glib: Fix hang on Windows when G_SLICE env is configured

Apply upstream fix https://gitlab.gnome.org/GNOME/glib/-/merge_requests/1698

Part-of: <https://gitlab.freedesktop.org/gstreamer/cerbero/-/merge_requests/712>

2 files changed, 91 insertions, 0 deletions

diff --git a/recipes/glib.recipe b/recipes/glib.recipe
index 8f86494b..e6f3a2d5 100644
--- a/recipes/glib.recipe
+++ b/recipes/glib.recipe
@@ -60,6 +60,8 @@ class Recipe(recipe.Recipe):
         'glib/0001-Windows-fix-FD_READ-condition-flag-still-set-on-reco.patch',
         # https://gitlab.gnome.org/GNOME/glib/-/merge_requests/1428
         'glib/0001-Add-missing-extern-to-the-dllexport-version-of-GLIB_.patch',
+        # https://gitlab.gnome.org/GNOME/glib/-/merge_requests/1698
+        'glib/0001-gslice-Inline-win32-implementation-of-g_getenv-to-av.patch',
     ]
 
     files_libs = [
diff --git a/recipes/glib/0001-gslice-Inline-win32-implementation-of-g_getenv-to-av.patch b/recipes/glib/0001-gslice-Inline-win32-implementation-of-g_getenv-to-av.patch
new file mode 100644
index 00000000..c4920a87
--- /dev/null
+++ b/recipes/glib/0001-gslice-Inline-win32-implementation-of-g_getenv-to-av.patch
@@ -0,0 +1,89 @@
+From b538cb0c8c829ba76d4a04be0c198e5d3b7c311c Mon Sep 17 00:00:00 2001
+From: Philip Withnall <pwithnall@endlessos.org>
+Date: Thu, 15 Oct 2020 10:20:10 +0100
+Subject: [PATCH] gslice: Inline win32 implementation of g_getenv() to avoid
+ deadlock
+
+The win32 implementation of `g_getenv()` uses GSlice (from within
+GQuark), which results in a deadlock when examining the `G_SLICE`
+environment variable.
+
+Fix that by inlining a basic implementation of `g_getenv()` at that call
+site.
+
+Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
+
+Fixes: #2225
+---
+ glib/gslice.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 44 insertions(+)
+
+diff --git a/glib/gslice.c b/glib/gslice.c
+index e6f278539..589619080 100644
+--- a/glib/gslice.c
++++ b/glib/gslice.c
+@@ -361,10 +361,52 @@ static void
+ slice_config_init (SliceConfig *config)
+ {
+   const gchar *val;
++  gchar *val_allocated = NULL;
+ 
+   *config = slice_config;
+ 
++  /* Note that the empty string (`G_SLICE=""`) is treated differently from the
++   * envvar being unset. In the latter case, we also check whether running under
++   * valgrind. */
++#ifndef G_OS_WIN32
+   val = g_getenv ("G_SLICE");
++#else
++  /* The win32 implementation of g_getenv() has to do UTF-8 ↔ UTF-16 conversions
++   * which use the slice allocator, leading to deadlock. Use a simple in-place
++   * implementation here instead.
++   *
++   * Ignore references to other environment variables: only support values which
++   * are a combination of always-malloc and debug-blocks. */
++  {
++
++  wchar_t wvalue[128];  /* at least big enough for `always-malloc,debug-blocks` */
++  int len;
++
++  len = GetEnvironmentVariableW (L"G_SLICE", wvalue, G_N_ELEMENTS (wvalue));
++
++  if (len == 0)
++    {
++      if (GetLastError () == ERROR_ENVVAR_NOT_FOUND)
++        val = NULL;
++      else
++        val = "";
++    }
++  else if (len >= G_N_ELEMENTS (wvalue))
++    {
++      /* @wvalue isn’t big enough. Give up. */
++      g_warning ("Unsupported G_SLICE value");
++      val = NULL;
++    }
++  else
++    {
++      /* it’s safe to use g_utf16_to_utf8() here as it only allocates using
++       * malloc() rather than GSlice */
++      val = val_allocated = g_utf16_to_utf8 (wvalue, -1, NULL, NULL, NULL);
++    }
++
++  }
++#endif  /* G_OS_WIN32 */
++
+   if (val != NULL)
+     {
+       gint flags;
+@@ -392,6 +434,8 @@ slice_config_init (SliceConfig *config)
+         config->always_malloc = TRUE;
+ #endif
+     }
++
++  g_free (val_allocated);
+ }
+ 
+ static void
+-- 
+2.25.1
+