Loader: disable the tracer in case of a potential incompatibility (extension/jit)

.circleci/continue_config.yml

@@ -3332,6 +3332,9 @@ jobs:
       switch_php_version:
         type: string
         default: none
+      use_valgrind:
+        type: boolean
+        default: false
       resource_class:
         type: string
         default: medium
@@ -3354,6 +3357,18 @@ jobs:
           command: |
             set -xeuo pipefail
 
+            if [[ "<< parameters.php_major_minor >>" == "8.3" ]]; then
+              export XDEBUG_SO_NAME=xdebug-3.3.0.so
+            elif [[ "<< parameters.php_major_minor >>" == "8.2" ]]; then
+              export XDEBUG_SO_NAME=xdebug-3.2.2.so
+            elif [[ "<< parameters.php_major_minor >>" == "8.1" ]]; then
+              export XDEBUG_SO_NAME=xdebug-3.1.0.so
+            elif [[ "<< parameters.php_major_minor >>" == "8.0" ]]; then
+              export XDEBUG_SO_NAME=xdebug-3.0.0.so
+            elif [[ "<< parameters.php_major_minor >>" == "7.4" ]]; then
+              export XDEBUG_SO_NAME=xdebug-2.9.5.so
+            fi
+
             rm -rf dd-library-php-ssi
             tar -xzf dd-library-php-ssi-*-linux.tar.gz
             export DD_LOADER_PACKAGE_PATH=${PWD}/dd-library-php-ssi
@@ -3362,6 +3377,10 @@ jobs:
             mkdir -p modules
             cp ../dd-library-php-ssi/linux-gnu/loader/dd_library_loader.so modules/
             ./bin/test.sh
+            if [[ "<< parameters.php_major_minor >>" == "8.3" ]]; then
+              true
+              <<# parameters.use_valgrind >>echo "Run with Valgrind" ; TEST_USE_VALGRIND=1 ./bin/test.sh<</ parameters.use_valgrind >>
+            fi
             ./bin/check_glibc_version.sh
 
   "test_loader_alpine":
@@ -3394,6 +3413,7 @@ jobs:
             set -xeuo pipefail
 
             apk add --no-cache curl-dev << parameters.alpine_packages >>
+            export XDEBUG_SO_NAME=xdebug.so
 
             rm -rf dd-library-php-ssi
             tar -xzf dd-library-php-ssi-*-linux.tar.gz
@@ -4921,6 +4941,7 @@ workflows:
           name: "[Linux/x86_64] Loader PHP << matrix.php_major_minor >>-<< matrix.switch_php_version >>"
           docker_image: "datadog/dd-trace-ci:php-<< matrix.php_major_minor >>_buster"
           resource_class: "medium"
+          use_valgrind: true
           matrix:
             parameters:
               php_major_minor:
@@ -4976,7 +4997,7 @@ workflows:
           name: "[Alpine/x86_64] Loader PHP Alpine << matrix.alpine_version >>"
           docker_image: "alpine:<< matrix.alpine_version >>"
           resource_class: "medium"
-          alpine_packages: "php83 php83-dev"
+          alpine_packages: "php83 php83-dev php83-pecl-xdebug"
           matrix:
             parameters:
               alpine_version:
@@ -4990,7 +5011,7 @@ workflows:
           name: "[Alpine/aarch64] Loader PHP Alpine << matrix.alpine_version >>"
           docker_image: "alpine:<< matrix.alpine_version >>"
           resource_class: "arm.medium"
-          alpine_packages: "php83 php83-dev"
+          alpine_packages: "php83 php83-dev php83-pecl-xdebug"
           matrix:
             parameters:
               alpine_version:

loader/compat_php.c

@@ -190,3 +190,14 @@ zval *ddloader_zend_hash_update(HashTable *ht, zend_string *key, zval *pData) {
 
     return NULL;
 }
+
+// From PHP 8.0
+bool ddloader_zend_ini_parse_bool(zend_string *str) {
+	if ((ZSTR_LEN(str) == 4 && strcasecmp(ZSTR_VAL(str), "true") == 0)
+	  || (ZSTR_LEN(str) == 3 && strcasecmp(ZSTR_VAL(str), "yes") == 0)
+	  || (ZSTR_LEN(str) == 2 && strcasecmp(ZSTR_VAL(str), "on") == 0)) {
+		return true;
+	} else {
+		return atoi(ZSTR_VAL(str)) != 0;
+	}
+}

loader/compat_php.h

@@ -10,5 +10,6 @@ zval *ddloader_zend_hash_set_bucket_key(int php_api_no, HashTable *ht, Bucket *b
 void ddloader_replace_zend_error_cb(int php_api_no);
 void ddloader_restore_zend_error_cb();
 zval *ddloader_zend_hash_update(HashTable *ht, zend_string *key, zval *pData);
+bool ddloader_zend_ini_parse_bool(zend_string *str);
 
