[RFC PATCH 5/6] libutil: Convert rootdir to a dynamically allocated array

In preparation for dropping the use of PATH_MAX, convert rootdir to a
dynamically allocated array. As rootdir is used to cache state across
function calls (iterating over files), free the buffer when it is no
longer being used (find_close).
---
 libutil/find.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/libutil/find.c b/libutil/find.c
index 1863df4..14d59d5 100644
--- a/libutil/find.c
+++ b/libutil/find.c
@@ -97,7 +97,7 @@ static regex_t *skip;			/**< regex for skipping units */
 static regex_t *suff;			/**< regex for suffixes */
 static FILE *ip;
 static FILE *temp;
-static char rootdir[PATH_MAX];
+static char *rootdir;
 static char cwddir[MAXPATHLEN];
 static int find_mode;
 static int find_eof;
@@ -635,7 +635,7 @@ find_open(const char *start, int explain)
 
 	if (!start)
 		start = "./";
-        if (realpath(start, rootdir) == NULL)
+        if ((rootdir = realpath(start, NULL)) == NULL)
                 die("cannot get real path of '%s'.", trimpath(dir));
 	/*
 	 * setup stack.
@@ -664,6 +664,7 @@ find_open(const char *start, int explain)
 void
 find_open_filelist(const char *filename, const char *root, int explain)
 {
+	size_t rootdir_len;
 	assert(find_mode == 0);
 	find_mode = FILELIST_OPEN;
 	find_explain = explain;
@@ -689,11 +690,19 @@ find_open_filelist(const char *filename, const char *root, int explain)
 	}
 	/*
 	 * rootdir always ends with '/'.
+	 *
+	 * rootdir_len is two characters longer than root to be able
+	 * to append a "/" if needed and the string terminator
+	 * ofcourse.
 	 */
-	if (!strcmp(root+ROOT, "/"))
-		strlimcpy(rootdir, root, sizeof(rootdir));
-	else
-		snprintf(rootdir, sizeof(rootdir), "%s/", root);
+	rootdir_len = strlen(root) + 2;
+	rootdir = malloc(rootdir_len);
+	if (!rootdir)
+		die("short of memory.");
+
+	snprintf(rootdir, rootdir_len, "%s%s", root,
+		 strcmp(root+ROOT, "/") ? "/" : "");
+
 	strlimcpy(cwddir, root, sizeof(cwddir));
 }
 /**
@@ -909,6 +918,8 @@ find_close(void)
 	} else {
 		die("find_close: internal error.");
 	}
+	if (rootdir)
+		free(rootdir);
 	if (suff)
 		regfree(suff);
 	if (skip)
-- 
2.11.0