export: change to read_segtype_and_lvflags

Instead of duplicating whole segtype string with flags and
using 2 calls read_segtype_lvflags() + get_segtype_from_string(),
merge the functionality into a single read_segtype_and_lvflags().
This allows to make only a local string copy (no allocs) and eventually
to not copy segtype string at all, when there are no flags.

lib/format_text/flags.c

@@ -17,6 +17,7 @@
 #include "lib/metadata/metadata.h"
 #include "import-export.h"
 #include "lib/misc/lvm-string.h"
+#include "lib/metadata/segtype.h"
 
 /*
  * Bitsets held in the 'status' flags get
@@ -234,47 +235,50 @@ int read_flags(uint64_t *status, enum pv_vg_lv_e type, int mask, const struct dm
  * Note: using these segtype status flags instead of actual
  * status flags ensures wanted incompatibility.
  */
-int read_segtype_lvflags(uint64_t *status, char *segtype_str)
+struct segment_type *read_segtype_and_lvflags(struct cmd_context *cmd, uint64_t *status,
+					      const char *segtype_str)
 {
 	unsigned i;
+	size_t len;
+	struct segment_type *segtype;
 	const struct flag *flags = _lv_flags;
-	char *delim;
+	char *delim, *flag, *str, buffer[2048];
-	char *flag, *buffer, *str;
 
-	if (!(str = strchr(segtype_str, '+')))
+	if ((str = strchr(segtype_str, '+'))) {
-		return 1; /* No flags */
+		if ((len = (strlen(segtype_str) + 1)) >= sizeof(buffer)) {
-
+			log_error("Segment string type string is too long.");
-	if (!(buffer = strdup(str + 1))) {
+			return NULL;
-		log_error("Cannot duplicate segment string.");
-		return 0;
 		}
 
-	delim = buffer;
+		memcpy(buffer, segtype_str, len);
+		delim = buffer + (str - segtype_str);
 
 		do {
 			flag = delim;
 			if ((delim = strchr(delim, '+')))
 				*delim++ = '\0';
 
-		for (i = 0; flags[i].description; i++)
+			for (i = 0; flags[i].kind; i++)
 				if ((flags[i].kind & SEGTYPE_FLAG) &&
 				    !strcmp(flags[i].description, flag)) {
 					*status |= flags[i].mask;
 					break;
 				}
 
-	} while (delim && flags[i].description); /* Till no more flags in type appear */
+		} while (delim && flags[i].kind); /* Till no more flags in type appear */
 
-	if (!flags[i].description)
+		if (!flags[i].kind)
 			/* Unknown flag is incompatible - returns unmodified segtype_str */
 			log_warn("WARNING: Unrecognised flag %s in segment type %s.",
 				 flag, segtype_str);
-	else
-		*str = '\0'; /* Cut away 1st. '+' */
 
-	free(buffer);
+		segtype_str = buffer;
+	}
 
-	return 1;
+	if (!(segtype = get_segtype_from_string(cmd, segtype_str)))
+		return_NULL;
+
+	return segtype;
 }
 
 int print_segtype_lvflags(char *buffer, size_t size, uint64_t status)

lib/format_text/import-export.h

@@ -67,7 +67,8 @@ int print_flags(char *buffer, size_t size, enum pv_vg_lv_e type, int mask, uint6
 int read_flags(uint64_t *status, enum pv_vg_lv_e type, int mask, const struct dm_config_value *cv);
 
 int print_segtype_lvflags(char *buffer, size_t size, uint64_t status);
-int read_segtype_lvflags(uint64_t *status, char *segtype_str);
+struct segment_type *read_segtype_and_lvflags(struct cmd_context *cmd, uint64_t *status,
+					      const char *segtype_str);
 
 int text_vg_export_file(struct volume_group *vg, const char *desc, FILE *fp);
 size_t text_vg_export_raw(struct volume_group *vg, const char *desc, char **buf, uint32_t *alloc_size);

lib/format_text/import_vsn1.c

@@ -386,7 +386,6 @@ static int _read_segment(struct cmd_context *cmd,
 	uint32_t area_extents, start_extent, extent_count, reshape_count, data_copies;
 	struct segment_type *segtype;
 	const char *segtype_str;
-	char *segtype_with_flags;
 
 	if (!sn_child) {
 		log_error("Empty segment section.");
@@ -418,24 +417,12 @@ static int _read_segment(struct cmd_context *cmd,
 		return 0;
 	}
 
-        /* Locally duplicate to parse out status flag bits */
+	if (!(segtype = read_segtype_and_lvflags(cmd, &lv->status, segtype_str))) {
-	if (!(segtype_with_flags = dm_pool_strdup(mem, segtype_str))) {
-		log_error("Cannot duplicate segtype string.");
-		return 0;
-	}
-
-	if (!read_segtype_lvflags(&lv->status, segtype_with_flags)) {
 		log_error("Couldn't read segtype for logical volume %s.",
 			  display_lvname(lv));
 		return 0;
 	}
 
-	if (!(segtype = get_segtype_from_string(cmd, segtype_with_flags)))
-		return_0;
-
-	/* Can drop temporary string here as nothing has allocated from VGMEM meanwhile */
-	dm_pool_free(mem, segtype_with_flags);
-
 	if (segtype->ops->text_import_area_count &&
 	    !segtype->ops->text_import_area_count(sn_child, &area_count))
 		return_0;