Improve KeysInUse logging performance during burst of first use events

SymCryptProvider/README.md

@@ -143,4 +143,5 @@ separate section. This section must be referenced in the symcrypt provider secti
 | -                     | -                                                                                                                                             | -         |
 | enabled               | 0 or 1 to disable or enable keysinuse logging.                                                                                                | 0         |
 | max_file_size         | Maximum size of the file events are written to. May be written as raw byte size or suffixed with KB/MB/GB                                     | 5KB       |
-| logging_delay_seconds | Duration in seconds between events being written to the file. Any events that happen in between will be aggregate and logged as one event.    | error     |
+| logging_delay_seconds | Duration in seconds between events being written to the file. Any events that happen in between will be aggregate and logged as one event.    | error     |
+| process_scope         | Controls which processes run the KeysInUse logging thread when an application forks. Can be <ul><li>main - only the process that first initialized KeysInUse logs</li><li>child - only forked child processes log</li><li>both - both the main process and forked children log</li></ul> May be overridden at runtime by the `KEYSINUSE_PROCESS_SCOPE` environment variable. | both      |

SymCryptProvider/src/p_scossl_base.c

@@ -24,6 +24,7 @@ extern "C" {
 #define CONF_KEYSINUSE_ENABLED       "keysinuse.enabled"
 #define CONF_KEYSINUSE_MAX_FILE_SIZE "keysinuse.max_file_size"
 #define CONF_KEYSINUSE_LOGGING_DELAY "keysinuse.logging_delay_seconds"
+#define CONF_KEYSINUSE_PROCESS_SCOPE "keysinuse.process_scope"
 
 // Cap configured file size at 2GB
 #define SCOSSL_MAX_CONFIGURABLE_FILE_SIZE (2l << 30)
@@ -413,12 +414,15 @@ static void p_scossl_start_keysinuse(_In_ const OSSL_CORE_HANDLE *handle)
     const char *confEnabled = NULL;
     const char *confMaxFileSize = NULL;
     const char *confLoggingDelay = NULL;
+    const char *confProcessScope = NULL;
+    const char *envProcessScope = NULL;
     const char *envEnabled = NULL;
 
     OSSL_PARAM keysinuseParams[] = {
         OSSL_PARAM_utf8_ptr(CONF_KEYSINUSE_ENABLED, &confEnabled, 0),
         OSSL_PARAM_utf8_ptr(CONF_KEYSINUSE_MAX_FILE_SIZE, &confMaxFileSize, 0),
         OSSL_PARAM_utf8_ptr(CONF_KEYSINUSE_LOGGING_DELAY, &confLoggingDelay, 0),
+        OSSL_PARAM_utf8_ptr(CONF_KEYSINUSE_PROCESS_SCOPE, &confProcessScope, 0),
         OSSL_PARAM_END};
 
     // Config related errors shouldn't surface to caller
@@ -501,6 +505,28 @@ static void p_scossl_start_keysinuse(_In_ const OSSL_CORE_HANDLE *handle)
             p_scossl_keysinuse_set_logging_delay(atol(confLoggingDelay));
         }
 
+        // Environment overrides config. Config value is alreday fetched core_get_params above
+        if ((envProcessScope = NCONF_get_string(NULL, NULL, "KEYSINUSE_PROCESS_SCOPE")) != NULL)
+        {
+            confProcessScope = envProcessScope;
+        }
+
+        if (confProcessScope != NULL)
+        {
+            if (OPENSSL_strcasecmp(confProcessScope, "main") == 0)
+            {
+                p_scossl_keysinuse_set_process_scope(KEYSINUSE_PROCESS_SCOPE_MAIN);
+            }
+            else if (OPENSSL_strcasecmp(confProcessScope, "child") == 0)
+            {
+                p_scossl_keysinuse_set_process_scope(KEYSINUSE_PROCESS_SCOPE_CHILD);
+            }
+            else
+            {
+                p_scossl_keysinuse_set_process_scope(KEYSINUSE_PROCESS_SCOPE_BOTH);
+            }
+        }
+
         p_scossl_keysinuse_init();
     }