libc: replace 0 with NULL for pointers.

While here also cleanup some surrounding code; particularly
drop some malloc() casts.

Found with devel/coccinelle.

Reviewed by:	bde (previous version - all new bugs are mine)

lib/libc/db/hash/hash.c

@@ -771,7 +771,7 @@ hash_seq(const DB *dbp, DBT *key, DBT *data, u_int32_t flag)
 		if (__big_keydata(hashp, bufp, key, data, 1))
 			return (ERROR);
 	} else {
-		if (hashp->cpage == 0)
+		if (hashp->cpage == NULL)
 			return (ERROR);
 		key->data = (u_char *)hashp->cpage->page + bp[ndx];
 		key->size = (ndx > 1 ? bp[ndx - 1] : hashp->BSIZE) - bp[ndx];

lib/libc/db/hash/hash_buf.c

@@ -245,7 +245,7 @@ newbuf(HTAB *hashp, u_int32_t addr, BUFHEAD *prev_bp)
 			 */
 			for (xbp = bp; xbp->ovfl;) {
 				next_xbp = xbp->ovfl;
-				xbp->ovfl = 0;
+				xbp->ovfl = NULL;
 				xbp = next_xbp;
 
 				/* Check that ovfl pointer is up date. */
@@ -350,7 +350,7 @@ __buf_free(HTAB *hashp, int do_free, int to_disk)
 void
 __reclaim_buf(HTAB *hashp, BUFHEAD *bp)
 {
-	bp->ovfl = 0;
+	bp->ovfl = NULL;
 	bp->addr = 0;
 	bp->flags = 0;
 	BUF_REMOVE(bp);

lib/libc/gen/err.c

@@ -96,7 +96,7 @@ errc(int eval, int code, const char *fmt, ...)
 void
 verrc(int eval, int code, const char *fmt, va_list ap)
 {
-	if (err_file == 0)
+	if (err_file == NULL)
 		err_set_file((FILE *)0);
 	fprintf(err_file, "%s: ", _getprogname());
 	if (fmt != NULL) {
@@ -121,7 +121,7 @@ errx(int eval, const char *fmt, ...)
 void
 verrx(int eval, const char *fmt, va_list ap)
 {
-	if (err_file == 0)
+	if (err_file == NULL)
 		err_set_file((FILE *)0);
 	fprintf(err_file, "%s: ", _getprogname());
 	if (fmt != NULL)
@@ -161,7 +161,7 @@ warnc(int code, const char *fmt, ...)
 void
 vwarnc(int code, const char *fmt, va_list ap)
 {
-	if (err_file == 0)
+	if (err_file == NULL)
 		err_set_file((FILE *)0);
 	fprintf(err_file, "%s: ", _getprogname());
 	if (fmt != NULL) {
@@ -183,7 +183,7 @@ warnx(const char *fmt, ...)
 void
 vwarnx(const char *fmt, va_list ap)
 {
-	if (err_file == 0)
+	if (err_file == NULL)
 		err_set_file((FILE *)0);
 	fprintf(err_file, "%s: ", _getprogname());
 	if (fmt != NULL)

lib/libc/gen/getmntinfo.c

@@ -56,7 +56,7 @@ getmntinfo(struct statfs **mntbufp, int flags)
 		if (mntbuf)
 			free(mntbuf);
 		bufsize = (mntsize + 1) * sizeof(struct statfs);
-		if ((mntbuf = (struct statfs *)malloc(bufsize)) == 0)
+		if ((mntbuf = malloc(bufsize)) == NULL)
 			return (0);
 		if ((mntsize = getfsstat(mntbuf, bufsize, flags)) < 0)
 			return (0);

lib/libc/gen/opendir.c

@@ -209,7 +209,7 @@ _filldir(DIR *dirp, bool use_current_pos)
 	 * On the second pass, save pointers to each one.
 	 * Then sort the pointers and remove duplicate names.
 	 */
-	for (dpv = 0;;) {
+	for (dpv = NULL;;) {
 		n = 0;
 		ddptr = buf;
 		while (ddptr < ddeptr) {

lib/libc/gen/tls.c

@@ -285,7 +285,7 @@ _init_tls(void)
 	while (*sp++ != 0)
 		;
 	aux = (Elf_Auxinfo *) sp;
-	phdr = 0;
+	phdr = NULL;
 	phent = phnum = 0;
 	for (auxp = aux; auxp->a_type != AT_NULL; auxp++) {
 		switch (auxp->a_type) {
@@ -302,7 +302,7 @@ _init_tls(void)
 			break;
 		}
 	}
-	if (phdr == 0 || phent != sizeof(Elf_Phdr) || phnum == 0)
+	if (phdr == NULL || phent != sizeof(Elf_Phdr) || phnum == 0)
 		return;
 
 	for (i = 0; (unsigned) i < phnum; i++) {

lib/libc/locale/xlocale_private.h

@@ -155,12 +155,11 @@ __attribute__((unused)) static void
 xlocale_release(void *val)
 {
 	struct xlocale_refcounted *obj = val;
-	long count = atomic_fetchadd_long(&(obj->retain_count), -1) - 1;
-	if (count < 0) {
-		if (0 != obj->destructor) {
-			obj->destructor(obj);
-		}
-	}
+	long count;
+
+	count = atomic_fetchadd_long(&(obj->retain_count), -1) - 1;
+	if (count < 0 && obj->destructor != NULL)
+		obj->destructor(obj);
 }
 
