PostgreSQL Source Code  git master
pg_backup_db.c
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1 /*-------------------------------------------------------------------------
2  *
3  * pg_backup_db.c
4  *
5  * Implements the basic DB functions used by the archiver.
6  *
7  * IDENTIFICATION
8  * src/bin/pg_dump/pg_backup_db.c
9  *
10  *-------------------------------------------------------------------------
11  */
12 #include "postgres_fe.h"
13 
14 #include <unistd.h>
15 #include <ctype.h>
16 #ifdef HAVE_TERMIOS_H
17 #include <termios.h>
18 #endif
19 
20 #include "common/connect.h"
21 #include "common/string.h"
22 #include "dumputils.h"
23 #include "fe_utils/string_utils.h"
24 #include "parallel.h"
25 #include "pg_backup_archiver.h"
26 #include "pg_backup_db.h"
27 #include "pg_backup_utils.h"
28 
29 static void _check_database_version(ArchiveHandle *AH);
30 static void notice_processor(void *arg, const char *message);
31 
32 static void
34 {
35  const char *remoteversion_str;
36  int remoteversion;
37  PGresult *res;
38 
39  remoteversion_str = PQparameterStatus(AH->connection, "server_version");
40  remoteversion = PQserverVersion(AH->connection);
41  if (remoteversion == 0 || !remoteversion_str)
42  fatal("could not get server_version from libpq");
43 
44  AH->public.remoteVersionStr = pg_strdup(remoteversion_str);
45  AH->public.remoteVersion = remoteversion;
46  if (!AH->archiveRemoteVersion)
48 
49  if (remoteversion != PG_VERSION_NUM
50  && (remoteversion < AH->public.minRemoteVersion ||
51  remoteversion > AH->public.maxRemoteVersion))
52  {
53  pg_log_error("server version: %s; %s version: %s",
54  remoteversion_str, progname, PG_VERSION);
55  fatal("aborting because of server version mismatch");
56  }
57 
58  /*
59  * When running against 9.0 or later, check if we are in recovery mode,
60  * which means we are on a hot standby.
61  */
62  if (remoteversion >= 90000)
63  {
64  res = ExecuteSqlQueryForSingleRow((Archive *) AH, "SELECT pg_catalog.pg_is_in_recovery()");
65 
66  AH->public.isStandby = (strcmp(PQgetvalue(res, 0, 0), "t") == 0);
67  PQclear(res);
68  }
69  else
70  AH->public.isStandby = false;
71 }
72 
73 /*
74  * Reconnect to the server. If dbname is not NULL, use that database,
75  * else the one associated with the archive handle.
76  */
77 void
79 {
80  PGconn *oldConn = AH->connection;
81  RestoreOptions *ropt = AH->public.ropt;
82 
83  /*
84  * Save the dbname, if given, in override_dbname so that it will also
85  * affect any later reconnection attempt.
86  */
87  if (dbname)
89 
90  /*
91  * Note: we want to establish the new connection, and in particular update
92  * ArchiveHandle's connCancel, before closing old connection. Otherwise
93  * an ill-timed SIGINT could try to access a dead connection.
94  */
95  AH->connection = NULL; /* dodge error check in ConnectDatabase */
96 
97  ConnectDatabase((Archive *) AH, &ropt->cparams, true);
98 
99  PQfinish(oldConn);
100 }
101 
102 /*
103  * Make, or remake, a database connection with the given parameters.
104  *
105  * The resulting connection handle is stored in AHX->connection.
106  *
107  * An interactive password prompt is automatically issued if required.
108  * We store the results of that in AHX->savedPassword.
109  * Note: it's not really all that sensible to use a single-entry password
110  * cache if the username keeps changing. In current usage, however, the
111  * username never does change, so one savedPassword is sufficient.
