From 3e53fec0027e79e10b1024a42e0ba8fa1aa6bc18 Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Tue, 26 Dec 2023 19:00:14 -0500
Subject: [PATCH] fb: Explicitly handle errors when getting or setting a colour
 palette

In the VESA driver, simply ignore errors.  It is not clear to me how to
return them to userspace.

This is in preparation for annotating copyin() and related functions
with __result_use_check.

MFC after:	1 week

(cherry picked from commit ddc8576d297937a1395f47550a8f5b1fac79afc2)
---
 sys/dev/fb/vesa.c | 16 ++++++++--------
 sys/dev/fb/vga.c  | 22 +++++++++++++++-------
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/sys/dev/fb/vesa.c b/sys/dev/fb/vesa.c
index ee3409dfa75..e1cca3a7072 100644
--- a/sys/dev/fb/vesa.c
+++ b/sys/dev/fb/vesa.c
@@ -1698,12 +1698,12 @@ get_palette(video_adapter_t *adp, int base, int count,
 	b = g + count;
 	error = vesa_bios_save_palette2(base, count, r, g, b, bits);
 	if (error == 0) {
-		copyout(r, red, count);
-		copyout(g, green, count);
-		copyout(b, blue, count);
+		(void)copyout(r, red, count);
+		(void)copyout(g, green, count);
+		(void)copyout(b, blue, count);
 		if (trans != NULL) {
 			bzero(r, count);
-			copyout(r, trans, count);
+			(void)copyout(r, trans, count);
 		}
 	}
 	free(r, M_DEVBUF);
@@ -1729,12 +1729,12 @@ set_palette(video_adapter_t *adp, int base, int count,
 		return (1);
 
 	bits = (adp->va_flags & V_ADP_DAC8) != 0 ? 8 : 6;
-	r = malloc(count * 3, M_DEVBUF, M_WAITOK);
+	r = malloc(count * 3, M_DEVBUF, M_WAITOK | M_ZERO);
 	g = r + count;
 	b = g + count;
-	copyin(red, r, count);
-	copyin(green, g, count);
-	copyin(blue, b, count);
+	(void)copyin(red, r, count);
+	(void)copyin(green, g, count);
+	(void)copyin(blue, b, count);
 
 	error = vesa_bios_load_palette2(base, count, r, g, b, bits);
 	free(r, M_DEVBUF);
diff --git a/sys/dev/fb/vga.c b/sys/dev/fb/vga.c
index eb081ae533d..9851838aa8f 100644
--- a/sys/dev/fb/vga.c
+++ b/sys/dev/fb/vga.c
@@ -2854,6 +2854,7 @@ get_palette(video_adapter_t *adp, int base, int count,
     u_char *r;
     u_char *g;
     u_char *b;
+    int error;
 
     if (count < 0 || base < 0 || count > 256 || base > 256 ||
 	base + count > 256)
@@ -2863,19 +2864,26 @@ get_palette(video_adapter_t *adp, int base, int count,
     g = r + count;
     b = g + count;
     if (vga_save_palette2(adp, base, count, r, g, b)) {
-	free(r, M_DEVBUF);
-	return ENODEV;
+	error = ENODEV;
+	goto out;
     }
-    copyout(r, red, count);
-    copyout(g, green, count);
-    copyout(b, blue, count);
+    error = copyout(r, red, count);
+    if (error != 0)
+	goto out;
+    error = copyout(g, green, count);
+    if (error != 0)
+	goto out;
+    error = copyout(b, blue, count);
+    if (error != 0)
+	goto out;
     if (trans != NULL) {
 	bzero(r, count);
-	copyout(r, trans, count);
+	error = copyout(r, trans, count);
     }
+out:
     free(r, M_DEVBUF);
 
-    return 0;
+    return error;
 }
 
 static int