 #endif /* DD_LIBRARY_LOADER_COMPAT_PHP_H */

loader/dd_library_loader.c

@@ -8,6 +8,7 @@
 #include <php.h>
 #include <php_ini.h>
 #include <stdbool.h>
+#include <main/SAPI.h>
 #include <ext/standard/basic_functions.h>
 
 #include "compat_php.h"
@@ -28,6 +29,8 @@ static bool injection_forced = false;
 # define OS_PATH "linux-gnu/"
 #endif
 
+static void ddloader_telemetryf(telemetry_reason reason, const char *format, ...);
+
 static char *ddtrace_pre_load_hook(void) {
     char *libddtrace_php;
     int res = asprintf(&libddtrace_php, "%s/%sloader/libddtrace_php.so", package_path, OS_PATH);
@@ -60,6 +63,74 @@ static char *ddtrace_pre_load_hook(void) {
     return NULL;
 }
 
+static bool ddloader_is_ext_loaded(const char *name) {
+    return zend_hash_str_find_ptr(&module_registry, name, strlen(name))
+        || zend_get_extension(name)
+    ;
+}
+
+static zval *ddloader_ini_get_configuration(const char *name, size_t name_len) {
+    HashTable *configuration_hash = php_ini_get_configuration_hash();
+    if (!configuration_hash) {
+        return NULL;
+    }
+    zend_string *ini = ddloader_zend_string_init(php_api_no, name, name_len, 1);
+    zval *val = zend_hash_find(configuration_hash, ini);
+    ddloader_zend_string_release(php_api_no, ini);
+
+    return val;
+}
+
+static void ddloader_ini_set_configuration(const char *name, size_t name_len, const char *value, size_t value_len) {
+    HashTable *configuration_hash = php_ini_get_configuration_hash();
+    if (!configuration_hash) {
+        return;
+    }
+
+    zend_string *zstr_name = ddloader_zend_string_init(php_api_no, name, name_len, 1);
+    zend_string *zstr_value = ddloader_zend_string_init(php_api_no, value, value_len, 1);
+
+    zval tmp;
+    ZVAL_STR(&tmp, zstr_value);
+    ddloader_zend_hash_update(configuration_hash, zstr_name, &tmp);
+    ddloader_zend_string_release(php_api_no, zstr_name);
+}
+
+static bool ddloader_is_opcache_jit_enabled() {
+    // JIT is only PHP 8.0+
+    if (php_api_no < 20200930 || !ddloader_is_ext_loaded("Zend OPcache")) {
+        return false;
+    }
+
+    // opcache.enable = false (default: true)
+    zval *opcache_enable = ddloader_ini_get_configuration(ZEND_STRL("opcache.enable"));
+    if (opcache_enable && Z_TYPE_P(opcache_enable) == IS_STRING && !ddloader_zend_ini_parse_bool(Z_STR_P(opcache_enable))) {
+        return false;
+    }
+    if (strcmp("cli", sapi_module.name) == 0) {
+        // opcache.enable_cli = false (default: false)
+        zval *opcache_enable_cli = ddloader_ini_get_configuration(ZEND_STRL("opcache.enable_cli"));
+        if (!opcache_enable_cli || Z_TYPE_P(opcache_enable_cli) != IS_STRING || !ddloader_zend_ini_parse_bool(Z_STR_P(opcache_enable_cli))) {
+            return false;
+        }
+    }
+    if (php_api_no > 20230831) { // PHP > 8.3 (https://php.watch/versions/8.4/opcache-jit-ini-default-changes)
+        // opcache.jit == disable (default: disable)
+        zval *opcache_jit = ddloader_ini_get_configuration(ZEND_STRL("opcache.jit"));
+        if (!opcache_jit || Z_TYPE_P(opcache_jit) != IS_STRING || strcmp(Z_STRVAL_P(opcache_jit), "disable") == 0 || strcmp(Z_STRVAL_P(opcache_jit), "off") == 0) {
+            return false;
+        }
+    } else {
+        // opcache.jit_buffer_size = 0 (default: 0)
+        zval *opcache_jit_buffer_size = ddloader_ini_get_configuration(ZEND_STRL("opcache.jit_buffer_size"));
+        if (!opcache_jit_buffer_size || Z_TYPE_P(opcache_jit_buffer_size) != IS_STRING || strcmp(Z_STRVAL_P(opcache_jit_buffer_size), "0") == 0) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
 static void ddtrace_pre_minit_hook(void) {
     HashTable *configuration_hash = php_ini_get_configuration_hash();
     if (configuration_hash) {
@@ -69,13 +140,36 @@ static void ddtrace_pre_minit_hook(void) {
         }
 