112  */
113 void
115  const ConnParams *cparams,
116  bool isReconnect)
117 {
118  ArchiveHandle *AH = (ArchiveHandle *) AHX;
119  trivalue prompt_password;
120  char *password;
121  bool new_pass;
122 
123  if (AH->connection)
124  fatal("already connected to a database");
125 
126  /* Never prompt for a password during a reconnection */
127  prompt_password = isReconnect ? TRI_NO : cparams->promptPassword;
128 
129  password = AH->savedPassword;
130 
131  if (prompt_password == TRI_YES && password == NULL)
132  password = simple_prompt("Password: ", false);
133 
134  /*
135  * Start the connection. Loop until we have a password if requested by
136  * backend.
137  */
138  do
139  {
140  const char *keywords[8];
141  const char *values[8];
142  int i = 0;
143 
144  /*
145  * If dbname is a connstring, its entries can override the other
146  * values obtained from cparams; but in turn, override_dbname can
147  * override the dbname component of it.
148  */
149  keywords[i] = "host";
150  values[i++] = cparams->pghost;
151  keywords[i] = "port";
152  values[i++] = cparams->pgport;
153  keywords[i] = "user";
154  values[i++] = cparams->username;
155  keywords[i] = "password";
156  values[i++] = password;
157  keywords[i] = "dbname";
158  values[i++] = cparams->dbname;
159  if (cparams->override_dbname)
160  {
161  keywords[i] = "dbname";
162  values[i++] = cparams->override_dbname;
163  }
164  keywords[i] = "fallback_application_name";
165  values[i++] = progname;
166  keywords[i] = NULL;
167  values[i++] = NULL;
168  Assert(i <= lengthof(keywords));
169 
170  new_pass = false;
171  AH->connection = PQconnectdbParams(keywords, values, true);
172 
173  if (!AH->connection)
174  fatal("could not connect to database");
175 
176  if (PQstatus(AH->connection) == CONNECTION_BAD &&
178  password == NULL &&
179  prompt_password != TRI_NO)
180  {
181  PQfinish(AH->connection);
182  password = simple_prompt("Password: ", false);
183  new_pass = true;
184  }
185  } while (new_pass);
186 
187  /* check to see that the backend connection was successfully made */
188  if (PQstatus(AH->connection) == CONNECTION_BAD)
189  {
190  if (isReconnect)
191  fatal("reconnection failed: %s",
193  else
194  fatal("%s",
196  }
197 
198  /* Start strict; later phases may override this. */
201 
202  if (password && password != AH->savedPassword)
203  free(password);
204 
205  /*
206  * We want to remember connection's actual password, whether or not we got
207  * it by prompting. So we don't just store the password variable.
208  */
210  {
211  if (AH->savedPassword)
212  free(AH->savedPassword);
214  }
215 
216  /* check for version mismatch */
218 
220 
221  /* arrange for SIGINT to issue a query cancel on this connection */
223 }
224 
225 /*
226  * Close the connection to the database and also cancel off the query if we
227  * have one running.
228  */
229 void
231 {
232  ArchiveHandle *AH = (ArchiveHandle *) AHX;
233  char errbuf[1];
234 
235  if (!AH->connection)
236  return;
237 
238  if (AH->connCancel)
239  {
240  /*
241  * If we have an active query, send a cancel before closing, ignoring
242  * any errors. This is of no use for a normal exit, but might be
243  * helpful during fatal().
244  */
246  (void) PQcancel(AH->connCancel, errbuf, sizeof(errbuf));
247 
248  /*
249  * Prevent signal handler from sending a cancel after this.
