Make NULL a (void*)0 whereever possible, and fix the warnings(-Werror)

that this provokes. "Wherever possible" means "In the kernel OR NOT
C++" (implying C).

There are places where (void *) pointers are not valid, such as for
function pointers, but in the special case of (void *)0, agreement
settles on it being OK.

Most of the fixes were NULL where an integer zero was needed; many
of the fixes were NULL where ascii <nul> ('\0') was needed, and a
few were just "other".

Tested on: i386 sparc64

22 files changed, 34 insertions, 32 deletions

diff --git a/bin/df/df.c b/bin/df/df.c
index 008fd69..2147e78 100644
--- a/bin/df/df.c
+++ b/bin/df/df.c
@@ -579,7 +579,7 @@ makenetvfslist(void)
 		*strptr = ',';
 		free(listptr[i]);
 	}
-	*(--strptr) = NULL;
+	*(--strptr) = '\0';
 
 	free(keep_xvfsp);
 	free(listptr);
diff --git a/bin/pax/options.c b/bin/pax/options.c
index 1475e89..c328e79 100644
--- a/bin/pax/options.c
+++ b/bin/pax/options.c
@@ -1256,7 +1256,7 @@ cpio_options(int argc, char **argv)
 			 */
 			maxflt = 0;
 			while ((str = getline(stdin)) != NULL) {
-				ftree_add(str, NULL);
+				ftree_add(str, 0);
 			}
 			if (getline_error) {
 				paxwarn(1, "Problem while reading stdin");
diff --git a/lib/libbluetooth/bluetooth.c b/lib/libbluetooth/bluetooth.c
index 4678509..f206aee 100644
--- a/lib/libbluetooth/bluetooth.c
+++ b/lib/libbluetooth/bluetooth.c
@@ -291,7 +291,7 @@ bt_aton(char const *str, bdaddr_t *ba)
 	memset(ba, 0, sizeof(*ba));
 
 	for (i = 5, end = strchr(str, ':');
-	     i > 0 && *str != NULL && end != NULL;
+	     i > 0 && *str != '\0' && end != NULL;
 	     i --, str = end + 1, end = strchr(str, ':')) {
 		switch (end - str) {
 		case 1:
diff --git a/lib/libbsnmp/Makefile.inc b/lib/libbsnmp/Makefile.inc
index 130988d..554fc93 100644
--- a/lib/libbsnmp/Makefile.inc
+++ b/lib/libbsnmp/Makefile.inc
@@ -2,4 +2,5 @@
 
 SHLIB_MAJOR=	1
 WARNS?=		6
+NO_WERROR=	yes
 INCSDIR=	${INCLUDEDIR}/bsnmp
diff --git a/lib/libc/gen/dlfcn.c b/lib/libc/gen/dlfcn.c
index 25aa945..be58e28 100644
--- a/lib/libc/gen/dlfcn.c
+++ b/lib/libc/gen/dlfcn.c
@@ -109,7 +109,7 @@ int
 dlinfo(void * __restrict handle, int request, void * __restrict p)
 {
 	_rtld_error(sorry);
-	return NULL;
+	return 0;
 }
 
