util: Add file tree walk interface

Add tftw() utility to emulate nftw() behavior with a userdata pointer.
This is repurposed from the csync project custom file tree walker.

Signed-off-by: Justin Stephenson <jstephen@redhat.com>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Bjoern Jacke <bjacke@samba.org>

lib/util/tftw.c

@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2008-2018 by Andreas Schneider <asn@samba.org>
+ *
+ * Adopted from the csync source code
+ */
+
+#include <errno.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include "memory.h"
+#include "debug.h"
+#include "replace.h"
+#include "system/locale.h"
+#include "lib/util/asn1.h"
+#include "lib/util/debug.h"
+#include "lib/util/samba_util.h"
+
+#include "tftw.h"
+
+
+int tftw(TALLOC_CTX *mem_ctx, const char *fpath, tftw_walker_fn fn, size_t depth, void *userdata)
+{
+	char *filename = NULL;
+	char *d_name = NULL;
+	DIR *dh = NULL;
+	struct dirent *dirent = NULL;
+	struct stat sb = {0};
+	int rc = 0;
+
+	if (fpath[0] == '\0') {
+		errno = ENOENT;
+		goto error;
+	}
+
+	if ((dh = opendir(fpath)) == NULL) {
+		/* permission denied */
+		if (errno == EACCES) {
+			return 0;
+		} else {
+			DBG_ERR("opendir failed for: [%s]\n", strerror(errno));
+			goto error;
+		}
+	}
+
+	while ((dirent = readdir(dh))) {
+		int flag;
+
+		d_name = dirent->d_name;
+		if (d_name == NULL) {
+			goto error;
+		}
+
+		/* skip "." and ".." */
+		if (d_name[0] == '.' && (d_name[1] == '\0'
+					|| (d_name[1] == '.' && d_name[2] == '\0'))) {
+			dirent = NULL;
+			continue;
+		}
+
+		filename = talloc_asprintf(mem_ctx, "%s/%s", fpath, d_name);
+		if (filename == NULL) {
+			goto error;
+		}
+
+		rc = lstat(filename, &sb);
+		if (rc < 0) {
+			dirent = NULL;
+			goto error;
+		}
+
+		switch (sb.st_mode & S_IFMT) {
+			case S_IFLNK:
+				flag = TFTW_FLAG_SLINK;
+				break;
+			case S_IFDIR:
+				flag = TFTW_FLAG_DIR;
+				break;
+			case S_IFBLK:
+			case S_IFCHR:
+			case S_IFSOCK:
+			case S_IFIFO:
+				flag = TFTW_FLAG_SPEC;
+				break;
+			default:
+				flag = TFTW_FLAG_FILE;
+				break;
+		}
+
+		DBG_INFO("walk: [%s]\n", filename);
+
+		/* Call walker function for each file */
+		rc = fn(mem_ctx, filename, &sb, flag, userdata);
+
+		if (rc < 0) {
+			DBG_ERR("provided callback fn() failed: [%s]\n",
+				strerror(errno));
+			closedir(dh);
+			goto done;
+		}
+
+		if (flag == TFTW_FLAG_DIR && depth) {
+			rc = tftw(mem_ctx, filename, fn, depth - 1, userdata);
+			if (rc < 0) {
+				closedir(dh);
+				goto done;
+			}
+		}
+		TALLOC_FREE(filename);
+		dirent = NULL;
+	}
+	closedir(dh);
+
+done:
+	TALLOC_FREE(filename);
+	return rc;
+error:
+	if (dh != NULL) {
+		closedir(dh);
+	}
+	TALLOC_FREE(filename);
+	return -1;
+}

lib/util/tftw.h

@@ -0,0 +1,32 @@
+#include <talloc.h>
+
+enum tftw_flags_e {
+	/* Regular file.  */
+	TFTW_FLAG_FILE,
+	/* Directory.  */
+	TFTW_FLAG_DIR,
+	/* Unreadable directory.  */
+	TFTW_FLAG_DNR,
+	/* Unstatable file.  */
+	TFTW_FLAG_NSTAT,
+	/* Symbolic link.  */
+	TFTW_FLAG_SLINK,
+	/* Special file (fifo, ...).  */
+	TFTW_FLAG_SPEC,
+
+	/* Directory, all subdirs have been visited. */
+	TFTW_FLAG_DP,
+	/* Symbolic link naming non-existing file.  */
+	TFTW_FLAG_SLN
+};
+
+/* Maximum number of subdirectories to descend into */
+#define TFTW_MAX_DEPTH 50
+
+typedef int (*tftw_walker_fn)(TALLOC_CTX *mem_ctx,
+			      const char *fpath,
+			      const struct stat *sb,
+			      enum tftw_flags_e flag,
+			      void *userdata);
+
+int tftw(TALLOC_CTX *mem_ctx, const char *fpath, tftw_walker_fn fn, size_t depth, void *userdata);

lib/util/wscript_build

@@ -123,7 +123,8 @@ else:
                     idtree_random.c base64.c
                     util_str.c util_str_common.c ms_fnmatch.c
                     server_id.c dprintf.c
-                    tevent_debug.c memcache.c unix_match.c tfork.c''',
+                    tevent_debug.c memcache.c unix_match.c tfork.c
+                    tftw.c''',
                   deps='samba-util-core DYNCONFIG close-low-fd tiniparser genrand util_str_hex',
                   public_deps='talloc tevent execinfo pthread LIBCRYPTO charset util_setid',
                   public_headers='debug.h attr.h byteorder.h data_blob.h memory.h safe_string.h time.h talloc_stack.h string_wrappers.h idtree.h idtree_random.h blocking.h signal.h substitute.h fault.h genrand.h tfork.h',