miscinit.c

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/*-------------------------------------------------------------------------
 *
 * miscinit.c
 *	  miscellaneous initialization support stuff
 *
 * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.166 2008/01/03 21:23:15 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <sys/param.h>
#include <signal.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <fcntl.h>
#include <unistd.h>
#include <grp.h>
#include <pwd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef HAVE_UTIME_H
#include <utime.h>
#endif

#include "catalog/pg_authid.h"
#include "miscadmin.h"
#include "postmaster/autovacuum.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/pg_shmem.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/syscache.h"


#define DIRECTORY_LOCK_FILE		"postmaster.pid"

ProcessingMode Mode = InitProcessing;

/* Note: we rely on this to initialize as zeroes */
static char socketLockFile[MAXPGPATH];


/* ----------------------------------------------------------------
 *		ignoring system indexes support stuff
 *
 * NOTE: "ignoring system indexes" means we do not use the system indexes
 * for lookups (either in hardwired catalog accesses or in planner-generated
 * plans).	We do, however, still update the indexes when a catalog
 * modification is made.
 * ----------------------------------------------------------------
 */

bool		IgnoreSystemIndexes = false;

/* ----------------------------------------------------------------
 *		system index reindexing support
 *
 * When we are busy reindexing a system index, this code provides support
 * for preventing catalog lookups from using that index.
 * ----------------------------------------------------------------
 */

static Oid	currentlyReindexedHeap = InvalidOid;
static Oid	currentlyReindexedIndex = InvalidOid;

/*
 * ReindexIsProcessingHeap
 *		True if heap specified by OID is currently being reindexed.
 */
bool
ReindexIsProcessingHeap(Oid heapOid)
{
	return heapOid == currentlyReindexedHeap;
}

/*
 * ReindexIsProcessingIndex
 *		True if index specified by OID is currently being reindexed.
 */
bool
ReindexIsProcessingIndex(Oid indexOid)
{
	return indexOid == currentlyReindexedIndex;
}

/*
 * SetReindexProcessing
 *		Set flag that specified heap/index are being reindexed.
 */
void
SetReindexProcessing(Oid heapOid, Oid indexOid)
{
	Assert(OidIsValid(heapOid) && OidIsValid(indexOid));
	/* Reindexing is not re-entrant. */
	if (OidIsValid(currentlyReindexedIndex))
		elog(ERROR, "cannot reindex while reindexing");
	currentlyReindexedHeap = heapOid;
	currentlyReindexedIndex = indexOid;
}

/*
 * ResetReindexProcessing
 *		Unset reindexing status.
 */
void
ResetReindexProcessing(void)
{
	currentlyReindexedHeap = InvalidOid;
	currentlyReindexedIndex = InvalidOid;
}

/* ----------------------------------------------------------------
 *				database path / name support stuff
 * ----------------------------------------------------------------
 */

void
SetDatabasePath(const char *path)
{
	if (DatabasePath)
	{
		free(DatabasePath);
		DatabasePath = NULL;
	}
	/* use strdup since this is done before memory contexts are set up */
	if (path)
	{
		DatabasePath = strdup(path);
		AssertState(DatabasePath);
	}
}

/*
 * Set data directory, but make sure it's an absolute path.  Use this,
 * never set DataDir directly.
 */
void
SetDataDir(const char *dir)
{
	char	   *new;

	AssertArg(dir);

	/* If presented path is relative, convert to absolute */
	new = make_absolute_path(dir);

	if (DataDir)
		free(DataDir);
	DataDir = new;
}

/*
 * Change working directory to DataDir.  Most of the postmaster and backend
 * code assumes that we are in DataDir so it can use relative paths to access
 * stuff in and under the data directory.  For convenience during path
 * setup, however, we don't force the chdir to occur during SetDataDir.
 */
void
ChangeToDataDir(void)
{
	AssertState(DataDir);

	if (chdir(DataDir) < 0)
		ereport(FATAL,
				(errcode_for_file_access(),
				 errmsg("could not change directory to \"%s\": %m",
						DataDir)));
}

/*
 * If the given pathname isn't already absolute, make it so, interpreting
 * it relative to the current working directory.
 *
 * Also canonicalizes the path.  The result is always a malloc'd copy.
 *
 * Note: interpretation of relative-path arguments during postmaster startup
 * should happen before doing ChangeToDataDir(), else the user will probably
 * not like the results.
 */
char *
make_absolute_path(const char *path)
{
	char	   *new;

	/* Returning null for null input is convenient for some callers */
	if (path == NULL)
		return NULL;

	if (!is_absolute_path(path))
	{
		char	   *buf;
		size_t		buflen;

		buflen = MAXPGPATH;
		for (;;)
		{
			buf = malloc(buflen);
			if (!buf)
				ereport(FATAL,
						(errcode(ERRCODE_OUT_OF_MEMORY),
						 errmsg("out of memory")));

			if (getcwd(buf, buflen))
				break;
			else if (errno == ERANGE)
			{
				free(buf);
				buflen *= 2;
				continue;
			}
			else
			{
				free(buf);
				elog(FATAL, "could not get current working directory: %m");
			}
		}

		new = malloc(strlen(buf) + strlen(path) + 2);
		if (!new)
			ereport(FATAL,
					(errcode(ERRCODE_OUT_OF_MEMORY),
					 errmsg("out of memory")));
		sprintf(new, "%s/%s", buf, path);
		free(buf);
	}
	else
	{
		new = strdup(path);
		if (!new)
			ereport(FATAL,
					(errcode(ERRCODE_OUT_OF_MEMORY),
					 errmsg("out of memory")));
	}

