Change output buffer size semantics for UTF functions.

Make them consistent with other string functions: now output buffer size
includes potential null terminator, i.e. this is total size. This change
also means that if output buffer isn't large enough it can be left
unterminated (indicated by the -ENAMETOOLONG return value).

libexfat/exfat.h

@@ -178,7 +178,7 @@ int exfat_find_used_sectors(const struct exfat* ef, off_t* a, off_t* b);
 void exfat_stat(const struct exfat* ef, const struct exfat_node* node,
 		struct stat* stbuf);
 void exfat_get_name(const struct exfat_node* node,
-		char buffer[UTF8_BYTES(EXFAT_NAME_MAX)]);
+		char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1]);
 uint16_t exfat_start_checksum(const struct exfat_entry_meta1* entry);
 uint16_t exfat_add_checksum(const void* entry, uint16_t sum);
 le16_t exfat_calc_checksum(const struct exfat_entry_meta1* meta1,

libexfat/lookup.c

@@ -86,7 +86,7 @@ static int lookup_name(struct exfat* ef, struct exfat_node* parent,
 
 	*node = NULL;
 
-	rc = utf8_to_utf16(buffer, name, EXFAT_NAME_MAX, n);
+	rc = utf8_to_utf16(buffer, name, EXFAT_NAME_MAX + 1, n);
 	if (rc != 0)
 		return rc;
 
@@ -194,7 +194,7 @@ int exfat_split(struct exfat* ef, struct exfat_node** parent,
 				exfat_put_node(ef, *parent);
 				return -ENOENT;
 			}
-			rc = utf8_to_utf16(name, p, EXFAT_NAME_MAX, n);
+			rc = utf8_to_utf16(name, p, EXFAT_NAME_MAX + 1, n);
 			if (rc != 0)
 			{
 				exfat_put_node(ef, *parent);

libexfat/node.c

@@ -523,7 +523,7 @@ static int readdir(struct exfat* ef, const struct exfat_node* parent,
 				goto error;
 			}
 			if (utf16_to_utf8(ef->label, label->name,
-						sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
+						sizeof(ef->label), EXFAT_ENAME_MAX) != 0)
 				goto error;
 			break;
 
@@ -1303,7 +1303,7 @@ int exfat_set_label(struct exfat* ef, const char* label)
 	struct exfat_entry_label entry;
 
 	memset(label_utf16, 0, sizeof(label_utf16));
-	rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
+	rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX + 1, strlen(label));
 	if (rc != 0)
 		return rc;
 

libexfat/utf.c

@@ -108,7 +108,7 @@ int utf16_to_utf8(char* output, const le16_t* input, size_t outsize,
 	char* outp = output;
 	wchar_t wc;
 
-	while (inp - input < insize && le16_to_cpu(*inp))
+	while (inp - input < insize)
 	{
 		inp = utf16_to_wchar(inp, &wc, insize - (inp - input));
 		if (inp == NULL)
@@ -122,6 +122,13 @@ int utf16_to_utf8(char* output, const le16_t* input, size_t outsize,
 			exfat_error("name is too long");
 			return -ENAMETOOLONG;
 		}
+		if (wc == 0)
+			return 0;
+	}
+	if (outp - output >= outsize)
+	{
+		exfat_error("name is too long");
+		return -ENAMETOOLONG;
 	}
 	*outp = '\0';
 	return 0;
@@ -202,7 +209,7 @@ int utf8_to_utf16(le16_t* output, const char* input, size_t outsize,
 	le16_t* outp = output;
 	wchar_t wc;
 
-	while (inp - input < insize && *inp)
+	while (inp - input < insize)
 	{
 		inp = utf8_to_wchar(inp, &wc, insize - (inp - input));
 		if (inp == NULL)
@@ -216,6 +223,13 @@ int utf8_to_utf16(le16_t* output, const char* input, size_t outsize,
 			exfat_error("name is too long");
 			return -ENAMETOOLONG;
 		}
+		if (wc == 0)
+			break;
+	}
+	if (outp - output >= outsize)
+	{
+		exfat_error("name is too long");
+		return -ENAMETOOLONG;
 	}
 	*outp = cpu_to_le16(0);
 	return 0;

libexfat/utils.c

@@ -47,9 +47,9 @@ void exfat_stat(const struct exfat* ef, const struct exfat_node* node,
 }
 
 void exfat_get_name(const struct exfat_node* node,
-		char buffer[UTF8_BYTES(EXFAT_NAME_MAX)])
+		char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1])
 {
-	if (utf16_to_utf8(buffer, node->name, UTF8_BYTES(EXFAT_NAME_MAX),
+	if (utf16_to_utf8(buffer, node->name, UTF8_BYTES(EXFAT_NAME_MAX) + 1,
 				EXFAT_NAME_MAX) != 0)
 		exfat_bug("failed to convert name to UTF-8");
 }

mkfs/main.c

@@ -136,7 +136,7 @@ static int setup_volume_label(le16_t label[EXFAT_ENAME_MAX + 1], const char* s)
 	memset(label, 0, (EXFAT_ENAME_MAX + 1) * sizeof(le16_t));
 	if (s == NULL)
 		return 0;
-	return utf8_to_utf16(label, s, EXFAT_ENAME_MAX, strlen(s));
+	return utf8_to_utf16(label, s, EXFAT_ENAME_MAX + 1, strlen(s));
 }
 
 static uint32_t setup_volume_serial(uint32_t user_defined)