1 | |
2 | /* Readline interface for tokenizer.c and [raw_]input() in bltinmodule.c. |
3 | By default, or when stdin is not a tty device, we have a super |
4 | simple my_readline function using fgets. |
5 | Optionally, we can use the GNU readline library. |
6 | my_readline() has a different return value from GNU readline(): |
7 | - NULL if an interrupt occurred or if an error occurred |
8 | - a malloc'ed empty string if EOF was read |
9 | - a malloc'ed string ending in \n normally |
10 | */ |
11 | |
12 | #include "Python.h" |
13 | #include "pycore_pystate.h" // _PyThreadState_GET() |
14 | #ifdef MS_WINDOWS |
15 | # define WIN32_LEAN_AND_MEAN |
16 | # include "windows.h" |
17 | #endif /* MS_WINDOWS */ |
18 | |
19 | |
20 | PyThreadState* _PyOS_ReadlineTState = NULL; |
21 | |
22 | static PyThread_type_lock _PyOS_ReadlineLock = NULL; |
23 | |
24 | int (*PyOS_InputHook)(void) = NULL; |
25 | |
26 | /* This function restarts a fgets() after an EINTR error occurred |
27 | except if _PyOS_InterruptOccurred() returns true. */ |
28 | |
29 | static int |
30 | my_fgets(PyThreadState* tstate, char *buf, int len, FILE *fp) |
31 | { |
32 | #ifdef MS_WINDOWS |
33 | HANDLE handle; |
34 | _Py_BEGIN_SUPPRESS_IPH |
35 | handle = (HANDLE)_get_osfhandle(fileno(fp)); |
36 | _Py_END_SUPPRESS_IPH |
37 | |
38 | /* bpo-40826: fgets(fp) does crash if fileno(fp) is closed */ |
39 | if (handle == INVALID_HANDLE_VALUE) { |
40 | return -1; /* EOF */ |
41 | } |
42 | #endif |
43 | |
44 | while (1) { |
45 | if (PyOS_InputHook != NULL) { |
46 | (void)(PyOS_InputHook)(); |
47 | } |
48 | |
49 | errno = 0; |
50 | clearerr(fp); |
51 | char *p = fgets(buf, len, fp); |
52 | if (p != NULL) { |
53 | return 0; /* No error */ |
54 | } |
55 | int err = errno; |
56 | |
57 | #ifdef MS_WINDOWS |
58 | /* Ctrl-C anywhere on the line or Ctrl-Z if the only character |
59 | on a line will set ERROR_OPERATION_ABORTED. Under normal |
60 | circumstances Ctrl-C will also have caused the SIGINT handler |
61 | to fire which will have set the event object returned by |
62 | _PyOS_SigintEvent. This signal fires in another thread and |
63 | is not guaranteed to have occurred before this point in the |
64 | code. |
65 | |
66 | Therefore: check whether the event is set with a small timeout. |
67 | If it is, assume this is a Ctrl-C and reset the event. If it |
68 | isn't set assume that this is a Ctrl-Z on its own and drop |
69 | through to check for EOF. |
70 | */ |
71 | if (GetLastError()==ERROR_OPERATION_ABORTED) { |
72 | HANDLE hInterruptEvent = _PyOS_SigintEvent(); |
73 | switch (WaitForSingleObjectEx(hInterruptEvent, 10, FALSE)) { |
74 | case WAIT_OBJECT_0: |
75 | ResetEvent(hInterruptEvent); |
76 | return 1; /* Interrupt */ |
77 | case WAIT_FAILED: |
78 | return -2; /* Error */ |
79 | } |
80 | } |
81 | #endif /* MS_WINDOWS */ |
82 | |
83 | if (feof(fp)) { |
84 | clearerr(fp); |
85 | return -1; /* EOF */ |
86 | } |
87 | |
88 | #ifdef EINTR |
89 | if (err == EINTR) { |
