From 89b08c0f0ba951ed385ffb6190a98465717f8b25 Mon Sep 17 00:00:00 2001
From: Martin Schwenke <martin@meltin.net>
Date: Sat, 7 Mar 2015 07:22:32 +1100
Subject: ctdb-common: New function ctdb_set_helper()

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Volker Lendecke <vl@samba.org>
---
 ctdb/common/ctdb_util.c     | 60 +++++++++++++++++++++++++++++++++++++++++++++
 ctdb/include/ctdb_private.h |  2 ++
 2 files changed, 62 insertions(+)

diff --git a/ctdb/common/ctdb_util.c b/ctdb/common/ctdb_util.c
index 137e0a8a09..bd68c55416 100644
--- a/ctdb/common/ctdb_util.c
+++ b/ctdb/common/ctdb_util.c
@@ -64,6 +64,66 @@ void ctdb_die(struct ctdb_context *ctdb, const char *msg)
 	exit(1);
 }
 
+/* Set the path of a helper program from envvar, falling back to
+ * dir/file if envvar unset. type is a string to print in log
+ * messages.  helper is assumed to point to a statically allocated
+ * array of size bytes, initialised to "".  If file is NULL don't fall
+ * back if envvar is unset.  If dir is NULL and envvar is unset (but
+ * file is not NULL) then this is an error.  Returns true if helper is
+ * set, either previously or this time. */
+bool ctdb_set_helper(const char *type, char *helper, size_t size,
+		     const char *envvar,
+		     const char *dir, const char *file)
+{
+	const char *t;
+	struct stat st;
+
+	if (helper[0] != '\0') {
+		/* Already set */
+		return true;
+	}
+
+	t = getenv(envvar);
+	if (t != NULL) {
+		if (strlen(t) >= size) {
+			DEBUG(DEBUG_ERR,
+			      ("Unable to set %s - path too long\n", type));
+			return false;
+		}
+
+		strncpy(helper, t, size);
+	} else if (file == NULL) {
+		return false;
+	} else if (dir == NULL) {
+			DEBUG(DEBUG_ERR,
+			      ("Unable to set %s - dir is NULL\n", type));
+		return false;
+	} else {
+		if (snprintf(helper, size, "%s/%s", dir, file) >= size) {
+			DEBUG(DEBUG_ERR,
+			      ("Unable to set %s - path too long\n", type));
+			return false;
+		}
+	}
+
+	if (stat(helper, &st) != 0) {
+		DEBUG(DEBUG_ERR,
+		      ("Unable to set %s \"%s\" - %s\n",
+		       type, helper, strerror(errno)));
+		return false;
+	}
+	if (!(st.st_mode & S_IXUSR)) {
+		DEBUG(DEBUG_ERR,
+		      ("Unable to set %s \"%s\" - not executable\n",
+		       type, helper));
+		return false;
+	}
+
+	DEBUG(DEBUG_NOTICE,
+	      ("Set %s to \"%s\"\n", type, helper));
+	return true;
+}
+
 /* Invoke an external program to do some sort of tracing on the CTDB
  * process.  This might block for a little while.  The external
  * program is specified by the environment variable
diff --git a/ctdb/include/ctdb_private.h b/ctdb/include/ctdb_private.h
index 7005fd802f..ed4d612620 100644
--- a/ctdb/include/ctdb_private.h
+++ b/ctdb/include/ctdb_private.h
@@ -722,6 +722,8 @@ struct ctdb_fetch_handle {
 void ctdb_set_error(struct ctdb_context *ctdb, const char *fmt, ...) PRINTF_ATTRIBUTE(2,3);
 void ctdb_fatal(struct ctdb_context *ctdb, const char *msg);
 void ctdb_die(struct ctdb_context *ctdb, const char *msg);
+bool ctdb_set_helper(const char *type, char *helper, size_t size,
+		     const char *envvar, const char *dir, const char *file);
 void ctdb_external_trace(void);
 bool ctdb_same_address(struct ctdb_address *a1, struct ctdb_address *a2);
 int ctdb_parse_address(struct ctdb_context *ctdb,
-- 
cgit