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xen/extras/mini-os/tpmback.c
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Jan Beulich af501e3af4 tpmif: fix identifier prefixes 
The definitions here shouldn't use vtpm_ or VPTM_ as their prefixes,
the interface should instead make use of tpmif_ and TPMIF_. This
fixes a build failure after syncing the public headers to
linux-2.6.18-xen.hg (where a struct vtpm_state already exists).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
2013-06-21 08:39:43 +02:00

1135 lines
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/*
* Copyright (c) 2010-2012 United States Government, as represented by
* the Secretary of Defense. All rights reserved.
*
* This code has been derived from drivers/xen/tpmback/tpmback.c
* from the xen 2.6.18 linux kernel
*
* Copyright (c) 2005, IBM Corporation
*
* which was itself derived from drivers/xen/netback/netback.c
* from the xen 2.6.18 linux kernel
*
* Copyright (c) 2002-2004, K A Fraser
*
* This code has also been derived from drivers/xen/tpmback/xenbus.c
* from the xen 2.6.18 linux kernel
*
* Copyright (C) 2005 IBM Corporation
* Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
*
* This code has also been derived from drivers/xen/tpmback/interface.c
* from the xen 2.6.18 linux kernel
*
* Copyright (c) 2005, IBM Corporation
*
* which was itself also derived from drvivers/xen/netback/interface.c
* from the xen 2.6.18 linux kernel
*
* Copyright (c) 2004, Keir Fraser
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2
* of the License
*/
#include <mini-os/os.h>
#include <mini-os/xenbus.h>
#include <mini-os/events.h>
#include <errno.h>
#include <mini-os/gnttab.h>
#include <xen/io/xenbus.h>
#include <xen/io/tpmif.h>
#include <xen/io/protocols.h>
#include <mini-os/xmalloc.h>
#include <time.h>
#include <mini-os/tpmback.h>
#include <mini-os/lib.h>
#include <fcntl.h>
#include <mini-os/mm.h>
#include <mini-os/posix/sys/mman.h>
#include <mini-os/semaphore.h>
#include <mini-os/wait.h>
#ifndef HAVE_LIBC
#define strtoul simple_strtoul
#endif
//#define TPMBACK_PRINT_DEBUG
#ifdef TPMBACK_PRINT_DEBUG
#define TPMBACK_DEBUG(fmt,...) printk("Tpmback:Debug("__FILE__":%d) " fmt, __LINE__, ##__VA_ARGS__)
#define TPMBACK_DEBUG_MORE(fmt,...) printk(fmt, ##__VA_ARGS__)
#else
#define TPMBACK_DEBUG(fmt,...)
#endif
#define TPMBACK_ERR(fmt,...) printk("Tpmback:Error " fmt, ##__VA_ARGS__)
#define TPMBACK_LOG(fmt,...) printk("Tpmback:Info " fmt, ##__VA_ARGS__)
#define min(a,b) (((a) < (b)) ? (a) : (b))
/* Default size of the tpmif array at initialization */
#define DEF_ARRAY_SIZE 1
/* tpmif and tpmdev flags */
#define TPMIF_CLOSED 1
#define TPMIF_REQ_READY 2
struct tpmif {
domid_t domid;
unsigned int handle;
char* fe_path;
char* fe_state_path;
/* Locally bound event channel*/
evtchn_port_t evtchn;
/* Shared page */
tpmif_shared_page_t *page;
enum xenbus_state state;
enum { DISCONNECTED, DISCONNECTING, CONNECTED } status;
unsigned char uuid[16];
void* opaque;
/* state flags */
int flags;
};
typedef struct tpmif tpmif_t;
struct tpmback_dev {
tpmif_t** tpmlist;
unsigned long num_tpms;
unsigned long num_alloc;
struct gntmap map;
/* True if at least one tpmif has a request to be handled */
int flags;
xenbus_event_queue events;
/* Callbacks */
