Vadim Bendebury | 5679752 | 2015-05-20 10:32:25 -0700 | [diff] [blame] | 1 | // This file was extracted from the TCG Published |
| 2 | // Trusted Platform Module Library |
| 3 | // Part 3: Commands |
| 4 | // Family "2.0" |
| 5 | // Level 00 Revision 01.16 |
| 6 | // October 30, 2014 |
| 7 | |
| 8 | #include "InternalRoutines.h" |
| 9 | // |
| 10 | // This function is called to process a _TPM_Hash_Start() indication. |
| 11 | // |
| 12 | void |
| 13 | _TPM_Hash_Start( |
| 14 | void |
| 15 | ) |
| 16 | { |
| 17 | TPM_RC result; |
| 18 | TPMI_DH_OBJECT handle; |
| 19 | |
| 20 | // If a DRTM sequence object exists, free it up |
| 21 | if(g_DRTMHandle != TPM_RH_UNASSIGNED) |
| 22 | { |
| 23 | ObjectFlush(g_DRTMHandle); |
| 24 | g_DRTMHandle = TPM_RH_UNASSIGNED; |
| 25 | } |
| 26 | |
| 27 | // Create an event sequence object and store the handle in global |
| 28 | // g_DRTMHandle. A TPM_RC_OBJECT_MEMORY error may be returned at this point |
| 29 | // The null value for the 'auth' parameter will cause the sequence structure to |
| 30 | // be allocated without being set as present. This keeps the sequence from |
| 31 | // being left behind if the sequence is terminated early. |
| 32 | result = ObjectCreateEventSequence(NULL, &g_DRTMHandle); |
| 33 | |
| 34 | // If a free slot was not available, then free up a slot. |
| 35 | if(result != TPM_RC_SUCCESS) |
| 36 | { |
| 37 | // An implementation does not need to have a fixed relationship between |
| 38 | // slot numbers and handle numbers. To handle the general case, scan for |
| 39 | // a handle that is assigned and free it for the DRTM sequence. |
| 40 | // In the reference implementation, the relationship between handles and |
| 41 | // slots is fixed. So, if the call to ObjectCreateEvenSequence() |
| 42 | // failed indicating that all slots are occupied, then the first handle we |
| 43 | // are going to check (TRANSIENT_FIRST) will be occupied. It will be freed |
| 44 | // so that it can be assigned for use as the DRTM sequence object. |
| 45 | for(handle = TRANSIENT_FIRST; handle < TRANSIENT_LAST; handle++) |
| 46 | { |
| 47 | // try to flush the first object |
| 48 | if(ObjectIsPresent(handle)) |
| 49 | break; |
| 50 | } |
| 51 | // If the first call to find a slot fails but none of the slots is occupied |
| 52 | // then there's a big problem |
| 53 | pAssert(handle < TRANSIENT_LAST); |
| 54 | |
| 55 | // Free the slot |
| 56 | ObjectFlush(handle); |
| 57 | |
| 58 | // Try to create an event sequence object again. This time, we must |
| 59 | // succeed. |
| 60 | result = ObjectCreateEventSequence(NULL, &g_DRTMHandle); |
| 61 | pAssert(result == TPM_RC_SUCCESS); |
| 62 | } |
| 63 | |
| 64 | return; |
| 65 | } |