[lttng-dev] [PATCH] lttng-tools lttng commands add_context.c: Plug memory leaks

[Mathieu Desnoyers]

* Thibault, Daniel (Daniel.Thibault at drdc-rddc.gc.ca) wrote:
> In lttng-tools lttng/commands/add_context.c, the instances of struct ctx_type that are malloc'ed were not cleaned up in most error cases.  Consider for example what the original code did with 'lttng add-context -t nice -h'.
> ------------------------------
> From e0b21686e686050369ecb929cb6c6ea78afcdb87 Thu, 26 Jan 2012 13:03:43 -0500
> From: Daniel U. Thibault <daniel.thibault at drdc-rddc.gc.ca>
> Date: Thu, 26 Jan 2012 13:03:29 -0500
> Subject: [PATCH] lttng-tools lttng commands add_context.c: Plug memory leaks
> 
> diff --git a/src/bin/lttng/commands/add_context.c b/src/bin/lttng/commands/add_context.c
> index 075b270..d0f5b6f 100644
> --- a/src/bin/lttng/commands/add_context.c
> +++ b/src/bin/lttng/commands/add_context.c
> @@ -383,7 +383,7 @@
>  		goto error;
>  	}
>  
> -	/* Iterate over all context type given */
> +	/* Iterate over all the context types given */
>  	cds_list_for_each_entry(type, &ctx_type_list.head, list) {
>  		context.ctx = type->opt->ctx_type;
>  		if (context.ctx == LTTNG_EVENT_CONTEXT_PERF_COUNTER) {
> @@ -420,17 +420,18 @@
>  }
>  
>  /*
> - * Add context on channel or event.
> + * Add context to channel or event.
>   */
>  int cmd_add_context(int argc, const char **argv)
>  {
> -	int index, opt, ret = CMD_SUCCESS;
> +	int index, opt, ret;
>  	static poptContext pc;
>  	struct ctx_type *type, *tmptype;
>  	char *session_name = NULL;
>  
>  	if (argc < 2) {
>  		usage(stderr);
> +		ret = CMD_ERROR;
>  		goto end;
>  	}
>  
> @@ -440,24 +441,30 @@
>  	while ((opt = poptGetNextOpt(pc)) != -1) {
>  		switch (opt) {
>  		case OPT_HELP:
> -			usage(stderr);
> +			usage(stdout);
>  			ret = CMD_SUCCESS;
>  			goto end;
>  		case OPT_TYPE:
> -			type = malloc(sizeof(struct ctx_type));
> -			if (type == NULL) {
> -				perror("malloc ctx_type");
> -				ret = -1;
> -				goto end;
> -			}
> +			//Look up the index of opt_type in ctx_opts[] first,
> +			//so we don't have to free(type) on failure

Please always use

/*
 * My comment.
 * For a multi-line comment.
 */

style of comment or

/* My comment. For single-line comment. */

Best regards,

Mathieu

>  			index = find_ctx_type_idx(opt_type);
>  			if (index < 0) {
>  				ERR("Unknown context type %s", opt_type);
> +				ret = CMD_ERROR;
> +				goto end;
> +			}
> +			type = malloc(sizeof(struct ctx_type));
> +			if (type == NULL) {
> +				perror("malloc ctx_type");
> +				ret = CMD_FATAL;
>  				goto end;
>  			}
>  			type->opt = &ctx_opts[index];
>  			if (type->opt->ctx_type == -1) {
>  				ERR("Unknown context type %s", opt_type);
> +				free(type);
> +				ret = CMD_ERROR;
> +				goto end;
>  			} else {
>  				cds_list_add(&type->list, &ctx_type_list.head);
>  			}
> @@ -482,7 +489,7 @@
>  	if (!opt_session_name) {
>  		session_name = get_session_name();
>  		if (session_name == NULL) {
> -			ret = -1;
> +			ret = CMD_ERROR;
>  			goto end;
>  		}
>  	} else {
> @@ -491,11 +498,11 @@
>  
>  	ret = add_context(session_name);
>  
> +end:
>  	/* Cleanup allocated memory */
>  	cds_list_for_each_entry_safe(type, tmptype, &ctx_type_list.head, list) {
>  		free(type);
>  	}
>  
> -end:
>  	return ret;
>  }
> ------------------------------
> 
> Daniel U. Thibault
> R & D pour la défense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
> Système de systèmes (SdS) / System of Systems (SoS)
> Solutions informatiques et expérimentations (SIE) / Computing Solutions and Experimentations (CSE)
> 2459 Boul. Pie XI Nord
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> Vox : (418) 844-4000 x4245
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> <http://www.valcartier.drdc-rddc.gc.ca/>
> 
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> 

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com