Logs extend invalid schedule delay tests (#3812)

Author: MPSAJID

sdk/src/common/env_variables.cc

@@ -97,7 +97,14 @@ static bool GetTimeoutFromString(const char *input, std::chrono::system_clock::d
 
   for (; *input && std::isdigit(*input); ++input)
   {
-    result = result * 10 + (*input - '0');
+    auto digit = (*input - '0');
+
+    if (result > (std::numeric_limits<decltype(result)>::max() - digit) / 10)
+    {
+      // Rejecting overflow as invalid.
+      return false;
+    }
+    result = result * 10 + digit;
   }
 
   if (result == 0)

sdk/test/logs/batch_log_record_processor_test.cc

@@ -407,6 +407,34 @@ TEST_F(BatchLogRecordProcessorTest, TestScheduleDelayInvalidValueFromEnv)
   unsetenv("OTEL_BLRP_SCHEDULE_DELAY");
 }
 
+TEST_F(BatchLogRecordProcessorTest, TestScheduleDelayInvalidEdgeCasesFromEnv)
+{
+  struct TestCase
+  {
+    const char *value;
+    const char *description;
+  };
+
+  const std::vector<TestCase> cases = {
+      {"-5ms", "negative duration"},
+      {"0ms", "zero duration"},
+      {"999999999999999999999s", "overflow"},
+      {"", "empty string"},
+  };
+
+  for (const auto &tc : cases)
+  {
+    setenv("OTEL_BLRP_SCHEDULE_DELAY", tc.value, 1);
+
+    BatchLogRecordProcessorOptions options;
+
+    EXPECT_EQ(options.schedule_delay_millis, std::chrono::milliseconds(1000))
+        << "Failed for case: " << tc.description << " (value='" << tc.value << "')";
+
+    unsetenv("OTEL_BLRP_SCHEDULE_DELAY");
+  }
+}
+
 TEST_F(BatchLogRecordProcessorTest, TestExportTimeoutFromEnv)
 {
   setenv("OTEL_BLRP_EXPORT_TIMEOUT", "250ms", 1);