Line data Source code
1 : /*
2 : * PL/Python main entry points
3 : *
4 : * src/pl/plpython/plpy_main.c
5 : */
6 :
7 : #include "postgres.h"
8 :
9 : #include "access/htup_details.h"
10 : #include "catalog/pg_proc.h"
11 : #include "catalog/pg_type.h"
12 : #include "commands/trigger.h"
13 : #include "executor/spi.h"
14 : #include "miscadmin.h"
15 : #include "plpy_elog.h"
16 : #include "plpy_exec.h"
17 : #include "plpy_main.h"
18 : #include "plpy_plpymodule.h"
19 : #include "plpy_procedure.h"
20 : #include "plpy_subxactobject.h"
21 : #include "plpython.h"
22 : #include "utils/guc.h"
23 : #include "utils/memutils.h"
24 : #include "utils/rel.h"
25 : #include "utils/syscache.h"
26 :
27 : /*
28 : * exported functions
29 : */
30 :
31 46 : PG_MODULE_MAGIC;
32 :
33 52 : PG_FUNCTION_INFO_V1(plpython3_validator);
34 52 : PG_FUNCTION_INFO_V1(plpython3_call_handler);
35 16 : PG_FUNCTION_INFO_V1(plpython3_inline_handler);
36 :
37 :
38 : static bool PLy_procedure_is_trigger(Form_pg_proc procStruct);
39 : static void plpython_error_callback(void *arg);
40 : static void plpython_inline_error_callback(void *arg);
41 : static void PLy_init_interp(void);
42 :
43 : static PLyExecutionContext *PLy_push_execution_context(bool atomic_context);
44 : static void PLy_pop_execution_context(void);
45 :
46 : /* static state for Python library conflict detection */
47 : static int *plpython_version_bitmask_ptr = NULL;
48 : static int plpython_version_bitmask = 0;
49 :
50 : /* initialize global variables */
51 : PyObject *PLy_interp_globals = NULL;
52 :
53 : /* this doesn't need to be global; use PLy_current_execution_context() */
54 : static PLyExecutionContext *PLy_execution_contexts = NULL;
55 :
56 :
57 : void
58 46 : _PG_init(void)
59 : {
60 : int **bitmask_ptr;
61 :
62 : /*
63 : * Set up a shared bitmask variable telling which Python version(s) are
64 : * loaded into this process's address space. If there's more than one, we
65 : * cannot call into libpython for fear of causing crashes. But postpone
66 : * the actual failure for later, so that operations like pg_restore can
67 : * load more than one plpython library so long as they don't try to do
68 : * anything much with the language.
69 : *
70 : * While we only support Python 3 these days, somebody might create an
71 : * out-of-tree version adding back support for Python 2. Conflicts with
72 : * such an extension should be detected.
73 : */
74 46 : bitmask_ptr = (int **) find_rendezvous_variable("plpython_version_bitmask");
75 46 : if (!(*bitmask_ptr)) /* am I the first? */
76 46 : *bitmask_ptr = &plpython_version_bitmask;
77 : /* Retain pointer to the agreed-on shared variable ... */
78 46 : plpython_version_bitmask_ptr = *bitmask_ptr;
79 : /* ... and announce my presence */
80 46 : *plpython_version_bitmask_ptr |= (1 << PY_MAJOR_VERSION);
81 :
82 : /*
83 : * This should be safe even in the presence of conflicting plpythons, and
84 : * it's necessary to do it before possibly throwing a conflict error, or
85 : * the error message won't get localized.
86 : */
87 46 : pg_bindtextdomain(TEXTDOMAIN);
88 46 : }
89 :
90 : /*
91 : * Perform one-time setup of PL/Python, after checking for a conflict
92 : * with other versions of Python.
93 : */
94 : static void
95 1890 : PLy_initialize(void)
96 : {
97 : static bool inited = false;
98 :
99 : /*
100 : * Check for multiple Python libraries before actively doing anything with
101 : * libpython. This must be repeated on each entry to PL/Python, in case a
102 : * conflicting library got loaded since we last looked.
103 : *
104 : * It is attractive to weaken this error from FATAL to ERROR, but there
105 : * would be corner cases, so it seems best to be conservative.
