bootstrap.c

Go to the documentation of this file.

/*-------------------------------------------------------------------------
 *
 * bootstrap.c
 *    routines to support running postgres in 'bootstrap' mode
 *  bootstrap mode is used to create the initial template database
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *    src/backend/bootstrap/bootstrap.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include <unistd.h>
#include <signal.h>
 
#include "access/genam.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "access/tableam.h"
#include "access/toast_compression.h"
#include "access/xact.h"
#include "bootstrap/bootstrap.h"
#include "catalog/index.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_type.h"
#include "common/link-canary.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "pg_getopt.h"
#include "postmaster/postmaster.h"
#include "storage/bufpage.h"
#include "storage/ipc.h"
#include "storage/proc.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/relmapper.h"
 
 
static void CheckerModeMain(void);
static void bootstrap_signals(void);
static Form_pg_attribute AllocateAttribute(void);
static void populate_typ_list(void);
static Oid  gettype(char *type);
static void cleanup(void);
 
/* ----------------
 *      global variables
 * ----------------
 */
 
Relation    boot_reldesc;       /* current relation descriptor */
 
Form_pg_attribute attrtypes[MAXATTR];   /* points to attribute info */
int         numattr;            /* number of attributes for cur. rel */
 
 
/*
 * Basic information associated with each type.  This is used before
 * pg_type is filled, so it has to cover the datatypes used as column types
 * in the core "bootstrapped" catalogs.
 *
 *      XXX several of these input/output functions do catalog scans
 *          (e.g., F_REGPROCIN scans pg_proc).  this obviously creates some
 *          order dependencies in the catalog creation process.
 */
struct typinfo
{
    char        name[NAMEDATALEN];
    Oid         oid;
    Oid         elem;
    int16       len;
    bool        byval;
    char        align;
    char        storage;
    Oid         collation;
    Oid         inproc;
    Oid         outproc;
};
 
static const struct typinfo TypInfo[] = {
    {"bool", BOOLOID, 0, 1, true, TYPALIGN_CHAR, TYPSTORAGE_PLAIN, InvalidOid,
    F_BOOLIN, F_BOOLOUT},
    {"bytea", BYTEAOID, 0, -1, false, TYPALIGN_INT, TYPSTORAGE_EXTENDED, InvalidOid,
    F_BYTEAIN, F_BYTEAOUT},
    {"char", CHAROID, 0, 1, true, TYPALIGN_CHAR, TYPSTORAGE_PLAIN, InvalidOid,
    F_CHARIN, F_CHAROUT},
    {"int2", INT2OID, 0, 2, true, TYPALIGN_SHORT, TYPSTORAGE_PLAIN, InvalidOid,
    F_INT2IN, F_INT2OUT},
    {"int4", INT4OID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_INT4IN, F_INT4OUT},
    {"float4", FLOAT4OID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_FLOAT4IN, F_FLOAT4OUT},
    {"name", NAMEOID, CHAROID, NAMEDATALEN, false, TYPALIGN_CHAR, TYPSTORAGE_PLAIN, C_COLLATION_OID,
    F_NAMEIN, F_NAMEOUT},
    {"regclass", REGCLASSOID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_REGCLASSIN, F_REGCLASSOUT},
    {"regproc", REGPROCOID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_REGPROCIN, F_REGPROCOUT},
    {"regtype", REGTYPEOID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_REGTYPEIN, F_REGTYPEOUT},
    {"regrole", REGROLEOID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_REGROLEIN, F_REGROLEOUT},
    {"regnamespace", REGNAMESPACEOID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_REGNAMESPACEIN, F_REGNAMESPACEOUT},
    {"text", TEXTOID, 0, -1, false, TYPALIGN_INT, TYPSTORAGE_EXTENDED, DEFAULT_COLLATION_OID,
    F_TEXTIN, F_TEXTOUT},
    {"oid", OIDOID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_OIDIN, F_OIDOUT},
    {"tid", TIDOID, 0, 6, false, TYPALIGN_SHORT, TYPSTORAGE_PLAIN, InvalidOid,
    F_TIDIN, F_TIDOUT},
    {"xid", XIDOID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_XIDIN, F_XIDOUT},
    {"cid", CIDOID, 0, 4, true, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_CIDIN, F_CIDOUT},
    {"pg_node_tree", PG_NODE_TREEOID, 0, -1, false, TYPALIGN_INT, TYPSTORAGE_EXTENDED, DEFAULT_COLLATION_OID,
    F_PG_NODE_TREE_IN, F_PG_NODE_TREE_OUT},
    {"int2vector", INT2VECTOROID, INT2OID, -1, false, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_INT2VECTORIN, F_INT2VECTOROUT},
    {"oidvector", OIDVECTOROID, OIDOID, -1, false, TYPALIGN_INT, TYPSTORAGE_PLAIN, InvalidOid,
    F_OIDVECTORIN, F_OIDVECTOROUT},
    {"_int4", INT4ARRAYOID, INT4OID, -1, false, TYPALIGN_INT, TYPSTORAGE_EXTENDED, InvalidOid,
    F_ARRAY_IN, F_ARRAY_OUT},
    {"_text", 1009, TEXTOID, -1, false, TYPALIGN_INT, TYPSTORAGE_EXTENDED, DEFAULT_COLLATION_OID,
    F_ARRAY_IN, F_ARRAY_OUT},
    {"_oid", 1028, OIDOID, -1, false, TYPALIGN_INT, TYPSTORAGE_EXTENDED, InvalidOid,
    F_ARRAY_IN, F_ARRAY_OUT},
    {"_char", 1002, CHAROID, -1, false, TYPALIGN_INT, TYPSTORAGE_EXTENDED, InvalidOid,
    F_ARRAY_IN, F_ARRAY_OUT},
    {"_aclitem", 1034, ACLITEMOID, -1, false, TYPALIGN_INT, TYPSTORAGE_EXTENDED, InvalidOid,
    F_ARRAY_IN, F_ARRAY_OUT}
};
 
