1 // Copyright 2015 CoreOS, Inc. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 // 15 //go:build linux 16 // +build linux 17 18 package dlopen 19 20 // #include <string.h> 21 // #include <stdlib.h> 22 // 23 // int 24 // my_strlen(void *f, const char *s) 25 // { 26 // size_t (*strlen)(const char *); 27 // 28 // strlen = (size_t (*)(const char *))f; 29 // return strlen(s); 30 // } 31 import "C" 32 33 import ( 34 "fmt" 35 "unsafe" 36 ) 37 38 func strlen(libs []string, s string) (int, error) { 39 h, err := GetHandle(libs) 40 if err != nil { 41 return -1, fmt.Errorf(`couldn't get a handle to the library: %v`, err) 42 } 43 defer h.Close() 44 45 f := "strlen" 46 cs := C.CString(s) 47 defer C.free(unsafe.Pointer(cs)) 48 49 strlen, err := h.GetSymbolPointer(f) 50 if err != nil { 51 return -1, fmt.Errorf(`couldn't get symbol %q: %v`, f, err) 52 } 53 54 len := C.my_strlen(strlen, cs) 55 56 return int(len), nil 57 } 58