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/*
* SCCS: @(#)tfname.c 1.11 (98/08/28)
*
* UniSoft Ltd., London, England
*
* (C) Copyright 1992 X/Open Company Limited
*
* All rights reserved. No part of this source code may be reproduced,
* stored in a retrieval system, or transmitted, in any form or by any
* means, electronic, mechanical, photocopying, recording or otherwise,
* except as stated in the end-user licence agreement, without the prior
* permission of the copyright owners.
*
* X/Open and the 'X' symbol are trademarks of X/Open Company Limited in
* the UK and other countries.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
/************************************************************************
SCCS: @(#)tfname.c 1.11 98/08/28 TETware release 3.3
NAME: tfname.c
PRODUCT: TETware
AUTHOR: Andrew Dingwall, UniSoft Ltd.
DATE CREATED: April 1992
DESCRIPTION:
function to generate a temporary file name with some guarantee that it
will be useful
MODIFICATIONS:
Geoff Clare, UniSoft Ltd., August 1996
Missing <unistd.h>.
Andrew Dingwall, UniSoft Ltd., July 1998
Added support for shared API libraries.
************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
# include <unistd.h>
#include "dtmac.h"
#include "globals.h"
#include "error.h"
#include "ltoa.h"
#include "bstring.h"
#include "dtetlib.h"
static char *dirs[] = { (char *) 0, "/usr/tmp", "/tmp", (char *) 0 };
static char **tmpdirs;
static char salt[] = "\000AAA";
/* tryone() return codes */
#define TR_OK 1 /* file could be created */
#define TR_NEXTDIR 2 /* try again in next directory */
#define TR_NEXTFNAME 3 /* try again with next file name */
#define TR_ERROR -1 /* error - give up */
/* mode for the open() call */
#define MODEANY \
((mode_t) (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH))
/* static function declarations */
static int tryone PROTOLIST((char *, char *, char **));
/*
** tet_mktfname() - generate a temporary file name and return a pointer
** thereto
**
** return (char *) 0 on error
*/
char *tet_mktfname(prefix)
char *prefix;
{
register char **tdp;
register char *p;
register int rc = TR_ERROR;
char *fname;
/* do initial setup first time through */
if (!tmpdirs) {
if ((p = getenv("TMPDIR")) == (char *) 0 || !*p)
tmpdirs = &dirs[1];
else {
dirs[0] = p;
tmpdirs = &dirs[0];
}
}
/* generate the file name */
for (;;) {
if (salt[0]) {
error(0, "out of tmp file names", (char *) 0);
break;
}
for (tdp = tmpdirs; *tdp; tdp++)
if ((rc = tryone(*tdp, prefix, &fname)) != TR_NEXTDIR)
break;
if (rc != TR_OK && rc != TR_NEXTFNAME)
break;
for (p = &salt[sizeof salt - 2]; p >= salt; p--)
if (++*p > 'Z')
*p = 'A';
else
break;
if (rc == TR_OK)
return(fname);
}
/* here to return after an error */
return((char *) 0);
}
/*
** tryone() - try to create a temporary file
**
** return TR_* return code to indicate success or failure
** if successful, the generated file name is stored indirectly through *np
**
** we try to make sure that there is a reasonable chance of being able to
** write some data to the file
*/
static int tryone(dir, prefix, np)
char *dir, *prefix;
char **np;
{
register char *fname, *pidstr;
register int fd, n, rc;
size_t needlen;
char buf[1024];
/* work out how big a buffer is needed */
pidstr = tet_i2a(tet_mypid);
needlen = strlen(dir) + strlen(prefix) + sizeof salt + strlen(pidstr);
/* get a buffer for the file name */
errno = 0;
if ((fname = malloc(needlen)) == (char *) 0) {
error(errno, "can't get tmp file name buffer", (char *) 0);
return(TR_ERROR);
}
TRACE2(tet_Tbuf, 6, "allocate tfname = %s", tet_i2x(fname));
/* generate the file name */
(void) sprintf(fname, "%s/%s%s%s", dir, prefix, &salt[1], pidstr);
/* try to open the file */
if ((fd = OPEN(fname, O_RDWR|O_CREAT|O_EXCL|O_BINARY, MODEANY)) < 0)
switch (errno) {
case EMFILE:
case ENFILE:
/* caller will have to take his chances! */
rc = TR_OK;
break;
case EEXIST:
case EISDIR:
case ENXIO:
rc = TR_NEXTFNAME;
break;
default:
rc = TR_NEXTDIR;
break;
}
else {
/* try to write a reasonable amount of data to the file */
bzero(buf, sizeof buf);
rc = TR_OK;
for (n = 0; n < 10; n++)
if (WRITE(fd, buf, sizeof buf) != sizeof buf) {
rc = TR_NEXTDIR;
break;
}
/* close the file and unlink it */
(void) CLOSE(fd);
if (UNLINK(fname) < 0)
error(errno, "can't unlink", fname);
}
/* store the file name if ok, otherwise free the buffer */
if (rc == TR_OK)
*np = fname;
else {
TRACE2(tet_Tbuf, 6, "free tfname = %s", tet_i2x(fname));
free(fname);
}
return(rc);
}
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