static const int n_types = sizeof(TypInfo) / sizeof(struct typinfo);
 
struct typmap
{                               /* a hack */
    Oid         am_oid;
    FormData_pg_type am_typ;
};
 
static List *Typ = NIL;         /* List of struct typmap* */
static struct typmap *Ap = NULL;
 
static Datum values[MAXATTR];   /* current row's attribute values */
static bool Nulls[MAXATTR];
 
static MemoryContext nogc = NULL;   /* special no-gc mem context */
 
/*
 *  At bootstrap time, we first declare all the indices to be built, and
 *  then build them.  The IndexList structure stores enough information
 *  to allow us to build the indices after they've been declared.
 */
 
typedef struct _IndexList
{
    Oid         il_heap;
    Oid         il_ind;
    IndexInfo  *il_info;
    struct _IndexList *il_next;
} IndexList;
 
static IndexList *ILHead = NULL;
 
 
/*
 * In shared memory checker mode, all we really want to do is create shared
 * memory and semaphores (just to prove we can do it with the current GUC
 * settings).  Since, in fact, that was already done by
 * CreateSharedMemoryAndSemaphores(), we have nothing more to do here.
 */
static void
CheckerModeMain(void)
{
    proc_exit(0);
}
 
/*
 *   The main entry point for running the backend in bootstrap mode
 *
 *   The bootstrap mode is used to initialize the template database.
 *   The bootstrap backend doesn't speak SQL, but instead expects
 *   commands in a special bootstrap language.
 *
 *   When check_only is true, startup is done only far enough to verify that
 *   the current configuration, particularly the passed in options pertaining
 *   to shared memory sizing, options work (or at least do not cause an error
 *   up to shared memory creation).
 */
void
BootstrapModeMain(int argc, char *argv[], bool check_only)
{
    int         i;
    char       *progname = argv[0];
    int         flag;
    char       *userDoption = NULL;
    uint32      bootstrap_data_checksum_version = 0;    /* No checksum */
    yyscan_t    scanner;
 
    Assert(!IsUnderPostmaster);
 
    InitStandaloneProcess(argv[0]);
 