250  */
251  set_archive_cancel_info(AH, NULL);
252  }
253 
254  PQfinish(AH->connection);
255  AH->connection = NULL;
256 }
257 
258 PGconn *
260 {
261  ArchiveHandle *AH = (ArchiveHandle *) AHX;
262 
263  return AH->connection;
264 }
265 
266 static void
267 notice_processor(void *arg, const char *message)
268 {
269  pg_log_generic(PG_LOG_INFO, "%s", message);
270 }
271 
272 /* Like fatal(), but with a complaint about a particular query. */
273 static void
274 die_on_query_failure(ArchiveHandle *AH, const char *query)
275 {
276  pg_log_error("query failed: %s",
278  fatal("query was: %s", query);
279 }
280 
281 void
282 ExecuteSqlStatement(Archive *AHX, const char *query)
283 {
284  ArchiveHandle *AH = (ArchiveHandle *) AHX;
285  PGresult *res;
286 
287  res = PQexec(AH->connection, query);
289  die_on_query_failure(AH, query);
290  PQclear(res);
291 }
292 
293 PGresult *
294 ExecuteSqlQuery(Archive *AHX, const char *query, ExecStatusType status)
295 {
296  ArchiveHandle *AH = (ArchiveHandle *) AHX;
297  PGresult *res;
298 
299  res = PQexec(AH->connection, query);
300  if (PQresultStatus(res) != status)
301  die_on_query_failure(AH, query);
302  return res;
303 }
304 
305 /*
306  * Execute an SQL query and verify that we got exactly one row back.
307  */
308 PGresult *
309 ExecuteSqlQueryForSingleRow(Archive *fout, const char *query)
310 {
311  PGresult *res;
312  int ntups;
313 
314  res = ExecuteSqlQuery(fout, query, PGRES_TUPLES_OK);
315 
316  /* Expecting a single result only */
317  ntups = PQntuples(res);
318  if (ntups != 1)
319  fatal(ngettext("query returned %d row instead of one: %s",
320  "query returned %d rows instead of one: %s",
321  ntups),
322  ntups, query);
323 
324  return res;
325 }
326 
327 /*
328  * Convenience function to send a query.
329  * Monitors result to detect COPY statements
330  */
331 static void
332 ExecuteSqlCommand(ArchiveHandle *AH, const char *qry, const char *desc)
333 {
334  PGconn *conn = AH->connection;
335  PGresult *res;
336 
337 #ifdef NOT_USED
338  fprintf(stderr, "Executing: '%s'\n\n", qry);
339 #endif
340  res = PQexec(conn, qry);
341 
342  switch (PQresultStatus(res))
343  {
344  case PGRES_COMMAND_OK:
345  case PGRES_TUPLES_OK:
346  case PGRES_EMPTY_QUERY:
347  /* A-OK */
348  break;
349  case PGRES_COPY_IN:
350  /* Assume this is an expected result */
351  AH->pgCopyIn = true;
352  break;
353  default:
354  /* trouble */
355  warn_or_exit_horribly(AH, "%s: %sCommand was: %s",
356  desc, PQerrorMessage(conn), qry);
357  break;
358  }
359 
360  PQclear(res);
361 }
362 
363 
364 /*
365  * Process non-COPY table data (that is, INSERT commands).
366  *
367  * The commands have been run together as one long string for compressibility,
368  * and we are receiving them in bufferloads with arbitrary boundaries, so we
369  * have to locate command boundaries and save partial commands across calls.
370  * All state must be kept in AH->sqlparse, not in local variables of this
371  * routine. We assume that AH->sqlparse was filled with zeroes when created.
372  *
373  * We have to lex the data to the extent of identifying literals and quoted
374  * identifiers, so that we can recognize statement-terminating semicolons.
375  * We assume that INSERT data will not contain SQL comments, E'' literals,
376  * or dollar-quoted strings, so this is much simpler than a full SQL lexer.
377  *
378  * Note: when restoring from a pre-9.0 dump file, this code is also used to
379  * process BLOB COMMENTS data, which has the same problem of containing
380  * multiple SQL commands that might be split across bufferloads. Fortunately,
381  * that data won't contain anything complicated to lex either.
382  */
383 static void
384 ExecuteSimpleCommands(ArchiveHandle *AH, const char *buf, size_t bufLen)
385 {
386  const char *qry = buf;
387  const char *eos = buf + bufLen;
388 
389  /* initialize command buffer if first time through */
390  if (AH->sqlparse.curCmd == NULL)
392 
393  for (; qry < eos; qry++)
394  {
395  char ch = *qry;
396 
397  /* For neatness, we skip any newlines between commands */
398  if (!(ch == '\n' && AH->sqlparse.curCmd->len == 0))
400 
401  switch (AH->sqlparse.state)
402  {
403  case SQL_SCAN: /* Default state == 0, set in _allocAH */
404  if (ch == ';')
405  {
406  /*
407  * We've found the end of a statement. Send it and reset
408  * the buffer.