void (*open_callback)(domid_t, unsigned int);
void (*close_callback)(domid_t, unsigned int);
};
typedef struct tpmback_dev tpmback_dev_t;
enum { EV_NONE, EV_NEWFE, EV_STCHNG } tpm_ev_enum;
/* Global objects */
static struct thread* eventthread = NULL;
static tpmback_dev_t gtpmdev = {
.tpmlist = NULL,
.num_tpms = 0,
.num_alloc = 0,
.flags = TPMIF_CLOSED,
.events = NULL,
.open_callback = NULL,
.close_callback = NULL,
};
struct wait_queue_head waitq;
int globalinit = 0;
/************************************
* TPMIF SORTED ARRAY FUNCTIONS
* tpmback_dev_t.tpmlist is a sorted array, sorted by domid and then handle number
* Duplicates are not allowed
* **********************************/
inline void tpmif_req_ready(tpmif_t* tpmif) {
tpmif->flags |= TPMIF_REQ_READY;
gtpmdev.flags |= TPMIF_REQ_READY;
}
inline void tpmdev_check_req(void) {
int i;
int flags;
local_irq_save(flags);
for(i = 0; i < gtpmdev.num_tpms; ++i) {
if(gtpmdev.tpmlist[i]->flags & TPMIF_REQ_READY) {
gtpmdev.flags |= TPMIF_REQ_READY;
local_irq_restore(flags);
return;
}
}
gtpmdev.flags &= ~TPMIF_REQ_READY;
local_irq_restore(flags);
}
inline void tpmif_req_finished(tpmif_t* tpmif) {
tpmif->flags &= ~TPMIF_REQ_READY;
tpmdev_check_req();
}
int __get_tpmif_index(int st, int n, domid_t domid, unsigned int handle)
{
int i = st + n /2;
tpmif_t* tmp;
if( n <= 0 )
return -1;
tmp = gtpmdev.tpmlist[i];
if(domid == tmp->domid && tmp->handle == handle) {
return i;
} else if ( (domid < tmp->domid) ||
(domid == tmp->domid && handle < tmp->handle)) {
return __get_tpmif_index(st, n/2, domid, handle);
} else {
return __get_tpmif_index(i + 1, n/2 - ((n +1) % 2), domid, handle);
}
}
/* Returns the array index of the tpmif domid/handle. Returns -1 if no such tpmif exists */
int get_tpmif_index(domid_t domid, unsigned int handle)
{
int flags;
int index;
local_irq_save(flags);
index = __get_tpmif_index(0, gtpmdev.num_tpms, domid, handle);
local_irq_restore(flags);
return index;
}
/* Returns the tpmif domid/handle or NULL if none exists */
tpmif_t* get_tpmif(domid_t domid, unsigned int handle)
{
int flags;
int i;
tpmif_t* ret;
local_irq_save(flags);
i = get_tpmif_index(domid, handle);
if (i < 0) {
ret = NULL;
} else {
ret = gtpmdev.tpmlist[i];
}
local_irq_restore(flags);
return ret;
}
/* Remove the given tpmif. Returns 0 if it was removed, -1 if it was not removed */
int remove_tpmif(tpmif_t* tpmif)
{
int i, j;
char* err;
int flags;
local_irq_save(flags);
/* Find the index in the array if it exists */
i = get_tpmif_index(tpmif->domid, tpmif->handle);
if (i < 0) {
goto error;
}
/* Remove the interface from the list */
for(j = i; j < gtpmdev.num_tpms - 1; ++j) {
gtpmdev.tpmlist[j] = gtpmdev.tpmlist[j+1];
}
gtpmdev.tpmlist[j] = NULL;
--gtpmdev.num_tpms;
/* If removed tpm was the only ready tpm, then we need to check and turn off the ready flag */
tpmdev_check_req();
local_irq_restore(flags);
/* Stop listening for events on this tpm interface */
if((err = xenbus_unwatch_path_token(XBT_NIL, tpmif->fe_state_path, tpmif->fe_state_path))) {
TPMBACK_ERR("Unable to unwatch path token `%s' Error was %s Ignoring..\n", tpmif->fe_state_path, err);
free(err);
}
return 0;
error:
local_irq_restore(flags);
return -1;
}
/* Insert tpmif into dev->tpmlist. Returns 0 on success and non zero on error.