    /* Set defaults, to be overridden by explicit options below */
    InitializeGUCOptions();
 
    /* an initial --boot or --check should be present */
    Assert(argc > 1
           && (strcmp(argv[1], "--boot") == 0
               || strcmp(argv[1], "--check") == 0));
    argv++;
    argc--;
 
    while ((flag = getopt(argc, argv, "B:c:d:D:Fkr:X:-:")) != -1)
    {
        switch (flag)
        {
            case 'B':
                SetConfigOption("shared_buffers", optarg, PGC_POSTMASTER, PGC_S_ARGV);
                break;
            case '-':
 
                /*
                 * Error if the user misplaced a special must-be-first option
                 * for dispatching to a subprogram.  parse_dispatch_option()
                 * returns DISPATCH_POSTMASTER if it doesn't find a match, so
                 * error for anything else.
                 */
                if (parse_dispatch_option(optarg) != DISPATCH_POSTMASTER)
                    ereport(ERROR,
                            (errcode(ERRCODE_SYNTAX_ERROR),
                             errmsg("--%s must be first argument", optarg)));
 
                /* FALLTHROUGH */
            case 'c':
                {
                    char       *name,
                               *value;
 
                    ParseLongOption(optarg, &name, &value);
                    if (!value)
                    {
                        if (flag == '-')
                            ereport(ERROR,
                                    (errcode(ERRCODE_SYNTAX_ERROR),
                                     errmsg("--%s requires a value",
                                            optarg)));
                        else
                            ereport(ERROR,
                                    (errcode(ERRCODE_SYNTAX_ERROR),
                                     errmsg("-c %s requires a value",
                                            optarg)));
                    }
 
                    SetConfigOption(name, value, PGC_POSTMASTER, PGC_S_ARGV);
                    pfree(name);
                    pfree(value);
                    break;
                }
            case 'D':
                userDoption = pstrdup(optarg);
                break;
            case 'd':
                {
                    /* Turn on debugging for the bootstrap process. */
                    char       *debugstr;
 
                    debugstr = psprintf("debug%s", optarg);
                    SetConfigOption("log_min_messages", debugstr,
                                    PGC_POSTMASTER, PGC_S_ARGV);
                    SetConfigOption("client_min_messages", debugstr,
                                    PGC_POSTMASTER, PGC_S_ARGV);
                    pfree(debugstr);
                }
                break;
            case 'F':
                SetConfigOption("fsync", "false", PGC_POSTMASTER, PGC_S_ARGV);
                break;
            case 'k':
                bootstrap_data_checksum_version = PG_DATA_CHECKSUM_VERSION;
                break;
            case 'r':
                strlcpy(OutputFileName, optarg, MAXPGPATH);
                break;
            case 'X':
                SetConfigOption("wal_segment_size", optarg, PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
                break;
            default:
                write_stderr("Try \"%s --help\" for more information.\n",
                             progname);
                proc_exit(1);
                break;
        }
    }
 
    if (argc != optind)
    {
        write_stderr("%s: invalid command-line arguments\n", progname);
        proc_exit(1);
    }
 
    /* Acquire configuration parameters */
    if (!SelectConfigFiles(userDoption, progname))
        proc_exit(1);
 
    /*
     * Validate we have been given a reasonable-looking DataDir and change
     * into it
     */
    checkDataDir();
    ChangeToDataDir();
 
    CreateDataDirLockFile(false);
 
    SetProcessingMode(BootstrapProcessing);
    IgnoreSystemIndexes = true;
 
    InitializeMaxBackends();
 
    /*
     * Even though bootstrapping runs in single-process mode, initialize
     * postmaster child slots array so that --check can detect running out of
     * shared memory or other resources if max_connections is set too high.
     */
    InitPostmasterChildSlots();
 
    InitializeFastPathLocks();
 
    CreateSharedMemoryAndSemaphores();
 
    /*
     * Estimate number of openable files.  This is essential too in --check
     * mode, because on some platforms semaphores count as open files.
     */
    set_max_safe_fds();
 
