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plpy_procedure.c
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1 /*
2  * Python procedure manipulation for plpython
3  *
4  * src/pl/plpython/plpy_procedure.c
5  */
6 
7 #include "postgres.h"
8 
9 #include "access/htup_details.h"
10 #include "access/transam.h"
11 #include "catalog/pg_proc.h"
12 #include "catalog/pg_type.h"
13 #include "funcapi.h"
14 #include "plpy_elog.h"
15 #include "plpy_main.h"
16 #include "plpy_procedure.h"
17 #include "plpython.h"
18 #include "utils/builtins.h"
19 #include "utils/hsearch.h"
20 #include "utils/inval.h"
21 #include "utils/lsyscache.h"
22 #include "utils/memutils.h"
23 #include "utils/syscache.h"
24 
25 static HTAB *PLy_procedure_cache = NULL;
26 
27 static PLyProcedure *PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger);
28 static bool PLy_procedure_valid(PLyProcedure *proc, HeapTuple procTup);
29 static char *PLy_procedure_munge_source(const char *name, const char *src);
30 
31 
32 void
34 {
35  HASHCTL hash_ctl;
36 
37  hash_ctl.keysize = sizeof(PLyProcedureKey);
38  hash_ctl.entrysize = sizeof(PLyProcedureEntry);
39  PLy_procedure_cache = hash_create("PL/Python procedures", 32, &hash_ctl,
41 }
42 
43 /*
44  * PLy_procedure_name: get the name of the specified procedure.
45  *
46  * NB: this returns the SQL name, not the internal Python procedure name
47  */
48 char *
50 {
51  if (proc == NULL)
52  return "<unknown procedure>";
53  return proc->proname;
54 }
55 
56 /*
57  * PLy_procedure_get: returns a cached PLyProcedure, or creates, stores and
58  * returns a new PLyProcedure.
59  *
60  * fn_oid is the OID of the function requested
61  * fn_rel is InvalidOid or the relation this function triggers on
62  * is_trigger denotes whether the function is a trigger function
63  *
64  * The reason that both fn_rel and is_trigger need to be passed is that when
65  * trigger functions get validated we don't know which relation(s) they'll
66  * be used with, so no sensible fn_rel can be passed.
67  */
69 PLy_procedure_get(Oid fn_oid, Oid fn_rel, bool is_trigger)
70 {
71  bool use_cache = !(is_trigger && fn_rel == InvalidOid);
72  HeapTuple procTup;
74  PLyProcedureEntry *volatile entry = NULL;
75  PLyProcedure *volatile proc = NULL;
76  bool found = false;
77 
78  procTup = SearchSysCache1(PROCOID, ObjectIdGetDatum(fn_oid));
79  if (!HeapTupleIsValid(procTup))
80  elog(ERROR, "cache lookup failed for function %u", fn_oid);
81 
82  /*
83  * Look for the function in the cache, unless we don't have the necessary
84  * information (e.g. during validation). In that case we just don't cache
85  * anything.
