linux-trace-devel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Yordan Karadzhov (VMware)" <y.karadz@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-trace-devel@vger.kernel.org
Subject: Re: [PATCH v4 1/7] libtracefs: Implement tracefs_instances()
Date: Fri, 2 Jul 2021 14:39:48 +0300	[thread overview]
Message-ID: <97c4e671-5ee9-3c1a-b957-1d0b6fbc0eb3@gmail.com> (raw)
In-Reply-To: <20210702073332.357ca775@rorschach.local.home>



On 2.07.21 г. 14:33, Steven Rostedt wrote:
> On Fri, 2 Jul 2021 14:10:46 +0300
> "Yordan Karadzhov (VMware)" <y.karadz@gmail.com> wrote:
> 
>>> +static int build_list(const char *name, void *data)
>>> +{
>>> +	struct instance_list *list = data;
>>> +	char **instances;
>>> +	int ret = -1;
>>> +
>>> +	if (!match(name, list->re))
>>> +		return 0;
>>> +
>>> +	instances = realloc(list->list, list->size + 2);
>>> +	if (!instances)
>>> +		goto out;
>>> +
>>> +	list->list = instances;
>> Hi Steven,
>>
>> I am not sure what was your original intention here, but this doesn't
>> seem to work properly. Maybe we need something like this:
>>
>> 	int size =  sizeof(*instances) * (list->size + 2);
>> 	instances = realloc(list->list, size);
> 
> Bah, that's what I get for trying to "multitask" while coding :-p
> That was suppose to be:
> 
> 	instances = realloc(list->list, sizeof(*instances) * (list->size + 2);
> 
> as you stated, but I'll keep it one line.
> 
>> 	if (!instances)
>> 		goto out;
>>
>> 	instances[list->size + 1] = NULL;

but you still need to make sure it is NULL terminated.
Y.

>>
>>
>>
>>
>>> +	list->list[list->size] = strdup(name);
>>> +	if (!list->list[list->size])
>>> +		goto out;
>>> +
>>> +	list->size++;
>>> +	ret = 0;
>>> +
>>> + out:
>>> +	list->failed = ret;
>>> +	return ret;
>>> +}
>>> +
>>> +/**
>>> + * tracefs_instances - return a list of instance names
>>> + * @regex: A regex of instances to filter on (NULL to match all)
>>> + *
>>> + * Returns a list of names of existing instances, that must be
>>> + * freed with tracefs_list_free(). Note, if there are no matches
>>> + * then an empty list will be returned (not NULL).
>>> + * NULL on error.
>>> + */
>>> +char **tracefs_instances(const char *regex)
>>> +{
>>> +	struct instance_list list = { .re = NULL, .list = NULL };
>>> +	regex_t re;
>>> +	int ret;
>>> +
>>> +	if (regex) {
>>> +		ret = regcomp(&re, regex, REG_ICASE|REG_NOSUB);
>>> +		if (ret < 0)
>>> +			return NULL;
>>> +		list.re = &re;
>>> +	}
>>> +
>>> +	ret = tracefs_instances_walk(build_list, &list);
>>> +	if (ret < 0 || list.failed) {
>>> +		tracefs_list_free(list.list);
>>> +		list.list = NULL;
>>> +	} else {
>>> +		if (!list.list) {
>>> +			/* No matches should produce an empty list */
>>> +			list.list = malloc(sizeof(*list.list));
>>> +			if (list.list)
>>> +				list.list[0] = NULL;
>>> +		}
>>
>> Or you can just do:
>> 				return calloc(1, sizeof(*list.list));
> 
> Which I do in tracefs_get_probes(), must have missed this one.
> 
> Will update, thanks for the review.
> 
> 
> -- Steve
> 
> 
>>
>> Thanks!
>> Yordan
>>
>>> +	}
>>> +	return list.list;
>>> +}

  reply	other threads:[~2021-07-02 11:39 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-02  3:54 [PATCH v4 0/7] libtracefs: Facilitate adding and removing kprobes Steven Rostedt
2021-07-02  3:54 ` [PATCH v4 1/7] libtracefs: Implement tracefs_instances() Steven Rostedt
2021-07-02 11:10   ` Yordan Karadzhov (VMware)
2021-07-02 11:33     ` Steven Rostedt
2021-07-02 11:39       ` Yordan Karadzhov (VMware) [this message]
2021-07-02 11:50         ` Steven Rostedt
2021-07-02  3:54 ` [PATCH v4 2/7] libtracefs: Implement tracefs_kprobe_raw() Steven Rostedt
2021-07-02  3:54 ` [PATCH v4 3/7] libtracefs: Implement tracefs_kretprobe_raw() Steven Rostedt
2021-07-02  3:54 ` [PATCH v4 4/7] libtracefs: Implement tracefs_get_kprobes() Steven Rostedt
2021-07-02  3:54 ` [PATCH v4 5/7] libtracefs: Implement tracefs_kprobe_clear_all() to remove all kprobes Steven Rostedt
2021-07-02 11:15   ` Yordan Karadzhov (VMware)
2021-07-02 11:35     ` Steven Rostedt
2021-07-02  3:54 ` [PATCH v4 6/7] libtracefs: Implement tracefs_kprobe_clear_probe() Steven Rostedt
2021-07-02  3:54 ` [PATCH v4 7/7] libtracefs: Add man pages for kprobe functions Steven Rostedt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=97c4e671-5ee9-3c1a-b957-1d0b6fbc0eb3@gmail.com \
    --to=y.karadz@gmail.com \
    --cc=linux-trace-devel@vger.kernel.org \
    --cc=rostedt@goodmis.org \
    --subject='Re: [PATCH v4 1/7] libtracefs: Implement tracefs_instances()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
on how to clone and mirror all data and code used for this inbox