port/stdio/tempnam.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1988 AT&T */
/*    All Rights Reserved   */

#pragma ident   "%Z%%M% %I% %E% SMI"

#pragma weak _tempnam = tempnam

#include "lint.h"
#include <mtlib.h>
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <thread.h>
#include <synch.h>
#include <unistd.h>
#include <sys/stat.h>

#define max(A, B) (((A) < (B))?(B):(A))

static char *pcopy(char *, const char *);

static char seed[] = "AAA";

static mutex_t seed_lk = DEFAULTMUTEX;

char *
tempnam(const char *dir,    /* use this directory please (if non-NULL) */
    const char *pfx)    /* use this (if non-NULL) as filename prefix */
{
    char *p, *q, *tdir;
    size_t x = 0, y = 0, z;
    struct stat64 statbuf;

    z = sizeof (P_tmpdir) - 1;
    if ((tdir = getenv("TMPDIR")) != NULL) {
        x = strlen(tdir);
    }
    if (dir != NULL) {
        if (stat64(dir, &statbuf) == 0 && S_ISDIR(statbuf.st_mode))
            y = strlen(dir);
    }
    if ((p = malloc(max(max(x, y), z)+16)) == NULL)
        return (NULL);
    if (x > 0 && access(pcopy(p, tdir), (W_OK | X_OK)) == 0)
        goto OK;
    if (y > 0 && access(pcopy(p, dir), (W_OK | X_OK)) == 0)
        goto OK;
    if (access(pcopy(p, P_tmpdir), (W_OK | X_OK)) == 0)
        goto OK;
    if (access(pcopy(p, "/tmp"), (W_OK | X_OK)) != 0) {
        free(p);
        return (NULL);
    }
OK:
    (void) strcat(p, "/");
    if (pfx) {
        *(p+strlen(p)+5) = '\0';
        (void) strncat(p, pfx, 5);
    }
    lmutex_lock(&seed_lk);
    (void) strcat(p, seed);
    (void) strcat(p, "XXXXXX");
    q = seed;
    while (*q == 'Z')
        *q++ = 'A';
    if (*q != '\0')
        ++*q;
    lmutex_unlock(&seed_lk);
    if (*mktemp(p) == '\0') {
        free(p);
        return (NULL);
    }
    return (p);
}

static char *
pcopy(char *space, const char *arg)
{
    char *p;

    if (arg) {
        (void) strcpy(space, arg);
        p = space-1+strlen(space);
        while ((p >= space) && (*p == '/'))
            *p-- = '\0';
    }
    return (space);
}