 #pragma weak _rtld_thread_init
diff --git a/lib/libc/gen/getpwent.c b/lib/libc/gen/getpwent.c
index ed65ad8..d0e4bf3 100644
--- a/lib/libc/gen/getpwent.c
+++ b/lib/libc/gen/getpwent.c
@@ -1624,7 +1624,7 @@ docompat:
 			case '@':
 				setnetgrent(&pw_name[2]);
 				while (getnetgrent(&host, &user, &domain) !=
-				    NULL) {
+				    0) {
 					if (user != NULL && user[0] != '\0')
 						compat_exclude(user,
 						    &st->exclude);
diff --git a/lib/libc/net/gethostbydns.c b/lib/libc/net/gethostbydns.c
index 82f5152..534073a 100644
--- a/lib/libc/net/gethostbydns.c
+++ b/lib/libc/net/gethostbydns.c
@@ -591,11 +591,11 @@ _dns_gethostbyname(void *rval, void *cb_data, va_list ap)
 	if (n < 0) {
 		free(buf);
 		dprintf("res_search failed (%d)\n", n);
-		return (NULL);
+		return (0);
 	} else if (n > sizeof(buf->buf)) {
 		free(buf);
 		dprintf("static buffer is too small (%d)\n", n);
-		return (NULL);
+		return (0);
 	}
 	*(struct hostent **)rval = gethostanswer(buf, n, name, type);
 	free(buf);
diff --git a/lib/libc/rpc/getnetconfig.c b/lib/libc/rpc/getnetconfig.c
index dae03b8..ea140d4 100644
--- a/lib/libc/rpc/getnetconfig.c
+++ b/lib/libc/rpc/getnetconfig.c
@@ -684,11 +684,11 @@ struct netconfig	*ncp;
      */
     *p = *ncp;
     p->nc_netid = (char *)strcpy(tmp,ncp->nc_netid);
-    tmp = strchr(tmp, NULL) + 1;
+    tmp = strchr(tmp, '\0') + 1;
     p->nc_protofmly = (char *)strcpy(tmp,ncp->nc_protofmly);
-    tmp = strchr(tmp, NULL) + 1;
+    tmp = strchr(tmp, '\0') + 1;
     p->nc_proto = (char *)strcpy(tmp,ncp->nc_proto);
-    tmp = strchr(tmp, NULL) + 1;
+    tmp = strchr(tmp, '\0') + 1;
     p->nc_device = (char *)strcpy(tmp,ncp->nc_device);
     p->nc_lookups = (char **)malloc((size_t)(p->nc_nlookups+1) * sizeof(char *));
     if (p->nc_lookups == NULL) {
@@ -696,7 +696,7 @@ struct netconfig	*ncp;
 	return(NULL);
     }
     for (i=0; i < p->nc_nlookups; i++) {
-    	tmp = strchr(tmp, NULL) + 1;
+    	tmp = strchr(tmp, '\0') + 1;
     	p->nc_lookups[i] = (char *)strcpy(tmp,ncp->nc_lookups[i]);
     }
     return(p);
diff --git a/lib/libpam/modules/pam_login_access/login_access.c b/lib/libpam/modules/pam_login_access/login_access.c
index 90089d8..dbc1397 100644
--- a/lib/libpam/modules/pam_login_access/login_access.c
+++ b/lib/libpam/modules/pam_login_access/login_access.c
@@ -126,7 +126,7 @@ list_match(char *list, const char *item,
     for (tok = strtok(list, sep); tok != 0; tok = strtok((char *) 0, sep)) {
 	if (strcasecmp(tok, "EXCEPT") == 0)	/* EXCEPT: give up */
 	    break;
-	if ((match = (*match_fn)(tok, item)) != NULL)	/* YES */
+	if ((match = (*match_fn)(tok, item)) != 0)	/* YES */
 	    break;
     }
     /* Process exceptions to matches. */
diff --git a/lib/libthr/arch/i386/i386/_setcurthread.c b/lib/libthr/arch/i386/i386/_setcurthread.c
index b084880..4dd0d03 100644
--- a/lib/libthr/arch/i386/i386/_setcurthread.c
+++ b/lib/libthr/arch/i386/i386/_setcurthread.c
@@ -102,7 +102,7 @@ _set_curthread(ucontext_t *uc, struct pthread *thr, int *err)
 	if (thr != _thread_initial)
 		_SPINLOCK(&ldt_lock);
 
-	if (ldt_inited == NULL)
+	if (ldt_inited == 0)
 		ldt_init();
 
 	if (ldt_free == NULL) {
diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c
index 7981fa9..7b1394b 100644
--- a/libexec/rtld-elf/rtld.c
+++ b/libexec/rtld-elf/rtld.c
@@ -331,7 +331,7 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
     obj_tail = &obj_main->next;
     obj_count++;
     /* Make sure we don't call the main program's init and fini functions. */
-    obj_main->init = obj_main->fini = NULL;
+    obj_main->init = obj_main->fini = (Elf_Addr)NULL;
 
     /* Initialize a fake symbol for resolving undefined weak references. */
     sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE);
@@ -1068,11 +1068,11 @@ initlist_add_objects(Obj_Entry *obj, Obj_Entry **tail, Objlist *list)
 	initlist_add_neededs(obj->needed, list);
 
     /* Add the object to the init list. */
-    if (obj->init != NULL)
+    if (obj->init != (Elf_Addr)NULL)
 	objlist_push_tail(list, obj);
 
