diff --git a/sbin/gpt/add.c b/sbin/gpt/add.c
index fc18f6e08b80..3d424467ad0f 100644
--- a/sbin/gpt/add.c
+++ b/sbin/gpt/add.c
@@ -33,7 +33,7 @@
 __FBSDID("$FreeBSD: src/sbin/gpt/add.c,v 1.14 2006/06/22 22:05:28 marcel Exp $");
 #endif
 #ifdef __RCSID
-__RCSID("$NetBSD: add.c,v 1.33 2015/12/01 19:25:24 christos Exp $");
+__RCSID("$NetBSD: add.c,v 1.34 2015/12/01 23:29:07 christos Exp $");
 #endif
 
 #include <sys/types.h>
@@ -152,28 +152,19 @@ static int
 cmd_add(gpt_t gpt, int argc, char *argv[])
 {
 	int ch;
-	int64_t human_num;
 
 	while ((ch = getopt(argc, argv, GPT_AIS "bl:t:")) != -1) {
 		switch(ch) {
 		case 'b':
-			if (block > 0)
-				return usage();
-			if (dehumanize_number(optarg, &human_num) < 0)
-				return usage();
-			block = human_num;
-			if (block < 1)
+			if (gpt_human_get(&block) == -1)
 				return usage();
 			break;
 		case 'l':
-			if (name != NULL)
+			if (gpt_name_get(gpt, &name) == -1)
 				return usage();
-			name = (uint8_t *)strdup(optarg);
 			break;
 		case 't':
-			if (!gpt_uuid_is_nil(type))
-				return usage();
-			if (gpt_uuid_parse(optarg, type) != 0)
+			if (gpt_uuid_get(gpt, &type) == -1)
 				return usage();
 			break;
 		default:
@@ -188,9 +179,8 @@ cmd_add(gpt_t gpt, int argc, char *argv[])
 		return usage();
 
 	/* Create NetBSD FFS partitions by default. */
-	if (gpt_uuid_is_nil(type)) {
+	if (gpt_uuid_is_nil(type))
 		gpt_uuid_create(GPT_TYPE_NETBSD_FFS, type, NULL, 0);
-	}
 
 	if (optind != argc)
 		return usage();
diff --git a/sbin/gpt/biosboot.c b/sbin/gpt/biosboot.c
index 0ded07d98bc4..0d3501461c33 100644
--- a/sbin/gpt/biosboot.c
+++ b/sbin/gpt/biosboot.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: biosboot.c,v 1.17 2015/12/01 16:32:19 christos Exp $ */
+/*	$NetBSD: biosboot.c,v 1.18 2015/12/01 23:29:07 christos Exp $ */
 
 /*
  * Copyright (c) 2009 The NetBSD Foundation, Inc.
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #ifdef __RCSID
-__RCSID("$NetBSD: biosboot.c,v 1.17 2015/12/01 16:32:19 christos Exp $");
+__RCSID("$NetBSD: biosboot.c,v 1.18 2015/12/01 23:29:07 christos Exp $");
 #endif
 
 #include <sys/stat.h>
@@ -252,34 +252,23 @@ cmd_biosboot(gpt_t gpt, int argc, char *argv[])
 #ifdef DIOCGWEDGEINFO
 	struct dkwedge_info dkw;
 #endif
-	char *dev, *p;
+	char *dev;
 	int ch;
 	gpt_t ngpt = gpt;
 