106 : */
107 1890 : if (*plpython_version_bitmask_ptr != (1 << PY_MAJOR_VERSION))
108 0 : ereport(FATAL,
109 : (errmsg("multiple Python libraries are present in session"),
110 : errdetail("Only one Python major version can be used in one session.")));
111 :
112 : /* The rest should only be done once per session */
113 1890 : if (inited)
114 1844 : return;
115 :
116 46 : PyImport_AppendInittab("plpy", PyInit_plpy);
117 46 : Py_Initialize();
118 46 : PyImport_ImportModule("plpy");
119 46 : PLy_init_interp();
120 46 : PLy_init_plpy();
121 46 : if (PyErr_Occurred())
122 0 : PLy_elog(FATAL, "untrapped error in initialization");
123 :
124 46 : init_procedure_caches();
125 :
126 46 : explicit_subtransactions = NIL;
127 :
128 46 : PLy_execution_contexts = NULL;
129 :
130 46 : inited = true;
131 : }
132 :
133 : /*
134 : * This should be called only once, from PLy_initialize. Initialize the Python
135 : * interpreter and global data.
136 : */
137 : static void
138 46 : PLy_init_interp(void)
139 : {
140 : static PyObject *PLy_interp_safe_globals = NULL;
141 : PyObject *mainmod;
142 :
143 46 : mainmod = PyImport_AddModule("__main__");
144 46 : if (mainmod == NULL || PyErr_Occurred())
145 0 : PLy_elog(ERROR, "could not import \"__main__\" module");
146 46 : Py_INCREF(mainmod);
147 46 : PLy_interp_globals = PyModule_GetDict(mainmod);
148 46 : PLy_interp_safe_globals = PyDict_New();
149 46 : if (PLy_interp_safe_globals == NULL)
150 0 : PLy_elog(ERROR, NULL);
151 46 : PyDict_SetItemString(PLy_interp_globals, "GD", PLy_interp_safe_globals);
152 46 : Py_DECREF(mainmod);
153 46 : if (PLy_interp_globals == NULL || PyErr_Occurred())
154 0 : PLy_elog(ERROR, "could not initialize globals");
155 46 : }
156 :
157 : Datum
158 494 : plpython3_validator(PG_FUNCTION_ARGS)
159 : {
160 494 : Oid funcoid = PG_GETARG_OID(0);
161 : HeapTuple tuple;
162 : Form_pg_proc procStruct;
163 : bool is_trigger;
164 :
165 494 : if (!CheckFunctionValidatorAccess(fcinfo->flinfo->fn_oid, funcoid))
166 0 : PG_RETURN_VOID();
167 :
168 494 : if (!check_function_bodies)
169 2 : PG_RETURN_VOID();
170 :
171 : /* Do this only after making sure we need to do something */
172 492 : PLy_initialize();
173 :
174 : /* Get the new function's pg_proc entry */
175 492 : tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcoid));
176 492 : if (!HeapTupleIsValid(tuple))
177 0 : elog(ERROR, "cache lookup failed for function %u", funcoid);
178 492 : procStruct = (Form_pg_proc) GETSTRUCT(tuple);
179 :
180 492 : is_trigger = PLy_procedure_is_trigger(procStruct);
181 :
182 492 : ReleaseSysCache(tuple);
183 :
184 : /* We can't validate triggers against any particular table ... */
185 492 : PLy_procedure_get(funcoid, InvalidOid, is_trigger);
186 :
187 490 : PG_RETURN_VOID();
188 : }
189 :
190 : Datum
191 1356 : plpython3_call_handler(PG_FUNCTION_ARGS)
192 : {
193 : bool nonatomic;
194 : Datum retval;
195 : PLyExecutionContext *exec_ctx;
196 : ErrorContextCallback plerrcontext;
197 :
198 1356 : PLy_initialize();
199 :
200 2820 : nonatomic = fcinfo->context &&
201 1372 : IsA(fcinfo->context, CallContext) &&
202 16 : !castNode(CallContext, fcinfo->context)->atomic;
203 :
204 : /* Note: SPI_finish() happens in plpy_exec.c, which is dubious design */
205 1356 : if (SPI_connect_ext(nonatomic ? SPI_OPT_NONATOMIC : 0) != SPI_OK_CONNECT)
206 0 : elog(ERROR, "SPI_connect failed");
207 :
208 : /*
209 : * Push execution context onto stack. It is important that this get
210 : * popped again, so avoid putting anything that could throw error between
211 : * here and the PG_TRY.
