src/bin/scripts/common.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  *      common.c
   4  *              Common support routines for bin/scripts/
   5  *
   6  *
   7  * Portions Copyright (c) 1996-2023, 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/query_utils.h"
  26 #include "fe_utils/string_utils.h"
  27
  28 /*
  29  * Split TABLE[(COLUMNS)] into TABLE and [(COLUMNS)] portions.  When you
  30  * finish using them, pg_free(*table).  *columns is a pointer into "spec",
  31  * possibly to its NUL terminator.
  32  */
  33 void
  34 splitTableColumnsSpec(const char *spec, int encoding,
  35                                           char **table, const char **columns)
  36 {
  37         bool            inquotes = false;
  38         const char *cp = spec;
  39
  40         /*
  41          * Find the first '(' not identifier-quoted.  Based on
  42          * dequote_downcase_identifier().
  43          */
  44         while (*cp && (*cp != '(' || inquotes))
  45         {
  46                 if (*cp == '"')
  47                 {
  48                         if (inquotes && cp[1] == '"')
  49                                 cp++;                   /* pair does not affect quoting */
  50                         else
  51                                 inquotes = !inquotes;
  52                         cp++;
  53                 }
  54                 else
  55                         cp += PQmblenBounded(cp, encoding);
  56         }
  57         *table = pnstrdup(spec, cp - spec);
  58         *columns = cp;
  59 }
  60
  61 /*
  62  * Break apart TABLE[(COLUMNS)] of "spec".  With the reset_val of search_path
  63  * in effect, have regclassin() interpret the TABLE portion.  Append to "buf"
  64  * the qualified name of TABLE, followed by any (COLUMNS).  Exit on failure.
  65  * We use this to interpret --table=foo under the search path psql would get,
  66  * in advance of "ANALYZE public.foo" under the always-secure search path.
  67  */
  68 void
  69 appendQualifiedRelation(PQExpBuffer buf, const char *spec,
  70                                                 PGconn *conn, bool echo)
  71 {
  72         char       *table;
  73         const char *columns;
  74         PQExpBufferData sql;
  75         PGresult   *res;
  76         int                     ntups;
  77
  78         splitTableColumnsSpec(spec, PQclientEncoding(conn), &table, &columns);
  79
  80         /*
  81          * Query must remain ABSOLUTELY devoid of unqualified names.  This would
  82          * be unnecessary given a regclassin() variant taking a search_path
  83          * argument.
  84          */
  85         initPQExpBuffer(&sql);
  86         appendPQExpBufferStr(&sql,
  87                                                  "SELECT c.relname, ns.nspname\n"
  88                                                  " FROM pg_catalog.pg_class c,"
  89                                                  " pg_catalog.pg_namespace ns\n"
  90                                                  " WHERE c.relnamespace OPERATOR(pg_catalog.=) ns.oid\n"
  91                                                  "  AND c.oid OPERATOR(pg_catalog.=) ");
  92         appendStringLiteralConn(&sql, table, conn);
  93         appendPQExpBufferStr(&sql, "::pg_catalog.regclass;");
  94
  95         executeCommand(conn, "RESET search_path;", echo);
  96
  97         /*
  98          * One row is a typical result, as is a nonexistent relation ERROR.
  99          * regclassin() unconditionally accepts all-digits input as an OID; if no
 100          * relation has that OID; this query returns no rows.  Catalog corruption
 101          * might elicit other row counts.
 102          */
 103         res = executeQuery(conn, sql.data, echo);
 104         ntups = PQntuples(res);
 105         if (ntups != 1)
 106         {
 107                 pg_log_error(ngettext("query returned %d row instead of one: %s",
 108                                                           "query returned %d rows instead of one: %s",
 109                                                           ntups),
 110                                          ntups, sql.data);
 111                 PQfinish(conn);
 112                 exit(1);
 113         }
 114         appendPQExpBufferStr(buf,
 115                                                  fmtQualifiedId(PQgetvalue(res, 0, 1),
 116                                                                                 PQgetvalue(res, 0, 0)));
 117         appendPQExpBufferStr(buf, columns);
 118         PQclear(res);
 119         termPQExpBuffer(&sql);
 120         pg_free(table);
 121
 122         PQclear(executeQuery(conn, ALWAYS_SECURE_SEARCH_PATH_SQL, echo));
 123 }
 124
 125
 126 /*
 127  * Check yes/no answer in a localized way.  1=yes, 0=no, -1=neither.
 128  */
 129
 130 /* translator: abbreviation for "yes" */
 131 #define PG_YESLETTER gettext_noop("y")
 132 /* translator: abbreviation for "no" */
 133 #define PG_NOLETTER gettext_noop("n")
 134
 135 bool
 136 yesno_prompt(const char *question)
 137 {
 138         char            prompt[256];
 139
 140         /*------
 141            translator: This is a question followed by the translated options for
 142            "yes" and "no". */
 143         snprintf(prompt, sizeof(prompt), _("%s (%s/%s) "),
 144                          _(question), _(PG_YESLETTER), _(PG_NOLETTER));
 145
 146         for (;;)
 147         {
 148                 char       *resp;
 149
 150                 resp = simple_prompt(prompt, true);
 151
 152                 if (strcmp(resp, _(PG_YESLETTER)) == 0)
 153                 {
 154                         free(resp);
 155                         return true;
 156                 }
 157                 if (strcmp(resp, _(PG_NOLETTER)) == 0)
 158                 {
 159                         free(resp);
 160                         return false;
 161                 }
 162                 free(resp);
 163
 164                 printf(_("Please answer \"%s\" or \"%s\".\n"),
 165                            _(PG_YESLETTER), _(PG_NOLETTER));
 166         }
 167 }