409  */
411  "could not execute query");
413  }
414  else if (ch == '\'')
415  {
417  AH->sqlparse.backSlash = false;
418  }
419  else if (ch == '"')
420  {
422  }
423  break;
424 
425  case SQL_IN_SINGLE_QUOTE:
426  /* We needn't handle '' specially */
427  if (ch == '\'' && !AH->sqlparse.backSlash)
428  AH->sqlparse.state = SQL_SCAN;
429  else if (ch == '\\' && !AH->public.std_strings)
431  else
432  AH->sqlparse.backSlash = false;
433  break;
434 
435  case SQL_IN_DOUBLE_QUOTE:
436  /* We needn't handle "" specially */
437  if (ch == '"')
438  AH->sqlparse.state = SQL_SCAN;
439  break;
440  }
441  }
442 }
443 
444 
445 /*
446  * Implement ahwrite() for direct-to-DB restore
447  */
448 int
449 ExecuteSqlCommandBuf(Archive *AHX, const char *buf, size_t bufLen)
450 {
451  ArchiveHandle *AH = (ArchiveHandle *) AHX;
452 
453  if (AH->outputKind == OUTPUT_COPYDATA)
454  {
455  /*
456  * COPY data.
457  *
458  * We drop the data on the floor if libpq has failed to enter COPY
459  * mode; this allows us to behave reasonably when trying to continue
460  * after an error in a COPY command.
461  */
462  if (AH->pgCopyIn &&
463  PQputCopyData(AH->connection, buf, bufLen) <= 0)
464  fatal("error returned by PQputCopyData: %s",
466  }
467  else if (AH->outputKind == OUTPUT_OTHERDATA)
468  {
469  /*
470  * Table data expressed as INSERT commands; or, in old dump files,
471  * BLOB COMMENTS data (which is expressed as COMMENT ON commands).
472  */
473  ExecuteSimpleCommands(AH, buf, bufLen);
474  }
475  else
476  {
477  /*
478  * General SQL commands; we assume that commands will not be split
479  * across calls.
480  *
481  * In most cases the data passed to us will be a null-terminated
482  * string, but if it's not, we have to add a trailing null.
483  */
484  if (buf[bufLen] == '\0')
485  ExecuteSqlCommand(AH, buf, "could not execute query");
486  else
487  {
488  char *str = (char *) pg_malloc(bufLen + 1);
489 
490  memcpy(str, buf, bufLen);
491  str[bufLen] = '\0';
492  ExecuteSqlCommand(AH, str, "could not execute query");
493  free(str);
494  }
495  }
496 
497  return bufLen;
498 }
499 
500 /*
501  * Terminate a COPY operation during direct-to-DB restore
502  */
503 void
504 EndDBCopyMode(Archive *AHX, const char *tocEntryTag)
505 {
506  ArchiveHandle *AH = (ArchiveHandle *) AHX;
507 
508  if (AH->pgCopyIn)
509  {
510  PGresult *res;
511 
512  if (PQputCopyEnd(AH->connection, NULL) <= 0)
513  fatal("error returned by PQputCopyEnd: %s",
515 
516  /* Check command status and return to normal libpq state */
517  res = PQgetResult(AH->connection);
519  warn_or_exit_horribly(AH, "COPY failed for table \"%s\": %s",
520  tocEntryTag, PQerrorMessage(AH->connection));
521  PQclear(res);
522 
523  /* Do this to ensure we've pumped libpq back to idle state */
524  if (PQgetResult(AH->connection) != NULL)
525  pg_log_warning("unexpected extra results during COPY of table \"%s\"",
526  tocEntryTag);
527 
528  AH->pgCopyIn = false;
529  }
530 }
531 
532 void
534 {
535  ArchiveHandle *AH = (ArchiveHandle *) AHX;
536 
537  ExecuteSqlCommand(AH, "BEGIN", "could not start database transaction");
538 }
539 
540 void
542 {
543  ArchiveHandle *AH = (ArchiveHandle *) AHX;
544 
545  ExecuteSqlCommand(AH, "COMMIT", "could not commit database transaction");
546 }
547 
548 void
550 {
551  /*
552  * If we are not restoring to a direct database connection, we have to
553  * guess about how to detect whether the blob exists. Assume new-style.
