feat: add support for NR Control [wip]

agent/php_globals.c

@@ -42,6 +42,7 @@ static void nr_php_per_process_globals_dispose(void) {
   nr_free(nr_php_per_process_globals.env_labels);
   nr_free(nr_php_per_process_globals.apache_add);
   nr_free(nr_php_per_process_globals.docker_id);
+  nr_free(nr_php_per_process_globals.agent_control_health_location);
 
   nr_memset(&nr_php_per_process_globals, 0, sizeof(nr_php_per_process_globals));
 }

agent/php_globals.h

@@ -85,6 +85,11 @@ typedef struct _nrphpglobals_t {
   /* Original PHP SAPI header callback */
   nrphphdrfn_t orig_header_handler;
 
+  /* NR Control configuration settings */
+  int agent_control_enabled;
+  char* agent_control_health_location;
+  nrtime_t agent_control_frequency;
+
   struct {
     uint8_t no_sql_parsing;
     uint8_t show_sql_parsing;

agent/php_minit.c

@@ -29,6 +29,7 @@
 #include "nr_app.h"
 #include "nr_banner.h"
 #include "nr_daemon_spawn.h"
+#include "util_health.h"
 #include "util_logging.h"
 #include "util_memory.h"
 #include "util_signals.h"
@@ -319,6 +320,25 @@ static void nr_php_check_high_security_log_forwarding(TSRMLS_D) {
   }
 }
 
+/*
+ * Check the INI values for 'agent_control_enabled' and
+ * `agent_control_health_location`, log a warning and set agent_control_enabled
+ * to 'false' on an invalid configuration state .
+ */
+static void nr_php_check_agent_control_health_file() {
+  if (NR_PHP_PROCESS_GLOBALS(agent_control_enabled)
+      && nr_strempty(NR_PHP_PROCESS_GLOBALS(agent_control_health_location))) {
+    nrl_warning(NRL_INIT,
+                "NR Control support will be DISABLED because a valid health "
+                "file location is not set. Please check "
+                "newrelic.agent_control.health.delivery_location in the agent "
+                "configuration file or the "
+                "NEW_RELIC_AGENT_CONTROL_HEALTH_DELIVERY_LOCATION environment "
+                "variable.");
+    NR_PHP_PROCESS_GLOBALS(agent_control_enabled) = 0;
+  }
+}
+
 static char* nr_php_get_agent_specific_info(void) {
   const char* php_version;
   const char* zend_type;
@@ -651,6 +671,8 @@ PHP_MINIT_FUNCTION(newrelic) {
   nr_php_check_logging_config(TSRMLS_C);
   nr_php_check_high_security_log_forwarding(TSRMLS_C);
 
+  nr_php_check_agent_control_health_file();
+
   /*
    * Save the original PHP hooks and then apply our own hooks. The agent is
    * almost fully operational now. The last remaining initialization that
@@ -719,6 +741,10 @@ PHP_MINIT_FUNCTION(newrelic) {
   nr_wordpress_minit();
   nr_php_set_opcode_handlers();
 
+  if (NR_PHP_PROCESS_GLOBALS(agent_control_enabled)) {
+    nrh_set_start_time();
+  }
+
   nrl_debug(NRL_INIT, "MINIT processing done");
 #if ZEND_MODULE_API_NO >= ZEND_8_0_X_API_NO /* PHP 7.4+ */
   NR_PHP_PROCESS_GLOBALS(zend_offset) = zend_get_resource_handle(dummy);

agent/php_nrini.c

@@ -15,6 +15,7 @@
 #include "nr_version.h"
 #include "nr_log_level.h"
 #include "util_buffer.h"
+#include "util_health.h"
 #include "util_json.h"
 #include "util_logging.h"
 #include "util_memory.h"
@@ -515,6 +516,89 @@ static PHP_INI_MH(nr_high_security_mh) {
   return SUCCESS;
 }
 
