diff options
Diffstat (limited to 'src/dl/dlfcn.go')
| -rw-r--r-- | src/dl/dlfcn.go | 62 |
1 files changed, 51 insertions, 11 deletions
diff --git a/src/dl/dlfcn.go b/src/dl/dlfcn.go index d5467f3..3ab5abb 100644 --- a/src/dl/dlfcn.go +++ b/src/dl/dlfcn.go @@ -1,3 +1,25 @@ +// Copyright 2015 Luke Shumaker <lukeshu@sbcglobal.net>. +// +// This is free software; you can redistribute it and/or +// modify it under the terms of the GNU General Public License as +// published by the Free Software Foundation; either version 2 of +// the License, or (at your option) any later version. +// +// The GNU General Public License's references to "object code" and +// "executables" are to be interpreted to also include the output of +// any document formatting or typesetting system, including +// intermediate and printed output. +// +// This software is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public +// License along with this manual; if not, see +// <http://www.gnu.org/licenses/>. + +// Package dl provides an interface to the POSIX runtime linker. package dl import ( @@ -12,26 +34,39 @@ import "C" type Flag int +// POSIX specifies these four flags to Open(). const ( - RTLD_LAZY Flag = C.RTLD_LAZY // Relocations are performed at an - // implementation-defined time. - RTLD_NOW Flag = C.RTLD_NOW // Relocations are performed when the - // object is loaded. - RTLD_GLOBAL Flag = C.RTLD_GLOBAL // All symbols are available for - // relocation processing of other - // modules. - RTLD_LOCAL Flag = C.RTLD_LOCAL // All symbols are not made available - // for relocation processing by other - // modules. + // Relocations are performed at an implementation-defined + // time. + RTLD_LAZY Flag = C.RTLD_LAZY + + // Relocations are performed when the object is loaded. + RTLD_NOW Flag = C.RTLD_NOW + + // All symbols are available for relocation processing of + // other modules. + RTLD_GLOBAL Flag = C.RTLD_GLOBAL + + // All symbols are not made available for relocation + // processing by other modules. + RTLD_LOCAL Flag = C.RTLD_LOCAL ) type Handle struct { c unsafe.Pointer } +// Open a shared object file, returning a Handle to it, or an error. +// If name is an empty string, then the returned handle is the global +// symbol table for the current process; if the name contains a slash, +// then it is interpretted as a pathname; otherwise, it is +// interpretted in an implementation-defined manner. func Open(name string, flags Flag) (Handle, error) { nameC := C.CString(name) defer C.free(unsafe.Pointer(nameC)) + if name == "" { + nameC = nil + } dlerror() ptr := C.dlopen(nameC, C.int(flags)) @@ -41,8 +76,10 @@ func Open(name string, flags Flag) (Handle, error) { return Handle{ptr}, nil } +// Look up a symbol, and return a pointer to it. +// // This returns uintptr instead of unsafe.Pointer so that code using -// reflect cannot obtain unsafe.Pointers without importing the unsafe +// dl cannot obtain unsafe.Pointers without importing the unsafe // package explicitly. func (h Handle) Sym(symbol string) (uintptr, error) { symbolC := C.CString(symbol) @@ -56,6 +93,9 @@ func (h Handle) Sym(symbol string) (uintptr, error) { return uintptr(ptr), nil } +// Close this handle on a shared object; decrementint the reference +// count; if the reference count drops below 0, then the object is +// unloaded. func (h Handle) Close() error { dlerror() r := C.dlclose(h.c) |