external/ibm-public/postfix/dist/src/util/make_dirs.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      make_dirs 3
   6 /* SUMMARY
   7 /*      create directory hierarchy
   8 /* SYNOPSIS
   9 /*      #include <make_dirs.h>
  10 /*
  11 /*      int     make_dirs(path, perms)
  12 /*      const char *path;
  13 /*      int     perms;
  14 /* DESCRIPTION
  15 /*      make_dirs() creates the directory specified in \fIpath\fR, and
  16 /*      creates any missing intermediate directories as well. Directories
  17 /*      are created with the permissions specified in \fIperms\fR, as
  18 /*      modified by the process umask.
  19 /* DIAGNOSTICS:
  20 /*      Fatal: out of memory. make_dirs() returns 0 in case of success.
  21 /*      In case of problems. make_dirs() returns -1 and \fIerrno\fR
  22 /*      reflects the nature of the problem.
  23 /* SEE ALSO
  24 /*      mkdir(2)
  25 /* LICENSE
  26 /* .ad
  27 /* .fi
  28 /*      The Secure Mailer license must be distributed with this software.
  29 /* AUTHOR(S)
  30 /*      Wietse Venema
  31 /*      IBM T.J. Watson Research
  32 /*      P.O. Box 704
  33 /*      Yorktown Heights, NY 10598, USA
  34 /*--*/
  35
  36 /* System library. */
  37
  38 #include <sys_defs.h>
  39 #include <sys/stat.h>
  40 #include <errno.h>
  41 #include <string.h>
  42
  43 /* Utility library. */
  44
  45 #include "msg.h"
  46 #include "mymalloc.h"
  47 #include "stringops.h"
  48 #include "make_dirs.h"
  49
  50 /* make_dirs - create directory hierarchy */
  51
  52 int     make_dirs(const char *path, int perms)
  53 {
  54     char   *saved_path;
  55     unsigned char *cp;
  56     int     saved_ch;
  57     struct stat st;
  58     int     ret;
  59     mode_t  saved_mode = 0;
  60
  61     /*
  62      * Initialize. Make a copy of the path that we can safely clobber.
  63      */
  64     cp = (unsigned char *) (saved_path = mystrdup(path));
  65
  66     /*
  67      * I didn't like the 4.4BSD "mkdir -p" implementation, but coming up with
  68      * my own took a day, spread out over several days.
  69      */
  70 #define SKIP_WHILE(cond, ptr) { while(*ptr && (cond)) ptr++; }
  71
  72     SKIP_WHILE(*cp == '/', cp);
  73
  74     for (;;) {
  75         SKIP_WHILE(*cp != '/', cp);
  76         if ((saved_ch = *cp) != 0)
  77             *cp = 0;
  78         if ((ret = stat(saved_path, &st)) >= 0) {
  79             if (!S_ISDIR(st.st_mode)) {
  80                 errno = ENOTDIR;
  81                 ret = -1;
  82                 break;
  83             }
  84             saved_mode = st.st_mode;
  85         } else {
  86             if (errno != ENOENT)
  87                 break;
  88
  89             /*
  90              * mkdir(foo) fails with EEXIST if foo is a symlink.
  91              */
  92 #if 0
  93
  94             /*
  95              * Create a new directory. Unfortunately, mkdir(2) has no
  96              * equivalent of open(2)'s O_CREAT|O_EXCL safety net, so we must
  97              * require that the parent directory is not world writable.
  98              * Detecting a lost race condition after the fact is not
  99              * sufficient, as an attacker could repeat the attack and add one
 100              * directory level at a time.
 101              */
 102             if (saved_mode & S_IWOTH) {
 103                 msg_warn("refusing to mkdir %s: parent directory is writable by everyone",
 104                          saved_path);
 105                 errno = EPERM;
 106                 ret = -1;
 107                 break;
 108             }
 109 #endif
 110             if ((ret = mkdir(saved_path, perms)) < 0) {
 111                 if (errno != EEXIST)
 112                     break;
 113                 /* Race condition? */
 114                 if ((ret = stat(saved_path, &st)) < 0)
 115                     break;
 116                 if (!S_ISDIR(st.st_mode)) {
 117                     errno = ENOTDIR;
 118                     ret = -1;
 119                     break;
 120                 }
 121             }
 122         }
 123         if (saved_ch != 0)
 124             *cp = saved_ch;
 125         SKIP_WHILE(*cp == '/', cp);
 126         if (*cp == 0)
 127             break;
 128     }
 129
 130     /*
 131      * Cleanup.
 132      */
 133     myfree(saved_path);
 134     return (ret);
 135 }
 136
 137 #ifdef TEST
 138
 139  /*
 140   * Test program. Usage: make_dirs path...
 141   */
 142 #include <stdlib.h>
 143 #include <msg_vstream.h>
 144
 145 int     main(int argc, char **argv)
 146 {
 147     msg_vstream_init(argv[0], VSTREAM_ERR);
 148     if (argc < 2)
 149         msg_fatal("usage: %s path...", argv[0]);
 150     while (--argc > 0 && *++argv != 0)
 151         if (make_dirs(*argv, 0755))
 152             msg_fatal("%s: %m", *argv);
 153     exit(0);
 154 }
 155
 156 #endif