+static PHP_INI_MH(nr_agent_control_enabled_mh) {
+  int val;
+
+  (void)entry;
+  (void)NEW_VALUE_LEN;
+  (void)mh_arg1;
+  (void)mh_arg2;
+  (void)mh_arg3;
+  (void)stage;
+  NR_UNUSED_TSRMLS;
+
+  val = nr_bool_from_str(NEW_VALUE);
+
+  if (-1 == val) {
+    return FAILURE;
+  }
+
+  if (val) {
+    NR_PHP_PROCESS_GLOBALS(agent_control_enabled) = 1;
+  } else {
+    NR_PHP_PROCESS_GLOBALS(agent_control_enabled) = 0;
+  }
+
+  return SUCCESS;
+}
+
+static PHP_INI_MH(nr_agent_control_location_mh) {
+  (void)entry;
+  (void)mh_arg1;
+  (void)mh_arg2;
+  (void)mh_arg3;
+  (void)stage;
+  NR_UNUSED_TSRMLS;
+
+  nr_free(NR_PHP_PROCESS_GLOBALS(agent_control_health_location));
+
+  if (0 == NEW_VALUE_LEN) {
+    return SUCCESS;
+  }
+
+  if (7 >= NEW_VALUE_LEN) {
+    // missing or malformed 'file://' prefix
+    return FAILURE;
+  }
+
+  NR_PHP_PROCESS_GLOBALS(agent_control_health_location)
+      = nrh_get_health_location(NEW_VALUE);
+
+  if (NULL == NR_PHP_PROCESS_GLOBALS(agent_control_health_location)) {
+    nrl_warning(NRL_INIT,
+                "failed to set health file location for provided uri '%s'",
+                NEW_VALUE);
+    return FAILURE;
+  }
+
+  return SUCCESS;
+}
+
+static PHP_INI_MH(nr_agent_control_frequency_mh) {
+  nrtime_t val;
+
+  (void)entry;
+  (void)mh_arg1;
+  (void)mh_arg2;
+  (void)mh_arg3;
+  (void)stage;
+  NR_UNUSED_TSRMLS;
+
+  if (0 != NEW_VALUE_LEN) {
+    val = nr_parse_time_from_config(NEW_VALUE);
+    if (val < 1) {
+      val = 1;
+    } else if (val > 300) {
+      val = 300;
+    }
+    NR_PHP_PROCESS_GLOBALS(agent_control_frequency) = val;
+  } else {
+    NR_PHP_PROCESS_GLOBALS(agent_control_frequency) = 5;
+  }
+
+  return SUCCESS;
+}
+
 static PHP_INI_MH(nr_preload_framework_library_detection_mh) {
   int val;
 
@@ -2169,6 +2253,25 @@ PHP_INI_ENTRY_EX("newrelic.daemon.utilization.detect_kubernetes",
                  NR_PHP_SYSTEM,
                  NR_PHP_UTILIZATION_MH_NAME(kubernetes),
                  nr_enabled_disabled_dh)
+
+PHP_INI_ENTRY_EX("newrelic.agent_control.enabled",
+                 "0",
+                 NR_PHP_SYSTEM,
+                 nr_agent_control_enabled_mh,
+                 0)
+
+PHP_INI_ENTRY_EX("newrelic.agent_control.health.delivery_location",
+                 "file:///newrelic/apm/health",
+                 NR_PHP_SYSTEM,
+                 nr_agent_control_location_mh,
+                 0)
+
+PHP_INI_ENTRY_EX("newrelic.agent_control.health.frequency",
+                 "5s",
+                 NR_PHP_SYSTEM,
+                 nr_agent_control_frequency_mh,
+                 0)
+
 /*
  * This daemon flag is for internal development use only.  It should not be
  * documented to customers.