 /**

lib/libc/net/base64.c

@@ -210,7 +210,7 @@ b64_pton(const char *src, u_char *target, size_t targsize)
 			break;
 
 		pos = strchr(Base64, ch);
-		if (pos == 0) 		/* A non-base64 character. */
+		if (pos == NULL)		/* A non-base64 character. */
 			return (-1);
 
 		switch (state) {

lib/libc/net/getifaddrs.c

@@ -85,7 +85,7 @@ getifaddrs(struct ifaddrs **pif)
 	size_t needed;
 	char *buf;
 	char *next;
-	struct ifaddrs *cif = 0;
+	struct ifaddrs *cif;
 	char *p, *p0;
 	struct rt_msghdr *rtm;
 	struct if_msghdrl *ifm;
@@ -214,6 +214,7 @@ getifaddrs(struct ifaddrs **pif)
 	ift = ifa;
 
 	idx = 0;
+	cif = NULL;
 	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
 		rtm = (struct rt_msghdr *)(void *)next;
 		if (rtm->rtm_version != RTM_VERSION)

lib/libc/net/getservent.c

@@ -406,14 +406,14 @@ files_servent(void *retval, void *mdata, va_list ap)
 
 			continue;
 		gotname:
-			if (proto == 0 || strcmp(serv->s_proto, proto) == 0)
+			if (proto == NULL || strcmp(serv->s_proto, proto) == 0)
 				rv = NS_SUCCESS;
 			break;
 		case nss_lt_id:
 			if (port != serv->s_port)
 				continue;
 
-			if (proto == 0 || strcmp(serv->s_proto, proto) == 0)
+			if (proto == NULL || strcmp(serv->s_proto, proto) == 0)
 				rv = NS_SUCCESS;
 			break;
 		case nss_lt_all:

lib/libc/net/rcmd.c

@@ -207,7 +207,7 @@ rcmd_af(char **ahost, int rport, const char *locuser, const char *remuser,
 		}
 	}
 	lport--;
-	if (fd2p == 0) {
+	if (fd2p == NULL) {
 		_write(s, "", 1);
 		lport = 0;
 	} else {

lib/libc/posix1e/acl_support_nfs4.c

@@ -81,7 +81,7 @@ static const char *
 format_flag(uint32_t *var, const struct flagnames_struct *flags)
 {
 
-	for (; flags->name != 0; flags++) {
+	for (; flags->name != NULL; flags++) {
 		if ((flags->flag & *var) == 0)
 			continue;
 

lib/libc/resolv/mtctxres.c

@@ -75,7 +75,7 @@ __res_init_ctx(void) {
 		return (0);
 	}
 
-	if ((mt = malloc(sizeof (mtctxres_t))) == 0) {
+	if ((mt = malloc(sizeof(mtctxres_t))) == NULL) {
 		errno = ENOMEM;
 		return (-1);
 	}
@@ -94,10 +94,7 @@ __res_init_ctx(void) {
 static void
 __res_destroy_ctx(void *value) {
 
-	mtctxres_t	*mt = (mtctxres_t *)value;
-
-	if (mt != 0)
-		free(mt);
+	free(value);
 }
 #endif
 
@@ -130,9 +127,9 @@ ___mtctxres(void) {
 	 * that fails return a global context.
 	 */
 	if (mt_key_initialized) {
-		if (((mt = pthread_getspecific(key)) != 0) ||
+		if (((mt = pthread_getspecific(key)) != NULL) ||
 		    (__res_init_ctx() == 0 &&
-		     (mt = pthread_getspecific(key)) != 0)) {
+		     (mt = pthread_getspecific(key)) != NULL)) {
 			return (mt);
 		}
 	}

lib/libc/resolv/res_init.c

@@ -315,7 +315,7 @@ __res_vinit(res_state statp, int preinit) {
 		while (*cp != '\0' && *cp != ' ' && *cp != '\t' && *cp != '\n')
 			cp++;
 		*cp = '\0';
-		*pp++ = 0;
+		*pp++ = NULL;
 	}
 
 #define	MATCH(line, name) \
@@ -391,7 +391,7 @@ __res_vinit(res_state statp, int preinit) {
 		    while (*cp != '\0' && *cp != ' ' && *cp != '\t')
 			    cp++;
 		    *cp = '\0';
-		    *pp++ = 0;
+		    *pp++ = NULL;
 		    havesearch = 1;
 		    continue;
 		}

lib/libc/resolv/res_mkupdate.c

@@ -1175,7 +1175,7 @@ res_protocolname(int num) {
 	if (protolist == (struct valuelist *)0)
 		res_buildprotolist();
 	pp = cgetprotobynumber(num);
-	if (pp == 0)  {
+	if (pp == NULL)  {
 		(void) sprintf(number, "%d", num);
 		return (number);
 	}
@@ -1190,7 +1190,7 @@ res_servicename(u_int16_t port, const char *proto) {	/*%< Host byte order. */
 	if (servicelist == (struct valuelist *)0)
 		res_buildservicelist();
 	ss = cgetservbyport(htons(port), proto);
-	if (ss == 0)  {
+	if (ss == NULL)  {
 		(void) sprintf(number, "%d", port);
 		return (number);
 	}