* It is an error to insert a tpmif with the same domid and handle
* number
* as something already in the list */
int insert_tpmif(tpmif_t* tpmif)
{
int flags;
unsigned int i, j;
tpmif_t* tmp;
char* err;
char path[512];
local_irq_save(flags);
/*Check if we need to allocate more space */
if (gtpmdev.num_tpms == gtpmdev.num_alloc) {
gtpmdev.num_alloc *= 2;
gtpmdev.tpmlist = realloc(gtpmdev.tpmlist, gtpmdev.num_alloc);
}
/*Find where to put the new interface */
for(i = 0; i < gtpmdev.num_tpms; ++i)
{
tmp = gtpmdev.tpmlist[i];
if(tpmif->domid == tmp->domid && tpmif->handle == tmp->handle) {
TPMBACK_ERR("Tried to insert duplicate tpm interface %u/%u\n", (unsigned int) tpmif->domid, tpmif->handle);
goto error;
}
if((tpmif->domid < tmp->domid) ||
(tpmif->domid == tmp->domid && tpmif->handle < tmp->handle)) {
break;
}
}
/*Shift all the tpm pointers past i down one */
for(j = gtpmdev.num_tpms; j > i; --j) {
gtpmdev.tpmlist[j] = gtpmdev.tpmlist[j-1];
}
/*Add the new interface */
gtpmdev.tpmlist[i] = tpmif;
++gtpmdev.num_tpms;
/*Should not be needed, anything inserted with ready flag is probably an error */
tpmdev_check_req();
local_irq_restore(flags);
snprintf(path, 512, "backend/vtpm/%u/%u/feature-protocol-v2", (unsigned int) tpmif->domid, tpmif->handle);
if ((err = xenbus_write(XBT_NIL, path, "1")))
{
/* if we got an error here we should carefully remove the interface and then return */
TPMBACK_ERR("Unable to write feature-protocol-v2 node: %s\n", err);
free(err);
remove_tpmif(tpmif);
goto error_post_irq;
}
/*Listen for state changes on the new interface */
if((err = xenbus_watch_path_token(XBT_NIL, tpmif->fe_state_path, tpmif->fe_state_path, &gtpmdev.events)))
{
/* if we got an error here we should carefully remove the interface and then return */
TPMBACK_ERR("Unable to watch path token `%s' Error was %s\n", tpmif->fe_state_path, err);
free(err);
remove_tpmif(tpmif);
goto error_post_irq;
}
return 0;
error:
local_irq_restore(flags);
error_post_irq:
return -1;
}
/*****************
* CHANGE BACKEND STATE
* *****************/
/*Attempts to change the backend state in xenstore
* returns 0 on success and non-zero on error */
int tpmif_change_state(tpmif_t* tpmif, enum xenbus_state state)
{
char path[512];
char *value;
char *err;
enum xenbus_state readst;
TPMBACK_DEBUG("Backend state change %u/%u from=%d to=%d\n", (unsigned int) tpmif->domid, tpmif->handle, tpmif->state, state);
if (tpmif->state == state)
return 0;
snprintf(path, 512, "backend/vtpm/%u/%u/state", (unsigned int) tpmif->domid, tpmif->handle);
if((err = xenbus_read(XBT_NIL, path, &value))) {
TPMBACK_ERR("Unable to read backend state %s, error was %s\n", path, err);
free(err);
return -1;
}
if(sscanf(value, "%d", &readst) != 1) {
TPMBACK_ERR("Non integer value (%s) in %s ??\n", value, path);
free(value);
return -1;
}
free(value);
/* It's possible that the backend state got updated by hotplug or something else behind our back */
if(readst != tpmif->state) {
TPMBACK_DEBUG("tpm interface state was %d but xenstore state was %d!\n", tpmif->state, readst);
tpmif->state = readst;
}
/*If if the state isnt changing, then we dont update xenstore b/c we dont want to fire extraneous events */
if(tpmif->state == state) {
return 0;
}
/*update xenstore*/
snprintf(path, 512, "backend/vtpm/%u/%u", (unsigned int) tpmif->domid, tpmif->handle);
if((err = xenbus_printf(XBT_NIL, path, "state", "%u", state))) {
TPMBACK_ERR("Error writing to xenstore %s, error was %s new state=%d\n", path, err, state);
free(err);
return -1;
}
tpmif->state = state;
return 0;
}
/**********************************
* TPMIF CREATION AND DELETION
* *******************************/
inline tpmif_t* __init_tpmif(domid_t domid, unsigned int handle)
{
tpmif_t* tpmif;
tpmif = malloc(sizeof(*tpmif));
tpmif->domid = domid;
tpmif->handle = handle;
tpmif->fe_path = NULL;
tpmif->fe_state_path = NULL;
tpmif->state = XenbusStateInitialising;
tpmif->status = DISCONNECTED;
tpmif->page = NULL;
tpmif->flags = 0;
tpmif->opaque = NULL;
memset(tpmif->uuid, 0, sizeof(tpmif->uuid));
return tpmif;
}
void __free_tpmif(tpmif_t* tpmif)
{
if(tpmif->fe_path) {
free(tpmif->fe_path);
}
if(tpmif->fe_state_path) {
free(tpmif->fe_state_path);
}
free(tpmif);
}
/* Creates a new tpm interface, adds it to the sorted array and returns it.