agent/scripts/newrelic.ini.template

@@ -1393,3 +1393,28 @@ newrelic.daemon.logfile = "/var/log/newrelic/newrelic-daemon.log"
 ;          requires that this value when the account ID is not part of the function name.
 ;
 ;newrelic.cloud.aws.account_id = ""
+
+; Setting: newrelic.agent_control.enabled
+; Type   : boolean
+; Scope  : per-directory
+; Default: false
+; Info   : Boolean value that denotes if agent control functionality should be enabled.
+;
+;newrelic.agent_control.enabled = false
+
+; Setting: newrelic.agent_control.health.delivery_location
+; Type   : string
+; Scope  : per-directory
+; Default: file:///newrelic/apm/health
+; Info   : String URI that specifies the fully qualified directory path for the
+;          health file(s) to be written to.
+;
+;newrelic.agent_control.health.delivery_location = "file:///newrelic/apm/health"
+
+; Setting: newrelic.agent_control.health.frequency
+; Type   : time specification string (in seconds, only)
+; Scope  : per-directory
+; Info   : Integer that specifies the interval, in seconds, of how often the health
+;          file will be written.
+;
+;newrelic.agent_control.health.frequency = 5s

axiom/Makefile

@@ -124,6 +124,7 @@ OBJS := \
 	nr_span_queue.o \
 	nr_synthetics.o \
 	nr_txn.o \
+	nr_uuid.o \
 	nr_version.o \
 	nr_php_packages.o \
 	util_apdex.o \
@@ -136,6 +137,7 @@ OBJS := \
 	util_hashmap.o \
 	util_json.o \
 	util_logging.o \
+	util_health.o \
 	util_labels.o \
 	util_matcher.o \
 	util_md5.o \

axiom/nr_uuid.c

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2020 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdlib.h>
+#include <time.h>
+
+#include "nr_uuid.h"
+#include "util_memory.h"
+
+static const char hex_values[16] = {'0', '1', '2', '3', '4', '5', '6', '7',
+                                    '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
+char* nr_uuid_create(int seed) {
+  char* uuid = nr_zalloc(NR_UUID_SIZE + 1);
+  if (0 < seed) {
+    srand(seed);
+  } else {
+    srand(time(NULL));
+  }
+
+  for (int i = 0; i < NR_UUID_SIZE; i++) {
+    int r = rand() % NR_UUID_RANGE;
+
+    uuid[i] = hex_values[r];
+  }
+
+  return uuid;
+}

axiom/nr_uuid.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2020 New Relic Corporation. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/*
+ * This file contains functions for simple uuid generation.
+ */
+#ifndef NR_UUID_HDR
+#define NR_UUID_HDR
+
+#define NR_UUID_SIZE 32
+#define NR_UUID_RANGE 16
+
+/**
+ * nr_uuid_create: pseudo-implementation of uuid generation logic
+ *
+ * This function will simply return a randomly generated 32 character hex
+ * string. It does not implement the spec for UUID generation, which requires
+ * specific adherence to implementation details and setting bits within the UUID
+ * to signify which UUID generation variant was used.
+ *
+ * Params: int seed (<1 for time based seed)
+ *
+ * Returns: 32 byte hex string (must be freed by caller)
+ */
+char* nr_uuid_create(int seed);
+#endif

axiom/tests/.gitignore

@@ -35,6 +35,9 @@ clang_header.h
 # vi/ex scripts
 *.ex
 
+# test file generation
+health-*.yml
+
 # Test binaries
 test_agent
 test_analytics_events
@@ -63,6 +66,7 @@ test_guid
 test_hash
 test_hashmap
 test_header
+test_health
 test_helgrind
 test_json
 test_labels
@@ -121,4 +125,5 @@ test_threads
 test_time
 test_txn
 test_url
+test_uuid
 test_vector

axiom/tests/Makefile

@@ -146,6 +146,7 @@ TESTS := \
   test_hash \
   test_hashmap \
   test_header \
+  test_health \
   test_json \
   test_labels \
   test_log_event \
@@ -198,6 +199,7 @@ TESTS := \
   test_time \
   test_txn \
   test_url \
+  test_uuid \
   test_vector
 
 #