    /*
     * XXX: It might make sense to move this into its own function at some
     * point. Right now it seems like it'd cause more code duplication than
     * it's worth.
     */
    if (check_only)
    {
        SetProcessingMode(NormalProcessing);
        CheckerModeMain();
        abort();
    }
 
    /*
     * Do backend-like initialization for bootstrap mode
     */
    InitProcess();
 
    BaseInit();
 
    bootstrap_signals();
    BootStrapXLOG(bootstrap_data_checksum_version);
 
    /*
     * To ensure that src/common/link-canary.c is linked into the backend, we
     * must call it from somewhere.  Here is as good as anywhere.
     */
    if (pg_link_canary_is_frontend())
        elog(ERROR, "backend is incorrectly linked to frontend functions");
 
    InitPostgres(NULL, InvalidOid, NULL, InvalidOid, 0, NULL);
 
    /* Initialize stuff for bootstrap-file processing */
    for (i = 0; i < MAXATTR; i++)
    {
        attrtypes[i] = NULL;
        Nulls[i] = false;
    }
 
    if (boot_yylex_init(&scanner) != 0)
        elog(ERROR, "yylex_init() failed: %m");
 
    /*
     * Process bootstrap input.
     */
    StartTransactionCommand();
    boot_yyparse(scanner);
    CommitTransactionCommand();
 
    /*
     * We should now know about all mapped relations, so it's okay to write
     * out the initial relation mapping files.
     */
    RelationMapFinishBootstrap();
 
    /* Clean up and exit */
    cleanup();
    proc_exit(0);
}
 
 
/* ----------------------------------------------------------------
 *                      misc functions
 * ----------------------------------------------------------------
 */
 
/*
 * Set up signal handling for a bootstrap process
 */
static void
bootstrap_signals(void)
{
    Assert(!IsUnderPostmaster);
 
    /*
     * We don't actually need any non-default signal handling in bootstrap
     * mode; "curl up and die" is a sufficient response for all these cases.
     * Let's set that handling explicitly, as documentation if nothing else.
     */
    pqsignal(SIGHUP, SIG_DFL);
    pqsignal(SIGINT, SIG_DFL);
    pqsignal(SIGTERM, SIG_DFL);
    pqsignal(SIGQUIT, SIG_DFL);
}
 
/* ----------------------------------------------------------------
 *              MANUAL BACKEND INTERACTIVE INTERFACE COMMANDS
 * ----------------------------------------------------------------
 */
 
/* ----------------
 *      boot_openrel
 *
 * Execute BKI OPEN command.
 * ----------------
 */
void
boot_openrel(char *relname)
{
    int         i;
 
    if (strlen(relname) >= NAMEDATALEN)
        relname[NAMEDATALEN - 1] = '\0';
 
    /*
     * pg_type must be filled before any OPEN command is executed, hence we
     * can now populate Typ if we haven't yet.
     */
    if (Typ == NIL)
        populate_typ_list();
 
    if (boot_reldesc != NULL)
        closerel(NULL);
 
    elog(DEBUG4, "open relation %s, attrsize %d",
         relname, (int) ATTRIBUTE_FIXED_PART_SIZE);
 
    boot_reldesc = table_openrv(makeRangeVar(NULL, relname, -1), NoLock);
    numattr = RelationGetNumberOfAttributes(boot_reldesc);
    for (i = 0; i < numattr; i++)
    {
        if (attrtypes[i] == NULL)
            attrtypes[i] = AllocateAttribute();
        memmove((char *) attrtypes[i],
                (char *) TupleDescAttr(boot_reldesc->rd_att, i),
                ATTRIBUTE_FIXED_PART_SIZE);
 
        {
            Form_pg_attribute at = attrtypes[i];
 
            elog(DEBUG4, "create attribute %d name %s len %d num %d type %u",
                 i, NameStr(at->attname), at->attlen, at->attnum,
                 at->atttypid);
        }
    }
}
 
