usr/src/lib/libc/port/stdio/tempnam.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #pragma weak _tempnam = tempnam
  33
  34 #include "lint.h"
  35 #include <mtlib.h>
  36 #include <sys/types.h>
  37 #include <stdio.h>
  38 #include <string.h>
  39 #include <stdlib.h>
  40 #include <thread.h>
  41 #include <synch.h>
  42 #include <unistd.h>
  43 #include <sys/stat.h>
  44
  45 #define max(A, B) (((A) < (B))?(B):(A))
  46
  47 static char *pcopy(char *, const char *);
  48
  49 static char seed[] = "AAA";
  50
  51 static mutex_t seed_lk = DEFAULTMUTEX;
  52
  53 char *
  54 tempnam(const char *dir,        /* use this directory please (if non-NULL) */
  55         const char *pfx)        /* use this (if non-NULL) as filename prefix */
  56 {
  57         char *p, *q, *tdir;
  58         size_t x = 0, y = 0, z;
  59         struct stat64 statbuf;
  60
  61         z = sizeof (P_tmpdir) - 1;
  62         if ((tdir = getenv("TMPDIR")) != NULL) {
  63                 x = strlen(tdir);
  64         }
  65         if (dir != NULL) {
  66                 if (stat64(dir, &statbuf) == 0 && S_ISDIR(statbuf.st_mode))
  67                         y = strlen(dir);
  68         }
  69         if ((p = malloc(max(max(x, y), z)+16)) == NULL)
  70                 return (NULL);
  71         if (x > 0 && access(pcopy(p, tdir), (W_OK | X_OK)) == 0)
  72                 goto OK;
  73         if (y > 0 && access(pcopy(p, dir), (W_OK | X_OK)) == 0)
  74                 goto OK;
  75         if (access(pcopy(p, P_tmpdir), (W_OK | X_OK)) == 0)
  76                 goto OK;
  77         if (access(pcopy(p, "/tmp"), (W_OK | X_OK)) != 0) {
  78                 free(p);
  79                 return (NULL);
  80         }
  81 OK:
  82         (void) strcat(p, "/");
  83         if (pfx) {
  84                 *(p+strlen(p)+5) = '\0';
  85                 (void) strncat(p, pfx, 5);
  86         }
  87         lmutex_lock(&seed_lk);
  88         (void) strcat(p, seed);
  89         (void) strcat(p, "XXXXXX");
  90         q = seed;
  91         while (*q == 'Z')
  92                 *q++ = 'A';
  93         if (*q != '\0')
  94                 ++*q;
  95         lmutex_unlock(&seed_lk);
  96         if (*mktemp(p) == '\0') {
  97                 free(p);
  98                 return (NULL);
  99         }
 100         return (p);
 101 }
 102
 103 static char *
 104 pcopy(char *space, const char *arg)
 105 {
 106         char *p;
 107
 108         if (arg) {
 109                 (void) strcpy(space, arg);
 110                 p = space-1+strlen(space);
 111                 while ((p >= space) && (*p == '/'))
 112                         *p-- = '\0';
 113         }
 114         return (space);
 115 }