Is it necessary to release resources?

[rebeccalee97y]

Hi, there exists a obvious memory leak in dma.c. See the following code, the allocated resource of calloc is not freed when strdup conducts error handling.

dma/dma.c

Lines 184 to 189 in 1b10f76

	it = calloc(1, sizeof(*it));
	if (it == NULL)
	return (-1);
	it->addr = strdup(str);
	if (it->addr == NULL)
	return (-1);

Moreover, I have noticed one possible memory leak in the following code. At line 218, when aliased < 0 , the allocated resource by function calloc and strdup should be freed, with adding free(it->addr); free(it);?

dma/dma.c

Lines 215 to 240 in 1b10f76

	aliased = do_alias(queue, it->addr);
	if (!aliased && expand == EXPAND_WILDCARD)
	aliased = do_alias(queue, "*");
	if (aliased < 0)
	return (-1);
	if (aliased) {
	LIST_REMOVE(it, next);
	} else {
	/* Local destination, check */
	pw = getpwnam(it->addr);
	if (pw == NULL)
	goto out;
	/* XXX read .forward */
	endpwent();
	}
	}
	} else {
	it->remote = 1;
	}
	return (0);
	out:
	free(it->addr);
	free(it);
	return (-1);

[corecode]

Hi, thanks for the code review.

The intent is that memory allocation failure is critical and we cannot recover from it. The code returns -1, which should signal to the caller a critical error, which should lead to exiting the process. Because we know we will exit immediately, there is no need to complicate code by free()ing structures.

If there is any code path where an error result does not lead to the process exiting, then we need to make sure that the allocations do not accumulate.

[rebeccalee97y]

Thanks for the explanation :)