86  */
87  if (use_cache)
88  {
89  key.fn_oid = fn_oid;
90  key.fn_rel = fn_rel;
91  entry = hash_search(PLy_procedure_cache, &key, HASH_ENTER, &found);
92  proc = entry->proc;
93  }
94 
95  PG_TRY();
96  {
97  if (!found)
98  {
99  /* Haven't found it, create a new procedure */
100  proc = PLy_procedure_create(procTup, fn_oid, is_trigger);
101  if (use_cache)
102  entry->proc = proc;
103  }
104  else if (!PLy_procedure_valid(proc, procTup))
105  {
106  /* Found it, but it's invalid, free and reuse the cache entry */
107  entry->proc = NULL;
108  if (proc)
109  PLy_procedure_delete(proc);
110  proc = PLy_procedure_create(procTup, fn_oid, is_trigger);
111  entry->proc = proc;
112  }
113  /* Found it and it's valid, it's fine to use it */
114  }
115  PG_CATCH();
116  {
117  /* Do not leave an uninitialized entry in the cache */
118  if (use_cache)
120  PG_RE_THROW();
121  }
122  PG_END_TRY();
123 
124  ReleaseSysCache(procTup);
125 
126  return proc;
127 }
128 
129 /*
130  * Create a new PLyProcedure structure
131  */
132 static PLyProcedure *
133 PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
134 {
135  char procName[NAMEDATALEN + 256];
136  Form_pg_proc procStruct;
137  PLyProcedure *volatile proc;
138  MemoryContext cxt;
139  MemoryContext oldcxt;
140  int rv;
141  char *ptr;
142 
143  procStruct = (Form_pg_proc) GETSTRUCT(procTup);
144  rv = snprintf(procName, sizeof(procName),
145  "__plpython_procedure_%s_%u",
146  NameStr(procStruct->proname),
147  fn_oid);
148  if (rv >= sizeof(procName) || rv < 0)
149  elog(ERROR, "procedure name would overrun buffer");
150 
151  /* Replace any not-legal-in-Python-names characters with '_' */
152  for (ptr = procName; *ptr; ptr++)
153  {
154  if (!((*ptr >= 'A' && *ptr <= 'Z') ||
155  (*ptr >= 'a' && *ptr <= 'z') ||
156  (*ptr >= '0' && *ptr <= '9')))
157  *ptr = '_';
158  }
159 
160  /* Create long-lived context that all procedure info will live in */
162  "PL/Python function",
164 
165  oldcxt = MemoryContextSwitchTo(cxt);
166 
167  proc = (PLyProcedure *) palloc0(sizeof(PLyProcedure));
168  proc->mcxt = cxt;
169 
170  PG_TRY();
171  {
172  Datum protrftypes_datum;
173  Datum prosrcdatum;
174  bool isnull;
175  char *procSource;
176  int i;
177 
178  proc->proname = pstrdup(NameStr(procStruct->proname));
180  proc->pyname = pstrdup(procName);
181  proc->fn_xmin = HeapTupleHeaderGetRawXmin(procTup->t_data);
182  proc->fn_tid = procTup->t_self;
183  proc->fn_readonly = (procStruct->provolatile != PROVOLATILE_VOLATILE);
184  proc->is_setof = procStruct->proretset;
185  proc->is_procedure = (procStruct->prokind == PROKIND_PROCEDURE);
186  proc->is_trigger = is_trigger;
187  proc->src = NULL;
188  proc->argnames = NULL;
189  proc->args = NULL;
190  proc->nargs = 0;
191  proc->langid = procStruct->prolang;
192  protrftypes_datum = SysCacheGetAttr(PROCOID, procTup,
193  Anum_pg_proc_protrftypes,
194  &isnull);
195  proc->trftypes = isnull ? NIL : oid_array_to_list(protrftypes_datum);
196  proc->code = NULL;
197  proc->statics = NULL;
198  proc->globals = NULL;
199  proc->calldepth = 0;
200  proc->argstack = NULL;
201 
202  /*
203  * get information required for output conversion of the return value,
204  * but only if this isn't a trigger.
205  */
206  if (!is_trigger)
207  {
208  Oid rettype = procStruct->prorettype;
209  HeapTuple rvTypeTup;
210  Form_pg_type rvTypeStruct;
211 
212  rvTypeTup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(rettype));
213  if (!HeapTupleIsValid(rvTypeTup))
214  elog(ERROR, "cache lookup failed for type %u", rettype);
215  rvTypeStruct = (Form_pg_type) GETSTRUCT(rvTypeTup);
216 
217  /* Disallow pseudotype result, except for void or record */
218  if (rvTypeStruct->typtype == TYPTYPE_PSEUDO)
219  {
220  if (rettype == VOIDOID ||
221  rettype == RECORDOID)
222  /* okay */ ;
223  else if (rettype == TRIGGEROID || rettype == EVENT_TRIGGEROID)
224  ereport(ERROR,
225  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
226  errmsg("trigger functions can only be called as triggers")));
227  else
228  ereport(ERROR,
229  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
230  errmsg("PL/Python functions cannot return type %s",
231  format_type_be(rettype))));
232  }
233 
234  /* set up output function for procedure result */
235  PLy_output_setup_func(&proc->result, proc->mcxt,
236  rettype, -1, proc);
237 
238  ReleaseSysCache(rvTypeTup);
239  }
240  else
241  {
242  /*
243  * In a trigger function, we use proc->result and proc->result_in
244  * for converting tuples, but we don't yet have enough info to set
245  * them up. PLy_exec_trigger will deal with it.
