Is it possible to get the variable name from the HashTable structure?

12 years ago by Aaron Lewis — view source — reply

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Hi,

So PHP uses HashTable to store variables like $_POST,

From a HashTable structure, can I get the array name?

--
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Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

12 years ago by Joe Watkins — view source — reply

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Hi,

So PHP uses HashTable to store variables like $_POST,

From a HashTable structure, can I get the array name?

--
Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

https://gist.github.com/krakjoe/50603be7ffb1ae6e9156

Cheers
Joe

12 years ago by johannes@schlueters.de — view source — reply

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Hi,

So PHP uses HashTable to store variables like $_POST,

From a HashTable structure, can I get the array name?

No, a zval (which might point to a hash tale) doesn't refer to a name.
For one there in 99.99% is no need but it would cost memory(and CPU
cycles to maintain) and then there miht e multiple nae (references) or
none (temporaries etc.)

If you know the parent such hacks like

https://gist.github.com/krakjoe/50603be7ffb1ae6e9156

might work, but even this solution is flawed: The easy thing it doesn't
support is references, it should return an array of all names. It won't
work for complex things, though.

If you need such a functionality I'd suggest to take a step back and
think what you actually want to do ... usually there is a better
solution.

johannes

12 years ago by Aaron Lewis — view source — reply

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Hi Watkins,

First of all, pthreads@pthreads.org? Nice account

I'm trying your patch, but in a different place

In static inline zval **zend_fetch_dimension_address_inner(HashTable
*ht, const zval *dim, int dim_type, int type TSRMLS_DC),

fetch_string_dim:
if (zend_hash_quick_find(ht, offset_key, offset_key_length+1, hval,
(void **) &retval) == FAILURE) {
...

fetch_string_dim:
if (zend_hash_quick_find(ht, offset_key, offset_key_length+1, hval,
(void **) &retval) == FAILURE) {
switch (type) {
case BP_VAR_R:
printf ("(R) Undefined index %s, looking up
array variable name\n", offset_key);

                    HashPosition position;
                    zval **test = NULL;
                    for

(zend_hash_internal_pointer_reset_ex(EG(active_symbol_table),
&position);

zend_hash_get_current_data_ex(EG(active_symbol_table), (void**)&test,
&position) == SUCCESS;

zend_hash_move_forward_ex(EG(active_symbol_table), &position)) {
printf ("Comparing with: %s\n",
((Bucket*)position)->arKey);
if (test == ht) {
printf ("Found variable name: %s\n",
((Bucket)position)->arKey);
//
RETURN_STRINGL(((Bucket*)position)->arKey,
((Bucket*)position)->nKeyLength, 1);
}
}

....

Hmm, I got no match ... am I wrong somewhere?

Hi,

So PHP uses HashTable to store variables like $_POST,

From a HashTable structure, can I get the array name?

--
Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

https://gist.github.com/krakjoe/50603be7ffb1ae6e9156

Cheers
Joe

--
Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

12 years ago by Aaron Lewis — view source — reply

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Please ignore that, it's badly formatted, see this one instead

https://gist.github.com/CaledoniaProject/2c2871b5fa36ab6a93e4#file-php-test-inner

Hi Watkins,

First of all, pthreads@pthreads.org? Nice account

I'm trying your patch, but in a different place

In static inline zval **zend_fetch_dimension_address_inner(HashTable
*ht, const zval *dim, int dim_type, int type TSRMLS_DC),

fetch_string_dim:
if (zend_hash_quick_find(ht, offset_key, offset_key_length+1, hval,
(void **) &retval) == FAILURE) {
...

fetch_string_dim:
if (zend_hash_quick_find(ht, offset_key, offset_key_length+1, hval,
(void **) &retval) == FAILURE) {
switch (type) {
case BP_VAR_R:
printf ("(R) Undefined index %s, looking up
array variable name\n", offset_key);
                    HashPosition position;
                    zval **test = NULL;
                    for
(zend_hash_internal_pointer_reset_ex(EG(active_symbol_table),
&position);

zend_hash_get_current_data_ex(EG(active_symbol_table), (void**)&test,
&position) == SUCCESS;

zend_hash_move_forward_ex(EG(active_symbol_table), &position)) {
printf ("Comparing with: %s\n",
((Bucket*)position)->arKey);
if (test == ht) {
printf ("Found variable name: %s\n",
((Bucket)position)->arKey);
//
RETURN_STRINGL(((Bucket*)position)->arKey,
((Bucket*)position)->nKeyLength, 1);
}
}

....

