PostgreSQL Source Code  git master
common.c
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1 /*-------------------------------------------------------------------------
2  *
3  * common.c
4  * Common support routines for bin/scripts/
5  *
6  *
7  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
8  * Portions Copyright (c) 1994, Regents of the University of California
9  *
10  * src/bin/scripts/common.c
11  *
12  *-------------------------------------------------------------------------
13  */
14 
15 #include "postgres_fe.h"
16 
17 #include <signal.h>
18 #include <unistd.h>
19 
20 #include "common.h"
21 #include "common/connect.h"
22 #include "common/logging.h"
23 #include "common/string.h"
24 #include "fe_utils/cancel.h"
25 #include "fe_utils/string_utils.h"
26 
27 #define ERRCODE_UNDEFINED_TABLE "42P01"
28 
29 /*
30  * Provide strictly harmonized handling of --help and --version
31  * options.
32  */
33 void
34 handle_help_version_opts(int argc, char *argv[],
35  const char *fixed_progname, help_handler hlp)
36 {
37  if (argc > 1)
38  {
39  if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
40  {
41  hlp(get_progname(argv[0]));
42  exit(0);
43  }
44  if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
45  {
46  printf("%s (PostgreSQL) " PG_VERSION "\n", fixed_progname);
47  exit(0);
48  }
49  }
50 }
51 
52 
53 /*
54  * Make a database connection with the given parameters.
55  *
56  * An interactive password prompt is automatically issued if needed and
57  * allowed by cparams->prompt_password.
58  *
59  * If allow_password_reuse is true, we will try to re-use any password
60  * given during previous calls to this routine. (Callers should not pass
61  * allow_password_reuse=true unless reconnecting to the same database+user
62  * as before, else we might create password exposure hazards.)
63  */
64 PGconn *
65 connectDatabase(const ConnParams *cparams, const char *progname,
66  bool echo, bool fail_ok, bool allow_password_reuse)
67 {
68  PGconn *conn;
69  bool new_pass;
70  static char *password = NULL;
71 
72  /* Callers must supply at least dbname; other params can be NULL */
73  Assert(cparams->dbname);
74 
75  if (!allow_password_reuse && password)
76  {
77  free(password);
78  password = NULL;
79  }
80 
81  if (cparams->prompt_password == TRI_YES && password == NULL)
82  password = simple_prompt("Password: ", false);
83 
84  /*
85  * Start the connection. Loop until we have a password if requested by
86  * backend.
87  */
88  do
89  {
90  const char *keywords[8];
91  const char *values[8];
92  int i = 0;
93 
94  /*
95  * If dbname is a connstring, its entries can override the other
96  * values obtained from cparams; but in turn, override_dbname can
97  * override the dbname component of it.
98  */
99  keywords[i] = "host";
100  values[i++] = cparams->pghost;
101  keywords[i] = "port";
102  values[i++] = cparams->pgport;
103  keywords[i] = "user";
104  values[i++] = cparams->pguser;
105  keywords[i] = "password";
106  values[i++] = password;
107  keywords[i] = "dbname";
108  values[i++] = cparams->dbname;
109  if (cparams->override_dbname)
110  {
111  keywords[i] = "dbname";
112  values[i++] = cparams->override_dbname;
113  }
114  keywords[i] = "fallback_application_name";
115  values[i++] = progname;
116  keywords[i] = NULL;
117  values[i++] = NULL;
118  Assert(i <= lengthof(keywords));
119 
120  new_pass = false;
121  conn = PQconnectdbParams(keywords, values, true);
122 
123  if (!conn)
124  {
125  pg_log_error("could not connect to database %s: out of memory",
126  cparams->dbname);
127  exit(1);
128  }
129 
130  /*
131  * No luck? Trying asking (again) for a password.
132  */
133  if (PQstatus(conn) == CONNECTION_BAD &&
135  cparams->prompt_password != TRI_NO)
136  {
137  PQfinish(conn);
138  if (password)
139  free(password);
140  password = simple_prompt("Password: ", false);
141  new_pass = true;
142  }
143  } while (new_pass);
144 
145  /* check to see that the backend connection was successfully made */
146  if (PQstatus(conn) == CONNECTION_BAD)
147  {
148  if (fail_ok)
149  {
150  PQfinish(conn);
151  return NULL;
152  }
153  pg_log_error("could not connect to database %s: %s",
154  cparams->dbname, PQerrorMessage(conn));
155  exit(1);
156  }
157 
158  /* Start strict; callers may override this. */
160 
161  return conn;
162 }
163 
164 /*
165  * Try to connect to the appropriate maintenance database.
166  *
167  * This differs from connectDatabase only in that it has a rule for
168  * inserting a default "dbname" if none was given (which is why cparams
169  * is not const). Note that cparams->dbname should typically come from
170  * a --maintenance-db command line parameter.
