go-ceph/internal/dlsym/dlsym.go

42 lines
1.0 KiB
Go

package dlsym
// #cgo LDFLAGS: -ldl
//
// #include <stdlib.h>
// #include <dlfcn.h>
//
// #ifndef RTLD_DEFAULT /* from dlfcn.h */
// #define RTLD_DEFAULT ((void *) 0)
// #endif
import "C"
import (
"errors"
"fmt"
"unsafe"
)
// ErrUndefinedSymbol is returned by LookupSymbol when the requested symbol
// could not be found.
var ErrUndefinedSymbol = errors.New("symbol not found")
// LookupSymbol resolves the named symbol from the already dynamically loaded
// libraries. If the symbol is found, a pointer to it is returned, in case of a
// failure, the message provided by dlerror() is included in the error message.
func LookupSymbol(symbol string) (unsafe.Pointer, error) {
cSymName := C.CString(symbol)
defer C.free(unsafe.Pointer(cSymName))
// clear dlerror before looking up the symbol
C.dlerror()
// resolve the address of the symbol
sym := C.dlsym(C.RTLD_DEFAULT, cSymName)
e := C.dlerror()
dlerr := C.GoString(e)
if dlerr != "" {
return nil, fmt.Errorf("%w: %s", ErrUndefinedSymbol, dlerr)
}
return sym, nil
}