Fix a memory leak in hstox interface

[nurupo]

transformed is leaking.

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This change is 

[iphydf]

Reviewed 1 of 1 files at r1.
Review status: all files reviewed at latest revision, 1 unresolved discussion, some commit checks failed.

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testing/hstox/methods.c, line 127 at r1 (raw file):

int method_cmp(char const *ptr, char const *expected, size_t max_size)
{
    char *transformed = malloc(max_size);

Use __attribute__((__destructor__)) here, instead. We're using that in other places. Yes, it's a GNU extension, but this code has a very specific use-case that is not supposed to be portable.

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Comments from Reviewable

[nurupo]

Review status: all files reviewed at latest revision, 1 unresolved discussion, some commit checks failed.

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testing/hstox/methods.c, line 127 at r1 (raw file):
I'm confused.

We don't use constuctor and destructor attributes anywhere in toxcore, unless grep lies to me.

Also, are you sure you want to use function attribute destructor here? Do you know what it does?

Similarly, the destructor attribute causes the function to be called automatically after main () completes or exit () is called.

A function attributed as destructor is called only once, when the program exits. transformed is allocated every single time method_cmp() is called, so free()'ing it only once won't work. I would need to pull transformed out of the function scope and create an appropriate constructor for it, like so:

I would need to create a functions

#define MAX_SIZE ???
static char *transformed;

static __attribute__((constructor)) void allocate_transformed(void)
{
    transformed = malloc(MAX_SIZE);
}

static __attribute__((destructor)) void deallocate_transformed(void)
{
    free(transformed);
}

int method_cmp(char const *ptr, char const *expected, size_t max_size)
{
...

Is this really better than my proposed change?

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Comments from Reviewable

[iphydf]

Review status: all files reviewed at latest revision, 1 unresolved discussion, some commit checks failed.

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testing/hstox/methods.c, line 127 at r1 (raw file):

Previously, nurupo wrote…

I'm confused.

We don't use constuctor and destructor attributes anywhere in toxcore, unless grep lies to me.

Also, are you sure you want to use function attribute destructor here? Do you know what it does?

Similarly, the destructor attribute causes the function to be called automatically after main () completes or exit () is called.

A function attributed as destructor is called only once, when the program exits. transformed is allocated every single time method_cmp() is called, so free()'ing it only once won't work. I would need to pull transformed out of the function scope and create an appropriate constructor for it, like so:

I would need to create a functions

#define MAX_SIZE ???
static char *transformed;

static __attribute__((constructor)) void allocate_transformed(void)
{
    transformed = malloc(MAX_SIZE);
}

static __attribute__((destructor)) void deallocate_transformed(void)
{
    free(transformed);
}

int method_cmp(char const *ptr, char const *expected, size_t max_size)
{
...

Is this really better than my proposed change?

Sorry, I meant `cleanup`.

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Comments from Reviewable

[iphydf]

Never mind the cleanup. This is fine.

[nurupo]

If you say so. Was about to add the cleanup function which would wrap around free().

[iphydf]

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Review status: all files reviewed at latest revision, 1 unresolved discussion.

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Comments from Reviewable