246  */
247  proc->result.typoid = InvalidOid;
248  proc->result_in.typoid = InvalidOid;
249  }
250 
251  /*
252  * Now get information required for input conversion of the
253  * procedure's arguments. Note that we ignore output arguments here.
254  * If the function returns record, those I/O functions will be set up
255  * when the function is first called.
256  */
257  if (procStruct->pronargs)
258  {
259  Oid *types;
260  char **names,
261  *modes;
262  int pos,
263  total;
264 
265  /* extract argument type info from the pg_proc tuple */
266  total = get_func_arg_info(procTup, &types, &names, &modes);
267 
268  /* count number of in+inout args into proc->nargs */
269  if (modes == NULL)
270  proc->nargs = total;
271  else
272  {
273  /* proc->nargs was initialized to 0 above */
274  for (i = 0; i < total; i++)
275  {
276  if (modes[i] != PROARGMODE_OUT &&
277  modes[i] != PROARGMODE_TABLE)
278  (proc->nargs)++;
279  }
280  }
281 
282  /* Allocate arrays for per-input-argument data */
283  proc->argnames = (char **) palloc0(sizeof(char *) * proc->nargs);
284  proc->args = (PLyDatumToOb *) palloc0(sizeof(PLyDatumToOb) * proc->nargs);
285 
286  for (i = pos = 0; i < total; i++)
287  {
288  HeapTuple argTypeTup;
289  Form_pg_type argTypeStruct;
290 
291  if (modes &&
292  (modes[i] == PROARGMODE_OUT ||
293  modes[i] == PROARGMODE_TABLE))
294  continue; /* skip OUT arguments */
295 
296  Assert(types[i] == procStruct->proargtypes.values[pos]);
297 
298  argTypeTup = SearchSysCache1(TYPEOID,
300  if (!HeapTupleIsValid(argTypeTup))
301  elog(ERROR, "cache lookup failed for type %u", types[i]);
302  argTypeStruct = (Form_pg_type) GETSTRUCT(argTypeTup);
303 
304  /* disallow pseudotype arguments */
305  if (argTypeStruct->typtype == TYPTYPE_PSEUDO)
306  ereport(ERROR,
307  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
308  errmsg("PL/Python functions cannot accept type %s",
309  format_type_be(types[i]))));
310 
311  /* set up I/O function info */
312  PLy_input_setup_func(&proc->args[pos], proc->mcxt,
313  types[i], -1, /* typmod not known */
314  proc);
315 
316  /* get argument name */
317  proc->argnames[pos] = names ? pstrdup(names[i]) : NULL;
318 
319  ReleaseSysCache(argTypeTup);
320 
321  pos++;
322  }
323  }
324 
325  /*
326  * get the text of the function.
327  */
328  prosrcdatum = SysCacheGetAttrNotNull(PROCOID, procTup,
329  Anum_pg_proc_prosrc);
330  procSource = TextDatumGetCString(prosrcdatum);
331 
332  PLy_procedure_compile(proc, procSource);
333 
334  pfree(procSource);
335  }
336  PG_CATCH();
337  {
338  MemoryContextSwitchTo(oldcxt);
339  PLy_procedure_delete(proc);
340  PG_RE_THROW();
341  }
342  PG_END_TRY();
343 
344  MemoryContextSwitchTo(oldcxt);
345  return proc;
346 }
347 
348 /*
349  * Insert the procedure into the Python interpreter
350  */
351 void
352 PLy_procedure_compile(PLyProcedure *proc, const char *src)
353 {
354  PyObject *crv = NULL;
355  char *msrc;
356 
357  proc->globals = PyDict_Copy(PLy_interp_globals);
358 
359  /*
360  * SD is private preserved data between calls. GD is global data shared by
361  * all functions
362  */
363  proc->statics = PyDict_New();
364  if (!proc->statics)
365  PLy_elog(ERROR, NULL);
366  PyDict_SetItemString(proc->globals, "SD", proc->statics);
