Commit 57c3d238 authored by Gabriel L. Somlo's avatar Gabriel L. Somlo Committed by Gerd Hoffmann
Browse files

fw_cfg: document fw_cfg_modify_iXX() update functions 



Document the behavior of fw_cfg_modify_iXX() for leak-less updating
of integer-type blobs.

Currently only fw_cfg_modify_i16() is coded, but 32- and 64-bit versions
may be added later if necessary..

Signed-off-by: default avatarGabriel Somlo <somlo@cmu.edu>
Reviewed-by: default avatarLaszlo Ersek <lersek@redhat.com>
Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
parent 6407d76e

docs/specs/fw_cfg.txt

+11 −0
Original line number Diff line number Diff line
@@ -159,6 +159,17 @@ will convert a 16-, 32-, or 64-bit integer to little-endian, then add 
a dynamically allocated copy of the appropriately sized item to fw_cfg

under the given selector key value.



== fw_cfg_modify_iXX() ==



Modify the value of an XX-bit item (where XX may be 16, 32, or 64).

Similarly to the corresponding fw_cfg_add_iXX() function set, convert

a 16-, 32-, or 64-bit integer to little endian, create a dynamically

allocated copy of the required size, and replace the existing item at

the given selector key value with the newly allocated one. The previous

item, assumed to have been allocated during an earlier call to

fw_cfg_add_iXX() or fw_cfg_modify_iXX() (of the same width XX), is freed

before the function returns.



== fw_cfg_add_file() ==



Given a filename (i.e., fw_cfg item name), starting pointer, and size,