/* ----------------
 *      closerel
 * ----------------
 */
void
closerel(char *relname)
{
    if (relname)
    {
        if (boot_reldesc)
        {
            if (strcmp(RelationGetRelationName(boot_reldesc), relname) != 0)
                elog(ERROR, "close of %s when %s was expected",
                     relname, RelationGetRelationName(boot_reldesc));
        }
        else
            elog(ERROR, "close of %s before any relation was opened",
                 relname);
    }
 
    if (boot_reldesc == NULL)
        elog(ERROR, "no open relation to close");
    else
    {
        elog(DEBUG4, "close relation %s",
             RelationGetRelationName(boot_reldesc));
        table_close(boot_reldesc, NoLock);
        boot_reldesc = NULL;
    }
}
 
 
 
/* ----------------
 * DEFINEATTR()
 *
 * define a <field,type> pair
 * if there are n fields in a relation to be created, this routine
 * will be called n times
 * ----------------
 */
void
DefineAttr(char *name, char *type, int attnum, int nullness)
{
    Oid         typeoid;
 
    if (boot_reldesc != NULL)
    {
        elog(WARNING, "no open relations allowed with CREATE command");
        closerel(NULL);
    }
 
    if (attrtypes[attnum] == NULL)
        attrtypes[attnum] = AllocateAttribute();
    MemSet(attrtypes[attnum], 0, ATTRIBUTE_FIXED_PART_SIZE);
 
    namestrcpy(&attrtypes[attnum]->attname, name);
    elog(DEBUG4, "column %s %s", NameStr(attrtypes[attnum]->attname), type);
    attrtypes[attnum]->attnum = attnum + 1;
 
    typeoid = gettype(type);
 
    if (Typ != NIL)
    {
        attrtypes[attnum]->atttypid = Ap->am_oid;
        attrtypes[attnum]->attlen = Ap->am_typ.typlen;
        attrtypes[attnum]->attbyval = Ap->am_typ.typbyval;
        attrtypes[attnum]->attalign = Ap->am_typ.typalign;
        attrtypes[attnum]->attstorage = Ap->am_typ.typstorage;
        attrtypes[attnum]->attcompression = InvalidCompressionMethod;
        attrtypes[attnum]->attcollation = Ap->am_typ.typcollation;
        /* if an array type, assume 1-dimensional attribute */
        if (Ap->am_typ.typelem != InvalidOid && Ap->am_typ.typlen < 0)
            attrtypes[attnum]->attndims = 1;
        else
            attrtypes[attnum]->attndims = 0;
    }
    else
    {
        attrtypes[attnum]->atttypid = TypInfo[typeoid].oid;
        attrtypes[attnum]->attlen = TypInfo[typeoid].len;
        attrtypes[attnum]->attbyval = TypInfo[typeoid].byval;
        attrtypes[attnum]->attalign = TypInfo[typeoid].align;
        attrtypes[attnum]->attstorage = TypInfo[typeoid].storage;
        attrtypes[attnum]->attcompression = InvalidCompressionMethod;
        attrtypes[attnum]->attcollation = TypInfo[typeoid].collation;
        /* if an array type, assume 1-dimensional attribute */
        if (TypInfo[typeoid].elem != InvalidOid &&
            attrtypes[attnum]->attlen < 0)
            attrtypes[attnum]->attndims = 1;
        else
            attrtypes[attnum]->attndims = 0;
    }
 
    /*
     * If a system catalog column is collation-aware, force it to use C
     * collation, so that its behavior is independent of the database's
     * collation.  This is essential to allow template0 to be cloned with a
     * different database collation.
     */
    if (OidIsValid(attrtypes[attnum]->attcollation))
        attrtypes[attnum]->attcollation = C_COLLATION_OID;
 
    attrtypes[attnum]->atttypmod = -1;
    attrtypes[attnum]->attislocal = true;
 
    if (nullness == BOOTCOL_NULL_FORCE_NOT_NULL)
    {
        attrtypes[attnum]->attnotnull = true;
    }
    else if (nullness == BOOTCOL_NULL_FORCE_NULL)
    {
        attrtypes[attnum]->attnotnull = false;
    }
    else
    {
        Assert(nullness == BOOTCOL_NULL_AUTO);
 