         // Set 'datadog.trace.sources_path' setting
-        zend_string *name = ddloader_zend_string_init(php_api_no, ZEND_STRL("datadog.trace.sources_path"), 1);
-        zend_string *value = ddloader_zend_string_init(php_api_no, sources_path, strlen(sources_path), 1);
+        ddloader_ini_set_configuration(ZEND_STRL("datadog.trace.sources_path"), sources_path, strlen(sources_path));
         free(sources_path);
+    }
 
-        zval tmp;
-        ZVAL_STR(&tmp, value);
-        ddloader_zend_hash_update(configuration_hash, name, &tmp);
+    // Load, but disable the tracer if runtime configuration is not safe for auto-injection
+    bool disable_tracer = false;
+
+    char *incompatible_exts[] = {"Xdebug", "the ionCube PHP Loader", "newrelic", "blackfire", "pcov"};
+    for (size_t i = 0; i < sizeof(incompatible_exts) / sizeof(incompatible_exts[0]); ++i) {
+        if (ddloader_is_ext_loaded(incompatible_exts[i])) {
+            if (force_load) {
+                LOG(WARN, "Potentially incompatible extension detected: %s. Ignoring as DD_INJECT_FORCE is enabled", incompatible_exts[i]);
+            } else {
+                LOG(WARN, "Potentially incompatible extension detected: %s. ddtrace will be disabled unless the environment DD_INJECT_FORCE is set to '1', 'true', 'yes' or 'on'", incompatible_exts[i]);
+                disable_tracer = true;
+            }
+        }
+    }
+
+    if (ddloader_is_opcache_jit_enabled()) {
+        if (force_load) {
+            LOG(WARN, "OPcache JIT is enabled and may cause instability. Ignoring as DD_INJECT_FORCE is enabled");
+        } else {
+            LOG(WARN, "OPcache JIT is enabled and may cause instability. ddtrace will be disabled unless the environment DD_INJECT_FORCE is set to '1', 'true', 'yes' or 'on'");
+            disable_tracer = true;
+        }
+    }
+
+    if (disable_tracer) {
+        ddloader_ini_set_configuration(ZEND_STRL("ddtrace.disable"), ZEND_STRL("1"));
     }
 }
 
@@ -460,26 +554,19 @@ static int ddloader_load_extension(unsigned int php_api_no, char *module_build_i
     config->module_number = module_entry->module_number;
     config->version = (char *)module_entry->version;
 
-    return SUCCESS;
+    goto ok;
 
 abort_and_unload:
     LOG(INFO, "Unloading the library");
     DL_UNLOAD(handle);
 abort:
     LOG(INFO, "Abort the loader");
+ok:
     free(ext_path);
 
     return SUCCESS;
 }
 
-static void ddloader_strtolower(char *dest, char *src) {
-    while (*src) {
-        *dest = (char)tolower((int)*src);
-        ++dest;
-        ++src;
-    }
-}
-
 static bool ddloader_is_truthy(char *str) {
     if (!str) {
         return false;
@@ -490,10 +577,7 @@ static bool ddloader_is_truthy(char *str) {
         return false;
     }
 
-    char lower[5] = {0};
-    ddloader_strtolower(lower, str);
-
-    return (strcmp(lower, "1") == 0 || strcmp(lower, "true") == 0 || strcmp(lower, "yes") == 0 || strcmp(lower, "on") == 0);
+    return (strcasecmp(str, "1") == 0 || strcasecmp(str, "true") == 0 || strcasecmp(str, "yes") == 0 || strcasecmp(str, "on") == 0);
 }
 
 static inline void ddloader_configure() {

loader/php_dd_library_loader.h

@@ -29,10 +29,12 @@ typedef enum {
 
 #define TELEMETRY(reason, format, ...) ddloader_telemetryf(reason, format, ##__VA_ARGS__);
 
