12260 Fix zpool history unbounded memory usage

Portions contributed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Tom Caputi <tcaputi@datto.com>
Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Igor Kozhukhov <igor@dilos.org>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Sanjay Nadkarni <Sanjay G Nadkarni <snadkarni@tintri.com>
Approved by: Dan McDonald <danmcd@joyent.com>

3 files changed, 42 insertions, 27 deletions

diff --git a/usr/src/cmd/zpool/zpool_main.c b/usr/src/cmd/zpool/zpool_main.c
index 50935f4112..0a8b06db2f 100644
--- a/usr/src/cmd/zpool/zpool_main.c
+++ b/usr/src/cmd/zpool/zpool_main.c
@@ -6529,24 +6529,12 @@ typedef struct hist_cbdata {
 	boolean_t internal;
 } hist_cbdata_t;
 
-/*
- * Print out the command history for a specific pool.
- */
-static int
-get_history_one(zpool_handle_t *zhp, void *data)
+static void
+print_history_records(nvlist_t *nvhis, hist_cbdata_t *cb)
 {
-	nvlist_t *nvhis;
 	nvlist_t **records;
 	uint_t numrecords;
-	int ret, i;
-	hist_cbdata_t *cb = (hist_cbdata_t *)data;
-
-	cb->first = B_FALSE;
-
-	(void) printf(gettext("History for '%s':\n"), zpool_get_name(zhp));
-
-	if ((ret = zpool_get_history(zhp, &nvhis)) != 0)
-		return (ret);
+	int i;
 
 	verify(nvlist_lookup_nvlist_array(nvhis, ZPOOL_HIST_RECORD,
 	    &records, &numrecords) == 0);
@@ -6647,8 +6635,32 @@ get_history_one(zpool_handle_t *zhp, void *data)
 		(void) printf("]");
 		(void) printf("\n");
 	}
+}
+
+/*
+ * Print out the command history for a specific pool.
+ */
+static int
+get_history_one(zpool_handle_t *zhp, void *data)
+{
+	nvlist_t *nvhis;
+	int ret;
+	hist_cbdata_t *cb = (hist_cbdata_t *)data;
+	uint64_t off = 0;
+	boolean_t eof = B_FALSE;
+
+	cb->first = B_FALSE;
+
+	(void) printf(gettext("History for '%s':\n"), zpool_get_name(zhp));
+
+	while (!eof) {
+		if ((ret = zpool_get_history(zhp, &nvhis, &off, &eof)) != 0)
+			return (ret);
+
+		print_history_records(nvhis, cb);
+		nvlist_free(nvhis);
+	}
 	(void) printf("\n");
-	nvlist_free(nvhis);
 
 	return (ret);
 }
diff --git a/usr/src/lib/libzfs/common/libzfs.h b/usr/src/lib/libzfs/common/libzfs.h
index 36b70c11fb..d7411f0b85 100644
--- a/usr/src/lib/libzfs/common/libzfs.h
+++ b/usr/src/lib/libzfs/common/libzfs.h
@@ -459,7 +459,8 @@ typedef enum {
 extern char *zpool_vdev_name(libzfs_handle_t *, zpool_handle_t *, nvlist_t *,
     int name_flags);
 extern int zpool_upgrade(zpool_handle_t *, uint64_t);
-extern int zpool_get_history(zpool_handle_t *, nvlist_t **);
+extern int zpool_get_history(zpool_handle_t *, nvlist_t **, uint64_t *,
+    boolean_t *);
 extern int zpool_history_unpack(char *, uint64_t, uint64_t *,
     nvlist_t ***, uint_t *);
 extern void zpool_obj_to_path(zpool_handle_t *, uint64_t, uint64_t, char *,
diff --git a/usr/src/lib/libzfs/common/libzfs_pool.c b/usr/src/lib/libzfs/common/libzfs_pool.c
index b7c95489c8..20894d450a 100644
--- a/usr/src/lib/libzfs/common/libzfs_pool.c
+++ b/usr/src/lib/libzfs/common/libzfs_pool.c
@@ -4342,33 +4342,37 @@ zpool_history_unpack(char *buf, uint64_t bytes_read, uint64_t *leftover,
  * Retrieve the command history of a pool.
  */
 int
-zpool_get_history(zpool_handle_t *zhp, nvlist_t **nvhisp)
+zpool_get_history(zpool_handle_t *zhp, nvlist_t **nvhisp, uint64_t *off,
+    boolean_t *eof)
 {
 	char *buf;
 	int buflen = 128 * 1024;
-	uint64_t off = 0;
 	nvlist_t **records = NULL;
 	uint_t numrecords = 0;
-	int err, i;
+	int err = 0, i;
+	uint64_t start = *off;
 
 	buf = malloc(buflen);
 	if (buf == NULL)
 		return (ENOMEM);
-	do {
+	/* process about 1MB a time */
+	while (*off - start < 1024 * 1024) {
 		uint64_t bytes_read = buflen;
 		uint64_t leftover;
 
-		if ((err = get_history(zhp, buf, &off, &bytes_read)) != 0)
+		if ((err = get_history(zhp, buf, off, &bytes_read)) != 0)
 			break;
 
 		/* if nothing else was read in, we're at EOF, just return */
-		if (!bytes_read)
+		if (!bytes_read) {
+			*eof = B_TRUE;
 			break;
+		}
 
 		if ((err = zpool_history_unpack(buf, bytes_read,
 		    &leftover, &records, &numrecords)) != 0)
 			break;
-		off -= leftover;
+		*off -= leftover;
 		if (leftover == bytes_read) {
 			/*
 			 * no progress made, because buffer is not big enough
@@ -4380,9 +4384,7 @@ zpool_get_history(zpool_handle_t *zhp, nvlist_t **nvhisp)
 			if (buf == NULL)
 				return (ENOMEM);
 		}
-
-		/* CONSTCOND */
-	} while (1);
+	}
 
 	free(buf);