lbr_save

Description of the 'lbr_save' function in HyperDbg Scripts

Function

lbr_save

Syntax

lbr_save();

Parameters

None

Description

Saves the Last Branch Record (LBR) entries that were captured since the Last Branch Record was enabled using the '!lbr' command. The entries are stored internally and can later be viewed using the '!lbrdump' command. Unlike lbr_print(), this function does not display the entries immediately.

If lbr_save() is called more than once on the same core, the previously saved entries for that core are replaced with the new ones.

Return value

Returns 1 if the LBR entries were saved successfully, or 0 if the operation failed (e.g., LBR was not initialized using the '!lbr enable' command or was already disabled using '!lbr disable').

Examples

First, enable the LBR using the '!lbr' command, then use lbr_save() in a script (e.g., inside an EPT hook), and finally disable the LBR.

!lbr enable

!epthook 7ff7393a2fd7 pid 3274 script {
		lbr_save();
}

!lbr disable

The above example enables LBR, hooks the target address in process with PID 0x3274, and each time execution reaches that address, the captured branch entries are saved. You can then use '!lbrdump' to inspect them.

Remarks

The support for this function is added from v0.19.

To use this function, the trace module should be loaded using the load command (load trace).

This function requires LBR to be active. It will return 0 and perform no operation if LBR was never started with '!lbr enable' or has already been stopped with '!lbr disable'.

Related

lbr_print

lbr_check

lbr_restore

lbr_restore_by_filter

!lbr (enable, disable, and configure Last Branch Record)

!lbrdump (dump Last Branch Record entries)