X-Git-Url: https://git.saurik.com/apple/security.git/blobdiff_plain/84aacf34eae6543be9f0280b2015385f91e5c2c6..b54c578e17e9bcbd74aa30ea75e25e955b9a6205:/keychain/SecureObjectSync/SOSGenCount.c?ds=inline

diff --git a/keychain/SecureObjectSync/SOSGenCount.c b/keychain/SecureObjectSync/SOSGenCount.c
new file mode 100644
index 00000000..5163e901
--- /dev/null
+++ b/keychain/SecureObjectSync/SOSGenCount.c
@@ -0,0 +1,142 @@
+//
+//  SOSGenCount.c
+//  sec
+//
+//  Created by Richard Murphy on 1/29/15.
+//
+//
+
+#include "SOSGenCount.h"
+#include <utilities/SecCFWrappers.h>
+#include <CoreFoundation/CFLocale.h>
+#include <utilities/der_plist.h>
+#include <utilities/der_plist_internal.h>
+
+
+static CFAbsoluteTime SOSGenerationCountGetDateBits(int64_t genValue) {
+    return (uint32_t) ((((uint64_t) genValue) >> 32) << 1);
+}
+
+void SOSGenerationCountWithDescription(SOSGenCountRef gen, void (^operation)(CFStringRef description)) {
+    CFStringRef description = SOSGenerationCountCopyDescription(gen);
+
+    operation(description);
+
+    CFReleaseSafe(description);
+}
+
+CFStringRef SOSGenerationCountCopyDescription(SOSGenCountRef gen) {
+    int64_t value = SOSGetGenerationSint(gen);
+
+    CFMutableStringRef gcDecsription = CFStringCreateMutableCopy(kCFAllocatorDefault, 0, CFSTR("["));
+
+    withStringOfAbsoluteTime(SOSGenerationCountGetDateBits(value), ^(CFStringRef decription) {
+        CFStringAppend(gcDecsription, decription);
+    });
+
+    CFStringAppendFormat(gcDecsription, NULL, CFSTR(" %u]"), (uint32_t)(value & 0xFFFFFFFF));
+
+    return gcDecsription;
+}
+
+int64_t SOSGetGenerationSint(SOSGenCountRef gen) {
+    int64_t value;
+    if(!gen) return 0;
+    CFNumberGetValue(gen, kCFNumberSInt64Type, &value);
+    return value;
+}
+
+static int64_t sosGenerationSetHighBits(int64_t value, int32_t high_31)
+{
+    value &= 0xFFFFFFFF; // Keep the low 32 bits.
+    value |= ((int64_t) high_31) << 32;
+
+    return value;
+}
+
+static SOSGenCountRef sosGenerationCreateOrIncrement(SOSGenCountRef gen) {
+    int64_t value = 0;
+
+    if(gen) {
+        value = SOSGetGenerationSint(gen);
+    }
+
+    if((value >> 32) == 0) {
+        uint32_t seconds = CFAbsoluteTimeGetCurrent(); // seconds
+        value = sosGenerationSetHighBits(value, (seconds >> 1));
+    }
+
+    value++;
+    return CFNumberCreate(NULL, kCFNumberSInt64Type, &value);
+}
+
+SOSGenCountRef SOSGenerationCreate() {
+    return sosGenerationCreateOrIncrement(NULL);
+}
+
+
+// We need this for a circle gencount test
+SOSGenCountRef SOSGenerationCreateWithValue(int64_t value) {
+    return CFNumberCreate(NULL, kCFNumberSInt64Type, &value);
+}
+
+SOSGenCountRef SOSGenerationIncrementAndCreate(SOSGenCountRef gen) {
+    return sosGenerationCreateOrIncrement(gen);
+}
+
+SOSGenCountRef SOSGenerationCopy(SOSGenCountRef gen) {
+    if(!gen) return NULL;
+    int64_t value = SOSGetGenerationSint(gen);
+    return CFNumberCreate(NULL, kCFNumberSInt64Type, &value);
+}
+
+// Is current older than proposed?
+bool SOSGenerationIsOlder(SOSGenCountRef older, SOSGenCountRef newer) {
+    switch(CFNumberCompare(older, newer, NULL)) {
+        case kCFCompareLessThan:  return true;
+        case kCFCompareEqualTo: return false;
+        case kCFCompareGreaterThan:  return false;
+    }
+    return false;
+}
+
+// Is current older than proposed?
+static bool SOSGenerationIsOlderOrEqual(SOSGenCountRef older, SOSGenCountRef newer) {
+    switch(CFNumberCompare(older, newer, NULL)) {
+        case kCFCompareLessThan:  return true;
+        case kCFCompareEqualTo: return true;
+        case kCFCompareGreaterThan:  return false;
+    }
+    return false;
+}
+
+
+SOSGenCountRef SOSGenerationCreateWithBaseline(SOSGenCountRef reference) {
+    SOSGenCountRef retval = SOSGenerationCreate();
+    if(SOSGenerationIsOlderOrEqual(retval, reference)) {
+        CFReleaseNull(retval);
+        retval = SOSGenerationIncrementAndCreate(reference);
+    }
+    return retval;
+}
+
+
+SOSGenCountRef SOSGenCountCreateFromDER(CFAllocatorRef allocator, CFErrorRef* error,
+                                        const uint8_t** der_p, const uint8_t *der_end) {
+    SOSGenCountRef retval = NULL;
+    *der_p = der_decode_number(allocator, 0, &retval, error, *der_p, der_end);
+    if(retval == NULL)
+        retval = SOSGenerationCreate();
+    return retval;
+}
+
+size_t SOSGenCountGetDEREncodedSize(SOSGenCountRef gencount, CFErrorRef *error) {
+    return der_sizeof_number(gencount, error);
+}
+
+uint8_t *SOSGenCountEncodeToDER(SOSGenCountRef gencount, CFErrorRef* error, const uint8_t* der, uint8_t* der_end) {
+    return der_encode_number(gencount, error, der, der_end);
+}
+
+
+