Subject: undefined symbol bug in 'netbind' (#139)
Index:	sys/conf/netbind.c 2.11BSD

Description:
	There is a bug in the program which resolves symbols between
	the kernel (/unix) and the networking (/netnix) images.  If the
	same symbol is undefined in both 'netbind' will not report the
	symbol undefined in the networking image and will instead use
	the kernel definition.

Repeat-By:
	This bug was seen when testing the updated compiler which
	supports the 'unsigned long' data type.  The unsigned long
	shift 'ulsh' routine was undefined in both /unix and /netnix
	but 'netbind' did not declare the symbol undefined in /netnix,
	using instead the value from the kernel.

Fix:
	The problem was that symbols were declared to be 'external' and
	'absolute' by default.  This could fool 'netbind' into thinking
	the symbol had been "defined" with a value of 0.

===============================cut here=============================
*** /usr/src/sys/conf/netbind.c.old	Mon May  2 08:18:33 1988
--- /usr/src/sys/conf/netbind.c	Sun Jun  6 16:16:19 1993
***************
*** 232,250 ****
  		if (!strncmp(sp->s_name, np->n_name, sizeof(np->n_name))) {
  			int type = (np->n_type & N_TYPE);
  
- 			sp->s_type = N_EXT|N_ABS;
  			switch (type) {
  			case N_TEXT:
  			case N_ABS:
  				sp->s_value = np->n_value;
  				break;
  			case N_DATA:
  			case N_BSS:
  				if (ep->a_flag)
  					sp->s_value = np->n_value;
  				else
  					sp->s_value = np->n_value - ep->a_text;
  				break;
  			default:
  				printf("netbind: symbol %.8s, unhandled type 0x%x\n",
  				    np->n_name, np->n_type);
--- 232,253 ----
  		if (!strncmp(sp->s_name, np->n_name, sizeof(np->n_name))) {
  			int type = (np->n_type & N_TYPE);
  
  			switch (type) {
  			case N_TEXT:
  			case N_ABS:
+ 				sp->s_type = N_EXT|N_ABS;
  				sp->s_value = np->n_value;
  				break;
  			case N_DATA:
  			case N_BSS:
+ 				sp->s_type = N_EXT|N_ABS;
  				if (ep->a_flag)
  					sp->s_value = np->n_value;
  				else
  					sp->s_value = np->n_value - ep->a_text;
  				break;
+ 			case N_UNDF:
+ 				return(0);
  			default:
  				printf("netbind: symbol %.8s, unhandled type 0x%x\n",
  				    np->n_name, np->n_type);
***************
*** 286,292 ****
  
  	qsort(symtab, symfree - symtab, sizeof(struct symbol), scmp);
  	for (sp = symtab; sp < symfree; sp++)
! 		if (sp->s_type == N_UNDF)
  			printf("%.8s\n", sp->s_name);
  }
  
--- 289,295 ----
  
  	qsort(symtab, symfree - symtab, sizeof(struct symbol), scmp);
  	for (sp = symtab; sp < symfree; sp++)
! 		if ((sp->s_type & N_TYPE) == N_UNDF)
  			printf("%.8s\n", sp->s_name);
  }