handle host detector with custom error handler and open_basedir (#1454)

if open_basedir is configured such that files that it tries to open are denied with a php warning, and
a custom error handler is installed which converts warnings to exceptions, an unhandled exception occurs.
add a test for this, suppress error handling around the code that can trigger this.

Author: brettmc

src/SDK/Resource/Detectors/Host.php

@@ -47,16 +47,32 @@ private function getMachineId(): ?string
         };
     }
 
+    /**
+     * @phan-suppress PhanTypeMismatchArgumentInternal
+     */
+    private function readFile(string $file): string|false
+    {
+        set_error_handler(static fn () => true);
+
+        try {
+            $contents = file_get_contents($file);
+
+            return $contents !== false ? trim($contents) : false;
+        } finally {
+            restore_error_handler();
+        }
+    }
+
     private function getLinuxId(): ?string
     {
         $paths = [self::PATH_ETC_MACHINEID, self::PATH_VAR_LIB_DBUS_MACHINEID];
 
         foreach ($paths as $path) {
             $file = $this->dir . $path;
-            if (is_file($file) && is_readable($file)) {
-                $contents = file_get_contents($file);
 
-                return $contents !== false ? trim($contents) : null;
+            $contents = $this->readFile($file);
+            if ($contents !== false) {
+                return $contents;
             }
         }
 
@@ -66,10 +82,10 @@ private function getLinuxId(): ?string
     private function getBsdId(): ?string
     {
         $file = $this->dir . self::PATH_ETC_HOSTID;
-        if (is_file($file) && is_readable($file)) {
-            $contents = file_get_contents($file);
 
-            return $contents !== false ? trim($contents) : null;
+        $contents = $this->readFile($file);
+        if ($contents !== false) {
+            return $contents;
         }
 
         $out = exec('which kenv && kenv -q smbios.system.uuid');

tests/Integration/SDK/Resource/Detectors/test_host_detector_with_open_basedir.phpt

@@ -0,0 +1,32 @@
+--TEST--
+Host detector with custom error handler and open_basedir
+--DESCRIPTION--
+An error handler is installed which converts PHP warnings to exceptions, and open_basedir
+is configured such that /etc/machine-id and friends cannot be read
+--SKIPIF--
+<?php if (!in_array(PHP_OS_FAMILY, ['Linux', 'BSD'])) die('skip requires Linux or BSD'); ?>
+--INI--
+open_basedir=${PWD}
+--FILE--
+<?php
+use OpenTelemetry\SDK\Resource\Detectors\Host;
+
+require_once 'vendor/autoload.php';
+
+function warningToException($errno, $errstr, $errfile, $errline)
+{
+    throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
+}
+set_error_handler('warningToException');
+
+$detector = new Host();
+$resource = $detector->getResource();
+var_dump($resource->getAttributes()->toArray());
+?>
+--EXPECTF--
+array(2) {
+  ["host.name"]=>
+  string(%d) "%s"
+  ["host.arch"]=>
+  string(%d) "%s"
+}