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Subject[PATCH 6/7] perf data: Fix duplicate field names and avoid reserved keywords
Date
From: Wang Nan <wangnan0@huawei.com>

Some parameters of syscall tracepoints named as 'nr', 'event', etc.
When dealing with them, perf convert to ctf meets some problem:

1. If a parameter with name 'nr', it will duplicate syscall's
common field 'nr'. One such syscall is io_submit().

2. If a parameter with name 'event', it is denied to be inserted
because 'event' is a babeltrace keywork. One such syscall is
epoll_ctl.

This patch appends '_dupl_X' suffix to avoid problem 1, prepend a '_'
prefix to avoid problem 2.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-4tlh4s2u3xnxr76d1w7qmckb@git.kernel.org
[ changed to use format_file::alias ]
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/perf/util/data-convert-bt.c | 86 +++++++++++++++++++++++++++++++++++++--
1 file changed, 82 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c
index b35c8d6c291d..8eda4ed628e7 100644
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -14,6 +14,7 @@
#include <babeltrace/ctf-writer/event.h>
#include <babeltrace/ctf-writer/event-types.h>
#include <babeltrace/ctf-writer/event-fields.h>
+#include <babeltrace/ctf-ir/utils.h>
#include <babeltrace/ctf/events.h>
#include <traceevent/event-parse.h>
#include "asm/bug.h"
@@ -184,6 +185,7 @@ static int add_tracepoint_field_value(struct ctf_writer *cw,
unsigned int len;
int ret;

+ name = fmtf->alias;
offset = fmtf->offset;
len = fmtf->size;
if (flags & FIELD_IS_STRING)
@@ -567,6 +569,82 @@ static int process_sample_event(struct perf_tool *tool,
return cs ? 0 : -1;
}

+/* If dup < 0, add a prefix. Else, add _dupl_X suffix. */
+static char *change_name(char *name, char *orig_name, int dup)
+{
+ char *new_name = NULL;
+ size_t len;
+
+ if (!name)
+ name = orig_name;
+
+ if (dup >= 10)
+ goto out;
+ /*
+ * Add '_' prefix to potential keywork. According to
+ * Mathieu Desnoyers (https://lkml.org/lkml/2015/1/23/652),
+ * futher CTF spec updating may require us to use '$'.
+ */
+ if (dup < 0)
+ len = strlen(name) + sizeof("_");
+ else
+ len = strlen(orig_name) + sizeof("_dupl_X");
+
+ new_name = malloc(len);
+ if (!new_name)
+ goto out;
+
+ if (dup < 0)
+ snprintf(new_name, len, "_%s", name);
+ else
+ snprintf(new_name, len, "%s_dupl_%d", orig_name, dup);
+
+out:
+ if (name != orig_name)
+ free(name);
+ return new_name;
+}
+
+static int event_class_add_field(struct bt_ctf_event_class *event_class,
+ struct bt_ctf_field_type *type,
+ struct format_field *field)
+{
+ struct bt_ctf_field_type *t = NULL;
+ char *name;
+ int dup = 1;
+ int ret;
+
+ /* alias was already assigned */
+ if (field->alias != field->name)
+ return bt_ctf_event_class_add_field(event_class, type,
+ (char *)field->alias);
+
+ name = field->name;
+
+ /* If 'name' is a keywork, add prefix. */
+ if (bt_ctf_validate_identifier(name))
+ name = change_name(name, field->name, -1);
+
+ if (!name) {
+ pr_err("Failed to fix invalid identifier.");
+ return -1;
+ }
+ while ((t = bt_ctf_event_class_get_field_by_name(event_class, name))) {
+ bt_ctf_field_type_put(t);
+ name = change_name(name, field->name, dup++);
+ if (!name) {
+ pr_err("Failed to create dup name for '%s'\n", field->name);
+ return -1;
+ }
+ }
+
+ ret = bt_ctf_event_class_add_field(event_class, type, name);
+ if (!ret)
+ field->alias = name;
+
+ return ret;
+}
+
static int add_tracepoint_fields_types(struct ctf_writer *cw,
struct format_field *fields,
struct bt_ctf_event_class *event_class)
@@ -595,14 +673,14 @@ static int add_tracepoint_fields_types(struct ctf_writer *cw,
if (flags & FIELD_IS_ARRAY)
type = bt_ctf_field_type_array_create(type, field->arraylen);

- ret = bt_ctf_event_class_add_field(event_class, type,
- field->name);
+ ret = event_class_add_field(event_class, type, field);

if (flags & FIELD_IS_ARRAY)
bt_ctf_field_type_put(type);

if (ret) {
- pr_err("Failed to add field '%s\n", field->name);
+ pr_err("Failed to add field '%s': %d\n",
+ field->name, ret);
return -1;
}
}
@@ -646,7 +724,7 @@ static int add_generic_types(struct ctf_writer *cw, struct perf_evsel *evsel,
do { \
pr2(" field '%s'\n", n); \
if (bt_ctf_event_class_add_field(cl, t, n)) { \
- pr_err("Failed to add field '%s;\n", n); \
+ pr_err("Failed to add field '%s';\n", n); \
return -1; \
} \
} while (0)
--
1.9.3


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