src/port/mkdtemp.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * mkdtemp.c
   4  *        create a mode-0700 temporary directory
   5  *
   6  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
   7  *
   8  *
   9  * IDENTIFICATION
  10  *        src/port/mkdtemp.c
  11  *
  12  * This code was taken from NetBSD to provide an implementation for platforms
  13  * that lack it.  (Among compatibly-licensed implementations, the OpenBSD
  14  * version better resists denial-of-service attacks.  However, it has a
  15  * cryptographic dependency.)  The NetBSD copyright terms follow.
  16  *-------------------------------------------------------------------------
  17  */
  18
  19 #include "c.h"
  20
  21 #define _DIAGASSERT(x) do {} while (0)
  22
  23
  24 /*      $NetBSD: gettemp.c,v 1.17 2014/01/21 19:09:48 seanb Exp $       */
  25
  26 /*
  27  * Copyright (c) 1987, 1993
  28  *      The Regents of the University of California.  All rights reserved.
  29  *
  30  * Redistribution and use in source and binary forms, with or without
  31  * modification, are permitted provided that the following conditions
  32  * are met:
  33  * 1. Redistributions of source code must retain the above copyright
  34  *        notice, this list of conditions and the following disclaimer.
  35  * 2. Redistributions in binary form must reproduce the above copyright
  36  *        notice, this list of conditions and the following disclaimer in the
  37  *        documentation and/or other materials provided with the distribution.
  38  * 3. Neither the name of the University nor the names of its contributors
  39  *        may be used to endorse or promote products derived from this software
  40  *        without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  */
  54
  55 #if HAVE_NBTOOL_CONFIG_H
  56 #include "nbtool_config.h"
  57 #endif
  58
  59 #if !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP || !HAVE_MKDTEMP
  60
  61 #ifdef NOT_POSTGRESQL
  62 #include <sys/cdefs.h>
  63 #if defined(LIBC_SCCS) && !defined(lint)
  64 #if 0
  65 static char sccsid[] = "@(#)mktemp.c    8.1 (Berkeley) 6/4/93";
  66 #else
  67 __RCSID("$NetBSD: gettemp.c,v 1.17 2014/01/21 19:09:48 seanb Exp $");
  68 #endif
  69 #endif                                                  /* LIBC_SCCS and not lint */
  70 #endif
  71
  72 #include <sys/types.h>
  73 #include <sys/stat.h>
  74
  75 #include <assert.h>
  76 #include <ctype.h>
  77 #include <errno.h>
  78 #include <fcntl.h>
  79 #include <stdio.h>
  80 #include <stdlib.h>
  81 #include <unistd.h>
  82
  83 #ifdef NOT_POSTGRESQL
  84 #if HAVE_NBTOOL_CONFIG_H
  85 #define GETTEMP         __nbcompat_gettemp
  86 #else
  87 #include "reentrant.h"
  88 #include "local.h"
  89 #define GETTEMP         __gettemp
  90 #endif
  91 #endif
  92
  93 static int
  94 GETTEMP(char *path, int *doopen, int domkdir)
  95 {
  96         char       *start,
  97                            *trv;
  98         struct stat sbuf;
  99         u_int           pid;
 100
 101         /*
 102          * To guarantee multiple calls generate unique names even if the file is
 103          * not created. 676 different possibilities with 7 or more X's, 26 with 6
 104          * or less.
 105          */
 106         static char xtra[2] = "aa";
 107         int                     xcnt = 0;
 108
 109         _DIAGASSERT(path != NULL);
 110         /* doopen may be NULL */
 111
 112         pid = getpid();
 113
 114         /* Move to end of path and count trailing X's. */
 115         for (trv = path; *trv; ++trv)
 116                 if (*trv == 'X')
 117                         xcnt++;
 118                 else
 119                         xcnt = 0;
 120
 121         /* Use at least one from xtra.  Use 2 if more than 6 X's. */
 122         if (xcnt > 0)
 123         {
 124                 *--trv = xtra[0];
 125                 xcnt--;
 126         }
 127         if (xcnt > 5)
 128         {
 129                 *--trv = xtra[1];
 130                 xcnt--;
 131         }
 132
 133         /* Set remaining X's to pid digits with 0's to the left. */
 134         for (; xcnt > 0; xcnt--)
 135         {
 136                 *--trv = (pid % 10) + '0';
 137                 pid /= 10;
 138         }
 139
 140         /* update xtra for next call. */
 141         if (xtra[0] != 'z')
 142                 xtra[0]++;
 143         else
 144         {
 145                 xtra[0] = 'a';
 146                 if (xtra[1] != 'z')
 147                         xtra[1]++;
 148                 else
 149                         xtra[1] = 'a';
 150         }
 151
 152         /*
 153          * check the target directory; if you have six X's and it doesn't exist
 154          * this runs for a *very* long time.