 	while ((ch = getopt(argc, argv, "c:i:L:")) != -1) {
 		switch(ch) {
 		case 'c':
-			if (bootpath != NULL)
-				usage();
-			if ((bootpath = strdup(optarg)) == NULL) {
-				gpt_warn(gpt, "strdup failed");
-				return -1;
-			}
+			if (gpt_name_get(gpt, &bootpath) == -1)
+				return usage();
 			break;
 		case 'i':
-			if (entry > 0)
-				usage();
-			entry = strtoul(optarg, &p, 10);
-			if (*p != 0 || entry < 1)
+			if (gpt_entry_get(&entry) == -1)
 				return usage();
 			break;
 		case 'L':
-			if (label != NULL)
+			if (gpt_name_get(gpt, &label) == -1)
 				return usage();
-			if ((label = (uint8_t *)strdup(optarg)) == NULL) {
-				gpt_warn(gpt, "strdup failed");
-				return -1;
-			}
 			break;
 		default:
 			return usage();
diff --git a/sbin/gpt/gpt.c b/sbin/gpt/gpt.c
index 297ee9cd6765..d0dc31a96ca5 100644
--- a/sbin/gpt/gpt.c
+++ b/sbin/gpt/gpt.c
@@ -35,7 +35,7 @@
 __FBSDID("$FreeBSD: src/sbin/gpt/gpt.c,v 1.16 2006/07/07 02:44:23 marcel Exp $");
 #endif
 #ifdef __RCSID
-__RCSID("$NetBSD: gpt.c,v 1.51 2015/12/01 19:25:24 christos Exp $");
+__RCSID("$NetBSD: gpt.c,v 1.52 2015/12/01 23:29:07 christos Exp $");
 #endif
 
 #include <sys/param.h>
@@ -850,7 +850,8 @@ gpt_create(gpt_t gpt, off_t last, u_int parts, int primary_only)
 	hdr->hdr_lba_alt = htole64(last);
 	hdr->hdr_lba_start = htole64(gpt->tbl->map_start + blocks);
 	hdr->hdr_lba_end = htole64(last - blocks - 1LL);
-	gpt_uuid_generate(hdr->hdr_guid);
+	if (gpt_uuid_generate(gpt, hdr->hdr_guid) == -1)
+		return -1;
 	hdr->hdr_lba_table = htole64(gpt->tbl->map_start);
 	hdr->hdr_entries = htole32((blocks * gpt->secsz) /
 	    sizeof(struct gpt_ent));
@@ -860,7 +861,8 @@ gpt_create(gpt_t gpt, off_t last, u_int parts, int primary_only)
 
 	ent = gpt->tbl->map_data;
 	for (i = 0; i < le32toh(hdr->hdr_entries); i++) {
-		gpt_uuid_generate(ent[i].ent_guid);
+		if (gpt_uuid_generate(gpt, ent[i].ent_guid) == -1)
+			return -1;
 	}
 
 	/*
@@ -895,12 +897,50 @@ gpt_create(gpt_t gpt, off_t last, u_int parts, int primary_only)
 	return last;
 }
 
-int
-gpt_add_find(gpt_t gpt, struct gpt_find *find, int ch) 
+static int
+gpt_size_get(gpt_t gpt, off_t *size)
 {
+	off_t sectors;
 	int64_t human_num;
 	char *p;
 
