Source file src/runtime/cgo/callbacks.go
1 // Copyright 2011 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package cgo 6 7 import "unsafe" 8 9 // These utility functions are available to be called from code 10 // compiled with gcc via crosscall2. 11 12 // The declaration of crosscall2 is: 13 // void crosscall2(void (*fn)(void *), void *, int); 14 // 15 // We need to export the symbol crosscall2 in order to support 16 // callbacks from shared libraries. This applies regardless of 17 // linking mode. 18 // 19 // Compatibility note: SWIG uses crosscall2 in exactly one situation: 20 // to call _cgo_panic using the pattern shown below. We need to keep 21 // that pattern working. In particular, crosscall2 actually takes four 22 // arguments, but it works to call it with three arguments when 23 // calling _cgo_panic. 24 // 25 //go:cgo_export_static crosscall2 26 //go:cgo_export_dynamic crosscall2 27 28 // Panic. The argument is converted into a Go string. 29 30 // Call like this in code compiled with gcc: 31 // struct { const char *p; } a; 32 // a.p = /* string to pass to panic */; 33 // crosscall2(_cgo_panic, &a, sizeof a); 34 // /* The function call will not return. */ 35 36 // TODO: We should export a regular C function to panic, change SWIG 37 // to use that instead of the above pattern, and then we can drop 38 // backwards-compatibility from crosscall2 and stop exporting it. 39 40 //go:linkname _runtime_cgo_panic_internal runtime._cgo_panic_internal 41 func _runtime_cgo_panic_internal(p *byte) 42 43 //go:linkname _cgo_panic _cgo_panic 44 //go:cgo_export_static _cgo_panic 45 //go:cgo_export_dynamic _cgo_panic 46 func _cgo_panic(a *struct{ cstr *byte }) { 47 _runtime_cgo_panic_internal(a.cstr) 48 } 49 50 // Indicates whether a dummy thread key has been created or not. 51 // 52 // When calling go exported function from C, we register a destructor 53 // callback, for a dummy thread key, by using pthread_key_create. 54 55 //go:cgo_import_static x_cgo_pthread_key_created 56 //go:linkname x_cgo_pthread_key_created x_cgo_pthread_key_created 57 //go:linkname _cgo_pthread_key_created _cgo_pthread_key_created 58 var x_cgo_pthread_key_created byte 59 var _cgo_pthread_key_created = &x_cgo_pthread_key_created 60 61 // Export crosscall2 to a c function pointer variable. 62 // Used to dropm in pthread key destructor, while C thread is exiting. 63 64 //go:cgo_import_static x_crosscall2_ptr 65 //go:linkname x_crosscall2_ptr x_crosscall2_ptr 66 //go:linkname _crosscall2_ptr _crosscall2_ptr 67 var x_crosscall2_ptr byte 68 var _crosscall2_ptr = &x_crosscall2_ptr 69 70 // Set the x_crosscall2_ptr C function pointer variable point to crosscall2. 71 // It's for the runtime package to call at init time. 72 func set_crosscall2() 73 74 //go:linkname _set_crosscall2 runtime.set_crosscall2 75 var _set_crosscall2 = set_crosscall2 76 77 // Notifies that the runtime has been initialized. 78 // 79 // We currently block at every CGO entry point (via _cgo_wait_runtime_init_done) 80 // to ensure that the runtime has been initialized before the CGO call is 81 // executed. This is necessary for shared libraries where we kickoff runtime 82 // initialization in a separate thread and return without waiting for this 83 // thread to complete the init. 84 85 //go:cgo_import_static x_cgo_notify_runtime_init_done 86 //go:linkname x_cgo_notify_runtime_init_done x_cgo_notify_runtime_init_done 87 //go:linkname _cgo_notify_runtime_init_done _cgo_notify_runtime_init_done 88 var x_cgo_notify_runtime_init_done byte 89 var _cgo_notify_runtime_init_done = &x_cgo_notify_runtime_init_done 90 91 // Sets the traceback, context, and symbolizer functions. See 92 // runtime.SetCgoTraceback. 93 94 //go:cgo_import_static x_cgo_set_traceback_functions 95 //go:linkname x_cgo_set_traceback_functions x_cgo_set_traceback_functions 96 //go:linkname _cgo_set_traceback_functions _cgo_set_traceback_functions 97 var x_cgo_set_traceback_functions byte 98 var _cgo_set_traceback_functions = &x_cgo_set_traceback_functions 99 100 // Call the traceback function registered with x_cgo_set_traceback_functions. 101 102 //go:cgo_import_static x_cgo_call_traceback_function 103 //go:linkname x_cgo_call_traceback_function x_cgo_call_traceback_function 104 //go:linkname _cgo_call_traceback_function _cgo_call_traceback_function 105 var x_cgo_call_traceback_function byte 106 var _cgo_call_traceback_function = &x_cgo_call_traceback_function 107 108 // Call the symbolizer function registered with x_cgo_set_symbolizer_functions. 109 110 //go:cgo_import_static x_cgo_call_symbolizer_function 111 //go:linkname x_cgo_call_symbolizer_function x_cgo_call_symbolizer_function 112 //go:linkname _cgo_call_symbolizer_function _cgo_call_symbolizer_function 113 var x_cgo_call_symbolizer_function byte 114 var _cgo_call_symbolizer_function = &x_cgo_call_symbolizer_function 115 116 // Calls a libc function to execute background work injected via libc 117 // interceptors, such as processing pending signals under the thread 118 // sanitizer. 119 // 120 // Left as a nil pointer if no libc interceptors are expected. 121 122 //go:cgo_import_static _cgo_yield 123 //go:linkname _cgo_yield _cgo_yield 124 var _cgo_yield unsafe.Pointer 125 126 //go:cgo_export_static _cgo_topofstack 127 //go:cgo_export_dynamic _cgo_topofstack 128