|
| 1 | +/*------------------------------------------------------------------------- |
| 2 | + * |
| 3 | + * database.c-- |
| 4 | + * miscellanious initialization support stuff |
| 5 | + * |
| 6 | + * Copyright (c) 1994, Regents of the University of California |
| 7 | + * |
| 8 | + * |
| 9 | + * IDENTIFICATION |
| 10 | + * $Header: /cvsroot/pgsql/src/backend/utils/misc/Attic/database.c,v 1.1 1997/11/07 07:05:46 thomas Exp $ |
| 11 | + * |
| 12 | + *------------------------------------------------------------------------- |
| 13 | + */ |
| 14 | +#include <string.h> |
| 15 | +#include <stdlib.h> |
| 16 | +#include <stdio.h> |
| 17 | +#include <unistd.h> |
| 18 | +#include <fcntl.h> |
| 19 | + |
| 20 | +#include "postgres.h" |
| 21 | +#include "miscadmin.h" |
| 22 | + |
| 23 | +#include "utils/elog.h" |
| 24 | +#include "utils/builtins.h" |
| 25 | +#include "utils/syscache.h" |
| 26 | + |
| 27 | +#include "access/heapam.h" |
| 28 | +#include "storage/bufmgr.h" |
| 29 | +#include "catalog/catname.h" |
| 30 | +#include "catalog/pg_proc.h" |
| 31 | +#include "catalog/pg_database.h" |
| 32 | + |
| 33 | +#include "access/xact.h" |
| 34 | +#include "storage/bufpage.h" |
| 35 | + |
| 36 | +/* GetDatabaseInfo() |
| 37 | + * Pull database information from pg_database. |
| 38 | + */ |
| 39 | +int |
| 40 | +GetDatabaseInfo(char *name, Oid *owner, char *path) |
| 41 | +{ |
| 42 | + Oid dbowner, |
| 43 | + dbid; |
| 44 | + char dbpath[MAXPGPATH+1]; |
| 45 | + text *dbtext; |
| 46 | + |
| 47 | + Relation dbrel; |
| 48 | + HeapTuple dbtup; |
| 49 | + HeapTuple tup; |
| 50 | + Buffer buf; |
| 51 | + HeapScanDesc scan; |
| 52 | + ScanKeyData scanKey; |
| 53 | + |
| 54 | + dbrel = heap_openr(DatabaseRelationName); |
| 55 | + if (!RelationIsValid(dbrel)) |
| 56 | + elog(FATAL,"GetDatabaseInfo: cannot open relation \"%-.*s\"", |
| 57 | + DatabaseRelationName); |
| 58 | + |
| 59 | + ScanKeyEntryInitialize(&scanKey, 0, Anum_pg_database_datname, |
| 60 | + NameEqualRegProcedure, NameGetDatum(name)); |
| 61 | + |
| 62 | + scan = heap_beginscan(dbrel, 0, NowTimeQual, 1, &scanKey); |
| 63 | + if (!HeapScanIsValid(scan)) |
| 64 | + elog(WARN, "GetDatabaseInfo: cannot begin scan of %s", DatabaseRelationName); |
| 65 | + |
| 66 | + /* |
| 67 | + * Since we're going to close the relation, copy the tuple. |
| 68 | + */ |
| 69 | + tup = heap_getnext(scan, 0, &buf); |
| 70 | + |
| 71 | + if (HeapTupleIsValid(tup)) |
| 72 | + { |
| 73 | + dbtup = heap_copytuple(tup); |
| 74 | + ReleaseBuffer(buf); |
| 75 | + } |
| 76 | + else |
| 77 | + dbtup = tup; |
| 78 | + |
| 79 | + heap_endscan(scan); |
| 80 | + |
| 81 | + if (!HeapTupleIsValid(dbtup)) |
| 82 | + { |
| 83 | + elog(NOTICE,"GetDatabaseInfo: %s entry not found %s", |
| 84 | + DatabaseRelationName,name); |
| 85 | + return TRUE; |
| 86 | + } |
| 87 | + |
| 88 | + dbowner = (Oid) heap_getattr(dbtup, InvalidBuffer, |
| 89 | + Anum_pg_database_datdba, |
| 90 | + RelationGetTupleDescriptor(dbrel), |
| 91 | + (char *) NULL); |
| 92 | + dbid = dbtup->t_oid; |
| 93 | + |
| 94 | + dbtext = (text *) heap_getattr(dbtup, InvalidBuffer, |
| 95 | + Anum_pg_database_datpath, |
| 96 | + RelationGetTupleDescriptor(dbrel), |
| 97 | + (char *) NULL); |
| 98 | + |
| 99 | + memcpy(dbpath, VARDATA(dbtext), (VARSIZE(dbtext)-VARHDRSZ)); |
| 100 | + *(dbpath+(VARSIZE(dbtext)-VARHDRSZ)) = '\0'; |
| 101 | + |
| 102 | + heap_close(dbrel); |
| 103 | + |
| 104 | + owner = palloc(sizeof(Oid)); |
| 105 | + *owner = dbowner; |
| 106 | + path = palloc(strlen(dbpath)+1); |