	/* Make sure punctuation is canonical, too */
	canonicalize_path(new);

	return new;
}


/* ----------------------------------------------------------------
 *	User ID state
 *
 * We have to track several different values associated with the concept
 * of "user ID".
 *
 * AuthenticatedUserId is determined at connection start and never changes.
 *
 * SessionUserId is initially the same as AuthenticatedUserId, but can be
 * changed by SET SESSION AUTHORIZATION (if AuthenticatedUserIsSuperuser).
 * This is the ID reported by the SESSION_USER SQL function.
 *
 * OuterUserId is the current user ID in effect at the "outer level" (outside
 * any transaction or function).  This is initially the same as SessionUserId,
 * but can be changed by SET ROLE to any role that SessionUserId is a
 * member of.  (XXX rename to something like CurrentRoleId?)
 *
 * CurrentUserId is the current effective user ID; this is the one to use
 * for all normal permissions-checking purposes.  At outer level this will
 * be the same as OuterUserId, but it changes during calls to SECURITY
 * DEFINER functions, as well as locally in some specialized commands.
 *
 * SecurityDefinerContext is TRUE if we are within a SECURITY DEFINER function
 * or another context that temporarily changes CurrentUserId.
 * ----------------------------------------------------------------
 */
static Oid	AuthenticatedUserId = InvalidOid;
static Oid	SessionUserId = InvalidOid;
static Oid	OuterUserId = InvalidOid;
static Oid	CurrentUserId = InvalidOid;

/* We also have to remember the superuser state of some of these levels */
static bool AuthenticatedUserIsSuperuser = false;
static bool SessionUserIsSuperuser = false;

static bool SecurityDefinerContext = false;

/* We also remember if a SET ROLE is currently active */
static bool SetRoleIsActive = false;


/*
 * GetUserId - get the current effective user ID.
 *
 * Note: there's no SetUserId() anymore; use SetUserIdAndContext().
 */
Oid
GetUserId(void)
{
	AssertState(OidIsValid(CurrentUserId));
	return CurrentUserId;
}


/*
 * GetOuterUserId/SetOuterUserId - get/set the outer-level user ID.
 */
Oid
GetOuterUserId(void)
{
	AssertState(OidIsValid(OuterUserId));
	return OuterUserId;
}


static void
SetOuterUserId(Oid userid)
{
	AssertState(!SecurityDefinerContext);
	AssertArg(OidIsValid(userid));
	OuterUserId = userid;

	/* We force the effective user ID to match, too */
	CurrentUserId = userid;
}


/*
 * GetSessionUserId/SetSessionUserId - get/set the session user ID.
 */
Oid
GetSessionUserId(void)
{
	AssertState(OidIsValid(SessionUserId));
	return SessionUserId;
}


static void
SetSessionUserId(Oid userid, bool is_superuser)
{
	AssertState(!SecurityDefinerContext);
	AssertArg(OidIsValid(userid));
	SessionUserId = userid;
	SessionUserIsSuperuser = is_superuser;
	SetRoleIsActive = false;

	/* We force the effective user IDs to match, too */
	OuterUserId = userid;
	CurrentUserId = userid;
}


/*
 * GetUserIdAndContext/SetUserIdAndContext - get/set the current user ID
 * and the SecurityDefinerContext flag.
 *
 * Unlike GetUserId, GetUserIdAndContext does *not* Assert that the current
 * value of CurrentUserId is valid; nor does SetUserIdAndContext require
 * the new value to be valid.  In fact, these routines had better not
 * ever throw any kind of error.  This is because they are used by
 * StartTransaction and AbortTransaction to save/restore the settings,
 * and during the first transaction within a backend, the value to be saved
 * and perhaps restored is indeed invalid.  We have to be able to get
 * through AbortTransaction without asserting in case InitPostgres fails.
 */
void
GetUserIdAndContext(Oid *userid, bool *sec_def_context)
{
	*userid = CurrentUserId;
	*sec_def_context = SecurityDefinerContext;
}

void
SetUserIdAndContext(Oid userid, bool sec_def_context)
{
	CurrentUserId = userid;
	SecurityDefinerContext = sec_def_context;
}


/*
 * InSecurityDefinerContext - are we inside a SECURITY DEFINER context?
 */
bool
InSecurityDefinerContext(void)
{
	return SecurityDefinerContext;
}


/*
 * Initialize user identity during normal backend startup
 */
void
InitializeSessionUserId(const char *rolename)
{
	HeapTuple	roleTup;
	Form_pg_authid rform;
	Datum		datum;
	bool		isnull;
	Oid			roleid;

	/*
	 * Don't do scans if we're bootstrapping, none of the system catalogs