* returns NULL on error
* If the tpm interface already exists, it is returned*/
tpmif_t* new_tpmif(domid_t domid, unsigned int handle)
{
tpmif_t* tpmif;
char* err;
char path[512];
/* Make sure we haven't already created this tpm
* Double events can occur */
if((tpmif = get_tpmif(domid, handle)) != NULL) {
return tpmif;
}
tpmif = __init_tpmif(domid, handle);
/* Get the uuid from xenstore */
snprintf(path, 512, "backend/vtpm/%u/%u/uuid", (unsigned int) domid, handle);
if((!xenbus_read_uuid(path, tpmif->uuid))) {
TPMBACK_ERR("Error reading %s\n", path);
goto error;
}
if(tpmif_change_state(tpmif, XenbusStateInitWait)) {
goto error;
}
snprintf(path, 512, "backend/vtpm/%u/%u/frontend", (unsigned int) domid, handle);
if((err = xenbus_read(XBT_NIL, path, &tpmif->fe_path))) {
TPMBACK_ERR("Error creating new tpm instance xenbus_read(%s), Error = %s", path, err);
free(err);
goto error;
}
/*Set the state path */
tpmif->fe_state_path = malloc(strlen(tpmif->fe_path) + 7);
strcpy(tpmif->fe_state_path, tpmif->fe_path);
strcat(tpmif->fe_state_path, "/state");
if(insert_tpmif(tpmif)) {
goto error;
}
TPMBACK_DEBUG("New tpmif %u/%u\n", (unsigned int) tpmif->domid, tpmif->handle);
/* Do the callback now */
if(gtpmdev.open_callback) {
gtpmdev.open_callback(tpmif->domid, tpmif->handle);
}
return tpmif;
error:
__free_tpmif(tpmif);
return NULL;
}
/* Removes tpmif from dev->tpmlist and frees it's memory usage */
void free_tpmif(tpmif_t* tpmif)
{
char* err;
char path[512];
TPMBACK_DEBUG("Free tpmif %u/%u\n", (unsigned int) tpmif->domid, tpmif->handle);
if(tpmif->flags & TPMIF_CLOSED) {
TPMBACK_ERR("Tried to free an instance twice! Theres a bug somewhere!\n");
BUG();
}
tpmif->flags = TPMIF_CLOSED;
tpmif_change_state(tpmif, XenbusStateClosing);
/* Unmap share page and unbind event channel */
if(tpmif->status == CONNECTED) {
tpmif->status = DISCONNECTING;
mask_evtchn(tpmif->evtchn);
if(gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->page, 1)) {
TPMBACK_ERR("%u/%u Error occured while trying to unmap shared page\n", (unsigned int) tpmif->domid, tpmif->handle);
}
unbind_evtchn(tpmif->evtchn);
}
tpmif->status = DISCONNECTED;
tpmif_change_state(tpmif, XenbusStateClosed);
/* Do the callback now */
if(gtpmdev.close_callback) {
gtpmdev.close_callback(tpmif->domid, tpmif->handle);
}
/* remove from array */
remove_tpmif(tpmif);
/* Wake up anyone possibly waiting on this interface and let them exit */
wake_up(&waitq);
schedule();
/* Remove the old xenbus entries */
snprintf(path, 512, "backend/vtpm/%u/%u", (unsigned int) tpmif->domid, tpmif->handle);
if((err = xenbus_rm(XBT_NIL, path))) {
TPMBACK_ERR("Error cleaning up xenbus entries path=%s error=%s\n", path, err);
free(err);
}
TPMBACK_LOG("Frontend %u/%u disconnected\n", (unsigned int) tpmif->domid, tpmif->handle);
/* free memory */
__free_tpmif(tpmif);
}
/**********************
* REMAINING TPMBACK FUNCTIONS
* ********************/
/*Event channel handler */
void tpmback_handler(evtchn_port_t port, struct pt_regs *regs, void *data)
{
tpmif_t* tpmif = (tpmif_t*) data;
tpmif_shared_page_t *pg = tpmif->page;
switch (pg->state)
{
case TPMIF_STATE_SUBMIT:
TPMBACK_DEBUG("EVENT CHANNEL FIRE %u/%u\n", (unsigned int) tpmif->domid, tpmif->handle);
tpmif_req_ready(tpmif);
wake_up(&waitq);
break;
case TPMIF_STATE_CANCEL:
/* If we are busy with a request, do nothing */
if (tpmif->flags & TPMIF_REQ_READY)
return;
/* Acknowledge the cancellation if we are idle */
pg->state = TPMIF_STATE_IDLE;
wmb();
notify_remote_via_evtchn(tpmif->evtchn);
return;
default:
/* Spurious wakeup; do nothing */
return;
}
}
/* Connect to frontend */
int connect_fe(tpmif_t* tpmif)
{
char path[512];
char* err, *value;
uint32_t domid;
grant_ref_t ringref;
evtchn_port_t evtchn;
/* If already connected then quit */
if (tpmif->status == CONNECTED) {
TPMBACK_DEBUG("%u/%u tried to connect while it was already connected?\n", (unsigned int) tpmif->domid, tpmif->handle);