lib/libc/rpc/auth_none.c

@@ -83,9 +83,9 @@ authnone_create(void)
 	XDR *xdrs;
 
 	mutex_lock(&authnone_lock);
-	if (ap == 0) {
-		ap = (struct authnone_private *)calloc(1, sizeof (*ap));
-		if (ap == 0) {
+	if (ap == NULL) {
+		ap = calloc(1, sizeof (*ap));
+		if (ap == NULL) {
 			mutex_unlock(&authnone_lock);
 			return (0);
 		}

lib/libc/rpc/clnt_perror.c

@@ -64,8 +64,8 @@ static char *
 _buf(void)
 {
 
-	if (buf == 0)
-		buf = (char *)malloc(CLNT_PERROR_BUFLEN);
+	if (buf == NULL)
+		buf = malloc(CLNT_PERROR_BUFLEN);
 	return (buf);
 }
 
@@ -85,7 +85,7 @@ clnt_sperror(CLIENT *rpch, const char *s)
 	assert(s != NULL);
 
 	str = _buf(); /* side effect: sets CLNT_PERROR_BUFLEN */
-	if (str == 0)
+	if (str == NULL)
 		return (0);
 	len = CLNT_PERROR_BUFLEN;
 	strstart = str;
@@ -240,7 +240,7 @@ clnt_spcreateerror(const char *s)
 	assert(s != NULL);
 
 	str = _buf(); /* side effect: sets CLNT_PERROR_BUFLEN */
-	if (str == 0)
+	if (str == NULL)
 		return(0);
 	len = CLNT_PERROR_BUFLEN;
 	i = snprintf(str, len, "%s: ", s);

lib/libc/rpc/mt_misc.c

@@ -95,7 +95,7 @@ rce_key_init(void)
 struct rpc_createerr *
 __rpc_createerr(void)
 {
-	struct rpc_createerr *rce_addr = 0;
+	struct rpc_createerr *rce_addr = NULL;
 
 	if (thr_main())
 		return (&rpc_createerr);

lib/libc/rpc/rpcdname.c

@@ -43,20 +43,20 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 #include "un-namespace.h"
 
-static char *default_domain = 0;
+static char *default_domain;
 
 static char *
 get_default_domain(void)
 {
 	char temp[256];
 
-	if (default_domain)
+	if (default_domain != NULL)
 		return (default_domain);
 	if (getdomainname(temp, sizeof(temp)) < 0)
 		return (0);
 	if ((int) strlen(temp) > 0) {
-		default_domain = (char *)malloc((strlen(temp)+(unsigned)1));
-		if (default_domain == 0)
+		default_domain = malloc((strlen(temp) + (unsigned)1));
+		if (default_domain == NULL)
 			return (0);
 		(void) strcpy(default_domain, temp);
 		return (default_domain);
@@ -73,7 +73,7 @@ get_default_domain(void)
 int
 __rpc_get_default_domain(char **domain)
 {
-	if ((*domain = get_default_domain()) != 0)
+	if ((*domain = get_default_domain()) != NULL)
 		return (0);
 	return (-1);
 }

lib/libc/softfloat/timesoftfloat.c

@@ -2068,14 +2068,14 @@ static void
         roundingPrecisionName = "80";
     }
     else {
-        roundingPrecisionName = 0;
+        roundingPrecisionName = NULL;
     }
 #ifdef FLOATX80
     floatx80_rounding_precision = roundingPrecision;
 #endif
     switch ( roundingMode ) {
      case 0:
-        roundingModeName = 0;
+        roundingModeName = NULL;
         roundingCode = float_round_nearest_even;
         break;
      case ROUND_NEAREST_EVEN:
@@ -2098,7 +2098,7 @@ static void
     float_rounding_mode = roundingCode;
     switch ( tininessMode ) {
      case 0:
-        tininessModeName = 0;
+        tininessModeName = NULL;
         tininessCode = float_tininess_after_rounding;
         break;
      case TININESS_BEFORE_ROUNDING:

lib/libc/uuid/uuid_to_string.c

@@ -49,7 +49,7 @@ uuid_to_string(const uuid_t *u, char **s, uint32_t *status)
 		*status = uuid_s_ok;
 
 	/* Why allow a NULL-pointer here? */
-	if (s == 0)
+	if (s == NULL)
 		return;
 
 	if (u == NULL) {

lib/libc/xdr/xdr_mem.c

@@ -215,7 +215,7 @@ xdrmem_setpos(XDR *xdrs, u_int pos)
 static int32_t *
 xdrmem_inline_aligned(XDR *xdrs, u_int len)
 {
-	int32_t *buf = 0;
+	int32_t *buf = NULL;
 
 	if (xdrs->x_handy >= len) {
 		xdrs->x_handy -= len;