        /*
         * Mark as "not null" if type is fixed-width and prior columns are
         * likewise fixed-width and not-null.  This corresponds to case where
         * column can be accessed directly via C struct declaration.
         */
        if (attrtypes[attnum]->attlen > 0)
        {
            int         i;
 
            /* check earlier attributes */
            for (i = 0; i < attnum; i++)
            {
                if (attrtypes[i]->attlen <= 0 ||
                    !attrtypes[i]->attnotnull)
                    break;
            }
            if (i == attnum)
                attrtypes[attnum]->attnotnull = true;
        }
    }
}
 
 
/* ----------------
 *      InsertOneTuple
 *
 * If objectid is not zero, it is a specific OID to assign to the tuple.
 * Otherwise, an OID will be assigned (if necessary) by heap_insert.
 * ----------------
 */
void
InsertOneTuple(void)
{
    HeapTuple   tuple;
    TupleDesc   tupDesc;
    int         i;
 
    elog(DEBUG4, "inserting row with %d columns", numattr);
 
    tupDesc = CreateTupleDesc(numattr, attrtypes);
    tuple = heap_form_tuple(tupDesc, values, Nulls);
    pfree(tupDesc);             /* just free's tupDesc, not the attrtypes */
 
    simple_heap_insert(boot_reldesc, tuple);
    heap_freetuple(tuple);
    elog(DEBUG4, "row inserted");
 
    /*
     * Reset null markers for next tuple
     */
    for (i = 0; i < numattr; i++)
        Nulls[i] = false;
}
 
/* ----------------
 *      InsertOneValue
 * ----------------
 */
void
InsertOneValue(char *value, int i)
{
    Oid         typoid;
    int16       typlen;
    bool        typbyval;
    char        typalign;
    char        typdelim;
    Oid         typioparam;
    Oid         typinput;
    Oid         typoutput;
 
    Assert(i >= 0 && i < MAXATTR);
 
    elog(DEBUG4, "inserting column %d value \"%s\"", i, value);
 
    typoid = TupleDescAttr(boot_reldesc->rd_att, i)->atttypid;
 
    boot_get_type_io_data(typoid,
                          &typlen, &typbyval, &typalign,
                          &typdelim, &typioparam,
                          &typinput, &typoutput);
 
    values[i] = OidInputFunctionCall(typinput, value, typioparam, -1);
 
    /*
     * We use ereport not elog here so that parameters aren't evaluated unless
     * the message is going to be printed, which generally it isn't
     */
    ereport(DEBUG4,
            (errmsg_internal("inserted -> %s",
                             OidOutputFunctionCall(typoutput, values[i]))));
}
 
/* ----------------
 *      InsertOneNull
 * ----------------
 */
void
InsertOneNull(int i)
{
    elog(DEBUG4, "inserting column %d NULL", i);
    Assert(i >= 0 && i < MAXATTR);
    if (TupleDescAttr(boot_reldesc->rd_att, i)->attnotnull)
        elog(ERROR,
             "NULL value specified for not-null column \"%s\" of relation \"%s\"",
             NameStr(TupleDescAttr(boot_reldesc->rd_att, i)->attname),
             RelationGetRelationName(boot_reldesc));
    values[i] = PointerGetDatum(NULL);
    Nulls[i] = true;
}
 
/* ----------------
 *      cleanup
 * ----------------
 */
static void
cleanup(void)
{
    if (boot_reldesc != NULL)
        closerel(NULL);
}
 
/* ----------------
 *      populate_typ_list
 *
 * Load the Typ list by reading pg_type.
 * ----------------
 */
static void
populate_typ_list(void)
{
    Relation    rel;
    TableScanDesc scan;
    HeapTuple   tup;
    MemoryContext old;
 
