mini-os/tpmback: Replace UUID field with opaque pointer

Instead of only recording the UUID field, which may not be of interest
to all tpmback implementations, provide a user-settable opaque pointer
associated with the tpmback instance.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>

extras/mini-os/include/tpmback.h

@@ -45,10 +45,10 @@ struct tpmcmd {
    domid_t domid;		/* Domid of the frontend */
    uint8_t locality;    /* Locality requested by the frontend */
    unsigned int handle;	/* Handle of the frontend */
-   unsigned char uuid[16];			/* uuid of the tpm interface */
+   void *opaque;        /* Opaque pointer taken from the tpmback instance */
 
-   unsigned int req_len;		/* Size of the command in buf - set by tpmback driver */
    uint8_t* req;			/* tpm command bits, allocated by driver, DON'T FREE IT */
+   unsigned int req_len;		/* Size of the command in buf - set by tpmback driver */
    unsigned int resp_len;	/* Size of the outgoing command,
 				   you set this before passing the cmd object to tpmback_resp */
    uint8_t* resp;		/* Buffer for response - YOU MUST ALLOCATE IT, YOU MUST ALSO FREE IT */
@@ -94,4 +94,9 @@ int tpmback_num_frontends(void);
  * The return value is internally allocated, so don't free it */
 unsigned char* tpmback_get_uuid(domid_t domid, unsigned int handle);
 
+/* Get and set the opaque pointer for a tpmback instance */
+void* tpmback_get_opaque(domid_t domid, unsigned int handle);
+/* Returns zero if successful, nonzero on failure (no such frontend) */
+int tpmback_set_opaque(domid_t domid, unsigned int handle, void* opaque);
+
 #endif

extras/mini-os/tpmback.c

@@ -92,6 +92,7 @@ struct tpmif {
    enum { DISCONNECTED, DISCONNECTING, CONNECTED } status;
 
    unsigned char uuid[16];
+   void* opaque;
 
    /* state flags */
    int flags;
@@ -391,6 +392,7 @@ inline tpmif_t* __init_tpmif(domid_t domid, unsigned int handle)
    tpmif->status = DISCONNECTED;
    tpmif->page = NULL;
    tpmif->flags = 0;
+   tpmif->opaque = NULL;
    memset(tpmif->uuid, 0, sizeof(tpmif->uuid));
    return tpmif;
 }
@@ -794,6 +796,29 @@ static void generate_backend_events(const char* path)
    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;
@@ -890,12 +915,12 @@ void shutdown_tpmback(void)
    schedule();
 }
 
-inline void init_tpmcmd(tpmcmd_t* tpmcmd, domid_t domid, unsigned int handle, unsigned char uuid[16])
+static void init_tpmcmd(tpmcmd_t* tpmcmd, domid_t domid, unsigned int handle, void *opaque)
 {
    tpmcmd->domid = domid;
    tpmcmd->locality = -1;
    tpmcmd->handle = handle;
-   memcpy(tpmcmd->uuid, uuid, sizeof(tpmcmd->uuid));
+   tpmcmd->opaque = opaque;
    tpmcmd->req = NULL;
    tpmcmd->req_len = 0;
    tpmcmd->resp = NULL;
@@ -917,7 +942,7 @@ tpmcmd_t* get_request(tpmif_t* tpmif) {
    if((cmd = malloc(sizeof(*cmd))) == NULL) {
       goto error;
    }
-   init_tpmcmd(cmd, tpmif->domid, tpmif->handle, tpmif->uuid);
+   init_tpmcmd(cmd, tpmif->domid, tpmif->handle, tpmif->opaque);
 
    shr = tpmif->page;
    cmd->req_len = shr->length;

stubdom/vtpmmgr/init.c

@@ -436,6 +436,12 @@ egress:
    return status;
 }
 
+/* Set up the opaque field to contain a pointer to the UUID */
+static void set_opaque_to_uuid(domid_t domid, unsigned int handle)
+{
+   tpmback_set_opaque(domid, handle, tpmback_get_uuid(domid, handle));
+}
+
 TPM_RESULT vtpmmgr_init(int argc, char** argv) {
    TPM_RESULT status = TPM_SUCCESS;
 
@@ -462,7 +468,7 @@ TPM_RESULT vtpmmgr_init(int argc, char** argv) {
    }
 
    //Setup tpmback device
-   init_tpmback(NULL, NULL);
+   init_tpmback(set_opaque_to_uuid, NULL);
 
    //Setup tpm access
    switch(opts.tpmdriver) {

stubdom/vtpmmgr/vtpmmgr.c

@@ -61,7 +61,7 @@ void main_loop(void) {
       tpmcmd->resp = respbuf;
 
       /* Process the command */
-      vtpmmgr_handle_cmd(tpmcmd->uuid, tpmcmd);
+      vtpmmgr_handle_cmd(tpmcmd->opaque, tpmcmd);
 
       /* Send response */
       tpmback_resp(tpmcmd);