Rework and simplify string argument parsing. All string arguments are at

most DPISTRLEN (32) characters so there is no need for fancy dynamic
growing strings. Use a DPISTRLEN long buffer and bail if it fills up.

Rename get_string() to get_dpistr() and get_string_argument() to
get_dpstr_argument() to emphasize they will return strings that fit
in DPISTRLEN.

Rework & simplify a pair of their consumers - do_rename_partition() and
do_change_type() - to be more obviously identitical to each other bar
the displayed verbiage.

3 files changed, 78 insertions, 95 deletions

diff --git a/sbin/pdisk/io.c b/sbin/pdisk/io.c
index 63571ce203c..ef130c3ebc1 100644
--- a/sbin/pdisk/io.c
+++ b/sbin/pdisk/io.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: io.c,v 1.23 2016/01/26 16:39:00 krw Exp $	*/
+/*	$OpenBSD: io.c,v 1.24 2016/01/26 23:41:48 krw Exp $	*/
 
 /*
  * io.c - simple io and input parsing routines
@@ -33,18 +33,18 @@
 #include <string.h>
 #include <stdarg.h>
 
+#include "dpme.h"
 #include "io.h"
 
 #define BAD_DIGIT 17		/* must be greater than any base */
-#define	STRING_CHUNK	16
 #define UNGET_MAX_COUNT 10
 
 short	unget_buf[UNGET_MAX_COUNT + 1];
 int	unget_count;
 
-long	get_number(int);
-char   *get_string(int);
-int	my_getch (void);
+static long	get_number(int);
+static char    *get_string(int);
+static int	my_getch (void);
 
 int
 my_getch()
@@ -215,11 +215,10 @@ get_number(int first_char)
 	return (ret_value);
 }
 
-int
-get_string_argument(const char *prompt, char **string)
+char *
+get_dpistr_argument(const char *prompt)
 {
 	int c;
-	int result = 0;
 
 	for (;;) {
 		c = my_getch();
@@ -231,68 +230,46 @@ get_string_argument(const char *prompt, char **string)
 		} else if (c == '\n') {
 			printf(prompt);
 		} else if (c == '"' || c == '\'') {
-			*string = get_string(c);
-			result = 1;
-			break;
+			return get_string(c);
 		} else if (('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') ||
 		    (c == '-' || c == '/' || c == '.' || c == ':')) {
 			my_ungetch(c);
-			*string = get_string(' ');
-			result = 1;
-			break;
+			return get_string(' ');
 		} else {
 			my_ungetch(c);
-			*string = NULL;
-			break;
+			return NULL;
 		}
 	}
-	return result;
+	return NULL;
 }
 
 
 char *
 get_string(int eos)
 {
-	char *s, *ret_value, *limit;
-	int c, length;
+	char buf[DPISTRLEN];
+	char *s, *limit;
+	int c;
 
-	ret_value = malloc(STRING_CHUNK);
-	if (ret_value == NULL) {
-		warn("can't allocate memory for string buffer");
-		return NULL;
-	}
-	length = STRING_CHUNK;
-	limit = ret_value + length;
+	memset(buf, 0, sizeof(buf));
+	limit = buf + sizeof(buf);
 
 	c = my_getch();
-	for (s = ret_value;; c = my_getch()) {
-		if (s >= limit) {
-			/* expand string */
-			limit = malloc(length + STRING_CHUNK);
-			if (limit == NULL) {
-				warn("can't allocate memory for string buffer");
-				ret_value[length - 1] = 0;
-				break;
-			}
-			strncpy(limit, ret_value, length);
-			free(ret_value);
-			s = limit + (s - ret_value);
-			ret_value = limit;
-			length += STRING_CHUNK;
-			limit = ret_value + length;
-		}
+	for (s = buf;; c = my_getch()) {
 		if (c <= 0 || c == eos || (eos == ' ' && c == '\t')) {
-			*s++ = 0;
+			*s = 0;
 			break;
 		} else if (c == '\n') {
-			*s++ = 0;
+			*s = 0;
 			my_ungetch(c);
 			break;
 		} else {
 			*s++ = c;
+			if (s >= limit)
+				return NULL;
 		}
 	}
-	return (ret_value);
+	return (strdup(buf));
 }
 
 
diff --git a/sbin/pdisk/io.h b/sbin/pdisk/io.h
index f09dbaf5d41..1188fb716f1 100644
--- a/sbin/pdisk/io.h
+++ b/sbin/pdisk/io.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: io.h,v 1.11 2016/01/24 01:38:32 krw Exp $	*/
+/*	$OpenBSD: io.h,v 1.12 2016/01/26 23:41:48 krw Exp $	*/
 
 /*
  * io.h - simple io and input parsing routines
@@ -38,7 +38,7 @@ int		get_command(const char *, int, int *);
 int		get_number_argument(const char *, long *);
 int		get_okay(const char *, int);
 int		get_partition_modifier(void);
-int		get_string_argument(const char *, char **);
+char	       *get_dpistr_argument(const char *);
 int		number_of_digits(unsigned long);
 