171  */
172 PGconn *
174  const char *progname, bool echo)
175 {
176  PGconn *conn;
177 
178  /* If a maintenance database name was specified, just connect to it. */
179  if (cparams->dbname)
180  return connectDatabase(cparams, progname, echo, false, false);
181 
182  /* Otherwise, try postgres first and then template1. */
183  cparams->dbname = "postgres";
184  conn = connectDatabase(cparams, progname, echo, true, false);
185  if (!conn)
186  {
187  cparams->dbname = "template1";
188  conn = connectDatabase(cparams, progname, echo, false, false);
189  }
190  return conn;
191 }
192 
193 /*
194  * Disconnect the given connection, canceling any statement if one is active.
195  */
196 void
198 {
199  char errbuf[256];
200 
201  Assert(conn != NULL);
202 
203  if (PQtransactionStatus(conn) == PQTRANS_ACTIVE)
204  {
205  PGcancel *cancel;
206 
207  if ((cancel = PQgetCancel(conn)))
208  {
209  (void) PQcancel(cancel, errbuf, sizeof(errbuf));
210  PQfreeCancel(cancel);
211  }
212  }
213 
214  PQfinish(conn);
215 }
216 
217 /*
218  * Run a query, return the results, exit program on failure.
219  */
220 PGresult *
221 executeQuery(PGconn *conn, const char *query, bool echo)
222 {
223  PGresult *res;
224 
225  if (echo)
226  printf("%s\n", query);
227 
228  res = PQexec(conn, query);
229  if (!res ||
231  {
232  pg_log_error("query failed: %s", PQerrorMessage(conn));
233  pg_log_info("query was: %s", query);
234  PQfinish(conn);
235  exit(1);
236  }
237 
238  return res;
239 }
240 
241 
242 /*
243  * As above for a SQL command (which returns nothing).
244  */
245 void
246 executeCommand(PGconn *conn, const char *query, bool echo)
247 {
248  PGresult *res;
249 
250  if (echo)
251  printf("%s\n", query);
252 
253  res = PQexec(conn, query);
254  if (!res ||
256  {
257  pg_log_error("query failed: %s", PQerrorMessage(conn));
258  pg_log_info("query was: %s", query);
259  PQfinish(conn);
260  exit(1);
261  }
262 
263  PQclear(res);
264 }
265 
266 
267 /*
268  * As above for a SQL maintenance command (returns command success).
269  * Command is executed with a cancel handler set, so Ctrl-C can
270  * interrupt it.
271  */
272 bool
273 executeMaintenanceCommand(PGconn *conn, const char *query, bool echo)
274 {
275  PGresult *res;
276  bool r;
277 
278  if (echo)
279  printf("%s\n", query);
280 
281  SetCancelConn(conn);
282  res = PQexec(conn, query);
283  ResetCancelConn();
284 
285  r = (res && PQresultStatus(res) == PGRES_COMMAND_OK);
286 
287  if (res)
288  PQclear(res);
289 
290  return r;
291 }
292 
293 /*
294  * Consume all the results generated for the given connection until
295  * nothing remains. If at least one error is encountered, return false.
296  * Note that this will block if the connection is busy.
297  */
298 bool
300 {
301  bool ok = true;
302  PGresult *result;
303 
304  SetCancelConn(conn);
305  while ((result = PQgetResult(conn)) != NULL)
306  {
307  if (!processQueryResult(conn, result))
308  ok = false;
309  }
310  ResetCancelConn();
311  return ok;
312 }
313 
314 /*
315  * Process (and delete) a query result. Returns true if there's no error,
316  * false otherwise -- but errors about trying to work on a missing relation
317  * are reported and subsequently ignored.
318  */
319 bool
321 {
322  /*
323  * If it's an error, report it. Errors about a missing table are harmless
324  * so we continue processing; but die for other errors.
325  */
326  if (PQresultStatus(result) != PGRES_COMMAND_OK)
327  {
328  char *sqlState = PQresultErrorField(result, PG_DIAG_SQLSTATE);
329 
330  pg_log_error("processing of database \"%s\" failed: %s",
331  PQdb(conn), PQerrorMessage(conn));
332 
333  if (sqlState && strcmp(sqlState, ERRCODE_UNDEFINED_TABLE) != 0)
334  {
335  PQclear(result);
336  return false;
337  }
338  }
339 
340  PQclear(result);
341  return true;
342 }
343 
344 
345 /*
346  * Split TABLE[(COLUMNS)] into TABLE and [(COLUMNS)] portions. When you
347  * finish using them, pg_free(*table). *columns is a pointer into "spec",
348  * possibly to its NUL terminator.
