I copied over the rmtree function (and other functions needed by this one)

from the postgresql code so we use that instead of issuing system calls
with rm -rf ....

I also eliminated the rm -rf for pg_xlog.

Will later do the same with the other system call to remove files
in pg_replslot/

Makefile

@@ -5,7 +5,7 @@
 HEADERS = $(wildcard *.h)
 
 repmgrd_OBJS = dbutils.o config.o repmgrd.o log.o strutil.o
-repmgr_OBJS = dbutils.o check_dir.o config.o repmgr.o log.o strutil.o
+repmgr_OBJS = dbutils.o check_dir.o config.o repmgr.o log.o strutil.o dirmod.o
 
 DATA = repmgr.sql uninstall_repmgr.sql
 

dirmod.c

@@ -0,0 +1,194 @@
+/*
+ *
+ * dirmod.c
+ *	  directory handling functions
+ *
+ * Copyright (C) 2ndQuadrant, 2010-2016
+ *
+ * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "postgres_fe.h"
+
+/* Don't modify declarations in system headers */
+
+#include <unistd.h>
+#include <dirent.h>
+#include <sys/stat.h>
+
+/*
+ * pgfnames
+ *
+ * return a list of the names of objects in the argument directory.  Caller
+ * must call pgfnames_cleanup later to free the memory allocated by this
+ * function.
+ */
+char	  **
+pgfnames(const char *path)
+{
+	DIR		   *dir;
+	struct dirent *file;
+	char	  **filenames;
+	int			numnames = 0;
+	int			fnsize = 200;	/* enough for many small dbs */
+
+	dir = opendir(path);
+	if (dir == NULL)
+	{
+		return NULL;
+	}
+
+	filenames = (char **) palloc(fnsize * sizeof(char *));
+
+	while (errno = 0, (file = readdir(dir)) != NULL)
+	{
+		if (strcmp(file->d_name, ".") != 0 && strcmp(file->d_name, "..") != 0)
+		{
+			if (numnames + 1 >= fnsize)
+			{
+				fnsize *= 2;
+				filenames = (char **) repalloc(filenames,
+											   fnsize * sizeof(char *));
+			}
+			filenames[numnames++] = pstrdup(file->d_name);
+		}
+	}
+
+	if (errno)
+	{
+		fprintf(stderr, _("could not read directory \"%s\": %s\n"),
+				path, strerror(errno));
+	}
+
+	filenames[numnames] = NULL;
+
+	if (closedir(dir))
+	{
+		fprintf(stderr, _("could not close directory \"%s\": %s\n"),
+				path, strerror(errno));
+	}
+
+	return filenames;
+}
+
+
+/*
+ *	pgfnames_cleanup
+ *
+ *	deallocate memory used for filenames
+ */
+void
+pgfnames_cleanup(char **filenames)
+{
+	char	  **fn;
+
+	for (fn = filenames; *fn; fn++)
+		pfree(*fn);
+
+	pfree(filenames);
+}
+
+
+/*
+ *	rmtree
+ *
+ *	Delete a directory tree recursively.
+ *	Assumes path points to a valid directory.
+ *	Deletes everything under path.
+ *	If rmtopdir is true deletes the directory too.
+ *	Returns true if successful, false if there was any problem.
+ *	(The details of the problem are reported already, so caller
+ *	doesn't really have to say anything more, but most do.)
+ */
+bool
+rmtree(const char *path, bool rmtopdir)
+{
+	bool		result = true;
+	char		pathbuf[MAXPGPATH];
+	char	  **filenames;
+	char	  **filename;
+	struct stat statbuf;
+
+	/*
+	 * we copy all the names out of the directory before we start modifying
+	 * it.
+	 */
+	filenames = pgfnames(path);
+
+	if (filenames == NULL)
+		return false;
+
+	/* now we have the names we can start removing things */
+	for (filename = filenames; *filename; filename++)
+	{
+		snprintf(pathbuf, MAXPGPATH, "%s/%s", path, *filename);
+
+		/*
+		 * It's ok if the file is not there anymore; we were just about to
+		 * delete it anyway.
+		 *
+		 * This is not an academic possibility. One scenario where this
+		 * happens is when bgwriter has a pending unlink request for a file in
+		 * a database that's being dropped. In dropdb(), we call
+		 * ForgetDatabaseFsyncRequests() to flush out any such pending unlink
+		 * requests, but because that's asynchronous, it's not guaranteed that
+		 * the bgwriter receives the message in time.
+		 */
+		if (lstat(pathbuf, &statbuf) != 0)
+		{
+			if (errno != ENOENT)
+			{
+				result = false;
+			}
+			continue;
+		}
+
+		if (S_ISDIR(statbuf.st_mode))
+		{
+			/* call ourselves recursively for a directory */
+			if (!rmtree(pathbuf, true))
+			{
+				/* we already reported the error */
+				result = false;
+			}
+		}
+		else
+		{
+			if (unlink(pathbuf) != 0)
+			{
+				if (errno != ENOENT)
+				{
+					result = false;
+				}
+			}
+		}
+	}
+
+	if (rmtopdir)
+	{
+		if (rmdir(path) != 0)
+		{
+			result = false;
+		}
+	}
+
+	pgfnames_cleanup(filenames);
+
+	return result;
+}
+

dirmod.h

@@ -0,0 +1,23 @@
+/*
+ * dirmod.h
+ * Copyright (c) 2ndQuadrant, 2010-2016
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef _DIRMOD_H_
+#define _DIRMOD_H_
+
+#endif

repmgr.c

@@ -1332,6 +1332,8 @@ do_standby_clone(void)
 	char	   *first_wal_segment = NULL;
 	char	   *last_wal_segment = NULL;
 
+	char       xlog_dir[MAXLEN] = "";
+
 	PQExpBufferData event_details;
 
 
@@ -1997,15 +1999,16 @@ stop_backup:
 			 * Remove any existing WAL from the target directory, since
 			 * rsync's --exclude option doesn't do it.
 			 */
-			maxlen_snprintf(script, "rm -rf %s/pg_xlog/*",
-							local_data_directory);
-			r = system(script);
-			if (r != 0)
+
+		        maxlen_snprintf(xlog_dir, "%s/pg_xlog/", local_data_directory);
+
+			if (!rmtree(xlog_dir, false))
 			{
-				log_err(_("unable to empty local WAL directory %s/pg_xlog/\n"),
-						local_data_directory);
+				log_err(_("unable to empty local WAL directory %s\n"),
+						xlog_dir);
 				exit(ERR_BAD_RSYNC);
 			}
+
 		}
 
 		/*

repmgr.h

@@ -28,6 +28,7 @@
 #include "dbutils.h"
 #include "errcode.h"
 #include "config.h"
+#include "dirmod.h"
 
 #define MIN_SUPPORTED_VERSION		"9.3"
 #define MIN_SUPPORTED_VERSION_NUM	90300