| 107 | + strcpy(path, dbpath); |
| 108 | + |
| 109 | + return FALSE; |
| 110 | +} /* GetDatabaseInfo() */ |
| 111 | + |
| 112 | +char * |
| 113 | +ExpandDatabasePath(char *dbpath) |
| 114 | +{ |
| 115 | + char *path; |
| 116 | + char *cp; |
| 117 | + char buf[MAXPGPATH+1]; |
| 118 | + |
| 119 | + /* leading path delimiter? then already absolute path */ |
| 120 | + if (*dbpath == SEP_CHAR) |
| 121 | + { |
| 122 | + cp = strrchr(dbpath, SEP_CHAR); |
| 123 | + strncpy(buf,dbpath,(cp-dbpath)); |
| 124 | + sprintf(&buf[cp-dbpath], "%cbase%c%s", SEP_CHAR, SEP_CHAR, (cp+1)); |
| 125 | + } |
| 126 | + /* path delimiter somewhere? then has leading environment variable */ |
| 127 | + else if (strchr(dbpath, SEP_CHAR) != NULL) |
| 128 | + { |
| 129 | + cp = strchr(dbpath, SEP_CHAR); |
| 130 | + strncpy(buf,dbpath,(cp-dbpath)); |
| 131 | + buf[cp-dbpath] = '\0'; |
| 132 | + path = getenv(buf); |
| 133 | + sprintf(buf, "%s%cbase%c%s", path, SEP_CHAR, SEP_CHAR, (cp+1)); |
| 134 | + } |
| 135 | + /* no path delimiter? then add the default path prefixes */ |
| 136 | + else |
| 137 | + { |
| 138 | + sprintf(buf, "%s%cbase%c%s", DataDir, SEP_CHAR, SEP_CHAR, dbpath); |
| 139 | + } |
| 140 | + |
| 141 | + path = palloc(strlen(buf)+1); |
| 142 | + strcpy(path,buf); |
| 143 | + |
| 144 | + return path; |
| 145 | +} /* ExpandDatabasePath() */ |
| 146 | + |
| 147 | + |
| 148 | +/* -------------------------------- |
| 149 | + * GetRawDatabaseInfo() -- Find the OID and path of the database. |
| 150 | + * |
| 151 | + * The database's oid forms half of the unique key for the system |
| 152 | + * caches and lock tables. We therefore want it initialized before |
| 153 | + * we open any relations, since opening relations puts things in the |
| 154 | + * cache. To get around this problem, this code opens and scans the |
| 155 | + * pg_database relation by hand. |
| 156 | + * |
| 157 | + * This algorithm relies on the fact that first attribute in the |
| 158 | + * pg_database relation schema is the database name. It also knows |
| 159 | + * about the internal format of tuples on disk and the length of |
| 160 | + * the datname attribute. It knows the location of the pg_database |
| 161 | + * file. |
| 162 | + * Actually, the code looks as though it is using the pg_database |
| 163 | + * tuple definition to locate the database name, so the above statement |
| 164 | + * seems to be no longer correct. - thomas 1997-11-01 |
| 165 | + * |
| 166 | + * This code is called from InitPostgres(), before we chdir() to the |
| 167 | + * local database directory and before we open any relations. |
| 168 | + * Used to be called after the chdir(), but we now want to confirm |
| 169 | + * the location of the target database using pg_database info. |
| 170 | + * - thomas 1997-11-01 |
| 171 | + * -------------------------------- |
| 172 | + */ |
| 173 | +void |
| 174 | +GetRawDatabaseInfo(char *name, Oid *owner, Oid *db_id, char *path) |
| 175 | +{ |
| 176 | + int dbfd; |
| 177 | + int fileflags; |
| 178 | + int nbytes; |
| 179 | + int max, |
| 180 | + i; |
| 181 | + HeapTuple tup; |
| 182 | + Page pg; |
| 183 | + PageHeader ph; |
| 184 | + char *dbfname; |
| 185 | + Form_pg_database tup_db; |
| 186 | + |
| 187 | + dbfname = (char *) palloc(strlen(DataDir) + strlen("pg_database") + 2); |
| 188 | + sprintf(dbfname, "%s%cpg_database", DataDir, SEP_CHAR); |
| 189 | + fileflags = O_RDONLY; |
| 190 | + |
| 191 | + if ((dbfd = open(dbfname, O_RDONLY, 0)) < 0) |
| 192 | + elog(FATAL, "Cannot open %s", dbfname); |
