The optional argument\n"
+            "@var{flags} is a bitmask.  If @code{AT_SYMLINK_NOFOLLOW} is\n"
+            "present, then @var{name} will not be dereferenced if it is a\n"
+            "symbolic link.")
+#define FUNC_NAME s_scm_chownat
+{
+  int rv;
+  int dir_fdes;
+  int c_flags;
+
+  if (SCM_UNBNDP (flags))
+    c_flags = 0;
+  else
+    c_flags = scm_to_int (flags);
+
+  SCM_VALIDATE_OPFPORT (SCM_ARG1, dir);
+  dir_fdes = SCM_FPORT_FDES (dir);
+
+  STRING_SYSCALL (name, c_name,
+                  rv = fchownat (dir_fdes, c_name,
+                                 scm_to_int (owner), scm_to_int (group),
+                                 c_flags));
+  scm_remember_upto_here_1 (dir);
+  if (rv == -1)
+    SCM_SYSERROR;
+  return SCM_UNSPECIFIED;
+}
+#undef FUNC_NAME
+#endif /* HAVE_FCHOWNAT */
+
 
 
 SCM_DEFINE (scm_open_fdes, "open-fdes", 2, 1, 0, 
diff --git a/libguile/filesys.h b/libguile/filesys.h
index 37d084cd5..7673c8051 100644
--- a/libguile/filesys.h
+++ b/libguile/filesys.h
@@ -39,6 +39,7 @@ SCM_API scm_t_bits scm_tc16_dir;
 
 
 SCM_API SCM scm_chown (SCM object, SCM owner, SCM group);
+SCM_API SCM scm_chownat (SCM dir, SCM object, SCM owner, SCM group, SCM flags);
 SCM_API SCM scm_chmod (SCM object, SCM mode);
 SCM_API SCM scm_chmodat (SCM dir, SCM pathname, SCM mode, SCM flags);
 SCM_API SCM scm_umask (SCM mode);
-- 
cgit v1.2.1