common.c

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/*-------------------------------------------------------------------------
 *
 *  common.c
 *      Common support routines for bin/scripts/
 *
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/bin/scripts/common.c
 *
 *-------------------------------------------------------------------------
 */
 
#include "postgres_fe.h"
 
#include <signal.h>
#include <unistd.h>
 
#include "common.h"
#include "common/connect.h"
#include "common/logging.h"
#include "common/string.h"
#include "fe_utils/query_utils.h"
#include "fe_utils/string_utils.h"
 
/*
 * Split TABLE[(COLUMNS)] into TABLE and [(COLUMNS)] portions.  When you
 * finish using them, pg_free(*table).  *columns is a pointer into "spec",
 * possibly to its NUL terminator.
 */
void
splitTableColumnsSpec(const char *spec, int encoding,
                      char **table, const char **columns)
{
    bool        inquotes = false;
    const char *cp = spec;
 
    /*
     * Find the first '(' not identifier-quoted.  Based on
     * dequote_downcase_identifier().
     */
    while (*cp && (*cp != '(' || inquotes))
    {
        if (*cp == '"')
        {
            if (inquotes && cp[1] == '"')
                cp++;           /* pair does not affect quoting */
            else
                inquotes = !inquotes;
            cp++;
        }
        else
            cp += PQmblenBounded(cp, encoding);
    }
    *table = pnstrdup(spec, cp - spec);
    *columns = cp;
}
 
/*
 * Break apart TABLE[(COLUMNS)] of "spec".  With the reset_val of search_path
 * in effect, have regclassin() interpret the TABLE portion.  Append to "buf"
 * the qualified name of TABLE, followed by any (COLUMNS).  Exit on failure.
 * We use this to interpret --table=foo under the search path psql would get,
 * in advance of "ANALYZE public.foo" under the always-secure search path.
 */
void
appendQualifiedRelation(PQExpBuffer buf, const char *spec,
                        PGconn *conn, bool echo)
{
    char       *table;
    const char *columns;
    PQExpBufferData sql;
    PGresult   *res;
    int         ntups;
 
    splitTableColumnsSpec(spec, PQclientEncoding(conn), &table, &columns);
 
    /*
     * Query must remain ABSOLUTELY devoid of unqualified names.  This would
     * be unnecessary given a regclassin() variant taking a search_path
     * argument.
     */
    initPQExpBuffer(&sql);
    appendPQExpBufferStr(&sql,
                         "SELECT c.relname, ns.nspname\n"
                         " FROM pg_catalog.pg_class c,"
                         " pg_catalog.pg_namespace ns\n"
                         " WHERE c.relnamespace OPERATOR(pg_catalog.=) ns.oid\n"
                         "  AND c.oid OPERATOR(pg_catalog.=) ");
    appendStringLiteralConn(&sql, table, conn);
    appendPQExpBufferStr(&sql, "::pg_catalog.regclass;");
 
    executeCommand(conn, "RESET search_path;", echo);
 
    /*
     * One row is a typical result, as is a nonexistent relation ERROR.
     * regclassin() unconditionally accepts all-digits input as an OID; if no
     * relation has that OID; this query returns no rows.  Catalog corruption
     * might elicit other row counts.
     */
    res = executeQuery(conn, sql.data, echo);
    ntups = PQntuples(res);
    if (ntups != 1)
    {
        pg_log_error(ngettext("query returned %d row instead of one: %s",
                              "query returned %d rows instead of one: %s",
                              ntups),
                     ntups, sql.data);
        PQfinish(conn);
        exit(1);
    }
    appendPQExpBufferStr(buf,
                         fmtQualifiedIdEnc(PQgetvalue(res, 0, 1),
                                           PQgetvalue(res, 0, 0),
                                           PQclientEncoding(conn)));
    appendPQExpBufferStr(buf, columns);
    PQclear(res);
    termPQExpBuffer(&sql);
    pg_free(table);
 
    PQclear(executeQuery(conn, ALWAYS_SECURE_SEARCH_PATH_SQL, echo));
}
 
 
/*
 * Check yes/no answer in a localized way.  1=yes, 0=no, -1=neither.
 */
 
/* translator: abbreviation for "yes" */
#define PG_YESLETTER gettext_noop("y")
/* translator: abbreviation for "no" */
#define PG_NOLETTER gettext_noop("n")
 
bool
yesno_prompt(const char *question)
{
    char        prompt[256];
 
    /*------
       translator: This is a question followed by the translated options for
       "yes" and "no". */
    snprintf(prompt, sizeof(prompt), _("%s (%s/%s) "),
             _(question), _(PG_YESLETTER), _(PG_NOLETTER));
 
    for (;;)
    {
        char       *resp;
 
        resp = simple_prompt(prompt, true);
 
        if (strcmp(resp, _(PG_YESLETTER)) == 0)
        {
            free(resp);
            return true;
        }
        if (strcmp(resp, _(PG_NOLETTER)) == 0)
        {
            free(resp);
            return false;
        }
        free(resp);
 
        printf(_("Please answer \"%s\" or \"%s\".\n"),
               _(PG_YESLETTER), _(PG_NOLETTER));
    }
}