+	if (*size > 0)
+		return -1;
+	sectors = strtoll(optarg, &p, 10);
+	if (sectors < 1)
+		return -1;
+	if (*p == '\0' || ((*p == 's' || *p == 'S') && p[1] == '\0')) {
+		*size = sectors * gpt->secsz;
+		return 0;
+	}
+	if ((*p == 'b' || *p == 'B') && p[1] == '\0') {
+		*size = sectors;
+		return 0;
+	}
+	if (dehumanize_number(optarg, &human_num) < 0)
+		return -1;
+	*size = human_num;
+	return 0;
+}
+
+int
+gpt_human_get(off_t *human)
+{
+	int64_t human_num;
+
+	if (*human > 0)
+		return -1;
+	if (dehumanize_number(optarg, &human_num) < 0)
+		return -1;
+	*human = human_num;
+	if (*human < 1)
+		return -1;
+	return 0;
+}
+
+int
+gpt_add_find(gpt_t gpt, struct gpt_find *find, int ch) 
+{
 	switch (ch) {
 	case 'a':
 		if (find->all > 0)
@@ -908,31 +948,19 @@ gpt_add_find(gpt_t gpt, struct gpt_find *find, int ch)
 		find->all = 1;
 		break;
 	case 'b':
-		if (find->block > 0)
-			return -1;
-		if (dehumanize_number(optarg, &human_num) < 0)
-			return -1;
-		find->block = human_num;
-		if (find->block < 1)
+		if (gpt_human_get(&find->block) == -1)
 			return -1;
 		break;
 	case 'i':
-		if (find->entry > 0)
-			return -1;
-		find->entry = strtoul(optarg, &p, 10);
-		if (*p != 0 || find->entry < 1)
+		if (gpt_entry_get(&find->entry) == -1)
 			return -1;
 		break;
 	case 'L':
-		if (find->label != NULL)
+		if (gpt_name_get(gpt, &find->label) == -1)
 			return -1;
-		find->label = (uint8_t *)strdup(optarg);
 		break;
 	case 's':
-		if (find->size > 0)
-			return -1;
-		find->size = strtoll(optarg, &p, 10);
-		if (*p != 0 || find->size < 1)
+		if (gpt_size_get(gpt, &find->size) == -1)
 			return -1;
 		break;
 	case 't':
@@ -1008,44 +1036,18 @@ gpt_change_ent(gpt_t gpt, const struct gpt_find *find,
 int
 gpt_add_ais(gpt_t gpt, off_t *alignment, u_int *entry, off_t *size, int ch)
 {
-	int64_t human_num;
-	off_t sectors;
-	char *p;
-
 	switch (ch) {
 	case 'a':
-		if (*alignment > 0)
-			return -1;
-		if (dehumanize_number(optarg, &human_num) < 0)
-			return -1;
-		*alignment = human_num;
-		if (*alignment < 1)
+		if (gpt_human_get(alignment) == -1)
 			return -1;
 		return 0;
 	case 'i':
-		if (*entry > 0)
-			return -1;
-		*entry = strtoul(optarg, &p, 10);
-		if (*p != 0 || *entry < 1)
+		if (gpt_entry_get(entry) == -1)
 			return -1;
 		return 0;
 	case 's':
-		if (*size > 0)
+		if (gpt_size_get(gpt, size) == -1)
 			return -1;
-		sectors = strtoll(optarg, &p, 10);
-		if (sectors < 1)
-			return -1;
-		if (*p == '\0' || ((*p == 's' || *p == 'S') && p[1] == '\0')) {
-			*size = sectors * gpt->secsz;
-			return 0;
-		}
-		if ((*p == 'b' || *p == 'B') && p[1] == '\0') {
-			*size = sectors;
-			return 0;
-		}
-		if (dehumanize_number(optarg, &human_num) < 0)
-			return -1;
-		*size = human_num;
 		return 0;
 	default:
 		return -1;
@@ -1142,3 +1144,28 @@ gpt_entry_get(u_int *entry)
 		return -1;
 	return 0;
 }
+int
+gpt_uuid_get(gpt_t gpt, gpt_uuid_t *uuid)
+{
+	if (!gpt_uuid_is_nil(*uuid))
+		return -1;
+	if (gpt_uuid_parse(optarg, *uuid) != 0) {
+		gpt_warn(gpt, "Can't parse uuid");
+		return -1;
+	}
+	return 0;
+}
+
+int
+gpt_name_get(gpt_t gpt, void *v)
+{
+	char **name = v;
+	if (*name != NULL)
+		return -1;
+	*name = strdup(optarg);
+	if (*name == NULL) {
+		gpt_warn(gpt, "Can't copy string");
+		return -1;
+	}
+	return 0;
+}
diff --git a/sbin/gpt/gpt.h b/sbin/gpt/gpt.h
index 8697d53e0b81..50d3a1272862 100644
--- a/sbin/gpt/gpt.h
+++ b/sbin/gpt/gpt.h
@@ -121,5 +121,8 @@ off_t	gpt_check_ais(gpt_t, off_t, u_int, off_t);
 int	gpt_attr_get(uint64_t *);
 int	gpt_attr_update(gpt_t, u_int, uint64_t, uint64_t);
 int	gpt_entry_get(u_int *);
+int	gpt_human_get(off_t *);
+int	gpt_uuid_get(gpt_t, gpt_uuid_t *);
+int	gpt_name_get(gpt_t, void *);
 
