Initial import of the CDE 2.1.30 sources from the Open Group.

cde/lib/tt/mini_isam/isamopen.c

@@ -0,0 +1,300 @@
+/*%%  (c) Copyright 1993, 1994 Hewlett-Packard Company			 */
+/*%%  (c) Copyright 1993, 1994 International Business Machines Corp.	 */
+/*%%  (c) Copyright 1993, 1994 Sun Microsystems, Inc.			 */
+/*%%  (c) Copyright 1993, 1994 Novell, Inc. 				 */
+/*%%  $TOG: isamopen.c /main/5 1998/04/10 08:03:57 mgreess $ 			 				 */
+#ifndef lint
+static char sccsid[] = "@(#)isamopen.c 1.10 89/07/17 Copyr 1988 Sun Micro";
+#endif
+/*
+ * Copyright (c) 1988 by Sun Microsystems, Inc.
+ */
+
+/*
+ * isamopen.c
+ *
+ * Description: _amopen()
+ *	Open an ISAM file.
+ *	
+ *
+ */
+
+#include <stdlib.h>
+#include "isam_impl.h"
+
+/*
+ * _amopen(isfname, varflag, minlen, maxlen, primkey, 
+ *	    isfhandle, curpos, errcode)
+ *
+ * _amopen() opens an ISAM file.
+ *
+ * Input params:
+ * isfname ISAM file name
+ * 
+ * Output params:
+ * isfhandle a file handle to be used in subsequent operations on the file
+ * varflag TRUE if file is for variable length records
+ * minlen, maxlen minimum and maximum record length
+ * curpos  initial current record position
+ * errcode {iserrno, isstat1-4} 
+ *
+ * _amopen() returns 0 if successful, or -1 to indicate an error.
+ */
+
+/* ARGSUSED */
+int
+_amopen(isfname, openmode, varflag, minlen, maxlen,
+	isfhandle, curpos, errcode)
+    char		*isfname;
+    enum openmode	openmode;
+    Bool		*varflag;
+    int			*minlen, *maxlen;
+    Bytearray		*isfhandle;
+    Bytearray		*curpos;
+    struct errcode	*errcode;
+{
+    Fcb			*fcb;
+    Bytearray		isfhandle0;
+    Crp			*crp;
+    int			err;
+
+
+    _isam_entryhook();
+
+    /*
+     * Make isfhandle0. 
+     */
+
+    isfhandle0 = _makeisfhandle(isfname);
+
+    /*
+     * Invalidate the FCB cache entry to avoid a problem found when using 
+     * multiple servers.
+     */
+    if ((fcb = _mngfcb_find(&isfhandle0)) != NULL) {
+	(void) _watchfd_decr(_isfcb_nfds(fcb));
+	_isfcb_close(fcb);
+	_mngfcb_delete(&isfhandle0);
+    }
+
+    /*
+     * Get the FCB that corresponds to the isfhandle handle.
+     */
+    if ((fcb = _openfcb(&isfhandle0, errcode)) == NULL) {
+	goto ERROR;
+    }
+
+    /* 
+     * Check if the FCB allows writes if INOUT or OUTPUT is needed.
+     */
+    if (fcb->rdonly==TRUE && (openmode==OM_INOUT || openmode==OM_OUTPUT)) {
+	_amseterrcode(errcode, EACCES);
+	goto ERROR;
+    }
+    
+    /*
+     * Fill output parameters. 
+     */
+    *minlen = fcb->minreclen;
+    *maxlen = fcb->maxreclen;
+    *varflag = fcb->varflag;
+    *isfhandle = isfhandle0;
+
+    /*
+     * Initial current record position.
+     */
+    if (FCB_NOPRIMARY_KEY(fcb)) {
+	/* Use physical order. */
+	crp = (Crp *) _ismalloc(sizeof(*crp));
+	memset ((char *) crp, 0, sizeof(*crp));
+
+	crp->keyid = PHYS_ORDER;
+	crp->flag = CRP_BEFOREANY;
+
+	curpos->length = sizeof(*crp);
+	curpos->data = (char *) crp;
+    }
+    else {
+	/* 
+	 * Use primary key order. 
+	 */
+
+	crp = (Crp *) _ismalloc((unsigned)(sizeof(*crp) + fcb->keys[0].k2_len));
+	memset((char *) crp, 0, (sizeof(*crp) + fcb->keys[0].k2_len)); 
+
+	crp->keyid = fcb->keys[0].k2_keyid;
+	crp->flag = CRP_BEFOREANY;
+
+	_iskey_fillmin(&fcb->keys[0], crp->key);
+
+	curpos->length = sizeof(*crp) + fcb->keys[0].k2_len;
+	curpos->data = (char *) crp;
+	
+	/*
+	 * Set full key length as the number of bytes to match in key comparison
+	 */
+	crp->matchkeylen = fcb->keys[0].k2_len - RECNOSIZE;
+	
+	if (ALLOWS_DUPS2(&fcb->keys[0]))
+	    crp->matchkeylen -= DUPIDSIZE;
+    }
+
+    _isam_exithook();
+    return (ISOK);
+
+ ERROR:
+    _bytearr_free(&isfhandle0);
+    _isam_exithook();
+    return (ISERROR);
+}
+
+
+/*
+ * fcb = _openfcb(isfhandle, errcode)
+ *
+ * Try to locate FCB in the FCB cache. If not found, open the FCB and
+ * insert it into the cache. 