return 0;
}
/* Fetch the grant reference */
snprintf(path, 512, "%s/ring-ref", tpmif->fe_path);
if((err = xenbus_read(XBT_NIL, path, &value))) {
TPMBACK_ERR("Error creating new tpm instance xenbus_read(%s) Error = %s", path, err);
free(err);
return -1;
}
if(sscanf(value, "%d", &ringref) != 1) {
TPMBACK_ERR("Non integer value (%s) in %s ??\n", value, path);
free(value);
return -1;
}
free(value);
/* Fetch the event channel*/
snprintf(path, 512, "%s/event-channel", tpmif->fe_path);
if((err = xenbus_read(XBT_NIL, path, &value))) {
TPMBACK_ERR("Error creating new tpm instance xenbus_read(%s) Error = %s", path, err);
free(err);
return -1;
}
if(sscanf(value, "%d", &evtchn) != 1) {
TPMBACK_ERR("Non integer value (%s) in %s ??\n", value, path);
free(value);
return -1;
}
free(value);
/* Check that protocol v2 is being used */
snprintf(path, 512, "%s/feature-protocol-v2", tpmif->fe_path);
if((err = xenbus_read(XBT_NIL, path, &value))) {
TPMBACK_ERR("Unable to read %s during tpmback initialization! error = %s\n", path, err);
free(err);
return -1;
}
if(strcmp(value, "1")) {
TPMBACK_ERR("%s has an invalid value (%s)\n", path, value);
free(value);
return -1;
}
free(value);
domid = tpmif->domid;
if((tpmif->page = gntmap_map_grant_refs(&gtpmdev.map, 1, &domid, 0, &ringref, PROT_READ | PROT_WRITE)) == NULL) {
TPMBACK_ERR("Failed to map grant reference %u/%u\n", (unsigned int) tpmif->domid, tpmif->handle);
return -1;
}
/*Bind the event channel */
if((evtchn_bind_interdomain(tpmif->domid, evtchn, tpmback_handler, tpmif, &tpmif->evtchn)))
{
TPMBACK_ERR("%u/%u Unable to bind to interdomain event channel!\n", (unsigned int) tpmif->domid, tpmif->handle);
goto error_post_map;
}
unmask_evtchn(tpmif->evtchn);
/* Write the ready flag and change status to connected */
snprintf(path, 512, "backend/vtpm/%u/%u", (unsigned int) tpmif->domid, tpmif->handle);
if((err = xenbus_printf(XBT_NIL, path, "ready", "%u", 1))) {
TPMBACK_ERR("%u/%u Unable to write ready flag on connect_fe()\n", (unsigned int) tpmif->domid, tpmif->handle);
free(err);
goto error_post_evtchn;
}
tpmif->status = CONNECTED;
if((tpmif_change_state(tpmif, XenbusStateConnected))){
goto error_post_evtchn;
}
TPMBACK_LOG("Frontend %u/%u connected\n", (unsigned int) tpmif->domid, tpmif->handle);
return 0;
error_post_evtchn:
mask_evtchn(tpmif->evtchn);
unbind_evtchn(tpmif->evtchn);
error_post_map:
gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->page, 1);
return -1;
}
static void disconnect_fe(tpmif_t* tpmif)
{
if (tpmif->status == CONNECTED) {
tpmif->status = DISCONNECTING;
mask_evtchn(tpmif->evtchn);
if(gntmap_munmap(&gtpmdev.map, (unsigned long)tpmif->page, 1)) {
TPMBACK_ERR("%u/%u Error occured while trying to unmap shared page\n", (unsigned int) tpmif->domid, tpmif->handle);
}
unbind_evtchn(tpmif->evtchn);
}
tpmif->status = DISCONNECTED;
tpmif_change_state(tpmif, XenbusStateInitWait);
TPMBACK_LOG("Frontend %u/%u disconnected\n", (unsigned int) tpmif->domid, tpmif->handle);
}
static int frontend_changed(tpmif_t* tpmif)
{
int state = xenbus_read_integer(tpmif->fe_state_path);
if(state < 0) {
state = XenbusStateUnknown;
}
TPMBACK_DEBUG("Frontend %u/%u state changed to %d\n", (unsigned int) tpmif->domid, tpmif->handle, state);
switch (state) {
case XenbusStateInitialising:
break;
case XenbusStateInitialised:
case XenbusStateConnected:
if(connect_fe(tpmif)) {
TPMBACK_ERR("Failed to connect to front end %u/%u\n", (unsigned int) tpmif->domid, tpmif->handle);
tpmif_change_state(tpmif, XenbusStateClosed);
return -1;
}
break;
case XenbusStateClosing:
tpmif_change_state(tpmif, XenbusStateClosing);
break;
case XenbusStateClosed:
disconnect_fe(tpmif);
break;
case XenbusStateUnknown: /* keep it here */
free_tpmif(tpmif);
break;
default:
TPMBACK_DEBUG("BAD STATE CHANGE %u/%u state = %d for tpmif\n", (unsigned int) tpmif->domid, tpmif->handle, state);
return -1;
}
return 0;
}