367 
368  /*
369  * insert the function code into the interpreter
370  */
371  msrc = PLy_procedure_munge_source(proc->pyname, src);
372  /* Save the mangled source for later inclusion in tracebacks */
373  proc->src = MemoryContextStrdup(proc->mcxt, msrc);
374  crv = PyRun_String(msrc, Py_file_input, proc->globals, NULL);
375  pfree(msrc);
376 
377  if (crv != NULL)
378  {
379  int clen;
380  char call[NAMEDATALEN + 256];
381 
382  Py_DECREF(crv);
383 
384  /*
385  * compile a call to the function
386  */
387  clen = snprintf(call, sizeof(call), "%s()", proc->pyname);
388  if (clen < 0 || clen >= sizeof(call))
389  elog(ERROR, "string would overflow buffer");
390  proc->code = Py_CompileString(call, "<string>", Py_eval_input);
391  if (proc->code != NULL)
392  return;
393  }
394 
395  if (proc->proname)
396  PLy_elog(ERROR, "could not compile PL/Python function \"%s\"",
397  proc->proname);
398  else
399  PLy_elog(ERROR, "could not compile anonymous PL/Python code block");
400 }
401 
402 void
404 {
405  Py_XDECREF(proc->code);
406  Py_XDECREF(proc->statics);
407  Py_XDECREF(proc->globals);
408  MemoryContextDelete(proc->mcxt);
409 }
410 
411 /*
412  * Decide whether a cached PLyProcedure struct is still valid
413  */
414 static bool
416 {
417  if (proc == NULL)
418  return false;
419 
420  /* If the pg_proc tuple has changed, it's not valid */
421  if (!(proc->fn_xmin == HeapTupleHeaderGetRawXmin(procTup->t_data) &&
422  ItemPointerEquals(&proc->fn_tid, &procTup->t_self)))
423  return false;
424 
425  return true;
426 }
427 
428 static char *
429 PLy_procedure_munge_source(const char *name, const char *src)
430 {
431  char *mrc,
432  *mp;
433  const char *sp;
434  size_t mlen;
435  int plen;
436 
437  /*
438  * room for function source and the def statement
439  */
440  mlen = (strlen(src) * 2) + strlen(name) + 16;
441 
442  mrc = palloc(mlen);
443  plen = snprintf(mrc, mlen, "def %s():\n\t", name);
444  Assert(plen >= 0 && plen < mlen);
445 
446  sp = src;
447  mp = mrc + plen;
448 
449  while (*sp != '\0')
450  {
451  if (*sp == '\r' && *(sp + 1) == '\n')
452  sp++;
453 
454  if (*sp == '\n' || *sp == '\r')
455  {
456  *mp++ = '\n';
457  *mp++ = '\t';
458  sp++;
459  }
460  else
461  *mp++ = *sp++;
462  }
463  *mp++ = '\n';
464  *mp++ = '\n';
465  *mp = '\0';
466 
467  if (mp > (mrc + mlen))
468  elog(FATAL, "buffer overrun in PLy_procedure_munge_source");
469 
470  return mrc;
471 }
#define TextDatumGetCString(d)
Definition: builtins.h:98
#define NameStr(name)
Definition: c.h:746
#define Assert(condition)
Definition: c.h:858
void * hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:955
HTAB * hash_create(const char *tabname, long nelem, const HASHCTL *info, int flags)
Definition: dynahash.c:352
struct typedefs * types
Definition: ecpg.c:29
int errcode(int sqlerrcode)
Definition: elog.c:857
int errmsg(const char *fmt,...)
Definition: elog.c:1070
#define PG_RE_THROW()
Definition: elog.h:411
#define FATAL
Definition: elog.h:41
#define PG_TRY(...)
Definition: elog.h:370
#define PG_END_TRY(...)
Definition: elog.h:395
#define ERROR
Definition: elog.h:39
#define PG_CATCH(...)
Definition: elog.h:380
#define elog(elevel,...)
Definition: elog.h:224
#define ereport(elevel,...)