+ *
+ * Return a pointer to the FCB, or NULL in the case of any error.
+ */
+
+#define FDNEEDED	3		     /* Needs 3 UNIX fd to open a file*/
+Fcb *
+_openfcb(isfhandle, errcode)
+    Bytearray		*isfhandle;
+    struct errcode	*errcode;
+{
+    Fcb			*fcb;
+    Bytearray		*isfhandle2;
+    char		errbuf[BUFSIZ];
+    char		*errmsg0;
+
+    if ((fcb = _mngfcb_find(isfhandle)) != NULL)
+	goto out;
+
+    /*
+     * Check that there are UNIX file descriptors available.	
+     */
+    while (_watchfd_check() < FDNEEDED) {
+	/*
+	 * Find victim (LRU FCB) and close it.
+	 */
+	if((isfhandle2 = _mngfcb_victim()) == NULL) 
+	    _isfatal_error ("_openfcb() cannot find LRU victim");
+
+	fcb = _mngfcb_find(isfhandle2);
+	(void) _watchfd_decr(_isfcb_nfds(fcb));
+	_isfcb_close(fcb);
+	_mngfcb_delete(isfhandle2);
+    }
+
+    /*
+     * Open files, create FCB block.
+     */
+    if ((fcb = _isfcb_open(_getisfname(isfhandle), errcode)) == NULL) {
+	return (NULL);
+    }
+
+    /*
+     * Check that ISAM file is not corrupted (only check magic number).
+     */
+    if (_check_isam_magic(fcb) != ISOK) {
+	_amseterrcode(errcode, EBADFILE);
+	_isfcb_close(fcb);
+	return (NULL);
+    }
+
+    /*
+     * Read information from CNTL PAGE and store it in the FCB.
+     */
+    if (_isfcb_cntlpg_r(fcb) == ISERROR)
+	_isfatal_error("_openfcb() cannot read CNTL PAGE");
+
+    /*
+     * Register UNIX file descriptors consumed.
+     */
+    (void) _watchfd_incr(_isfcb_nfds(fcb));
+
+    /*
+     * Insert new entry into the FCB cache.
+     */
+    _mngfcb_insert(fcb, isfhandle); 
+
+ out:
+
+    /*
+     * Check that all file descriptors are open. This is needed to handle
+     * user errors such as removing .ind or .var files.
+     */
+    if (fcb->varflag==TRUE && fcb->varfd == -1) {
+	char *fmt = "%s.var has been removed";
+	if (strlen(fmt) + strlen(fcb->isfname) + 1 >= BUFSIZ)
+	  errmsg0 = (char*) malloc(strlen(fmt) + strlen(fcb->isfname) + 1);
+	else
+	  errmsg0 = errbuf;
+
+	(void)sprintf(errmsg0, fmt, fcb->isfname);
+	_isam_warning(errmsg0);
+	_amseterrcode(errcode, EBADFILE);
+	if (errmsg0 != errbuf) free(errmsg0);
+	goto err;
+    }
+
+    if ((fcb->nkeys > 1 || !FCB_NOPRIMARY_KEY(fcb)) && fcb->indfd == -1) {
+	char *fmt = "%s.ind has been removed";
+	if (strlen(fmt) + strlen(fcb->isfname) + 1 >= BUFSIZ)
+	  errmsg0 = (char*) malloc(strlen(fmt) + strlen(fcb->isfname) + 1);
+	else
+	  errmsg0 = errbuf;
+
+	(void)sprintf(errmsg0, fmt, fcb->isfname);
+	_isam_warning(errmsg0);
+	_amseterrcode(errcode, EBADFILE);
+	if (errmsg0 != errbuf) free(errmsg0);
+	goto err;
+    }
+
+    return (fcb);
+
+ err:
+    /*
+     * Delete FCB and remove it from FCB cache. Close UNIX fds.
+     *
+     * This is needed to recover netisamd server if users remove .ind or
+     * or .var files.
+     */
+    (void) _watchfd_decr(_isfcb_nfds(fcb));
+    _isfcb_close(fcb);
+    _mngfcb_delete(isfhandle);
+
+    return (NULL);
+
+}
+
+/*
+ * isfname = _getisfname(isfhandle)
+ *
+ * Get ISAM file name from ISAM file handle.
+ */
+
+char *
+_getisfname(isfhandle)
+    Bytearray		*isfhandle;
+{
+    return (isfhandle->data);
+}
+
+
+/*
+ * isfhandle = _makeisfhandle(isfname)
+ *
+ * Make ISAM file handle.
+ */
+
+Bytearray 
+_makeisfhandle(isfname)
+    char	*isfname;
+{
+    return (_bytearr_new((u_short)(strlen(isfname) + 1), isfname));
+}
+