212 : */
213 1356 : exec_ctx = PLy_push_execution_context(!nonatomic);
214 :
215 1356 : PG_TRY();
216 : {
217 1356 : Oid funcoid = fcinfo->flinfo->fn_oid;
218 : PLyProcedure *proc;
219 :
220 : /*
221 : * Setup error traceback support for ereport(). Note that the PG_TRY
222 : * structure pops this for us again at exit, so we needn't do that
223 : * explicitly, nor do we risk the callback getting called after we've
224 : * destroyed the exec_ctx.
225 : */
226 1356 : plerrcontext.callback = plpython_error_callback;
227 1356 : plerrcontext.arg = exec_ctx;
228 1356 : plerrcontext.previous = error_context_stack;
229 1356 : error_context_stack = &plerrcontext;
230 :
231 1356 : if (CALLED_AS_TRIGGER(fcinfo))
232 74 : {
233 92 : Relation tgrel = ((TriggerData *) fcinfo->context)->tg_relation;
234 : HeapTuple trv;
235 :
236 92 : proc = PLy_procedure_get(funcoid, RelationGetRelid(tgrel), true);
237 92 : exec_ctx->curr_proc = proc;
238 92 : trv = PLy_exec_trigger(fcinfo, proc);
239 74 : retval = PointerGetDatum(trv);
240 : }
241 : else
242 : {
243 1264 : proc = PLy_procedure_get(funcoid, InvalidOid, false);
244 1258 : exec_ctx->curr_proc = proc;
245 1258 : retval = PLy_exec_function(fcinfo, proc);
246 : }
247 : }
248 186 : PG_CATCH();
249 : {
250 186 : PLy_pop_execution_context();
251 186 : PyErr_Clear();
252 186 : PG_RE_THROW();
253 : }
254 1170 : PG_END_TRY();
255 :
256 : /* Destroy the execution context */
257 1170 : PLy_pop_execution_context();
258 :
259 1170 : return retval;
260 : }
261 :
262 : Datum
263 42 : plpython3_inline_handler(PG_FUNCTION_ARGS)
264 : {
265 42 : LOCAL_FCINFO(fake_fcinfo, 0);
266 42 : InlineCodeBlock *codeblock = (InlineCodeBlock *) DatumGetPointer(PG_GETARG_DATUM(0));
267 : FmgrInfo flinfo;
268 : PLyProcedure proc;
269 : PLyExecutionContext *exec_ctx;
270 : ErrorContextCallback plerrcontext;
271 :
272 42 : PLy_initialize();
273 :
274 : /* Note: SPI_finish() happens in plpy_exec.c, which is dubious design */
275 42 : if (SPI_connect_ext(codeblock->atomic ? 0 : SPI_OPT_NONATOMIC) != SPI_OK_CONNECT)
276 0 : elog(ERROR, "SPI_connect failed");
277 :
278 210 : MemSet(fcinfo, 0, SizeForFunctionCallInfo(0));
279 294 : MemSet(&flinfo, 0, sizeof(flinfo));
280 42 : fake_fcinfo->flinfo = &flinfo;
281 42 : flinfo.fn_oid = InvalidOid;
282 42 : flinfo.fn_mcxt = CurrentMemoryContext;
283 :
284 1722 : MemSet(&proc, 0, sizeof(PLyProcedure));
285 42 : proc.mcxt = AllocSetContextCreate(TopMemoryContext,
286 : "__plpython_inline_block",
287 : ALLOCSET_DEFAULT_SIZES);
288 42 : proc.pyname = MemoryContextStrdup(proc.mcxt, "__plpython_inline_block");
289 42 : proc.langid = codeblock->langOid;
290 :
291 : /*
292 : * This is currently sufficient to get PLy_exec_function to work, but
293 : * someday we might need to be honest and use PLy_output_setup_func.
294 : */
295 42 : proc.result.typoid = VOIDOID;
296 :
297 : /*
298 : * Push execution context onto stack. It is important that this get
299 : * popped again, so avoid putting anything that could throw error between
300 : * here and the PG_TRY.
301 : */
302 42 : exec_ctx = PLy_push_execution_context(codeblock->atomic);
303 :
304 42 : PG_TRY();
305 : {
306 : /*
307 : * Setup error traceback support for ereport().
