Can someone respoond to this.
With regards Kamesh Jayachandran On Thu, 07 Oct 2004 23:10:24 -0700, "Kamesh Jayachandran" <[EMAIL PROTECTED]> said: > 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? >
Actually this existed beforehand, the change just shifted code around (the point of this commit was actually NOT to call php_output_startup() on every request startup, and it introduced php_output_activate() which is the one being called on every request startup instead).
From looking at the source code it appears that the call to php_output_activate() during php_module_startup() was added to keep 'compatibility' with the code prior to this commit. It looks that this commit fixed the main problem but kept a minor one. I *think* it can be safely removed.
> 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?
It has to do with errors that happen during request startup (such as file upload related errors) which cannot be trapped in userland. The check currently present php_error_cb() appears to be messy, though - it should probably be fixed to be just:
if (PG(display_errors)
&& module_initialized
&& (!PG(during_request_startup) || PG(display_startup_errors)) {
This messiness may be related to the other issue you mentioned.
Zeev
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