[DTrace-devel] [PATCH] Add workstatus error conditions

[Kris Van Hees]

The processing of perf event output buffer data can fail in a few
different ways, all leading to returning DTRACE_WORKSTATUS_ERROR.
In order to better troubleshoot such issues we add two new DTrace
error codes:

- EDT_DSIZE: Data record has an incrreoct size
- EDT_BADEPID: Data record contains an invalid EPID

Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
---
 libdtrace/dt_consume.c | 12 +++++++++---
 libdtrace/dt_error.c   |  4 +++-
 libdtrace/dt_impl.h    |  4 +++-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/libdtrace/dt_consume.c b/libdtrace/dt_consume.c
index 497fdd27..46b03641 100644
--- a/libdtrace/dt_consume.c
+++ b/libdtrace/dt_consume.c
@@ -1950,14 +1950,18 @@ dt_consume_one(dtrace_hdl_t *dtp, FILE *fp, char *buf,
 		 * and 'data' points to the 'size' member at this point.
 		 * (Note that 'n' may be 0.)
 		 */
-		if (ptr > buf + hdr->size)
+		if (ptr > buf + hdr->size) {
+			dt_set_errno(dtp, EDT_DSIZE);
 			return DTRACE_WORKSTATUS_ERROR;
+		}
 
 		size = *(uint32_t *)data;
 		data += sizeof(size);
 		ptr += sizeof(size) + size;
-		if (ptr != buf + hdr->size)
+		if (ptr != buf + hdr->size) {
+			dt_set_errno(dtp, EDT_DSIZE);
 			return DTRACE_WORKSTATUS_ERROR;
+		}
 
 		data += sizeof(uint32_t);		/* skip padding */
 		size -= sizeof(uint32_t);
@@ -1976,8 +1980,10 @@ dt_consume_one(dtrace_hdl_t *dtp, FILE *fp, char *buf,
 
 		rval = dt_epid_lookup(dtp, epid, &pdat->dtpda_ddesc,
 						 &pdat->dtpda_pdesc);
-		if (rval != 0)
+		if (rval != 0) {
+			dt_set_errno(dtp, EDT_BADEPID);
 			return DTRACE_WORKSTATUS_ERROR;
+		}
 
 		if (flow)
 			dt_flowindent(dtp, pdat, *last, DTRACE_EPIDNONE);
diff --git a/libdtrace/dt_error.c b/libdtrace/dt_error.c
index b2688402..6276d52c 100644
--- a/libdtrace/dt_error.c
+++ b/libdtrace/dt_error.c
@@ -1,6 +1,6 @@
 /*
  * Oracle Linux DTrace.
- * Copyright (c) 2009, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2009, 2021, Oracle and/or its affiliates. All rights reserved.
  * Licensed under the Universal Permissive License v 1.0 as shown at
  * http://oss.oracle.com/licenses/upl.
  */
@@ -52,6 +52,8 @@ static const struct {
 	{ EDT_DMISMATCH, "Data record list does not match statement" },
 	{ EDT_DOFFSET,	"Data record offset exceeds buffer boundary" },
 	{ EDT_DALIGN,	"Data record has inappropriate alignment" },
+	{ EDT_DSIZE,	"Data record has incorrect size" },
+	{ EDT_BADEPID,	"Invalid EPID" },
 	{ EDT_BADOPTNAME, "Invalid option name" },
 	{ EDT_BADOPTVAL, "Invalid value for specified option" },
 	{ EDT_BADOPTCTX, "Option cannot be used from within a D program" },
diff --git a/libdtrace/dt_impl.h b/libdtrace/dt_impl.h
index 4548a11d..0cc4bfab 100644
--- a/libdtrace/dt_impl.h
+++ b/libdtrace/dt_impl.h
@@ -1,6 +1,6 @@
 /*
  * Oracle Linux DTrace.
- * Copyright (c) 2010, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2021, Oracle and/or its affiliates. All rights reserved.
  * Licensed under the Universal Permissive License v 1.0 as shown at
  * http://oss.oracle.com/licenses/upl.
  */
@@ -585,6 +585,8 @@ enum {
 	EDT_DMISMATCH,		/* record list does not match statement */
 	EDT_DOFFSET,		/* record data offset error */
 	EDT_DALIGN,		/* record data alignment error */
+	EDT_DSIZE,		/* record data size error */
+	EDT_BADEPID,		/* bad enabled probe id */
 	EDT_BADOPTNAME,		/* invalid dtrace_setopt option name */
 	EDT_BADOPTVAL,		/* invalid dtrace_setopt option value */
 	EDT_BADOPTCTX,		/* invalid dtrace_setopt option context */
-- 
2.28.0