/* parses the string that comes out of xenbus_watch_wait_return. */
static int parse_eventstr(const char* evstr, domid_t* domid, unsigned int* handle)
{
int ret;
char cmd[40];
char* err;
char* value;
unsigned int udomid = 0;
tpmif_t* tpmif;
/* First check for new frontends, this occurs when /backend/vtpm/<domid>/<handle> gets created. Note we what the sscanf to fail on the last %s */
if (sscanf(evstr, "backend/vtpm/%u/%u/%40s", &udomid, handle, cmd) == 2) {
*domid = udomid;
/* Make sure the entry exists, if this event triggers because the entry dissapeared then ignore it */
if((err = xenbus_read(XBT_NIL, evstr, &value))) {
free(err);
return EV_NONE;
}
free(value);
/* Make sure the tpmif entry does not already exist, this should not happen */
if((tpmif = get_tpmif(*domid, *handle)) != NULL) {
TPMBACK_DEBUG("Duplicate tpm entries! %u %u\n", tpmif->domid, tpmif->handle);
return EV_NONE;
}
return EV_NEWFE;
} else if((ret = sscanf(evstr, "/local/domain/%u/device/vtpm/%u/%40s", &udomid, handle, cmd)) == 3) {
*domid = udomid;
if (!strcmp(cmd, "state"))
return EV_STCHNG;
}
return EV_NONE;
}
void handle_backend_event(char* evstr) {
tpmif_t* tpmif;
domid_t domid;
unsigned int handle;
int event;
TPMBACK_DEBUG("Xenbus Event: %s\n", evstr);
event = parse_eventstr(evstr, &domid, &handle);
switch(event) {
case EV_NEWFE:
if(new_tpmif(domid, handle) == NULL) {
TPMBACK_ERR("Failed to create new tpm instance %u/%u\n", (unsigned int) domid, handle);
}
wake_up(&waitq);
break;
case EV_STCHNG:
if((tpmif = get_tpmif(domid, handle))) {
frontend_changed(tpmif);
} else {
TPMBACK_DEBUG("Event Received for non-existant tpm! instance=%u/%u xenbus_event=%s\n", (unsigned int) domid, handle, evstr);
}
break;
}
}
/* Runs through the given path and creates events recursively
* for all of its children.
* @path - xenstore path to scan */
static void generate_backend_events(const char* path)
{
char* err;
int i, len;
char **dirs;
char *entry;
if((err = xenbus_ls(XBT_NIL, path, &dirs)) != NULL) {
free(err);
return;
}
for(i = 0; dirs[i] != NULL; ++i) {
len = strlen(path) + strlen(dirs[i]) + 2;
entry = malloc(len);
snprintf(entry, len, "%s/%s", path, dirs[i]);
/* Generate and handle event for the entry itself */
handle_backend_event(entry);
/* Do children */
generate_backend_events(entry);
/* Cleanup */
free(entry);
free(dirs[i]);
}
free(dirs);
return;
}
void* tpmback_get_opaque(domid_t domid, unsigned int handle)
{
tpmif_t* tpmif;
if((tpmif = get_tpmif(domid, handle)) == NULL) {
TPMBACK_DEBUG("get_opaque() failed, %u/%u is an invalid frontend\n", (unsigned int) domid, handle);
return NULL;
}
return tpmif->opaque;
}
int tpmback_set_opaque(domid_t domid, unsigned int handle, void *opaque)
{
tpmif_t* tpmif;
if((tpmif = get_tpmif(domid, handle)) == NULL) {
TPMBACK_DEBUG("set_opaque() failed, %u/%u is an invalid frontend\n", (unsigned int) domid, handle);
return -1;
}
tpmif->opaque = opaque;
return 0;
}
unsigned char* tpmback_get_uuid(domid_t domid, unsigned int handle)
{
tpmif_t* tpmif;
if((tpmif = get_tpmif(domid, handle)) == NULL) {
TPMBACK_DEBUG("get_uuid() failed, %u/%u is an invalid frontend\n", (unsigned int) domid, handle);
return NULL;
}
return tpmif->uuid;
}
int tpmback_get_peercontext(domid_t domid, unsigned int handle, void* buffer, int buflen)
{
tpmif_t* tpmif;
if((tpmif = get_tpmif(domid, handle)) == NULL) {
TPMBACK_DEBUG("get_uuid() failed, %u/%u is an invalid frontend\n", (unsigned int) domid, handle);
return -1;
}
return evtchn_get_peercontext(tpmif->evtchn, buffer, buflen);
}
static void event_listener(void)
{
const char* bepath = "backend/vtpm";
char **path;
char* err;
/* Setup the backend device watch */
if((err = xenbus_watch_path_token(XBT_NIL, bepath, bepath, &gtpmdev.events)) != NULL) {
TPMBACK_ERR("xenbus_watch_path_token(%s) failed with error %s!\n", bepath, err);
free(err);
goto egress;
}
/* Check for any frontends that connected before we set the watch.
