[glib: 1/2] gfile: Add Linux kernel headers compatibility kludge

[Philip Withnall <pwithnall src gnome org>]

commit 94a8a60a7e4aedd54aae11ca5b64226a50e467a3
Author: Ole André Vadla Ravnås <oleavr gmail com>
Date:   Sun Apr 1 01:54:48 2018 +0200

    gfile: Add Linux kernel headers compatibility kludge
    
    So we can still run at full speed on modern kernels in cases where an
    old toolchain was used to build GLib. This is often done deliberately
    to allow shipping binaries that need to run on a wide range of systems.

 gio/gfile.c | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)
---
diff --git a/gio/gfile.c b/gio/gfile.c
index b3acc25f1..22ec43247 100644
--- a/gio/gfile.c
+++ b/gio/gfile.c
@@ -35,6 +35,20 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
+
+/*
+ * We duplicate the following Linux kernel header defines here so we can still
+ * run at full speed on modern kernels in cases where an old toolchain was used
+ * to build GLib. This is often done deliberately to allow shipping binaries
+ * that need to run on a wide range of systems.
+ */
+#ifndef F_SETPIPE_SZ
+#define F_SETPIPE_SZ 1031
+#endif
+#ifndef F_GETPIPE_SZ
+#define F_GETPIPE_SZ 1032
+#endif
+
 #endif
 
 #include <string.h>
@@ -3015,31 +3029,22 @@ splice_stream_with_progress (GInputStream           *in,
   if (!g_unix_open_pipe (buffer, FD_CLOEXEC, error))
     return FALSE;
 
-#if defined(F_SETPIPE_SZ) && defined(F_GETPIPE_SZ)
   /* Try a 1MiB buffer for improved throughput. If that fails, use the default
    * pipe size. See: https://bugzilla.gnome.org/791457 */
   buffer_size = fcntl (buffer[1], F_SETPIPE_SZ, 1024 * 1024);
   if (buffer_size <= 0)
     {
-      int errsv;
       buffer_size = fcntl (buffer[1], F_GETPIPE_SZ);
-      errsv = errno;
-
       if (buffer_size <= 0)
         {
-          g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv),
-                       _("Error splicing file: %s"), g_strerror (errsv));
-          res = FALSE;
-          goto out;
+          /* If #F_GETPIPE_SZ isn’t available, assume we’re on Linux < 2.6.35,
+           * but ≥ 2.6.11, meaning the pipe capacity is 64KiB. Ignore the
+           * possibility of running on Linux < 2.6.11 (where the capacity was
+           * the system page size, typically 4KiB) because it’s ancient.
+           * See pipe(7). */
+          buffer_size = 1024 * 64;
         }
     }
-#else
-  /* If #F_GETPIPE_SZ isn’t available, assume we’re on Linux < 2.6.35,
-   * but ≥ 2.6.11, meaning the pipe capacity is 64KiB. Ignore the possibility of
-   * running on Linux < 2.6.11 (where the capacity was the system page size,
-   * typically 4KiB) because it’s ancient. See pipe(7). */
-  buffer_size = 1024 * 64;
-#endif
 
   g_assert (buffer_size > 0);