 #endif /* _GPT_H_ */
diff --git a/sbin/gpt/gpt_uuid.c b/sbin/gpt/gpt_uuid.c
index 93560fcf0b36..27e033e3ae59 100644
--- a/sbin/gpt/gpt_uuid.c
+++ b/sbin/gpt/gpt_uuid.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: gpt_uuid.c,v 1.10 2014/12/06 12:24:22 mlelstv Exp $	*/
+/*	$NetBSD: gpt_uuid.c,v 1.11 2015/12/01 23:29:07 christos Exp $	*/
 
 /*-
  * Copyright (c) 2014 The NetBSD Foundation, Inc.
@@ -32,7 +32,7 @@
 
 #include <sys/cdefs.h>
 #ifdef __RCSID
-__RCSID("$NetBSD: gpt_uuid.c,v 1.10 2014/12/06 12:24:22 mlelstv Exp $");
+__RCSID("$NetBSD: gpt_uuid.c,v 1.11 2015/12/01 23:29:07 christos Exp $");
 #endif
 
 #include <err.h>
@@ -238,8 +238,8 @@ gpt_uuid_create(gpt_type_t t, gpt_uuid_t u, uint16_t *b, size_t s)
 		utf8_to_utf16((const uint8_t *)gpt_nv[t].d, b, s / sizeof(*b));
 }
 
-void
-gpt_uuid_generate(gpt_uuid_t t)
+int
+gpt_uuid_generate(gpt_t gpt, gpt_uuid_t t)
 {
 	struct dce_uuid u;
 	int fd;
@@ -249,16 +249,24 @@ gpt_uuid_generate(gpt_uuid_t t)
 
 	/* Randomly generate the content.  */
 	fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
-	if (fd == -1)
-		err(1, "open(/dev/urandom)");
+	if (fd == -1) {
+		gpt_warn(gpt, "Can't open `/dev/urandom'");
+		return -1;
+	}
 	for (p = (void *)&u, n = sizeof u; 0 < n; p += nread, n -= nread) {
 		nread = read(fd, p, n);
-		if (nread < 0)
-			err(1, "read(/dev/urandom)");
-		if (nread == 0)
-			errx(1, "EOF from /dev/urandom");
-		if ((size_t)nread > n)
-			errx(1, "read too much: %zd > %zu", nread, n);
+		if (nread < 0) {
+			gpt_warn(gpt, "Can't read `/dev/urandom'");
+			goto out;
+		}
+		if (nread == 0) {
+			gpt_warn(gpt, "EOF from /dev/urandom");
+			goto out;
+		}
+		if ((size_t)nread > n) {
+			gpt_warnx(gpt, "read too much: %zd > %zu", nread, n);
+			goto out;
+		}
 	}
 	(void)close(fd);
 
@@ -271,4 +279,8 @@ gpt_uuid_generate(gpt_uuid_t t)
 	u.clock_seq_hi_and_reserved |= 0x80;
 
 	gpt_dce_to_uuid(&u, t);
+	close(fd);
+	return 0;
+out:
+	return -1;
 }
diff --git a/sbin/gpt/gpt_uuid.h b/sbin/gpt/gpt_uuid.h
index 3e15ea576b82..d468742f92bb 100644
--- a/sbin/gpt/gpt_uuid.h
+++ b/sbin/gpt/gpt_uuid.h
@@ -94,7 +94,8 @@ void gpt_uuid_create(gpt_type_t, gpt_uuid_t, uint16_t *, size_t);
 
 int gpt_uuid_parse(const char *, gpt_uuid_t);
 
-void gpt_uuid_generate(gpt_uuid_t);
+struct gpt;
+int gpt_uuid_generate(struct gpt *, gpt_uuid_t);
 
 __END_DECLS
 
diff --git a/sbin/gpt/label.c b/sbin/gpt/label.c
index 1e3d33ea9e59..2f140a799524 100644
--- a/sbin/gpt/label.c
+++ b/sbin/gpt/label.c
@@ -33,7 +33,7 @@
 __FBSDID("$FreeBSD: src/sbin/gpt/label.c,v 1.3 2006/10/04 18:20:25 marcel Exp $");
 #endif
 #ifdef __RCSID
-__RCSID("$NetBSD: label.c,v 1.22 2015/12/01 19:25:24 christos Exp $");
+__RCSID("$NetBSD: label.c,v 1.23 2015/12/01 23:29:07 christos Exp $");
 #endif
 
