I had noticed for years that eeprom(8) always reported failure when
attempting to change OpenFirmware environment variables on macppc.
Upon further examination, it doesn't - the variables get changed, but
error is reported. This is caused by a difference in implementation
behaviour between Apple's OpenFirmware and Sun's.
Suggested diff below; clue from NetBSD.
Before:
# eeprom boot-command
boot-command=mac-boot
# eeprom boot-command=boot
eeprom: invalid keyword: boot-command
# eeprom boot-command
boot-command=boot <-- yet the value has been changed
After:
# eeprom boot-command
boot-command=mac-boot
# eeprom boot-command=boot
# eeprom boot-command
boot-command=boot
Index: openprom.c
===================================================================
RCS file: /OpenBSD/src/sys/arch/macppc/macppc/openprom.c,v
retrieving revision 1.4
diff -u -p -r1.4 openprom.c
--- openprom.c 19 Sep 2015 21:07:04 -0000 1.4
+++ openprom.c 20 Sep 2020 17:56:35 -0000
@@ -186,7 +186,11 @@ openpromioctl(dev_t dev, u_long cmd, cad
strlcpy(buf, name, 32); /* XXX */
len = OF_setprop(node, buf, value, op->op_buflen + 1);
splx(s);
- if (len != op->op_buflen)
+ /*
+ * For string properties, the Apple OpenFirmware implementation
+ * returns the buffer length including the trailing NUL.
+ */
+ if (len != op->op_buflen && len != op->op_buflen + 1)
error = EINVAL;
break;