90 | PyEval_RestoreThread(tstate); |
91 | int s = PyErr_CheckSignals(); |
92 | PyEval_SaveThread(); |
93 | |
94 | if (s < 0) { |
95 | return 1; |
96 | } |
97 | /* try again */ |
98 | continue; |
99 | } |
100 | #endif |
101 | |
102 | if (_PyOS_InterruptOccurred(tstate)) { |
103 | return 1; /* Interrupt */ |
104 | } |
105 | return -2; /* Error */ |
106 | } |
107 | /* NOTREACHED */ |
108 | } |
109 | |
110 | #ifdef MS_WINDOWS |
111 | /* Readline implementation using ReadConsoleW */ |
112 | |
113 | extern char _get_console_type(HANDLE handle); |
114 | |
115 | char * |
116 | _PyOS_WindowsConsoleReadline(PyThreadState *tstate, HANDLE hStdIn) |
117 | { |
118 | static wchar_t wbuf_local[1024 * 16]; |
119 | const DWORD chunk_size = 1024; |
120 | |
121 | DWORD n_read, total_read, wbuflen, u8len; |
122 | wchar_t *wbuf; |
123 | char *buf = NULL; |
124 | int err = 0; |
125 | |
126 | n_read = (DWORD)-1; |
127 | total_read = 0; |
128 | wbuf = wbuf_local; |
129 | wbuflen = sizeof(wbuf_local) / sizeof(wbuf_local[0]) - 1; |
130 | while (1) { |
131 | if (PyOS_InputHook != NULL) { |
132 | (void)(PyOS_InputHook)(); |
133 | } |
134 | if (!ReadConsoleW(hStdIn, &wbuf[total_read], wbuflen - total_read, &n_read, NULL)) { |
135 | err = GetLastError(); |
136 | goto exit; |
137 | } |
138 | if (n_read == (DWORD)-1 && (err = GetLastError()) == ERROR_OPERATION_ABORTED) { |
139 | break; |
140 | } |
141 | if (n_read == 0) { |
142 | int s; |
143 | err = GetLastError(); |
144 | if (err != ERROR_OPERATION_ABORTED) |
145 | goto exit; |
146 | err = 0; |
147 | HANDLE hInterruptEvent = _PyOS_SigintEvent(); |
148 | if (WaitForSingleObjectEx(hInterruptEvent, 100, FALSE) |
149 | == WAIT_OBJECT_0) { |
150 | ResetEvent(hInterruptEvent); |
151 | PyEval_RestoreThread(tstate); |
152 | s = PyErr_CheckSignals(); |
153 | PyEval_SaveThread(); |
154 | if (s < 0) { |
155 | goto exit; |
156 | } |
157 | } |
158 | break; |
159 | } |
160 | |
161 | total_read += n_read; |
162 | if (total_read == 0 || wbuf[total_read - 1] == L'\n') { |
163 | break; |
164 | } |
165 | wbuflen += chunk_size; |
166 | if (wbuf == wbuf_local) { |
167 | wbuf[total_read] = '\0'; |
168 | wbuf = (wchar_t*)PyMem_RawMalloc(wbuflen * sizeof(wchar_t)); |
169 | if (wbuf) { |
170 | wcscpy_s(wbuf, wbuflen, wbuf_local); |
171 | } |
172 | else { |
173 | PyEval_RestoreThread(tstate); |
174 | PyErr_NoMemory(); |
175 | PyEval_SaveThread(); |
176 | goto exit; |
177 | } |
178 | } |
179 | else { |
180 | wchar_t *tmp = PyMem_RawRealloc(wbuf, wbuflen * sizeof(wchar_t)); |
181 | if (tmp == NULL) { |
182 | PyEval_RestoreThread(tstate); |
183 | PyErr_NoMemory(); |
184 | PyEval_SaveThread(); |
185 | goto exit; |
186 | } |
187 | wbuf = tmp; |
188 | } |
189 | } |
190 | |
191 | if (wbuf[0] == '\x1a') { |
192 | buf = PyMem_RawMalloc(1); |
193 | if (buf) { |
194 | buf[0] = '\0'; |
195 | } |
196 | else { |
197 | PyEval_RestoreThread(tstate); |
198 | PyErr_NoMemory(); |
199 | PyEval_SaveThread(); |