Hmm, I got no match ... am I wrong somewhere?

Hi,

So PHP uses HashTable to store variables like $_POST,

From a HashTable structure, can I get the array name?

--
Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

https://gist.github.com/krakjoe/50603be7ffb1ae6e9156

Cheers
Joe

--
Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

--
Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

12 years ago by Aaron Lewis — view source — reply

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FWD I forgot to CC the list ;-(

---------- Forwarded message ----------

Here's what I want,

If a user runs code like this, and $_GET['MH'] happens to be
undefined, I want to know both '_GET' and 'MH':

if ($_GET['MH'] == 'dog')
{
do-something
}

But so far I can only get the 'MH' part ( I checked the 'Undefined
index' part in a zend function, can't remember the exact name )

On Sun, May 4, 2014 at 11:46 PM, Johannes Schlüter
johannes@schlueters.de wrote:

Hi,

So PHP uses HashTable to store variables like $_POST,

From a HashTable structure, can I get the array name?

No, a zval (which might point to a hash tale) doesn't refer to a name.
For one there in 99.99% is no need but it would cost memory(and CPU
cycles to maintain) and then there miht e multiple nae (references) or
none (temporaries etc.)

If you know the parent such hacks like

https://gist.github.com/krakjoe/50603be7ffb1ae6e9156

might work, but even this solution is flawed: The easy thing it doesn't
support is references, it should return an array of all names. It won't
work for complex things, though.

If you need such a functionality I'd suggest to take a step back and
think what you actually want to do ... usually there is a better
solution.

johannes

--
Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

12 years ago by Tjerk Meesters — view source — reply

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Hi,

FWD I forgot to CC the list ;-(

---------- Forwarded message ----------

Here's what I want,

If a user runs code like this, and $_GET['MH'] happens to be
undefined, I want to know both '_GET' and 'MH':

I suppose you could compare the hash table against the few super globals there are :)

if ($_GET['MH'] == 'dog')
{
do-something
}

But so far I can only get the 'MH' part ( I checked the 'Undefined
index' part in a zend function, can't remember the exact name )

On Sun, May 4, 2014 at 11:46 PM, Johannes Schlüter
johannes@schlueters.de wrote:

Hi,

So PHP uses HashTable to store variables like $_POST,

From a HashTable structure, can I get the array name?

No, a zval (which might point to a hash tale) doesn't refer to a name.
For one there in 99.99% is no need but it would cost memory(and CPU
cycles to maintain) and then there miht e multiple nae (references) or
none (temporaries etc.)

If you know the parent such hacks like

https://gist.github.com/krakjoe/50603be7ffb1ae6e9156

might work, but even this solution is flawed: The easy thing it doesn't
support is references, it should return an array of all names. It won't
work for complex things, though.

If you need such a functionality I'd suggest to take a step back and
think what you actually want to do ... usually there is a better
solution.

johannes

--
Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

--
Best Regards,
Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
Finger Print: 9F67 391B B770 8FF6 99DC D92D 87F6 2602 1371 4D33

12 years ago by johannes@schlueters.de — view source — reply

unread

Here's what I want,

If a user runs code like this, and $_GET['MH'] happens to be
undefined, I want to know both '_GET' and 'MH':

if ($_GET['MH'] == 'dog')
{
do-something
}

But so far I can only get the 'MH' part ( I checked the 'Undefined
index' part in a zend function, can't remember the exact name )

What do you want to achieve? Some developer tool for better messages?

For the general case of

$someVar->method()['key1']['key2'] == 'baz'

there is no good solution (well, you could try to analyze the current
opcode array, try to find current opline in there and do magic, but
that's quite crazy and notable effort)

For the simple case you can look at Joe's example on how to iterate over
the current symbol table, and if need be combine that with a recursive
search (mind infinite recursion caused by references) but there the
effort makes it questionable whether the information gained brings
value ...

johannes