patch_active_text(5)						File Formats Manual					      patch_active_text(5)

NAME

       patch_active_text - dynamically enable or disable running executable text to be modified via mprotect()

VALUES

   Fail Safe
   Default
       semantics is enabled

   Allowed values
       or

DESCRIPTION

       This tunable allows write access to text of a running process such that the active text can be modified.  When this tunable is enabled, can
       be used with a special flag, to modify the text of a running executable.

       By default, does not work on text of a process.	Enabling the tunable allows to work on text segments of a process.  Making  text  writable
       will create a private copy of the text to the process using this feature.

       Once  with  special  flag  allows  running  text to be modified, further invocations of on text of a process with other prot flags are also
       allowed.

       For must always be used with (see mprotect(2)).	must always be used on text address range.

       After the first invocation of further mprotect(2) calls will work on text segments of process with any other prot flags;  in  other  words,
       will work on text with or any combinations of the above.  The only requirement is that both these flags must be invoked first.

   Who Is Expected to Change This Tunable?
       System administrators who wish to change the default behavior.

   Restrictions on Changing
       Changes to this tunable take effect immediately.

   When Should the Tunable Be Turned Off?
       If an application expects to fail on text segments, the tunable should be turned off.

   What Are the Side Effects of Turning the Tunable Off?
       Applications will no longer be able to use on text of a process.

   When Should the Tunable Be Turned On?
       If an application wants its text segment to be writable and also wants to be able to work on text of processes, this tunable must be turned
       on.  Making text writable will create a private copy of the text to the process using this feature.

   What Are the Side Effects of Turning the Tunable On?
       Memory consumption in the system will increase.	This is because with the process will create a private copy of the shared  text  on  first
       invocation.  It should also be noted that large page benefits on text segments will be lost.

   What Other Tunables Should Be Changed at the Same Time?
       None.

WARNINGS

       All  HP-UX kernel tunable parameters are release specific.  This parameter may be removed or have its meaning changed in future releases of
       HP-UX.

       Installation of optional kernel software, from HP or other vendors, may cause changes to tunable  parameter  values.   After  installation,
       some  tunable  parameters may no longer be at the default or recommended values.  For information about the effects of installation on tun-
       able values, consult the documentation for the kernel software being installed.	For information about optional kernel  software  that  was
       factory installed on your system, see at

AUTHOR

       was developed by HP.

SEE ALSO

       mprotect(2), copy_on_write(5)

							     Tunable Kernel Parameters					      patch_active_text(5)