 155          */
 156         for (start = trv + 1;; --trv)
 157         {
 158                 if (trv <= path)
 159                         break;
 160                 if (*trv == '/')
 161                 {
 162                         int                     e;
 163
 164                         *trv = '\0';
 165                         e = stat(path, &sbuf);
 166                         *trv = '/';
 167                         if (e == -1)
 168                                 return doopen == NULL && !domkdir;
 169                         if (!S_ISDIR(sbuf.st_mode))
 170                         {
 171                                 errno = ENOTDIR;
 172                                 return doopen == NULL && !domkdir;
 173                         }
 174                         break;
 175                 }
 176         }
 177
 178         for (;;)
 179         {
 180                 if (doopen)
 181                 {
 182                         if ((*doopen =
 183                                  open(path, O_CREAT | O_EXCL | O_RDWR, 0600)) >= 0)
 184                                 return 1;
 185                         if (errno != EEXIST)
 186                                 return 0;
 187                 }
 188                 else if (domkdir)
 189                 {
 190                         if (mkdir(path, 0700) >= 0)
 191                                 return 1;
 192                         if (errno != EEXIST)
 193                                 return 0;
 194                 }
 195                 else if (lstat(path, &sbuf))
 196                         return errno == ENOENT ? 1 : 0;
 197
 198                 /* tricky little algorithm for backward compatibility */
 199                 for (trv = start;;)
 200                 {
 201                         if (!*trv)
 202                                 return 0;
 203                         if (*trv == 'z')
 204                                 *trv++ = 'a';
 205                         else
 206                         {
 207                                 if (isdigit((unsigned char) *trv))
 208                                         *trv = 'a';
 209                                 else
 210                                         ++*trv;
 211                                 break;
 212                         }
 213                 }
 214         }
 215         /* NOTREACHED */
 216 }
 217
 218 #endif                                                  /* !HAVE_NBTOOL_CONFIG_H || !HAVE_MKSTEMP ||
 219                                                                  * !HAVE_MKDTEMP */
 220
 221
 222 /*      $NetBSD: mkdtemp.c,v 1.11 2012/03/15 18:22:30 christos Exp $    */
 223
 224 /*
 225  * Copyright (c) 1987, 1993
 226  *      The Regents of the University of California.  All rights reserved.
 227  *
 228  * Redistribution and use in source and binary forms, with or without
 229  * modification, are permitted provided that the following conditions
 230  * are met:
 231  * 1. Redistributions of source code must retain the above copyright
 232  *        notice, this list of conditions and the following disclaimer.
 233  * 2. Redistributions in binary form must reproduce the above copyright
 234  *        notice, this list of conditions and the following disclaimer in the
 235  *        documentation and/or other materials provided with the distribution.
 236  * 3. Neither the name of the University nor the names of its contributors
 237  *        may be used to endorse or promote products derived from this software
 238  *        without specific prior written permission.
 239  *
 240  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 241  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 242  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 243  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 244  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 245  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 246  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 247  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 248  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 249  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 250  * SUCH DAMAGE.
 251  */
 252
 253 #if HAVE_NBTOOL_CONFIG_H
 254 #include "nbtool_config.h"
 255 #endif
 256
 257 #if !HAVE_NBTOOL_CONFIG_H || !HAVE_MKDTEMP
 258
 259 #ifdef NOT_POSTGRESQL
 260
 261 #include <sys/cdefs.h>
 262 #if defined(LIBC_SCCS) && !defined(lint)
 263 #if 0
 264 static char sccsid[] = "@(#)mktemp.c    8.1 (Berkeley) 6/4/93";
 265 #else
 266 __RCSID("$NetBSD: mkdtemp.c,v 1.11 2012/03/15 18:22:30 christos Exp $");
 267 #endif
 268 #endif                                                  /* LIBC_SCCS and not lint */
 269
 270 #if HAVE_NBTOOL_CONFIG_H
 271 #define GETTEMP         __nbcompat_gettemp
 272 #else
 273 #include <assert.h>
 274 #include <errno.h>
 275 #include <stdio.h>
 276 #include <stdlib.h>
 277 #include <unistd.h>
 278 #include "reentrant.h"
 279 #include "local.h"
 280 #define GETTEMP         __gettemp
 281 #endif
 282
 283 #endif
 284
 285 char *
 286 mkdtemp(char *path)
 287 {
 288         _DIAGASSERT(path != NULL);
 289
 290         return GETTEMP(path, NULL, 1) ? path : NULL;
 291 }
 292
 293 #endif                                                  /* !HAVE_NBTOOL_CONFIG_H || !HAVE_MKDTEMP */