* This is almost guaranteed to happen if both domains are started
* immediatly one after the other.
* We do this by manually generating events on everything in the backend
* path */
generate_backend_events(bepath);
/* Wait and listen for changes in frontend connections */
while(1) {
path = xenbus_wait_for_watch_return(&gtpmdev.events);
/*If quit flag was set then exit */
if(gtpmdev.flags & TPMIF_CLOSED) {
TPMBACK_DEBUG("listener thread got quit event. Exiting..\n");
free(path);
break;
}
handle_backend_event(*path);
free(path);
}
if((err = xenbus_unwatch_path_token(XBT_NIL, bepath, bepath)) != NULL) {
free(err);
}
egress:
return;
}
void event_thread(void* p) {
event_listener();
}
void init_tpmback(void (*open_cb)(domid_t, unsigned int), void (*close_cb)(domid_t, unsigned int))
{
if(!globalinit) {
init_waitqueue_head(&waitq);
globalinit = 1;
}
printk("============= Init TPM BACK ================\n");
gtpmdev.tpmlist = malloc(sizeof(tpmif_t*) * DEF_ARRAY_SIZE);
gtpmdev.num_alloc = DEF_ARRAY_SIZE;
gtpmdev.num_tpms = 0;
gtpmdev.flags = 0;
gtpmdev.open_callback = open_cb;
gtpmdev.close_callback = close_cb;
eventthread = create_thread("tpmback-listener", event_thread, NULL);
}
void shutdown_tpmback(void)
{
TPMBACK_LOG("Shutting down tpm backend\n");
/* Set the quit flag */
gtpmdev.flags = TPMIF_CLOSED;
//printk("num tpms is %d\n", gtpmdev.num_tpms);
/*Free all backend instances */
while(gtpmdev.num_tpms) {
free_tpmif(gtpmdev.tpmlist[0]);
}
free(gtpmdev.tpmlist);
gtpmdev.tpmlist = NULL;
gtpmdev.num_alloc = 0;
/* Wake up anyone possibly waiting on the device and let them exit */
wake_up(&waitq);
schedule();
}
static void init_tpmcmd(tpmcmd_t* tpmcmd, domid_t domid, unsigned int handle, void *opaque)
{
tpmcmd->domid = domid;
tpmcmd->locality = -1;
tpmcmd->handle = handle;
tpmcmd->opaque = opaque;
tpmcmd->req = NULL;
tpmcmd->req_len = 0;
tpmcmd->resp = NULL;
tpmcmd->resp_len = 0;
}
tpmcmd_t* get_request(tpmif_t* tpmif) {
tpmcmd_t* cmd;
tpmif_shared_page_t *shr;
unsigned int offset;
int flags;
#ifdef TPMBACK_PRINT_DEBUG
int i;
#endif
local_irq_save(flags);
/* Allocate the cmd object to hold the data */
if((cmd = malloc(sizeof(*cmd))) == NULL) {
goto error;
}
init_tpmcmd(cmd, tpmif->domid, tpmif->handle, tpmif->opaque);
shr = tpmif->page;
cmd->req_len = shr->length;
cmd->locality = shr->locality;
offset = sizeof(*shr) + 4*shr->nr_extra_pages;
if (offset > PAGE_SIZE || offset + cmd->req_len > PAGE_SIZE) {
TPMBACK_ERR("%u/%u Command size too long for shared page!\n", (unsigned int) tpmif->domid, tpmif->handle);
goto error;
}
/* Allocate the buffer */
if(cmd->req_len) {
if((cmd->req = malloc(cmd->req_len)) == NULL) {
goto error;
}
}
/* Copy the bits from the shared page(s) */
memcpy(cmd->req, offset + (uint8_t*)shr, cmd->req_len);
#ifdef TPMBACK_PRINT_DEBUG
TPMBACK_DEBUG("Received Tpm Command from %u/%u of size %u", (unsigned int) tpmif->domid, tpmif->handle, cmd->req_len);
for(i = 0; i < cmd->req_len; ++i) {
if (!(i % 30)) {
TPMBACK_DEBUG_MORE("\n");
}
TPMBACK_DEBUG_MORE("%02hhX ", cmd->req[i]);
}
TPMBACK_DEBUG_MORE("\n\n");
#endif
local_irq_restore(flags);
return cmd;
error:
if(cmd != NULL) {
if (cmd->req != NULL) {
free(cmd->req);
cmd->req = NULL;
}
free(cmd);
cmd = NULL;
}
local_irq_restore(flags);
return NULL;
}