-#define DECLARE_INJECTED_EXT(name, dir, _pre_load_hook, _pre_minit_hook, deps)                                                                                                 \
-    {                                                                                                                                               \
-        .ext_name = name, .ext_dir = dir, .tmp_name = name "_injected", .tmp_deps = deps, .pre_load_hook = _pre_load_hook, .pre_minit_hook = _pre_minit_hook, .orig_module_startup_func = NULL, \
-        .orig_module_deps = NULL, .orig_module_functions = NULL, .module_number = -1, .version = NULL                                               \
+#define DECLARE_INJECTED_EXT(name, dir, _pre_load_hook, _pre_minit_hook, deps)                      \
+    {                                                                                               \
+        .ext_name = name, .ext_dir = dir, .tmp_name = name "_injected", .tmp_deps = deps,           \
+        .pre_load_hook = _pre_load_hook, .pre_minit_hook = _pre_minit_hook,                         \
+        .orig_module_startup_func = NULL, .orig_module_deps = NULL, .orig_module_functions = NULL,  \
+        .module_number = -1, .version = NULL                                                        \
     }
 
 typedef struct _injected_ext {

loader/tests/functional/fixtures/opcache_jit.php

@@ -0,0 +1,23 @@
+<?php
+
+function boolstr($bool) {
+    return ($bool ? 'YES' : 'NO');
+}
+
+echo "ddtrace.disable: ".boolstr((bool) ini_get('ddtrace.disable'))."\n";
+
+if (!extension_loaded('Zend OPcache')) {
+    echo "OPcache is not loaded\n";
+    return;
+}
+
+$status = opcache_get_status();
+if ($status === false) {
+    echo "OPcache is disabled\n";
+    return;
+}
+
+echo "opcache_enabled: ".boolstr($status['opcache_enabled'])."\n";
+echo "jit.enabled: ".boolstr($status['jit']['enabled'])."\n";
+echo "jit.on: ".boolstr($status['jit']['on'])."\n";
+echo "jit.buffer_size: ".$status['jit']['buffer_size']."\n";

loader/tests/functional/includes/autoload.php

@@ -2,7 +2,7 @@
 
 require_once __DIR__.'/assert.php';
 
-set_exception_handler(function (\Exception $ex) {
+set_exception_handler(function (\Throwable $ex) {
     $trace = $ex->getTrace();
     $file = $trace[0]['file'] ?: '';
     $line = $trace[0]['line'] ?: '';
@@ -22,8 +22,20 @@ function runCLI($args, $useLoader = true, $env = [], $noIni = true) {
     if (!isset($_SERVER['DD_LOADER_PACKAGE_PATH'])) {
         $env[] = "DD_LOADER_PACKAGE_PATH=/home/circleci/app/dd-library-php";
     }
+
+    $valgrind = use_valgrind();
+    if ($valgrind) {
+        $env[] = 'USE_ZEND_ALLOC=0';
+        $env[] = 'ZEND_DONT_UNLOAD_MODULES=1';
+    }
+
     $cmd = implode(' ', $env).' ';
 
+    $valgrindLogFile = tempnam(sys_get_temp_dir(), 'valgrind_loader_test_');;
+    if ($valgrind) {
+        $cmd .= "valgrind  -q --log-file=$valgrindLogFile --suppressions=./valgrind.supp --gen-suppressions=all --tool=memcheck --trace-children=no --undef-value-errors=no --vex-iropt-register-updates=allregs-at-mem-access --leak-check=full ";
+    }
+
     $cmd .= 'php';
     if ($noIni) {
         $cmd .= ' -n';
@@ -40,10 +52,22 @@ function runCLI($args, $useLoader = true, $env = [], $noIni = true) {
     }
 
     $res = exec($cmd, $output, $result_code);
+
+    if ($valgrind) {
+        $valgrindOutput = file_get_contents($valgrindLogFile);
+        @unlink($valgrindLogFile);
+    }
+
     if (!is_string($res) || $result_code !== 0) {
         throw new \Exception(sprintf('Error while executing "%s" (exit code: %d): \n\n', $cmd, $result_code, $output));
     }
 
+    if ($valgrind) {
+        if (strlen($valgrindOutput)) {
+            throw new \Exception("Memory leak detected:\n".$valgrindOutput);
+        }
+    }
+
     return implode("\n", $output);
 }
 
@@ -55,6 +79,10 @@ function debug() {
     return (bool) (isset($_SERVER['DEBUG']) ? $_SERVER['DEBUG'] : false);
 }
 
+function use_valgrind() {
+    return (bool) (isset($_SERVER['TEST_USE_VALGRIND']) ? $_SERVER['TEST_USE_VALGRIND'] : false);
+}
+
 function skip_if_php5() {
     if (PHP_MAJOR_VERSION <= 5) {
         echo "Skip: test is not compatible with PHP 5\n";
@@ -69,6 +97,13 @@ function skip_if_not_php5() {
     }
 }
 
+function skip_if_not_php8() {
+    if (PHP_MAJOR_VERSION < 8) {
+        echo "Skip: test requires PHP 8\n";
+        exit(0);
+    }
+}
+
 function skip_if_opcache_missing() {
     $output = runCLI('-dzend_extension=opcache -m');
     if (strpos($output, 'Zend OPcache') === false) {