[ci] Changed use of strcpy to snprintf (fixes #1990) (#2973)

* [ci] Changed use of strcpy to snprintf

* fix

* fully enable cpplint

.ci/test.sh

@@ -56,7 +56,7 @@ if [[ $TRAVIS == "true" ]] && [[ $TASK == "lint" ]]; then
     echo "Linting R code"
     Rscript ${BUILD_DIRECTORY}/.ci/lint_r_code.R ${BUILD_DIRECTORY} || exit -1
     echo "Linting C++ code"
-    cpplint --filter=-build/c++11,-build/include_subdir,-build/header_guard,-whitespace/line_length --recursive ./src ./include || exit 0
+    cpplint --filter=-build/c++11,-build/include_subdir,-build/header_guard,-whitespace/line_length --recursive ./src ./include || exit -1
     exit 0
 fi
 

include/LightGBM/c_api.h

@@ -16,6 +16,7 @@
 #include <LightGBM/export.h>
 
 #include <cstdint>
+#include <cstdio>
 #include <cstring>
 
 
@@ -1074,7 +1075,8 @@ static char* LastErrorMsg() { static THREAD_LOCAL char err_msg[512] = "Everythin
  * \param msg Error message
  */
 inline void LGBM_SetLastError(const char* msg) {
-  std::strcpy(LastErrorMsg(), msg);
+  const int err_buf_len = 512;
+  snprintf(LastErrorMsg(), err_buf_len, "%s", msg);
 }
 
 #endif  // LIGHTGBM_C_API_H_