src/port/pgmkdirp.c

   1 /*
   2  * This is adapted from FreeBSD's src/bin/mkdir/mkdir.c, which bears
   3  * the following copyright notice:
   4  *
   5  * Copyright (c) 1983, 1992, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *        notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *        notice, this list of conditions and the following disclaimer in the
  15  *        documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *        may be used to endorse or promote products derived from this software
  18  *        without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include "c.h"
  34
  35 #include <sys/stat.h>
  36
  37
  38 /*
  39  * pg_mkdir_p --- create a directory and, if necessary, parent directories
  40  *
  41  * This is equivalent to "mkdir -p" except we don't complain if the target
  42  * directory already exists.
  43  *
  44  * We assume the path is in canonical form, i.e., uses / as the separator.
  45  *
  46  * omode is the file permissions bits for the target directory.  Note that any
  47  * parent directories that have to be created get permissions according to the
  48  * prevailing umask, but with u+wx forced on to ensure we can create there.
  49  * (We declare omode as int, not mode_t, to minimize dependencies for port.h.)
  50  *
  51  * Returns 0 on success, -1 (with errno set) on failure.
  52  *
  53  * Note that on failure, the path arg has been modified to show the particular
  54  * directory level we had problems with.
  55  */
  56 int
  57 pg_mkdir_p(char *path, int omode)
  58 {
  59         struct stat sb;
  60         mode_t          numask,
  61                                 oumask;
  62         int                     last,
  63                                 retval;
  64         char       *p;
  65
  66         retval = 0;
  67         p = path;
  68
  69 #ifdef WIN32
  70         /* skip network and drive specifiers for win32 */
  71         if (strlen(p) >= 2)
  72         {
  73                 if (p[0] == '/' && p[1] == '/')
  74                 {
  75                         /* network drive */
  76                         p = strstr(p + 2, "/");
  77                         if (p == NULL)
  78                         {
  79                                 errno = EINVAL;
  80                                 return -1;
  81                         }
  82                 }
  83                 else if (p[1] == ':' &&
  84                                  ((p[0] >= 'a' && p[0] <= 'z') ||
  85                                   (p[0] >= 'A' && p[0] <= 'Z')))
  86                 {
  87                         /* local drive */
  88                         p += 2;
  89                 }
  90         }
  91 #endif
  92
  93         /*
  94          * POSIX 1003.2: For each dir operand that does not name an existing
  95          * directory, effects equivalent to those caused by the following command
  96          * shall occur:
  97          *
  98          * mkdir -p -m $(umask -S),u+wx $(dirname dir) && mkdir [-m mode] dir
  99          *
 100          * We change the user's umask and then restore it, instead of doing
 101          * chmod's.  Note we assume umask() can't change errno.
 102          */
 103         oumask = umask(0);
 104         numask = oumask & ~(S_IWUSR | S_IXUSR);
 105         (void) umask(numask);
 106
 107         if (p[0] == '/')                        /* Skip leading '/'. */
 108                 ++p;
 109         for (last = 0; !last; ++p)
 110         {
 111                 if (p[0] == '\0')
 112                         last = 1;
 113                 else if (p[0] != '/')
 114                         continue;
 115                 *p = '\0';
 116                 if (!last && p[1] == '\0')
 117                         last = 1;
 118
 119                 if (last)
 120                         (void) umask(oumask);
 121
 122                 /* check for pre-existing directory */
 123                 if (stat(path, &sb) == 0)
 124                 {
 125                         if (!S_ISDIR(sb.st_mode))
 126                         {
 127                                 if (last)
 128                                         errno = EEXIST;
 129                                 else
 130                                         errno = ENOTDIR;
 131                                 retval = -1;
 132                                 break;
 133                         }
 134                 }
 135                 else if (mkdir(path, last ? omode : S_IRWXU | S_IRWXG | S_IRWXO) < 0)
 136                 {
 137                         retval = -1;
 138                         break;
 139                 }
 140                 if (!last)
 141                         *p = '/';
 142         }
 143
 144         /* ensure we restored umask */
 145         (void) umask(oumask);
 146
 147         return retval;
 148 }