| 193 | + |
| 194 | + pfree(dbfname); |
| 195 | + |
| 196 | + /* ---------------- |
| 197 | + * read and examine every page in pg_database |
| 198 | + * |
| 199 | + * Raw I/O! Read those tuples the hard way! Yow! |
| 200 | + * |
| 201 | + * Why don't we use the access methods or move this code |
| 202 | + * someplace else? This is really pg_database schema dependent |
| 203 | + * code. Perhaps it should go in lib/catalog/pg_database? |
| 204 | + * -cim 10/3/90 |
| 205 | + * |
| 206 | + * mao replies 4 apr 91: yeah, maybe this should be moved to |
| 207 | + * lib/catalog. however, we CANNOT use the access methods since |
| 208 | + * those use the buffer cache, which uses the relation cache, which |
| 209 | + * requires that the dbid be set, which is what we're trying to do |
| 210 | + * here. |
| 211 | + * ---------------- |
| 212 | + */ |
| 213 | + pg = (Page) palloc(BLCKSZ); |
| 214 | + ph = (PageHeader) pg; |
| 215 | + |
| 216 | + while ((nbytes = read(dbfd, pg, BLCKSZ)) == BLCKSZ) |
| 217 | + { |
| 218 | + max = PageGetMaxOffsetNumber(pg); |
| 219 | + |
| 220 | + /* look at each tuple on the page */ |
| 221 | + for (i = 0; i <= max; i++) |
| 222 | + { |
| 223 | + int offset; |
| 224 | + |
| 225 | + /* if it's a freed tuple, ignore it */ |
| 226 | + if (!(ph->pd_linp[i].lp_flags & LP_USED)) |
| 227 | + continue; |
| 228 | + |
| 229 | + /* get a pointer to the tuple itself */ |
| 230 | + offset = (int) ph->pd_linp[i].lp_off; |
| 231 | + tup = (HeapTuple) (((char *) pg) + offset); |
| 232 | + |
| 233 | + /* |
| 234 | + * if the tuple has been deleted (the database was destroyed), |
| 235 | + * skip this tuple. XXX warning, will robinson: violation of |
| 236 | + * transaction semantics happens right here. we should check |
| 237 | + * to be sure that the xact that deleted this tuple actually |
| 238 | + * committed. only way to do this at init time is to paw over |
| 239 | + * the log relation by hand, too. let's be optimistic. |
| 240 | + * |
| 241 | + * XXX This is an evil type cast. tup->t_xmax is char[5] while |
| 242 | + * TransactionId is struct * { char data[5] }. It works but |
| 243 | + * if data is ever moved and no longer the first field this |
| 244 | + * will be broken!! -mer 11 Nov 1991. |
| 245 | + */ |
| 246 | + if (TransactionIdIsValid((TransactionId) tup->t_xmax)) |
| 247 | + continue; |
| 248 | + |
| 249 | + /* |
| 250 | + * Okay, see if this is the one we want. XXX 1 july 91: mao |
| 251 | + * and mer discover that tuples now squash t_bits. Why is |
| 252 | + * this? |
| 253 | + * |
| 254 | + * 24 july 92: mer realizes that the t_bits field is only used |
| 255 | + * in the event of null values. If no fields are null we |
| 256 | + * reduce the header size by doing the squash. t_hoff tells |
| 257 | + * you exactly how big the header actually is. use the PC |
| 258 | + * means of getting at sys cat attrs. |
| 259 | + */ |
| 260 | + tup_db = (Form_pg_database) GETSTRUCT(tup); |
| 261 | + |
| 262 | + if (strncmp(name, |
| 263 | + &(tup_db->datname.data[0]), |
| 264 | + 16) == 0) |
| 265 | + { |
| 266 | + *db_id = tup->t_oid; |
| 267 | + strncpy(path, VARDATA(&(tup_db->datpath)), |
| 268 | + (VARSIZE(&(tup_db->datpath))-VARHDRSZ)); |
| 269 | + *(path+VARSIZE(&(tup_db->datpath))-VARHDRSZ) = '\0'; |
| 270 | + |
| 271 | + goto done; |
| 272 | + } |
| 273 | + } |
| 274 | + } |
| 275 | + |
| 276 | +done: |
| 277 | + close(dbfd); |
| 278 | + pfree(pg); |
| 279 | +} /* GetRawDatabaseInfo() */ |
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