void send_response(tpmcmd_t* cmd, tpmif_t* tpmif)
{
tpmif_shared_page_t *shr;
unsigned int offset;
int flags;
#ifdef TPMBACK_PRINT_DEBUG
int i;
#endif
local_irq_save(flags);
shr = tpmif->page;
shr->length = cmd->resp_len;
offset = sizeof(*shr) + 4*shr->nr_extra_pages;
if (offset > PAGE_SIZE || offset + cmd->resp_len > PAGE_SIZE) {
TPMBACK_ERR("%u/%u Command size too long for shared page!\n", (unsigned int) tpmif->domid, tpmif->handle);
goto error;
}
memcpy(offset + (uint8_t*)shr, cmd->resp, cmd->resp_len);
#ifdef TPMBACK_PRINT_DEBUG
TPMBACK_DEBUG("Sent response to %u/%u of size %u", (unsigned int) tpmif->domid, tpmif->handle, cmd->resp_len);
for(i = 0; i < cmd->resp_len; ++i) {
if (!(i % 30)) {
TPMBACK_DEBUG_MORE("\n");
}
TPMBACK_DEBUG_MORE("%02hhX ", cmd->resp[i]);
}
TPMBACK_DEBUG_MORE("\n\n");
#endif
/* clear the ready flag and send the event channel notice to the frontend */
tpmif_req_finished(tpmif);
barrier();
shr->state = TPMIF_STATE_FINISH;
wmb();
notify_remote_via_evtchn(tpmif->evtchn);
error:
local_irq_restore(flags);
return;
}
tpmcmd_t* tpmback_req_any(void)
{
int i;
/* Block until something has a request */
wait_event(waitq, (gtpmdev.flags & (TPMIF_REQ_READY | TPMIF_CLOSED)));
/* Check if were shutting down */
if(gtpmdev.flags & TPMIF_CLOSED) {
/* if something was waiting for us to give up the queue so it can shutdown, let it finish */
schedule();
return NULL;
}
for(i = 0; i < gtpmdev.num_tpms; ++i) {
if(gtpmdev.tpmlist[i]->flags & TPMIF_REQ_READY) {
return get_request(gtpmdev.tpmlist[i]);
}
}
TPMBACK_ERR("backend request ready flag was set but no interfaces were actually ready\n");
return NULL;
}
tpmcmd_t* tpmback_req(domid_t domid, unsigned int handle)
{
tpmif_t* tpmif;
tpmif = get_tpmif(domid, handle);
if(tpmif == NULL) {
return NULL;
}
wait_event(waitq, (tpmif->flags & (TPMIF_REQ_READY | TPMIF_CLOSED) || gtpmdev.flags & TPMIF_CLOSED));
/* Check if were shutting down */
if(tpmif->flags & TPMIF_CLOSED || gtpmdev.flags & TPMIF_CLOSED) {
/* if something was waiting for us to give up the queue so it can free this instance, let it finish */
schedule();
return NULL;
}
return get_request(tpmif);
}
void tpmback_resp(tpmcmd_t* tpmcmd)
{
tpmif_t* tpmif;
/* Get the associated interface, if it doesnt exist then just quit */
tpmif = get_tpmif(tpmcmd->domid, tpmcmd->handle);
if(tpmif == NULL) {
TPMBACK_ERR("Tried to send a reponse to non existant frontend %u/%u\n", (unsigned int) tpmcmd->domid, tpmcmd->handle);
goto end;
}
if(!(tpmif->flags & TPMIF_REQ_READY)) {
TPMBACK_ERR("Tried to send response to a frontend that was not waiting for one %u/%u\n", (unsigned int) tpmcmd->domid, tpmcmd->handle);
goto end;
}
/* Send response to frontend */
send_response(tpmcmd, tpmif);
end:
if(tpmcmd->req != NULL) {
free(tpmcmd->req);
}
free(tpmcmd);
return;
}
int tpmback_wait_for_frontend_connect(domid_t *domid, unsigned int *handle)
{
tpmif_t* tpmif;
int flags;
wait_event(waitq, ((gtpmdev.num_tpms > 0) || gtpmdev.flags & TPMIF_CLOSED));
if(gtpmdev.flags & TPMIF_CLOSED) {
return -1;
}
local_irq_save(flags);
tpmif = gtpmdev.tpmlist[0];
*domid = tpmif->domid;
*handle = tpmif->handle;
local_irq_restore(flags);
return 0;
}
int tpmback_num_frontends(void)
{
return gtpmdev.num_tpms;
}
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