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SubjectRe: [PATCH 6/7] perf data: Fix duplicate field names and avoid reserved keywords
From
On Sat, Apr 18, 2015 at 11:50 AM, Jiri Olsa <jolsa@kernel.org> wrote:
> 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.

Minor nitpick: "event" is a reserved keyword in the CTF specification
[1], the rule is only enforced by Babeltrace. Also, keywork ->
keyword.

Jérémie

[1] http://diamon.org/docs/ctf/v1.8.2/#specC.1.2

>
> 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
>



--
Jérémie Galarneau
EfficiOS Inc.
http://www.efficios.com


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