308 : * plpython_inline_error_callback doesn't currently need exec_ctx, but
309 : * for consistency with plpython3_call_handler we do it the same way.
310 : */
311 42 : plerrcontext.callback = plpython_inline_error_callback;
312 42 : plerrcontext.arg = exec_ctx;
313 42 : plerrcontext.previous = error_context_stack;
314 42 : error_context_stack = &plerrcontext;
315 :
316 42 : PLy_procedure_compile(&proc, codeblock->source_text);
317 42 : exec_ctx->curr_proc = &proc;
318 42 : PLy_exec_function(fake_fcinfo, &proc);
319 : }
320 22 : PG_CATCH();
321 : {
322 22 : PLy_pop_execution_context();
323 22 : PLy_procedure_delete(&proc);
324 22 : PyErr_Clear();
325 22 : PG_RE_THROW();
326 : }
327 20 : PG_END_TRY();
328 :
329 : /* Destroy the execution context */
330 20 : PLy_pop_execution_context();
331 :
332 : /* Now clean up the transient procedure we made */
333 20 : PLy_procedure_delete(&proc);
334 :
335 20 : PG_RETURN_VOID();
336 : }
337 :
338 : static bool
339 492 : PLy_procedure_is_trigger(Form_pg_proc procStruct)
340 : {
341 492 : return (procStruct->prorettype == TRIGGEROID);
342 : }
343 :
344 : static void
345 904 : plpython_error_callback(void *arg)
346 : {
347 904 : PLyExecutionContext *exec_ctx = (PLyExecutionContext *) arg;
348 :
349 904 : if (exec_ctx->curr_proc)
350 : {
351 898 : if (exec_ctx->curr_proc->is_procedure)
352 8 : errcontext("PL/Python procedure \"%s\"",
353 : PLy_procedure_name(exec_ctx->curr_proc));
354 : else
355 890 : errcontext("PL/Python function \"%s\"",
356 : PLy_procedure_name(exec_ctx->curr_proc));
357 : }
358 904 : }
359 :
360 : static void
361 56 : plpython_inline_error_callback(void *arg)
362 : {
363 56 : errcontext("PL/Python anonymous code block");
364 56 : }
365 :
366 : PLyExecutionContext *
367 2820 : PLy_current_execution_context(void)
368 : {
369 2820 : if (PLy_execution_contexts == NULL)
370 0 : elog(ERROR, "no Python function is currently executing");
371 :
372 2820 : return PLy_execution_contexts;
373 : }
374 :
375 : MemoryContext
376 1558 : PLy_get_scratch_context(PLyExecutionContext *context)
377 : {
378 : /*
379 : * A scratch context might never be needed in a given plpython procedure,
380 : * so allocate it on first request.
381 : */
382 1558 : if (context->scratch_ctx == NULL)
383 866 : context->scratch_ctx =
384 866 : AllocSetContextCreate(TopTransactionContext,
385 : "PL/Python scratch context",
386 : ALLOCSET_DEFAULT_SIZES);
387 1558 : return context->scratch_ctx;
388 : }
389 :
390 : static PLyExecutionContext *
391 1398 : PLy_push_execution_context(bool atomic_context)
392 : {
393 : PLyExecutionContext *context;
394 :
395 : /* Pick a memory context similar to what SPI uses. */
396 : context = (PLyExecutionContext *)
397 1398 : MemoryContextAlloc(atomic_context ? TopTransactionContext : PortalContext,
398 : sizeof(PLyExecutionContext));
399 1398 : context->curr_proc = NULL;
400 1398 : context->scratch_ctx = NULL;
401 1398 : context->next = PLy_execution_contexts;
402 1398 : PLy_execution_contexts = context;
403 1398 : return context;
404 : }
405 :
406 : static void
407 1398 : PLy_pop_execution_context(void)
408 : {
409 1398 : PLyExecutionContext *context = PLy_execution_contexts;
410 :
411 1398 : if (context == NULL)
412 0 : elog(ERROR, "no Python function is currently executing");
413 :
414 1398 : PLy_execution_contexts = context->next;
415 :
416 1398 : if (context->scratch_ctx)
417 832 : MemoryContextDelete(context->scratch_ctx);
418 1398 : pfree(context);
419 1398 : }
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