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To: internals@lists.php.net, zeev@php.net
Date: Thu, 07 Oct 2004 23:10:24 -0700
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Subject: why to call php_output_activate(TSRMLS_C) from php_module_startup
From: kameshj@fastmail.fm ("Kamesh Jayachandran")

Hi All,
I could see php_output_activate(TSRMLS_C) getting called from
php_module_startup immedeately after php_output_startup.

Why is this needed? As each SAPI modules call
php_output_activate(TSRMLS_C) explicitly as a part of request startup.

Why am I concerned about this?

Ans: php_output_activate(TSRMLS_C) sets
OG(php_body_write) = php_ub_body_write;
which causes calls to php_printf to use php_ub_body_write which depends
on SG(request_info) which is null while php_printf is invoked as part of
apache startup error(Like Invalid extension/ Non existent extension)
logging.

This causes segmentation fault.

This change seems to have been introduced in version 1.371 of
main/main.c by Zeev(3 years and 3 months ago).
The comment says,
Fix a major thread safety bug in the output mechanism
@- Fixed a major memory corruption bug in the thread safe version (Zeev) 


Can I remove a call to php_output_activate(TSRMLS_C) from
php_module_startup?

PS:What is the use of display_startup_errors? What does display mean
with respect to startup as it might not have any associated request
context?

With regards
Kamesh Jayachandran