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)