 #include <sys/types.h>
@@ -73,33 +73,46 @@ change(struct gpt_ent *ent, void *v)
 	utf8_to_utf16(name, ent->ent_name, 36);
 }
 
-static char *
-name_from_file(const char *fn)
+static int
+name_from_file(gpt_t gpt, void *v)
 {
 	FILE *f;
 	char *p;
 	size_t maxlen = 1024;
 	size_t len;
-	char *name;
+	const char *fn = optarg;
+	char **name = v;
+
+	if (*name != NULL)
+		return -1;
 
 	if (strcmp(fn, "-") != 0) {
 		f = fopen(fn, "r");
-		if (f == NULL)
-			err(1, "unable to open file %s", fn);
+		if (f == NULL) {
+			gpt_warn(gpt, "Can't open `%s'", fn);
+			return -1;
+		}
 	} else
 		f = stdin;
-	name = malloc(maxlen);
-	len = fread(name, 1, maxlen - 1, f);
-	if (ferror(f))
-		err(1, "unable to read label from file %s", fn);
+
+	if ((*name = malloc(maxlen)) == NULL) {
+		gpt_warn(gpt, "Can't copy string");
+		return -1;
+	}
+	len = fread(*name, 1, maxlen - 1, f);
+	if (ferror(f)) {
+		free(*name);
+		gpt_warn(gpt, "Can't label from `%s'", fn);
+		return -1;
+	}
 	if (f != stdin)
 		fclose(f);
-	name[len] = '\0';
+	(*name)[len] = '\0';
 	/* Only keep the first line, excluding the newline character. */
-	p = strchr((const char *)name, '\n');
+	p = strchr(*name, '\n');
 	if (p != NULL)
 		*p = '\0';
-	return name;
+	return 0;
 }
 
 static int
@@ -116,14 +129,12 @@ cmd_label(gpt_t gpt, int argc, char *argv[])
 	while ((ch = getopt(argc, argv, GPT_FIND "f:l:")) != -1) {
 		switch(ch) {
 		case 'f':
-			if (name != NULL)
+			if (name_from_file(gpt, &name) == -1)
 				return usage();
-			name = name_from_file(optarg);
 			break;
 		case 'l':
-			if (name != NULL)
+			if (gpt_name_get(gpt, &name) == -1)
 				return usage();
-			name = strdup(optarg);
 			break;
 		default:
 			if (gpt_add_find(gpt, &find, ch) == -1)
diff --git a/sbin/gpt/show.c b/sbin/gpt/show.c
index 26ef7d301e2d..1fdce411ff0e 100644
--- a/sbin/gpt/show.c
+++ b/sbin/gpt/show.c
@@ -33,7 +33,7 @@
 __FBSDID("$FreeBSD: src/sbin/gpt/show.c,v 1.14 2006/06/22 22:22:32 marcel Exp $");
 #endif
 #ifdef __RCSID
-__RCSID("$NetBSD: show.c,v 1.25 2015/12/01 16:32:19 christos Exp $");
+__RCSID("$NetBSD: show.c,v 1.26 2015/12/01 23:29:07 christos Exp $");
 #endif
 
 #include <sys/types.h>
@@ -237,7 +237,6 @@ show_one(gpt_t gpt)
 static int
 cmd_show(gpt_t gpt, int argc, char *argv[])
 {
-	char *p;
 	int ch;
 
 	while ((ch = getopt(argc, argv, "gi:lu")) != -1) {
@@ -246,10 +245,7 @@ cmd_show(gpt_t gpt, int argc, char *argv[])
 			show_guid = 1;
 			break;
 		case 'i':
-			if (entry > 0)
-				return usage();
-			entry = strtoul(optarg, &p, 10);
-			if (*p != 0 || entry < 1)
+			if (gpt_entry_get(&entry) == -1)
 				return usage();
 			break;
 		case 'l':