7431 ZFS Channel Programs

Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

3 files changed, 67 insertions, 4 deletions

diff --git a/usr/src/lib/libzfs_core/common/libzfs_core.c b/usr/src/lib/libzfs_core/common/libzfs_core.c
index 87f7ea4f46..5d92d3b1fa 100644
--- a/usr/src/lib/libzfs_core/common/libzfs_core.c
+++ b/usr/src/lib/libzfs_core/common/libzfs_core.c
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+ * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
  * Copyright (c) 2014 Integros [integros.com]
  * Copyright 2017 RackTop Systems.
@@ -152,7 +152,15 @@ lzc_ioctl(zfs_ioc_t ioc, const char *name,
 	}
 
 	while (ioctl(g_fd, ioc, &zc) != 0) {
-		if (errno == ENOMEM && resultp != NULL) {
+		/*
+		 * If ioctl exited with ENOMEM, we retry the ioctl after
+		 * increasing the size of the destination nvlist.
+		 *
+		 * Channel programs that exit with ENOMEM probably ran over the
+		 * lua memory sandbox; they should not be retried.
+		 */
+		if (errno == ENOMEM && resultp != NULL &&
+		    ioc != ZFS_IOC_CHANNEL_PROGRAM) {
 			free((void *)(uintptr_t)zc.zc_nvlist_dst);
 			zc.zc_nvlist_dst_size *= 2;
 			zc.zc_nvlist_dst = (uint64_t)(uintptr_t)
@@ -843,3 +851,54 @@ lzc_destroy_bookmarks(nvlist_t *bmarks, nvlist_t **errlist)
 
 	return (error);
 }
+
+/*
+ * Executes a channel program.
+ *
+ * If this function returns 0 the channel program was successfully loaded and
+ * ran without failing. Note that individual commands the channel program ran
+ * may have failed and the channel program is responsible for reporting such
+ * errors through outnvl if they are important.
+ *
+ * This method may also return:
+ *
+ * EINVAL   The program contains syntax errors, or an invalid memory or time
+ *          limit was given. No part of the channel program was executed.
+ *          If caused by syntax errors, 'outnvl' contains information about the
+ *          errors.
+ *
+ * ECHRNG   The program was executed, but encountered a runtime error, such as
+ *          calling a function with incorrect arguments, invoking the error()
+ *          function directly, failing an assert() command, etc. Some portion
+ *          of the channel program may have executed and committed changes.
+ *          Information about the failure can be found in 'outnvl'.
+ *
+ * ENOMEM   The program fully executed, but the output buffer was not large
+ *          enough to store the returned value. No output is returned through
+ *          'outnvl'.
+ *
+ * ENOSPC   The program was terminated because it exceeded its memory usage
+ *          limit. Some portion of the channel program may have executed and
+ *          committed changes to disk. No output is returned through 'outnvl'.
+ *
+ * ETIME    The program was terminated because it exceeded its Lua instruction
+ *          limit. Some portion of the channel program may have executed and
+ *          committed changes to disk. No output is returned through 'outnvl'.
+ */
+int
+lzc_channel_program(const char *pool, const char *program, uint64_t instrlimit,
+    uint64_t memlimit, nvlist_t *argnvl, nvlist_t **outnvl)
+{
+	int error;
+	nvlist_t *args;
+
+	args = fnvlist_alloc();
+	fnvlist_add_string(args, ZCP_ARG_PROGRAM, program);
+	fnvlist_add_nvlist(args, ZCP_ARG_ARGLIST, argnvl);
+	fnvlist_add_uint64(args, ZCP_ARG_INSTRLIMIT, instrlimit);
+	fnvlist_add_uint64(args, ZCP_ARG_MEMLIMIT, memlimit);
+	error = lzc_ioctl(ZFS_IOC_CHANNEL_PROGRAM, pool, args, outnvl);
+	fnvlist_free(args);
+
+	return (error);
+}
diff --git a/usr/src/lib/libzfs_core/common/libzfs_core.h b/usr/src/lib/libzfs_core/common/libzfs_core.h
index 3d9e14d3da..caa6dcb2a6 100644
--- a/usr/src/lib/libzfs_core/common/libzfs_core.h
+++ b/usr/src/lib/libzfs_core/common/libzfs_core.h
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+ * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
  * Copyright (c) 2014 Integros [integros.com]
  * Copyright 2017 RackTop Systems.
  */
@@ -85,6 +85,9 @@ boolean_t lzc_exists(const char *);
 
 int lzc_rollback(const char *, char *, int);
 
+int lzc_channel_program(const char *, const char *, uint64_t, uint64_t,
+    nvlist_t *, nvlist_t **);
+
 #ifdef	__cplusplus
 }
 #endif
diff --git a/usr/src/lib/libzfs_core/common/mapfile-vers b/usr/src/lib/libzfs_core/common/mapfile-vers
index fd7650c977..aa1bf945d6 100644
--- a/usr/src/lib/libzfs_core/common/mapfile-vers
+++ b/usr/src/lib/libzfs_core/common/mapfile-vers
@@ -19,7 +19,7 @@
 # CDDL HEADER END
 #
 # Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
-# Copyright (c) 2012, 2014 by Delphix. All rights reserved.
+# Copyright (c) 2012, 2016 by Delphix. All rights reserved.
 # Copyright 2017 RackTop Systems.
 #
 # MAPFILE HEADER START
@@ -43,6 +43,7 @@ SYMBOL_VERSION ILLUMOS_0.1 {
 	libzfs_core_fini;
 	libzfs_core_init;
 	lzc_bookmark;
+	lzc_channel_program;
 	lzc_clone;
 	lzc_promote;
 	lzc_create;