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php

A question about php_streams

php.internals

Mikey

21 years ago

Hi NG!

This is my first post to this NG and would like to prefix my question with
the following:

- I have read the manual, thoroughly. There is absolutely nothing in there
apart from how to call the funtion.

- I have searched the mailing list archives, to no avail.

- I have grep'ed the source, and have found one use of this function in
opendir(), this has had limited usefulness.

- I have googled, and this had provided a great big list of manual mirrors
for my future reference ;-) Although I did find a page with a CVS commit on
it that had modified my example code.

I am trying to write a function that will recurse a directory, now the logic
of that is my bat and I am not seeking help with that. But I have tried
using the php_streams API to open the base directory with the following
code:

php_stream *base_dir = NULL;

php_stream_context *context = NULL;

TSRMLS_FETCH();

base_dir = php_stream_opendir (TMPL_G(template_dir),
ENFORCE_SAFE_MODE|REPORT_ERRORS, context);

However, everytime I try to run the module with this last line, I get a
segfault in apache. Now I am not very capable when it comes to Linux C
development and am only vaguely familiar with what gdb does, so I can't
really provide you with any other info than this.

Any help, pointers, etc would be greatly appreciated...

Mikey

Sara Golemon

21 years ago

> php_stream *base_dir = NULL;
>
> php_stream_context *context = NULL;
>
> TSRMLS_FETCH();
>
> base_dir = php_stream_opendir (TMPL_G(template_dir),
> ENFORCE_SAFE_MODE|REPORT_ERRORS, context);
>

That code is (on the surface at least) fine.

> However, everytime I try to run the module with this last line, I get a
> segfault in apache. Now I am not very capable when it comes to Linux C
> development and am only vaguely familiar with what gdb does, so I can't
> really provide you with any other info than this.
>

Here's some instructions on generating a backtrace:
http://bugs.php.net/bugs-generating-backtrace.php

Also, check to make sure that TMPL_G(template_dir) is (A) defined, and (B)
points to a NULL terminated string in a memory segmet accessable to the
process.  Of course, the backtrace will reveal that anyway.

-Sara

Mikey

21 years ago

> Here's some instructions on generating a backtrace:
> http://bugs.php.net/bugs-generating-backtrace.php

OK, well this is the only output I get from gdb that isn't (no debugging
symbols found):

Program received signal SIGSEGV, Segmentation fault.
0x4045853b in zend_hash_index_update_or_next_insert (ht=0x40538dc8, h=0,
pData=0xbffff3e0,
nDataSize=12, pDest=0x0, flag=1) at
/usr/local/src/php-4.3.10/Zend/zend_hash.c:390
390             p = ht->arBuckets[nIndex];

Does this help?

> Also, check to make sure that TMPL_G(template_dir) is (A)
> defined, and (B) points to a NULL terminated string in a
> memory segmet accessable to the process.  Of course, the
> backtrace will reveal that anyway.

A) Has to be defined as it is the macro for accessing global variables:
#define TMPL_G(v) (tmpl_globals.v)
B) I read in the header file that the TSRMLS_FETCH(); call was all I needed
to make for access to the global vars in a helper function.  Is this
correct?

Thanks for your help,

Mikey

Sara Golemon

21 years ago

>> Here's some instructions on generating a backtrace:
>> http://bugs.php.net/bugs-generating-backtrace.php
>
> OK, well this is the only output I get from gdb that isn't (no debugging
> symbols found):
>
> Program received signal SIGSEGV, Segmentation fault.
> 0x4045853b in zend_hash_index_update_or_next_insert (ht=0x40538dc8, h=0,
> pData=0xbffff3e0,
>    nDataSize=12, pDest=0x0, flag=1) at
> /usr/local/src/php-4.3.10/Zend/zend_hash.c:390
> 390             p = ht->arBuckets[nIndex];
>
> Does this help?
>

Not really...can you include the entire backtrace?  Did you compile
with --enable-debug?

>> Also, check to make sure that TMPL_G(template_dir) is (A)
>> defined, and (B) points to a NULL terminated string in a
>> memory segmet accessable to the process.  Of course, the
>> backtrace will reveal that anyway.
>
> A) Has to be defined as it is the macro for accessing global variables:
> #define TMPL_G(v) (tmpl_globals.v)
> B) I read in the header file that the TSRMLS_FETCH(); call was all I
> needed
> to make for access to the global vars in a helper function.  Is this
> correct?
>

You misunderstood.  I mean make sure that TMPL_G(template_dir) != NULL, and
that whatever TMPL_G(template_dir) points to (as in the address referred to
by the  char* datatype) has meaningful data in it.

-Sara