From 29ff903bb0379f6fef0f7dc60977e05a8c60f147 Mon Sep 17 00:00:00 2001
From: Eli Zaretskii <eliz@gnu.org>
Date: Thu, 3 Mar 2022 20:31:33 +0200
Subject: [PATCH] Avoid crashes when fringe bitmaps are defined in daemon mode

* src/dispextern.h (gui_define_fringe_bitmap): Add prototype.
(max_used_fringe_bitmap): Add declaration.
* src/fringe.c (gui_define_fringe_bitmap): New function.
* src/w32term.c (w32_draw_fringe_bitmap):
* src/xterm.c (x_draw_fringe_bitmap) [USE_CAIRO]: Call
'gui_define_fringe_bitmap' if the terminal-specific bitmap data is
not available when a fringe bitmap is about to be drawn.  Don't
try to draw a bitmap that is not known to fringe.c.  (Bug#54183)
---
 src/dispextern.h |  3 +++
 src/fringe.c     | 17 +++++++++++++++++
 src/w32term.c    | 15 ++++++++++++++-
 src/xterm.c      | 14 +++++++++++++-
 4 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/src/dispextern.h b/src/dispextern.h
index bc5f7a52e08..65801596d5d 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -3449,6 +3449,9 @@ bool update_window_fringes (struct window *, bool);
 
 void gui_init_fringe (struct redisplay_interface *);
 
+extern int max_used_fringe_bitmap;
+void gui_define_fringe_bitmap (struct frame *, int);
+
 #ifdef HAVE_NTGUI
 void w32_reset_fringes (void);
 #endif
diff --git a/src/fringe.c b/src/fringe.c
index f857aedaf02..14148a67ab1 100644
--- a/src/fringe.c
+++ b/src/fringe.c
@@ -1802,6 +1802,23 @@ gui_init_fringe (struct redisplay_interface *rif)
     }
 }
 
+/* Call frame F's specific define_fringe_bitmap method for a fringe
+   bitmap number N.  Called by various *term.c functions when they
+   need to display a fringe bitmap whose terminal-specific data is not
+   available.  */
+void
+gui_define_fringe_bitmap (struct frame *f, int n)
+{
+  struct redisplay_interface *rif = FRAME_RIF (f);
+
+  if (!rif || !rif->define_fringe_bitmap || n >= max_used_fringe_bitmap)
+    return;
+
+  struct fringe_bitmap *fb = fringe_bitmaps[n];
+  if (fb)
+    rif->define_fringe_bitmap (n, fb->bits, fb->height, fb->width);
+}
+
 #ifdef HAVE_NTGUI
 void
 w32_reset_fringes (void)
diff --git a/src/w32term.c b/src/w32term.c
index 6b41b1d324f..ae99d9948e6 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -777,12 +777,25 @@ w32_draw_fringe_bitmap (struct window *w, struct glyph_row *row,
     w32_fill_area (f, hdc, face->background,
 		   p->bx, p->by, p->nx, p->ny);
 
-  if (p->which && p->which < max_fringe_bmp)
+  if (p->which
+      && p->which < max_fringe_bmp
+      && p->which < max_used_fringe_bitmap)
     {
       HBITMAP pixmap = fringe_bmp[p->which];
       HDC compat_hdc;
       HANDLE horig_obj;
 
+      if (!fringe_bmp[p->which])
+	{
+	  /* This fringe bitmap is known to fringe.c, but lacks the
+	     HBITMAP data which shadows that bitmap.  This is typical
+	     to define-fringe-bitmap being called when the selected
+	     frame was not a GUI frame, for example, when packages
+	     that define fringe bitmaps are loaded by a daemon Emacs.
+	     Create the missing HBITMAP now.  */
+	  gui_define_fringe_bitmap (f, p->which);
+	}
+
       compat_hdc = CreateCompatibleDC (hdc);
 
       SaveDC (hdc);
diff --git a/src/xterm.c b/src/xterm.c
index 59413eafd48..9a8c3e9ad76 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -1426,7 +1426,9 @@ x_draw_fringe_bitmap (struct window *w, struct glyph_row *row, struct draw_fring
     }
 
 #ifdef USE_CAIRO
-  if (p->which && p->which < max_fringe_bmp)
+  if (p->which
+      && p->which < max_fringe_bmp
+      && p->which < max_used_fringe_bitmap)
     {
       XGCValues gcv;
 
@@ -1436,6 +1438,16 @@ x_draw_fringe_bitmap (struct window *w, struct glyph_row *row, struct draw_fring
 				       : f->output_data.x->cursor_pixel)
 				    : face->foreground));
       XSetBackground (display, gc, face->background);
+      if (!fringe_bmp[p->which])
+	{
+	  /* This fringe bitmap is known to fringe.c, but lacks the
+	     cairo_pattern_t pattern which shadows that bitmap.  This
+	     is typical to define-fringe-bitmap being called when the
+	     selected frame was not a GUI frame, for example, when
+	     packages that define fringe bitmaps are loaded by a
+	     daemon Emacs.  Create the missing pattern now.  */
+	  gui_define_fringe_bitmap (f, p->which);
+	}
       x_cr_draw_image (f, gc, fringe_bmp[p->which], 0, p->dh,
 		       p->wd, p->h, p->x, p->y, p->overlay_p);
       XSetForeground (display, gc, gcv.foreground);
-- 
2.39.2