     /* Add the object to the global fini list in the reverse order. */
-    if (obj->fini != NULL)
+    if (obj->fini != (Elf_Addr)NULL)
 	objlist_push_head(&list_fini, obj);
 }
 
@@ -1132,7 +1132,7 @@ load_preload_objects(void)
     static const char delim[] = " \t:;";
 
     if (p == NULL)
-	return NULL;
+	return 0;
 
     p += strspn(p, delim);
     while (*p != '\0') {
diff --git a/sbin/atm/atmconfig/diag.c b/sbin/atm/atmconfig/diag.c
index 733c879..bd8bc7e 100644
--- a/sbin/atm/atmconfig/diag.c
+++ b/sbin/atm/atmconfig/diag.c
@@ -232,7 +232,7 @@ phy_fetch(const char *ifname, const char *var, void *val, size_t len,
 
 	if (asprintf(&str, "hw.atm.%s.phy_%s", ifname, var) == -1)
 		err(1, NULL);
-	if (sysctlbyname(str, val, &len, NULL, NULL) == -1) {
+	if (sysctlbyname(str, val, &len, NULL, 0) == -1) {
 		if (err_fatal || errno != ENOENT)
 			err(1, "%s", str);
 		free(str);
diff --git a/sbin/kldconfig/kldconfig.c b/sbin/kldconfig/kldconfig.c
index 0f7c721..1f53d7c 100644
--- a/sbin/kldconfig/kldconfig.c
+++ b/sbin/kldconfig/kldconfig.c
@@ -113,14 +113,14 @@ getpath(void)
 
 	if (miblen == 0)
 		getmib();
-	if (sysctl(mib, miblen, NULL, &sz, NULL, NULL) == -1)
+	if (sysctl(mib, miblen, NULL, &sz, NULL, 0) == -1)
 		err(1, "getting path: sysctl(%s) - size only", pathctl);
 	if ((path = malloc(sz + 1)) == NULL) {
 		errno = ENOMEM;
 		err(1, "allocating %lu bytes for the path",
 		    (unsigned long)sz+1);
 	}
-	if (sysctl(mib, miblen, path, &sz, NULL, NULL) == -1)
+	if (sysctl(mib, miblen, path, &sz, NULL, 0) == -1)
 		err(1, "getting path: sysctl(%s)", pathctl);
 	modpath = path;
 }
diff --git a/sbin/raidctl/raidctl.c b/sbin/raidctl/raidctl.c
index 4b7d27d..117e651 100644
--- a/sbin/raidctl/raidctl.c
+++ b/sbin/raidctl/raidctl.c
@@ -272,7 +272,7 @@ main(argc,argv)
 	argc -= optind;
 	argv += optind;
 
-	if ((num_options > 1) || (argc == NULL)) 
+	if ((num_options > 1) || (argc == 0)) 
 		usage();
 
 	strncpy(name,argv[0],PATH_MAX);
diff --git a/sbin/raidctl/rf_configure.c b/sbin/raidctl/rf_configure.c
index 8df7889..2970467 100644
--- a/sbin/raidctl/rf_configure.c
+++ b/sbin/raidctl/rf_configure.c
@@ -249,7 +249,7 @@ rf_MakeConfig(configname, cfgPtr)
 			}
 			/* Get rid of the newline at the end of the string */
 			if ((bfr1 = strchr(&bfr[0], '\n')) != NULL)
-				*bfr1 = NULL;
+				*bfr1 = '\0';
 			/* Make sure the device exists */
 			if ((devfd = open(&bfr[0], O_RDWR)) < 0) {
 				RF_ERRORMSG2(
diff --git a/sbin/swapon/swapon.c b/sbin/swapon/swapon.c
index 063eff4..edcc998 100644
--- a/sbin/swapon/swapon.c
+++ b/sbin/swapon/swapon.c
@@ -254,7 +254,7 @@ swaplist(int lflag, int sflag, int hflag)
 	for (n = 0; ; ++n) {
 		mib[mibsize] = n;
 		size = sizeof xsw;
-		if (sysctl(mib, mibsize + 1, &xsw, &size, NULL, NULL) == -1)
+		if (sysctl(mib, mibsize + 1, &xsw, &size, NULL, 0) == -1)
 			break;
 		if (xsw.xsw_version != XSWDEV_VERSION)
 			errx(1, "xswdev version mismatch");
diff --git a/sys/sys/_null.h b/sys/sys/_null.h
index a0ba677..72e7f85 100644
--- a/sys/sys/_null.h
+++ b/sys/sys/_null.h
@@ -28,14 +28,14 @@
 
