how to change data in pagein hooked function

[sdhzdmzzl]

Hi,slavaim:
I used this code to modify some data , read write rename truncate all works.
but I don't know how to modify data in pagein and pageout procedure.
my code like belows:
`int
FltVnopPageinHook(
__in struct vnop_pagein_args *ap
)

{
int (origVnop)(struct vnop_pagein_args ap);
origVnop = (int ()(struct vnop_pagein_args))FltGetOriginalVnodeOp( ap->a_vp, FltVopEnum_pagein );
assert( origVnop );

char procname[1024] ={0};
proc_selfname( procname, 1024);
int ret = origVnop( ap );
if(0 == strcmp("test", procname))
{
    char path[1024] = {0};
    int len = 1024;
    vn_getpath(ap->a_vp, path, &len);
    int flags =UPL_RET_ONLY_DIRTY;
    vm_offset_t map = NULL;
    vm_offset_t map1 = NULL;
    upl_t upl = NULL;
    upl_page_info_t* uplpageinfo = NULL;
    if(ap->a_flags&UPL_MSYNC)
    {
        flags = flags | UPL_UBC_MSYNC;
    }
    else{
        flags = flags | UPL_UBC_PAGEIN;
    }
    //ubc_create_upl(ap->a_vp, ap->a_f_offset, ap->a_size, &upl, &uplpageinfo, UPL_UBC_PAGEIN|UPL_RET_ONLY_ABSENT);
    ubc_create_upl(ap->a_vp, ap->a_f_offset, ap->a_size, &upl, &uplpageinfo, UPL_UBC_PAGEIN|UPL_FLAGS_NONE);
    //ubc_upl_map(ap->a_pl, &map);
    ubc_upl_map(upl, &map1);
    char *p = (char*)map1;
    *p = '5';
    if(map1)
    {
        ubc_upl_unmap(upl);
    }
    if(upl)
    {
        ubc_upl_commit(upl);
        //ubc_upl_abort_range(upl,  ap->a_f_offset, ap->a_size, UPL_ABORT_FREE_ON_EMPTY);
    }
}
return ret;

}
`
for example, If a text file which content is "aaaa", after hook pagein function, I want the user who view it to see its content as "5aaa"，but above codes don't work.
thanks for your reply.

[kingfly629]

hey,sdhzdmzzl!
how do you solve this problem?
as i known , the action of read() may no trigger pagein()