 #endif /* __io__ */
diff --git a/sbin/pdisk/pdisk.c b/sbin/pdisk/pdisk.c
index 2649e889a91..56927b1aed8 100644
--- a/sbin/pdisk/pdisk.c
+++ b/sbin/pdisk/pdisk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pdisk.c,v 1.71 2016/01/26 21:07:54 krw Exp $	*/
+/*	$OpenBSD: pdisk.c,v 1.72 2016/01/26 23:41:48 krw Exp $	*/
 
 /*
  * pdisk - an editor for Apple format partition tables
@@ -242,41 +242,43 @@ do_create_partition(struct partition_map_header *map, int get_type)
 {
 	long base, length;
 	char *name = NULL;
-	char *type_name = NULL;
+	char *type = NULL;
 
-	if (get_base_argument(&base, map) == 0) {
+	if (get_base_argument(&base, map) == 0)
 		return;
-	}
-	if (get_size_argument(&length, map) == 0) {
+	if (get_size_argument(&length, map) == 0)
 		return;
-	}
-	if (get_string_argument("Name of partition: ", &name) == 0) {
+
+	name = get_dpistr_argument("Name of partition: ");
+	if (name == NULL) {
 		bad_input("Bad name");
-		return;
+		goto out;
 	}
-	if (get_type == 0) {
-		add_partition_to_map(name, kUnixType, base, length, map);
-	} else if (get_string_argument("Type of partition: ", &type_name) ==
-	    0) {
+
+	if (get_type == 0)
+		type = strdup(kUnixType);
+	else
+		type = get_dpistr_argument("Type of partition: ");
+	if (type == NULL) {
 		bad_input("Bad type");
-		goto xit1;
-	} else {
-		if (strncasecmp(type_name, kFreeType, DPISTRLEN) == 0) {
-			bad_input("Can't create a partition with the Free "
-			    "type");
-			goto xit2;
-		}
-		if (strncasecmp(type_name, kMapType, DPISTRLEN) == 0) {
-			bad_input("Can't create a partition with the Map "
-			    "type");
-			goto xit2;
-		}
-		add_partition_to_map(name, type_name, base, length, map);
+		goto out;
+	}
+
+	if (strncasecmp(type, kFreeType, DPISTRLEN) == 0) {
+		bad_input("Can't create a partition with the Free type");
+		goto out;
+	}
+	if (strncasecmp(type, kMapType, DPISTRLEN) == 0) {
+		bad_input("Can't create a partition with the Map type");
+		goto out;
 	}
-xit2:
-	free(type_name);
-xit1:
+
+	add_partition_to_map(name, type, base, length, map);
+
+out:
+	free(type);
 	free(name);
+
 	return;
 }
 
@@ -347,24 +349,27 @@ do_rename_partition(struct partition_map_header *map)
 		bad_input("Bad partition number");
 		return;
 	}
-	if (get_string_argument("New name of partition: ", &name) == 0) {
-		bad_input("Bad name");
-		return;
-	}
-	/* find partition and change it */
 	entry = find_entry_by_disk_address(ix, map);
 	if (entry == NULL) {
 		printf("No such partition\n");
-	} else {
-		/*
-		 * Since dpme_name is supposed to be NUL-filled, make sure
-		 * current contents are zapped before copying in new name!
-		 */
-		memset(entry->dpme->dpme_name, 0,
-		    sizeof(entry->dpme->dpme_name));
-		strlcpy(entry->dpme->dpme_name, name, DPISTRLEN);
-		map->changed = 1;
+		return;
 	}
+
+	printf("Existing partition name ``%s''.\n", entry->dpme->dpme_name);
+	name = get_dpistr_argument("New name of partition: ");
+	if (name == NULL) {
+		bad_input("Bad name");
+		return;
+	}
+
+	/*
+	 * Since dpme_name is supposed to be NUL-filled, make sure
+	 * current contents are zapped before copying in new name!
+	 */
+	memset(entry->dpme->dpme_name, 0, sizeof(entry->dpme->dpme_name));
+	strlcpy(entry->dpme->dpme_name, name, DPISTRLEN);
+	map->changed = 1;
+
 	free(name);
 	return;
 }
@@ -373,7 +378,7 @@ void
 do_change_type(struct partition_map_header *map)
 {
 	struct partition_map *entry;
-	char *type = NULL;
+	char *type;
 	long ix;
 
 	if (get_number_argument("Partition number: ", &ix) == 0) {
@@ -381,16 +386,18 @@ do_change_type(struct partition_map_header *map)
 		return;
 	}
 	entry = find_entry_by_disk_address(ix, map);
-
 	if (entry == NULL) {
 		printf("No such partition\n");
-		goto out;
+		return;
 	}
+
 	printf("Existing partition type ``%s''.\n", entry->dpme->dpme_type);
-	if (get_string_argument("New type of partition: ", &type) == 0) {
+	type = get_dpistr_argument("New type of partition: ");
+	if (type == NULL) {
 		bad_input("Bad type");
-		goto out;
+		return;
 	}
+
         /*
 	 * Since dpme_type is supposed to be NUL-filled, make sure
          * current contents are zapped before copying in new type!
@@ -399,7 +406,6 @@ do_change_type(struct partition_map_header *map)
 	strncpy(entry->dpme->dpme_type, type, DPISTRLEN);
 	map->changed = 1;
 
-out:
 	free(type);
 	return;
 }