200 | } |
201 | goto exit; |
202 | } |
203 | |
204 | u8len = WideCharToMultiByte(CP_UTF8, 0, |
205 | wbuf, total_read, |
206 | NULL, 0, |
207 | NULL, NULL); |
208 | buf = PyMem_RawMalloc(u8len + 1); |
209 | if (buf == NULL) { |
210 | PyEval_RestoreThread(tstate); |
211 | PyErr_NoMemory(); |
212 | PyEval_SaveThread(); |
213 | goto exit; |
214 | } |
215 | |
216 | u8len = WideCharToMultiByte(CP_UTF8, 0, |
217 | wbuf, total_read, |
218 | buf, u8len, |
219 | NULL, NULL); |
220 | buf[u8len] = '\0'; |
221 | |
222 | exit: |
223 | if (wbuf != wbuf_local) { |
224 | PyMem_RawFree(wbuf); |
225 | } |
226 | |
227 | if (err) { |
228 | PyEval_RestoreThread(tstate); |
229 | PyErr_SetFromWindowsErr(err); |
230 | PyEval_SaveThread(); |
231 | } |
232 | return buf; |
233 | } |
234 | |
235 | #endif |
236 | |
237 | |
238 | /* Readline implementation using fgets() */ |
239 | |
240 | char * |
241 | PyOS_StdioReadline(FILE *sys_stdin, FILE *sys_stdout, const char *prompt) |
242 | { |
243 | size_t n; |
244 | char *p, *pr; |
245 | PyThreadState *tstate = _PyOS_ReadlineTState; |
246 | assert(tstate != NULL); |
247 | |
248 | #ifdef MS_WINDOWS |
249 | if (!Py_LegacyWindowsStdioFlag && sys_stdin == stdin) { |
250 | HANDLE hStdIn, hStdErr; |
251 | |
252 | hStdIn = _Py_get_osfhandle_noraise(fileno(sys_stdin)); |
253 | hStdErr = _Py_get_osfhandle_noraise(fileno(stderr)); |
254 | |
255 | if (_get_console_type(hStdIn) == 'r') { |
256 | fflush(sys_stdout); |
257 | if (prompt) { |
258 | if (_get_console_type(hStdErr) == 'w') { |
259 | wchar_t *wbuf; |
260 | int wlen; |
261 | wlen = MultiByteToWideChar(CP_UTF8, 0, prompt, -1, |
262 | NULL, 0); |
263 | if (wlen) { |
264 | wbuf = PyMem_RawMalloc(wlen * sizeof(wchar_t)); |
265 | if (wbuf == NULL) { |
266 | PyEval_RestoreThread(tstate); |
267 | PyErr_NoMemory(); |
268 | PyEval_SaveThread(); |
269 | return NULL; |
270 | } |
271 | wlen = MultiByteToWideChar(CP_UTF8, 0, prompt, -1, |
272 | wbuf, wlen); |
273 | if (wlen) { |
274 | DWORD n; |
275 | fflush(stderr); |
276 | /* wlen includes null terminator, so subtract 1 */ |
277 | WriteConsoleW(hStdErr, wbuf, wlen - 1, &n, NULL); |
278 | } |
279 | PyMem_RawFree(wbuf); |
280 | } |
281 | } else { |
282 | fprintf(stderr, "%s" , prompt); |
283 | fflush(stderr); |
284 | } |
285 | } |
286 | clearerr(sys_stdin); |
287 | return _PyOS_WindowsConsoleReadline(tstate, hStdIn); |
288 | } |
289 | } |
290 | #endif |
291 | |
292 | fflush(sys_stdout); |
293 | if (prompt) { |
294 | fprintf(stderr, "%s" , prompt); |
295 | } |
296 | fflush(stderr); |
297 | |
298 | n = 0; |
299 | p = NULL; |
300 | do { |
301 | size_t incr = (n > 0) ? n + 2 : 100; |
302 | if (incr > INT_MAX) { |
303 | PyMem_RawFree(p); |
304 | PyEval_RestoreThread(tstate); |
305 | PyErr_SetString(PyExc_OverflowError, "input line too long" ); |
306 | PyEval_SaveThread(); |
307 | return NULL; |
308 | } |
309 | pr = (char *)PyMem_RawRealloc(p, n + incr); |
310 | if (pr == NULL) { |
311 | PyMem_RawFree(p); |
