From 3ecd9acbc96a4798901e55599ca7fce195085994 Mon Sep 17 00:00:00 2001
From: Patrick McDermott <patrick.mcdermott@libiquity.com>
Date: Mon, 31 Jul 2023 15:57:14 -0400
Subject: dirent: Add function to allocate & build long name

And add test cases.

Based on code from commit 42156fbb5d41e2360336c32365e89b14fe5b01ca,
which was removed in commit bceab75f6330f82e55381c49026878e3a339a984.
---
diff --git a/opkg-opk/dirent.c b/opkg-opk/dirent.c
index 0080d44..9d27cfd 100644
--- a/opkg-opk/dirent.c
+++ b/opkg-opk/dirent.c
@@ -115,3 +115,59 @@ opkg_opk_dirent_name_prefix(struct opkg_opk_dirent *dirent, int is_dir,
 
 	return OPKG_OPK_OK;
 }
+
+static char *
+_opkg_opk_dirent_name_alloc(struct opkg_opk_dirent *dirent, int is_dir,
+		char **cur, size_t *buf_len)
+{
+	size_t  len;
+	int     sep;
+	char   *buf;
+
+	len = strlen(dirent->name);
+	if (*buf_len > 1 /* 1 for NUL */ || is_dir) {
+		/* Not last node, or is a directory, so append separator. */
+		sep = 1;  /* Used in math below, so must be 1, not just != 0. */
+		++len;
+	} else {
+		/* Last node (first in recursion), so don't append separator. */
+		sep = 0;
+	}
+	*buf_len += len;
+
+	if (dirent->parent == NULL) {
+		buf = malloc(*buf_len);
+		if (buf == NULL) {
+			return NULL;
+		}
+		*cur = buf;
+	} else if ((buf = _opkg_opk_dirent_name_alloc(dirent->parent, is_dir,
+					cur, buf_len)) == NULL) {
+		return NULL;
+	}
+
+	/* Copy node name and possibly separator suffix. */
+	memcpy(*cur, dirent->name, len - sep);
+	*cur += len - sep;
+	if (sep == 1) {
+		**cur = '/';
+		*cur += 1;
+	}
+
+	return buf;
+}
+
+char *
+opkg_opk_dirent_name_alloc(struct opkg_opk_dirent *dirent, int is_dir)
+{
+	char   *buf;
+	char   *cur     = NULL;
+	size_t  buf_len = 1;     /* 1 for NUL */
+
+	if ((buf = _opkg_opk_dirent_name_alloc(dirent, is_dir, &cur, &buf_len))
+			== NULL) {
+		return NULL;
+	}
+	*cur = '\0';
+	return buf;
+}
diff --git a/opkg-opk/dirent.h b/opkg-opk/dirent.h
index 959ca1b..6eefa54 100644
--- a/opkg-opk/dirent.h
+++ b/opkg-opk/dirent.h
@@ -30,4 +30,7 @@ opkg_opk_dirent_name_prefix(struct opkg_opk_dirent *dirent, int is_dir,
 		char *name_buf, size_t name_buf_len,
 		char *pref_buf, size_t pref_buf_len);
 
+char *
+opkg_opk_dirent_name_alloc(struct opkg_opk_dirent *dirent, int is_dir);
+
 #endif  /* OPKG_OPK_DIRENT_H_ */
diff --git a/tests/dirent.c b/tests/dirent.c
index de20b86..bb84cf5 100644
--- a/tests/dirent.c
+++ b/tests/dirent.c
@@ -40,8 +40,9 @@ main()
 	};
 	char  name[9];
 	char  pref[4];
+	char *full_name;
 
-	puts("1..2");
+	puts("1..4");
 
 	if (opkg_opk_dirent_name_prefix(&baz, 0, name, sizeof(name),
 				pref, sizeof(pref)) != OPKG_OPK_OK ||
@@ -59,5 +60,19 @@ main()
 	}
 	printf("ok 2 - \"%s\" + \"%s\"\n", pref, name);
 
+	full_name = opkg_opk_dirent_name_alloc(&baz, 0);
+	if  (full_name == NULL || strcmp(full_name, "foo/bar/baz") != 0) {
+		fputs("not ", stdout);
+	}
+	printf("ok 3 - \"%s\"\n", full_name);
+	free(full_name);
+
+	full_name = opkg_opk_dirent_name_alloc(&baz, 1);
+	if  (full_name == NULL || strcmp(full_name, "foo/bar/baz/") != 0) {
+		fputs("not ", stdout);
+	}
+	printf("ok 4 - \"%s\"\n", full_name);
+	free(full_name);
+
 	return EXIT_SUCCESS;
 }
--
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