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 //go:cgo_import_static _cgo_init 51 //go:linkname _cgo_init _cgo_init 52 var _cgo_init unsafe.Pointer 53 54 //go:cgo_import_static _cgo_thread_start 55 //go:linkname _cgo_thread_start _cgo_thread_start 56 var _cgo_thread_start unsafe.Pointer 57 58 // Creates a new system thread without updating any Go state. 59 // 60 // This method is invoked during shared library loading to create a new OS 61 // thread to perform the runtime initialization. This method is similar to 62 // x_cgo_thread_start except that it doesn't update any Go state. 63 64 //go:cgo_import_static _cgo_sys_thread_create 65 //go:linkname _cgo_sys_thread_create _cgo_sys_thread_create 66 var _cgo_sys_thread_create unsafe.Pointer 67 68 // Indicates whether a dummy thread key has been created or not. 69 // 70 // When calling go exported function from C, we register a destructor 71 // callback, for a dummy thread key, by using pthread_key_create. 72 73 //go:cgo_import_static x_cgo_pthread_key_created 74 //go:linkname x_cgo_pthread_key_created x_cgo_pthread_key_created 75 //go:linkname _cgo_pthread_key_created _cgo_pthread_key_created 76 var x_cgo_pthread_key_created byte 77 var _cgo_pthread_key_created = &x_cgo_pthread_key_created 78 79 // Export crosscall2 to a c function pointer variable. 80 // Used to dropm in pthread key destructor, while C thread is exiting. 81 82 //go:cgo_import_static x_crosscall2_ptr 83 //go:linkname x_crosscall2_ptr x_crosscall2_ptr 84 //go:linkname _crosscall2_ptr _crosscall2_ptr 85 var x_crosscall2_ptr byte 86 var _crosscall2_ptr = &x_crosscall2_ptr 87 88 // Set the x_crosscall2_ptr C function pointer variable point to crosscall2. 89 // It's for the runtime package to call at init time. 90 func set_crosscall2() 91 92 //go:linkname _set_crosscall2 runtime.set_crosscall2 93 var _set_crosscall2 = set_crosscall2 94 95 // Store the g into the thread-specific value. 96 // So that pthread_key_destructor will dropm when the thread is exiting. 97 98 //go:cgo_import_static _cgo_bindm 99 //go:linkname _cgo_bindm _cgo_bindm 100 var _cgo_bindm unsafe.Pointer 101 102 // Notifies that the runtime has been initialized. 103 // 104 // We currently block at every CGO entry point (via _cgo_wait_runtime_init_done) 105 // to ensure that the runtime has been initialized before the CGO call is 106 // executed. This is necessary for shared libraries where we kickoff runtime 107 // initialization in a separate thread and return without waiting for this 108 // thread to complete the init. 109 110 //go:cgo_import_static x_cgo_notify_runtime_init_done 111 //go:linkname x_cgo_notify_runtime_init_done x_cgo_notify_runtime_init_done 112 //go:linkname _cgo_notify_runtime_init_done _cgo_notify_runtime_init_done 113 var x_cgo_notify_runtime_init_done byte 114 var _cgo_notify_runtime_init_done = &x_cgo_notify_runtime_init_done 115 116 // Sets the traceback, context, and symbolizer functions. See 117 // runtime.SetCgoTraceback. 118 119 //go:cgo_import_static x_cgo_set_traceback_functions 120 //go:linkname x_cgo_set_traceback_functions x_cgo_set_traceback_functions 121 //go:linkname _cgo_set_traceback_functions _cgo_set_traceback_functions 122 var x_cgo_set_traceback_functions byte 123 var _cgo_set_traceback_functions = &x_cgo_set_traceback_functions 124 125 // Call the traceback function registered with x_cgo_set_traceback_functions. 126 127 //go:cgo_import_static x_cgo_call_traceback_function 128 //go:linkname x_cgo_call_traceback_function x_cgo_call_traceback_function 129 //go:linkname _cgo_call_traceback_function _cgo_call_traceback_function 130 var x_cgo_call_traceback_function byte 131 var _cgo_call_traceback_function = &x_cgo_call_traceback_function 132 133 // Call the symbolizer function registered with x_cgo_set_symbolizer_functions. 134 135 //go:cgo_import_static x_cgo_call_symbolizer_function 136 //go:linkname x_cgo_call_symbolizer_function x_cgo_call_symbolizer_function 137 //go:linkname _cgo_call_symbolizer_function _cgo_call_symbolizer_function 138 var x_cgo_call_symbolizer_function byte 139 var _cgo_call_symbolizer_function = &x_cgo_call_symbolizer_function 140 141 // Calls a libc function to execute background work injected via libc 142 // interceptors, such as processing pending signals under the thread 143 // sanitizer. 144 // 145 // Left as a nil pointer if no libc interceptors are expected. 146 147 //go:cgo_import_static _cgo_yield 148 //go:linkname _cgo_yield _cgo_yield 149 var _cgo_yield unsafe.Pointer 150 151 //go:cgo_export_static _cgo_topofstack 152 //go:cgo_export_dynamic _cgo_topofstack 153 154 // x_cgo_getstackbound gets the thread's C stack size and 155 // set the G's stack bound based on the stack size. 156 157 //go:cgo_import_static _cgo_getstackbound 158 //go:linkname _cgo_getstackbound _cgo_getstackbound 159 var _cgo_getstackbound unsafe.Pointer 160