312 | PyEval_RestoreThread(tstate); |
313 | PyErr_NoMemory(); |
314 | PyEval_SaveThread(); |
315 | return NULL; |
316 | } |
317 | p = pr; |
318 | int err = my_fgets(tstate, p + n, (int)incr, sys_stdin); |
319 | if (err == 1) { |
320 | // Interrupt |
321 | PyMem_RawFree(p); |
322 | return NULL; |
323 | } else if (err != 0) { |
324 | // EOF or error |
325 | p[n] = '\0'; |
326 | break; |
327 | } |
328 | n += strlen(p + n); |
329 | } while (p[n-1] != '\n'); |
330 | |
331 | pr = (char *)PyMem_RawRealloc(p, n+1); |
332 | if (pr == NULL) { |
333 | PyMem_RawFree(p); |
334 | PyEval_RestoreThread(tstate); |
335 | PyErr_NoMemory(); |
336 | PyEval_SaveThread(); |
337 | return NULL; |
338 | } |
339 | return pr; |
340 | } |
341 | |
342 | |
343 | /* By initializing this function pointer, systems embedding Python can |
344 | override the readline function. |
345 | |
346 | Note: Python expects in return a buffer allocated with PyMem_Malloc. */ |
347 | |
348 | char *(*PyOS_ReadlineFunctionPointer)(FILE *, FILE *, const char *) = NULL; |
349 | |
350 | |
351 | /* Interface used by tokenizer.c and bltinmodule.c */ |
352 | |
353 | char * |
354 | PyOS_Readline(FILE *sys_stdin, FILE *sys_stdout, const char *prompt) |
355 | { |
356 | char *rv, *res; |
357 | size_t len; |
358 | |
359 | PyThreadState *tstate = _PyThreadState_GET(); |
360 | if (_PyOS_ReadlineTState == tstate) { |
361 | PyErr_SetString(PyExc_RuntimeError, |
362 | "can't re-enter readline" ); |
363 | return NULL; |
364 | } |
365 | |
366 | |
367 | if (PyOS_ReadlineFunctionPointer == NULL) { |
368 | PyOS_ReadlineFunctionPointer = PyOS_StdioReadline; |
369 | } |
370 | |
371 | if (_PyOS_ReadlineLock == NULL) { |
372 | _PyOS_ReadlineLock = PyThread_allocate_lock(); |
373 | if (_PyOS_ReadlineLock == NULL) { |
374 | PyErr_SetString(PyExc_MemoryError, "can't allocate lock" ); |
375 | return NULL; |
376 | } |
377 | } |
378 | |
379 | _PyOS_ReadlineTState = tstate; |
380 | Py_BEGIN_ALLOW_THREADS |
381 | PyThread_acquire_lock(_PyOS_ReadlineLock, 1); |
382 | |
383 | /* This is needed to handle the unlikely case that the |
384 | * interpreter is in interactive mode *and* stdin/out are not |
385 | * a tty. This can happen, for example if python is run like |
386 | * this: python -i < test1.py |
387 | */ |
388 | if (!isatty (fileno (sys_stdin)) || !isatty (fileno (sys_stdout))) |
389 | rv = PyOS_StdioReadline (sys_stdin, sys_stdout, prompt); |
390 | else |
391 | rv = (*PyOS_ReadlineFunctionPointer)(sys_stdin, sys_stdout, |
392 | prompt); |
393 | Py_END_ALLOW_THREADS |
394 | |
395 | PyThread_release_lock(_PyOS_ReadlineLock); |
396 | |
397 | _PyOS_ReadlineTState = NULL; |
398 | |
399 | if (rv == NULL) |
400 | return NULL; |
401 | |
402 | len = strlen(rv) + 1; |
403 | res = PyMem_Malloc(len); |
404 | if (res != NULL) { |
405 | memcpy(res, rv, len); |
406 | } |
407 | else { |
408 | PyErr_NoMemory(); |
409 | } |
410 | PyMem_RawFree(rv); |
411 | |
412 | return res; |
413 | } |
414 | |