    Assert(Typ == NIL);
 
    rel = table_open(TypeRelationId, NoLock);
    scan = table_beginscan_catalog(rel, 0, NULL);
    old = MemoryContextSwitchTo(TopMemoryContext);
    while ((tup = heap_getnext(scan, ForwardScanDirection)) != NULL)
    {
        Form_pg_type typForm = (Form_pg_type) GETSTRUCT(tup);
        struct typmap *newtyp;
 
        newtyp = (struct typmap *) palloc(sizeof(struct typmap));
        Typ = lappend(Typ, newtyp);
 
        newtyp->am_oid = typForm->oid;
        memcpy(&newtyp->am_typ, typForm, sizeof(newtyp->am_typ));
    }
    MemoryContextSwitchTo(old);
    table_endscan(scan);
    table_close(rel, NoLock);
}
 
/* ----------------
 *      gettype
 *
 * NB: this is really ugly; it will return an integer index into TypInfo[],
 * and not an OID at all, until the first reference to a type not known in
 * TypInfo[].  At that point it will read and cache pg_type in Typ,
 * and subsequently return a real OID (and set the global pointer Ap to
 * point at the found row in Typ).  So caller must check whether Typ is
 * still NIL to determine what the return value is!
 * ----------------
 */
static Oid
gettype(char *type)
{
    if (Typ != NIL)
    {
        ListCell   *lc;
 
        foreach(lc, Typ)
        {
            struct typmap *app = lfirst(lc);
 
            if (strncmp(NameStr(app->am_typ.typname), type, NAMEDATALEN) == 0)
            {
                Ap = app;
                return app->am_oid;
            }
        }
 
        /*
         * The type wasn't known; reload the pg_type contents and check again
         * to handle composite types, added since last populating the list.
         */
 
        list_free_deep(Typ);
        Typ = NIL;
        populate_typ_list();
 
        /*
         * Calling gettype would result in infinite recursion for types
         * missing in pg_type, so just repeat the lookup.
         */
        foreach(lc, Typ)
        {
            struct typmap *app = lfirst(lc);
 
            if (strncmp(NameStr(app->am_typ.typname), type, NAMEDATALEN) == 0)
            {
                Ap = app;
                return app->am_oid;
            }
        }
    }
    else
    {
        int         i;
 
        for (i = 0; i < n_types; i++)
        {
            if (strncmp(type, TypInfo[i].name, NAMEDATALEN) == 0)
                return i;
        }
        /* Not in TypInfo, so we'd better be able to read pg_type now */
        elog(DEBUG4, "external type: %s", type);
        populate_typ_list();
        return gettype(type);
    }
    elog(ERROR, "unrecognized type \"%s\"", type);
    /* not reached, here to make compiler happy */
    return 0;
}
 
/* ----------------
 *      boot_get_type_io_data
 *
 * Obtain type I/O information at bootstrap time.  This intentionally has
 * almost the same API as lsyscache.c's get_type_io_data, except that
 * we only support obtaining the typinput and typoutput routines, not
 * the binary I/O routines.  It is exported so that array_in and array_out
 * can be made to work during early bootstrap.
 * ----------------
 */
void
boot_get_type_io_data(Oid typid,
                      int16 *typlen,
                      bool *typbyval,
                      char *typalign,
                      char *typdelim,
                      Oid *typioparam,
                      Oid *typinput,
                      Oid *typoutput)
{
    if (Typ != NIL)
    {
        /* We have the boot-time contents of pg_type, so use it */
        struct typmap *ap = NULL;
        ListCell   *lc;
 
        foreach(lc, Typ)
        {
            ap = lfirst(lc);
            if (ap->am_oid == typid)
                break;
        }
 
        if (!ap || ap->am_oid != typid)
            elog(ERROR, "type OID %u not found in Typ list", typid);
 
        *typlen = ap->am_typ.typlen;
        *typbyval = ap->am_typ.typbyval;
        *typalign = ap->am_typ.typalign;
        *typdelim = ap->am_typ.typdelim;
 
        /* XXX this logic must match getTypeIOParam() */
        if (OidIsValid(ap->am_typ.typelem))
            *typioparam = ap->am_typ.typelem;
        else
            *typioparam = typid;
 