Definition: elog.h:149
char * format_type_be(Oid type_oid)
Definition: format_type.c:343
int get_func_arg_info(HeapTuple procTup, Oid **p_argtypes, char ***p_argnames, char **p_argmodes)
Definition: funcapi.c:1379
@ HASH_REMOVE
Definition: hsearch.h:115
@ HASH_ENTER
Definition: hsearch.h:114
#define HASH_ELEM
Definition: hsearch.h:95
#define HASH_BLOBS
Definition: hsearch.h:97
#define HeapTupleIsValid(tuple)
Definition: htup.h:78
#define HeapTupleHeaderGetRawXmin(tup)
Definition: htup_details.h:304
#define GETSTRUCT(TUP)
Definition: htup_details.h:653
int i
Definition: isn.c:73
bool ItemPointerEquals(ItemPointer pointer1, ItemPointer pointer2)
Definition: itemptr.c:35
#define PLy_elog
char * pstrdup(const char *in)
Definition: mcxt.c:1695
void pfree(void *pointer)
Definition: mcxt.c:1520
MemoryContext TopMemoryContext
Definition: mcxt.c:149
void * palloc0(Size size)
Definition: mcxt.c:1346
char * MemoryContextStrdup(MemoryContext context, const char *string)
Definition: mcxt.c:1682
void MemoryContextDelete(MemoryContext context)
Definition: mcxt.c:454
void * palloc(Size size)
Definition: mcxt.c:1316
void MemoryContextSetIdentifier(MemoryContext context, const char *id)
Definition: mcxt.c:612
#define AllocSetContextCreate
Definition: memutils.h:129
#define ALLOCSET_DEFAULT_SIZES
Definition: memutils.h:160
#define NAMEDATALEN
#define NIL
Definition: pg_list.h:68
List * oid_array_to_list(Datum datum)
Definition: pg_proc.c:1184
FormData_pg_proc * Form_pg_proc
Definition: pg_proc.h:136
FormData_pg_type * Form_pg_type
Definition: pg_type.h:261
PyObject * PLy_interp_globals
Definition: plpy_main.c:51
void init_procedure_caches(void)
static PLyProcedure * PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
static char * PLy_procedure_munge_source(const char *name, const char *src)
char * PLy_procedure_name(PLyProcedure *proc)
PLyProcedure * PLy_procedure_get(Oid fn_oid, Oid fn_rel, bool is_trigger)
static bool PLy_procedure_valid(PLyProcedure *proc, HeapTuple procTup)
static HTAB * PLy_procedure_cache
void PLy_procedure_compile(PLyProcedure *proc, const char *src)
void PLy_procedure_delete(PLyProcedure *proc)
struct PLyProcedureKey PLyProcedureKey
struct PLyProcedureEntry PLyProcedureEntry
void PLy_output_setup_func(PLyObToDatum *arg, MemoryContext arg_mcxt, Oid typeOid, int32 typmod, PLyProcedure *proc)
Definition: plpy_typeio.c:296
void PLy_input_setup_func(PLyDatumToOb *arg, MemoryContext arg_mcxt, Oid typeOid, int32 typmod, PLyProcedure *proc)
Definition: plpy_typeio.c:418
#define snprintf
Definition: port.h:238
uintptr_t Datum
Definition: postgres.h:64
static Datum ObjectIdGetDatum(Oid X)
Definition: postgres.h:252
#define InvalidOid
Definition: postgres_ext.h:36
unsigned int Oid
Definition: postgres_ext.h:31
MemoryContextSwitchTo(old_ctx)
Size keysize
Definition: hsearch.h:75
Size entrysize
Definition: hsearch.h:76
Definition: dynahash.c:220
ItemPointerData t_self
Definition: htup.h:65
HeapTupleHeader t_data
Definition: htup.h:68
PLyProcedure * proc
PLyDatumToOb * args
PLyObToDatum result
PyObject * code
PLyDatumToOb result_in
PLySavedArgs * argstack
MemoryContext mcxt
char ** argnames
PyObject * globals
ItemPointerData fn_tid
TransactionId fn_xmin
PyObject * statics
void ReleaseSysCache(HeapTuple tuple)
Definition: syscache.c:266
HeapTuple SearchSysCache1(int cacheId, Datum key1)
Definition: syscache.c:218
Datum SysCacheGetAttr(int cacheId, HeapTuple tup, AttrNumber attributeNumber, bool *isNull)
Definition: syscache.c:479
Datum SysCacheGetAttrNotNull(int cacheId, HeapTuple tup, AttrNumber attributeNumber)
Definition: syscache.c:510
const char * name