Subject: autoconfig can drop core (#87)
Index:	sys/autoconfig/read_dtab.c 2.11BSD

Description:
	/etc/autoconfig can (depending on the number of devices, order of
	entries in /etc/dtab, etc) crash.  This causes 'init' to leave
	the system in single user mode with no devices except the boot
	device and network devices configured.

Repeat-By:
	Difficult to specify the exact order and number of devices
	in /etc/dtab which triggers the problem.

	This problem only occurs with the recent version of autoconfig
	(which passes vectors thru to drivers support programmable 
	vectors).

	The bug was induced when an extra symbol (that of the 'xxVec'
	entry point for device 'xx') was added to the list of symbols
	read from the kernel symbol table.  The space allocated for 
	holding the 'nlist' results was not increased, causing autoconfig
	to over run a 'malloc'd memory area which in turn causes random
	crashes of the program.

Fix:
	Apply the patch below to read_dtab.c.  Recompile and install
	autoconfig.

===============================cut here=================================
*** /sys/autoconfig/read_dtab.c.old	Sat Dec  5 12:55:26 1987
--- /sys/autoconfig/read_dtab.c	Tue Dec  8 20:12:30 1992
***************
*** 3,9 ****
   * All rights reserved.  The Berkeley software License Agreement
   * specifies the terms and conditions for redistribution.
   *
!  *	@(#)read_dtab.c	1.1 (2.10BSD Berkeley) 12/1/86
   */
  
  #include <machine/autoconfig.h>
--- 3,9 ----
   * All rights reserved.  The Berkeley software License Agreement
   * specifies the terms and conditions for redistribution.
   *
!  *	@(#)read_dtab.c	2.0 (2.11BSD GTE) 12/8/92
   */
  
  #include <machine/autoconfig.h>
***************
*** 78,84 ****
  			addent(&dp->dt_handlers,STRSAVE(save));
  			for (++cp;isspace(*cp);++cp);
  		}
! 		guess_ndev += nhandlers + 2;
  		for (up = uprobe;up->up_name;++up)
  			if (!strcmp(dp->dt_name,up->up_name)) {
  				dp->dt_uprobe = up->up_func;
--- 78,92 ----
  			addent(&dp->dt_handlers,STRSAVE(save));
  			for (++cp;isspace(*cp);++cp);
  		}
! 		guess_ndev += nhandlers;
! /*
!  * In addition to the "handler" symbols for a device we need 3 more
!  * symbols: 'xxVec', 'xxprobe', and 'xxattach'.
!  *
!  * N.B.  If more symbols are added (to the 'DTAB' structure) the following
!  *       line may need to be modified.
! */
! 		guess_ndec += 3;
  		for (up = uprobe;up->up_name;++up)
  			if (!strcmp(dp->dt_name,up->up_name)) {
  				dp->dt_uprobe = up->up_func;