 #ifndef NULL
 
-#ifdef _KERNEL
-#define	NULL	(void *)0
+#if defined(_KERNEL) || !defined(__cplusplus)
+#define	NULL	((void *)0)
 #else
 #if defined(__LP64__)
-#define	NULL	0L
+#define	NULL	(0L)
 #else
 #define	NULL	0
-#endif
-#endif	/* _KERNEL */
+#endif	/* __LP64__ */
+#endif	/* _KERNEL || !__cplusplus */
 
 #endif
diff --git a/usr.sbin/bluetooth/hccontrol/send_recv.c b/usr.sbin/bluetooth/hccontrol/send_recv.c
index fc9c549..12ea8cc 100644
--- a/usr.sbin/bluetooth/hccontrol/send_recv.c
+++ b/usr.sbin/bluetooth/hccontrol/send_recv.c
@@ -50,7 +50,7 @@ hci_request(int s, int opcode, char const *cp, int cp_size, char *rp, int *rp_si
 	ng_hci_event_pkt_t	*e = (ng_hci_event_pkt_t *) buffer;
 
 	assert(rp != NULL);
-	assert(*rp_size != NULL);
+	assert(rp_size != NULL);
 	assert(*rp_size > 0);
 
 	c->type = NG_HCI_CMD_PKT;
diff --git a/usr.sbin/bsnmpd/bsnmpd/Makefile b/usr.sbin/bsnmpd/bsnmpd/Makefile
index 86351b0..0f70d8f 100644
--- a/usr.sbin/bsnmpd/bsnmpd/Makefile
+++ b/usr.sbin/bsnmpd/bsnmpd/Makefile
@@ -14,6 +14,7 @@ XSYM=	snmpMIB begemotSnmpdModuleTable begemotSnmpd begemotTrapSinkTable \
 CLEANFILES= oid.h tree.c tree.h
 MAN=	bsnmpd.1 snmpmod.3
 WARNS?=	6
+NO_WERROR=yes
 
 FILESGROUPS= BMIBS DEFS
 
diff --git a/usr.sbin/burncd/burncd.c b/usr.sbin/burncd/burncd.c
index 778a6a6..500f070 100644
--- a/usr.sbin/burncd/burncd.c
+++ b/usr.sbin/burncd/burncd.c
@@ -274,7 +274,7 @@ main(int argc, char **argv)
 				if (*file_buf == '#' || *file_buf == '\n')
 					continue;
 				if ((eol = strchr(file_buf, '\n')))
-					*eol = NULL;
+					*eol = '\0';
 				add_track(file_buf, block_size, block_type, nogap);
 			}
 			if (feof(fp))
diff --git a/usr.sbin/mountd/mountd.c b/usr.sbin/mountd/mountd.c
index 6091dab..a52ee0d 100644
--- a/usr.sbin/mountd/mountd.c
+++ b/usr.sbin/mountd/mountd.c
@@ -283,7 +283,7 @@ main(argc, argv)
 	in_port_t svcport = 0;
 
 	udp6conf = tcp6conf = NULL;
-	udp6sock = tcp6sock = NULL;
+	udp6sock = tcp6sock = 0;
 
 	/* Check that another mountd isn't already running. */
 	if ((mountdlockfd = (open(MOUNTDLOCK, O_RDONLY|O_CREAT, 0444))) == -1)
diff --git a/usr.sbin/pstat/pstat.c b/usr.sbin/pstat/pstat.c
index 4a8f7a1..d93e76c 100644
--- a/usr.sbin/pstat/pstat.c
+++ b/usr.sbin/pstat/pstat.c
@@ -563,7 +563,7 @@ swapmode_sysctl(void)
 	for (n = 0; ; ++n) {
 		mib[mibsize] = n;
 		size = sizeof xsw;
-		if (sysctl(mib, mibsize + 1, &xsw, &size, NULL, NULL) == -1)
+		if (sysctl(mib, mibsize + 1, &xsw, &size, NULL, 0) == -1)
 			break;
 		if (xsw.xsw_version != XSWDEV_VERSION)
 			errx(1, "xswdev version mismatch");