        *typinput = ap->am_typ.typinput;
        *typoutput = ap->am_typ.typoutput;
    }
    else
    {
        /* We don't have pg_type yet, so use the hard-wired TypInfo array */
        int         typeindex;
 
        for (typeindex = 0; typeindex < n_types; typeindex++)
        {
            if (TypInfo[typeindex].oid == typid)
                break;
        }
        if (typeindex >= n_types)
            elog(ERROR, "type OID %u not found in TypInfo", typid);
 
        *typlen = TypInfo[typeindex].len;
        *typbyval = TypInfo[typeindex].byval;
        *typalign = TypInfo[typeindex].align;
        /* We assume typdelim is ',' for all boot-time types */
        *typdelim = ',';
 
        /* XXX this logic must match getTypeIOParam() */
        if (OidIsValid(TypInfo[typeindex].elem))
            *typioparam = TypInfo[typeindex].elem;
        else
            *typioparam = typid;
 
        *typinput = TypInfo[typeindex].inproc;
        *typoutput = TypInfo[typeindex].outproc;
    }
}
 
/* ----------------
 *      AllocateAttribute
 *
 * Note: bootstrap never sets any per-column ACLs, so we only need
 * ATTRIBUTE_FIXED_PART_SIZE space per attribute.
 * ----------------
 */
static Form_pg_attribute
AllocateAttribute(void)
{
    return (Form_pg_attribute)
        MemoryContextAllocZero(TopMemoryContext, ATTRIBUTE_FIXED_PART_SIZE);
}
 
/*
 *  index_register() -- record an index that has been set up for building
 *                      later.
 *
 *      At bootstrap time, we define a bunch of indexes on system catalogs.
 *      We postpone actually building the indexes until just before we're
 *      finished with initialization, however.  This is because the indexes
 *      themselves have catalog entries, and those have to be included in the
 *      indexes on those catalogs.  Doing it in two phases is the simplest
 *      way of making sure the indexes have the right contents at the end.
 */
void
index_register(Oid heap,
               Oid ind,
               const IndexInfo *indexInfo)
{
    IndexList  *newind;
    MemoryContext oldcxt;
 
    /*
     * XXX mao 10/31/92 -- don't gc index reldescs, associated info at
     * bootstrap time.  we'll declare the indexes now, but want to create them
     * later.
     */
 
    if (nogc == NULL)
        nogc = AllocSetContextCreate(NULL,
                                     "BootstrapNoGC",
                                     ALLOCSET_DEFAULT_SIZES);
 
    oldcxt = MemoryContextSwitchTo(nogc);
 
    newind = (IndexList *) palloc(sizeof(IndexList));
    newind->il_heap = heap;
    newind->il_ind = ind;
    newind->il_info = (IndexInfo *) palloc(sizeof(IndexInfo));
 
    memcpy(newind->il_info, indexInfo, sizeof(IndexInfo));
    /* expressions will likely be null, but may as well copy it */
    newind->il_info->ii_Expressions =
        copyObject(indexInfo->ii_Expressions);
    newind->il_info->ii_ExpressionsState = NIL;
    /* predicate will likely be null, but may as well copy it */
    newind->il_info->ii_Predicate =
        copyObject(indexInfo->ii_Predicate);
    newind->il_info->ii_PredicateState = NULL;
    /* no exclusion constraints at bootstrap time, so no need to copy */
    Assert(indexInfo->ii_ExclusionOps == NULL);
    Assert(indexInfo->ii_ExclusionProcs == NULL);
    Assert(indexInfo->ii_ExclusionStrats == NULL);
 
    newind->il_next = ILHead;
    ILHead = newind;
 
    MemoryContextSwitchTo(oldcxt);
}
 
 
/*
 * build_indices -- fill in all the indexes registered earlier
 */
void
build_indices(void)
{
    for (; ILHead != NULL; ILHead = ILHead->il_next)
    {
        Relation    heap;
        Relation    ind;
 
        /* need not bother with locks during bootstrap */
        heap = table_open(ILHead->il_heap, NoLock);
        ind = index_open(ILHead->il_ind, NoLock);
 
        index_build(heap, ind, ILHead->il_info, false, false);
 
        index_close(ind, NoLock);
        table_close(heap, NoLock);
    }
}