349  */
350 void
351 splitTableColumnsSpec(const char *spec, int encoding,
352  char **table, const char **columns)
353 {
354  bool inquotes = false;
355  const char *cp = spec;
356 
357  /*
358  * Find the first '(' not identifier-quoted. Based on
359  * dequote_downcase_identifier().
360  */
361  while (*cp && (*cp != '(' || inquotes))
362  {
363  if (*cp == '"')
364  {
365  if (inquotes && cp[1] == '"')
366  cp++; /* pair does not affect quoting */
367  else
368  inquotes = !inquotes;
369  cp++;
370  }
371  else
372  cp += PQmblen(cp, encoding);
373  }
374  *table = pnstrdup(spec, cp - spec);
375  *columns = cp;
376 }
377 
378 /*
379  * Break apart TABLE[(COLUMNS)] of "spec". With the reset_val of search_path
380  * in effect, have regclassin() interpret the TABLE portion. Append to "buf"
381  * the qualified name of TABLE, followed by any (COLUMNS). Exit on failure.
382  * We use this to interpret --table=foo under the search path psql would get,
383  * in advance of "ANALYZE public.foo" under the always-secure search path.
384  */
385 void
387  PGconn *conn, bool echo)
388 {
389  char *table;
390  const char *columns;
391  PQExpBufferData sql;
392  PGresult *res;
393  int ntups;
394 
395  splitTableColumnsSpec(spec, PQclientEncoding(conn), &table, &columns);
396 
397  /*
398  * Query must remain ABSOLUTELY devoid of unqualified names. This would
399  * be unnecessary given a regclassin() variant taking a search_path
400  * argument.
401  */
402  initPQExpBuffer(&sql);
404  "SELECT c.relname, ns.nspname\n"
405  " FROM pg_catalog.pg_class c,"
406  " pg_catalog.pg_namespace ns\n"
407  " WHERE c.relnamespace OPERATOR(pg_catalog.=) ns.oid\n"
408  " AND c.oid OPERATOR(pg_catalog.=) ");
409  appendStringLiteralConn(&sql, table, conn);
410  appendPQExpBufferStr(&sql, "::pg_catalog.regclass;");
411 
412  executeCommand(conn, "RESET search_path;", echo);
413 
414  /*
415  * One row is a typical result, as is a nonexistent relation ERROR.
416  * regclassin() unconditionally accepts all-digits input as an OID; if no
417  * relation has that OID; this query returns no rows. Catalog corruption
418  * might elicit other row counts.
419  */
420  res = executeQuery(conn, sql.data, echo);
421  ntups = PQntuples(res);
422  if (ntups != 1)
423  {
424  pg_log_error(ngettext("query returned %d row instead of one: %s",
425  "query returned %d rows instead of one: %s",
426  ntups),
427  ntups, sql.data);
428  PQfinish(conn);
429  exit(1);
430  }
432  fmtQualifiedId(PQgetvalue(res, 0, 1),
433  PQgetvalue(res, 0, 0)));
434  appendPQExpBufferStr(buf, columns);
435  PQclear(res);
436  termPQExpBuffer(&sql);
437  pg_free(table);
438 
440 }
441 
442 
443 /*
444  * Check yes/no answer in a localized way. 1=yes, 0=no, -1=neither.
445  */
446 
447 /* translator: abbreviation for "yes" */
448 #define PG_YESLETTER gettext_noop("y")
449 /* translator: abbreviation for "no" */
450 #define PG_NOLETTER gettext_noop("n")
451 
452 bool
453 yesno_prompt(const char *question)
454 {
455  char prompt[256];
456 
457  /*------
458  translator: This is a question followed by the translated options for
459  "yes" and "no". */
460  snprintf(prompt, sizeof(prompt), _("%s (%s/%s) "),
461  _(question), _(PG_YESLETTER), _(PG_NOLETTER));
462 
463  for (;;)
464  {
465  char *resp;
466 
467  resp = simple_prompt(prompt, true);
468 
469  if (strcmp(resp, _(PG_YESLETTER)) == 0)
470  {
471  free(resp);
472  return true;
473  }
474  if (strcmp(resp, _(PG_NOLETTER)) == 0)
475  {
476  free(resp);
477  return false;
478  }
479  free(resp);
480 
481  printf(_("Please answer \"%s\" or \"%s\".\n"),
483  }
484 }
char * PQerrorMessage(const PGconn *conn)
Definition: fe-connect.c:6669
char * pnstrdup(const char *in, Size len)
Definition: mcxt.c:1198
#define PG_YESLETTER
Definition: common.c:448
bool yesno_prompt(const char *question)
Definition: common.c:453
char * pgport
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void executeCommand(PGconn *conn, const char *query, bool echo)
Definition: common.c:246
bool processQueryResult(PGconn *conn, PGresult *result)
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#define printf(...)
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#define lengthof(array)
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Definition: common.c:273
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Definition: cancel.c:70
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int i
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