554  */
555  if (AH->connection == NULL ||
556  PQserverVersion(AH->connection) >= 90000)
557  {
558  ahprintf(AH,
559  "SELECT pg_catalog.lo_unlink(oid) "
560  "FROM pg_catalog.pg_largeobject_metadata "
561  "WHERE oid = '%u';\n",
562  oid);
563  }
564  else
565  {
566  /* Restoring to pre-9.0 server, so do it the old way */
567  ahprintf(AH,
568  "SELECT CASE WHEN EXISTS("
569  "SELECT 1 FROM pg_catalog.pg_largeobject WHERE loid = '%u'"
570  ") THEN pg_catalog.lo_unlink('%u') END;\n",
571  oid, oid);
572  }
573 }
void set_archive_cancel_info(ArchiveHandle *AH, PGconn *conn)
Definition: parallel.c:735
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Definition: bootstrap.c:156
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@ CONNECTION_BAD
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ExecStatusType
Definition: libpq-fe.h:93
@ PGRES_COPY_IN
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@ PGRES_COMMAND_OK
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@ PGRES_EMPTY_QUERY
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@ PGRES_TUPLES_OK
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@ PQTRANS_ACTIVE
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Definition: logging.c:197
#define pg_log_error(...)
Definition: logging.h:80
@ PG_LOG_INFO
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Definition: main.c:46
void warn_or_exit_horribly(ArchiveHandle *AH, const char *fmt,...)
int ahprintf(ArchiveHandle *AH, const char *fmt,...)
@ SQL_IN_DOUBLE_QUOTE
@ SQL_IN_SINGLE_QUOTE
@ SQL_SCAN
@ OUTPUT_COPYDATA
@ OUTPUT_OTHERDATA
void ConnectDatabase(Archive *AHX, const ConnParams *cparams, bool isReconnect)
Definition: pg_backup_db.c:114
void ExecuteSqlStatement(Archive *AHX, const char *query)
Definition: pg_backup_db.c:282
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Definition: pg_backup_db.c:549
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Definition: pg_backup_db.c:504
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Definition: pg_backup_db.c:274
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Definition: pg_backup_db.c:294
static void _check_database_version(ArchiveHandle *AH)
Definition: pg_backup_db.c:33
PGconn * GetConnection(Archive *AHX)
Definition: pg_backup_db.c:259
void ReconnectToServer(ArchiveHandle *AH, const char *dbname)
Definition: pg_backup_db.c:78
static void ExecuteSimpleCommands(ArchiveHandle *AH, const char *buf, size_t bufLen)
Definition: pg_backup_db.c:384
void StartTransaction(Archive *AHX)
Definition: pg_backup_db.c:533
int ExecuteSqlCommandBuf(Archive *AHX, const char *buf, size_t bufLen)
Definition: pg_backup_db.c:449
static void ExecuteSqlCommand(ArchiveHandle *AH, const char *qry, const char *desc)
Definition: pg_backup_db.c:332
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Definition: pg_backup_db.c:267
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Definition: pg_backup_db.c:230
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Definition: pg_backup.h:196
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Definition: pg_backup.h:195
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bool std_strings
Definition: pg_backup.h:207
RestoreOptions * ropt
Definition: pg_backup.h:192
PGcancel *volatile connCancel
sqlparseInfo sqlparse
ArchiverOutput outputKind
char * override_dbname
Definition: pg_backup.h:72
char * pgport
Definition: pg_backup.h:66
char * pghost
Definition: pg_backup.h:67
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Definition: vacuumlo.c:35
@ TRI_YES
Definition: vacuumlo.c:38
@ TRI_NO
Definition: vacuumlo.c:37