From 94f955fa909b0d3bb216b9c6ddaf365c9d7c861d Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Tue, 26 Mar 2019 18:39:40 +0000
Subject: [PATCH] Add an autoconf test and workaround for futimes(3).

Not every system provides it (e.g. uClibc-ng); if one does not, the
Uppity SFTP server should now degrade sensibly to refusing attempts to
set the utimes on an already-open file.
---
 configure.ac        |  2 +-
 unix/uxsftpserver.c | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 35552ed2..38b3e8b9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -173,7 +173,7 @@ AC_CHECK_LIB(X11, XOpenDisplay,
              [GTK_LIBS="-lX11 $GTK_LIBS"
               AC_DEFINE([HAVE_LIBX11],[],[Define if libX11.a is available])])
 
-AC_CHECK_FUNCS([getaddrinfo posix_openpt ptsname setresuid strsignal updwtmpx fstatat dirfd])
+AC_CHECK_FUNCS([getaddrinfo posix_openpt ptsname setresuid strsignal updwtmpx fstatat dirfd futimes])
 AC_CHECK_DECLS([CLOCK_MONOTONIC], [], [], [[#include <time.h>]])
 AC_SEARCH_LIBS([clock_gettime], [rt], [AC_DEFINE([HAVE_CLOCK_GETTIME],[],[Define if clock_gettime() is available])])
 
diff --git a/unix/uxsftpserver.c b/unix/uxsftpserver.c
index 6fab0ba0..a90344e0 100644
--- a/unix/uxsftpserver.c
+++ b/unix/uxsftpserver.c
@@ -412,6 +412,16 @@ static void uss_fstat(SftpServer *srv, SftpReplyBuilder *reply,
     }
 }
 
+#if !HAVE_FUTIMES
+static inline int futimes(int fd, const struct timeval tv[2])
+{
+    /* If the OS doesn't support futimes(3) then we have to pretend it
+     * always returns failure */
+    errno = EINVAL;
+    return -1;
+}
+#endif
+
 /*
  * The guts of setstat and fsetstat, macroised so that they can call
  * fchown(fd,...) or chown(path,...) depending on parameters.