lib/makepath.c

   1 /* makepath.c -- Ensure that a directory path exists.
   2    Copyright (C) 1990, 1997, 1998 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by David MacKenzie <djm@gnu.ai.mit.edu> and Jim Meyering.  */
  19
  20 #if HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #if __GNUC__
  25 # define alloca __builtin_alloca
  26 #else
  27 # if HAVE_ALLOCA_H
  28 #  include <alloca.h>
  29 # else
  30 #  ifdef _AIX
  31  #  pragma alloca
  32 #  else
  33 char *alloca ();
  34 #  endif
  35 # endif
  36 #endif
  37
  38 #include <stdio.h>
  39 #include <sys/types.h>
  40 #include <sys/stat.h>
  41 #if HAVE_UNISTD_H
  42 # include <unistd.h>
  43 #endif
  44
  45 #if STAT_MACROS_BROKEN
  46 # undef S_ISDIR
  47 #endif
  48
  49 #if !defined(S_ISDIR) && defined(S_IFDIR)
  50 # define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
  51 #endif
  52
  53 #if STDC_HEADERS
  54 # include <stdlib.h>
  55 #endif
  56
  57 #if HAVE_ERRNO_H
  58 # include <errno.h>
  59 #endif
  60
  61 #ifndef errno
  62 extern int errno;
  63 #endif
  64
  65 #if HAVE_STRING_H
  66 # include <string.h>
  67 #else
  68 # include <strings.h>
  69 # ifndef strchr
  70 #  define strchr index
  71 # endif
  72 #endif
  73
  74 #ifndef S_IWUSR
  75 # define S_IWUSR 0200
  76 #endif
  77
  78 #ifndef S_IXUSR
  79 # define S_IXUSR 0100
  80 #endif
  81
  82 #define WX_USR (S_IWUSR | S_IXUSR)
  83
  84 #ifdef __MSDOS__
  85 typedef int uid_t;
  86 typedef int gid_t;
  87 #endif
  88
  89 #include "save-cwd.h"
  90 #include "makepath.h"
  91 #include "error.h"
  92
  93 void strip_trailing_slashes ();
  94
  95 #define CLEANUP_CWD                                     \
  96   do                                                    \
  97     {                                                   \
  98       /* We're done operating on basename_dir.          \
  99          Restore working directory.  */                 \
 100       if (do_chdir)                                     \
 101         {                                               \
 102           int fail = restore_cwd (&cwd, NULL, NULL);    \
 103           free_cwd (&cwd);                              \
 104           if (fail)                                     \
 105             return 1;                                   \
 106         }                                               \
 107     }                                                   \
 108   while (0)
 109
 110 #define CLEANUP                                         \
 111   do                                                    \
 112     {                                                   \
 113       umask (oldmask);                                  \
 114       CLEANUP_CWD;                                      \
 115     }                                                   \
 116   while (0)
 117
 118 /* Ensure that the directory ARGPATH exists.
 119    Remove any trailing slashes from ARGPATH before calling this function.
 120
 121    Create any leading directories that don't already exist, with
 122    permissions PARENT_MODE.
 123    If the last element of ARGPATH does not exist, create it as
 124    a new directory with permissions MODE.
 125    If OWNER and GROUP are non-negative, use them to set the UID and GID of
 126    any created directories.
 127    If VERBOSE_FMT_STRING is nonzero, use it as a printf format
 128    string for printing a message after successfully making a directory,
 129    with the name of the directory that was just made as an argument.
 130    If PRESERVE_EXISTING is non-zero and ARGPATH is an existing directory,
 131    then do not attempt to set its permissions and ownership.
 132
 133    Return 0 if ARGPATH exists as a directory with the proper
 134    ownership and permissions when done, otherwise 1.  */
 135
 136 int
 137 make_path (const char *argpath,
 138            int mode,
 139            int parent_mode,
 140            uid_t owner,
 141            gid_t group,
 142            int preserve_existing,
 143            const char *verbose_fmt_string)
 144 {
 145   struct stat stats;
 146   int retval = 0;
 147
 148   if (stat (argpath, &stats))
 149     {
 150       char *slash;
 151       int tmp_mode;             /* Initial perms for leading dirs.  */
 152       int re_protect;           /* Should leading dirs be unwritable? */
 153       struct ptr_list
 154       {
 155         char *dirname_end;
 156         struct ptr_list *next;
 157       };
 158       struct ptr_list *p, *leading_dirs = NULL;
 159       int do_chdir;             /* Whether to chdir before each mkdir.  */
 160       struct saved_cwd cwd;
 161       char *basename_dir;
 162       char *dirpath;
 163
 164       /* Temporarily relax umask in case it's overly restrictive.  */
 165       int oldmask = umask (0);
 166
 167       /* Make a copy of ARGPATH that we can scribble NULs on.  */
 168       dirpath = (char *) alloca (strlen (argpath) + 1);
 169       strcpy (dirpath, argpath);
 170       strip_trailing_slashes (dirpath);
 171
 172       /* If leading directories shouldn't be writable or executable,
 173          or should have set[ug]id or sticky bits set and we are setting
 174          their owners, we need to fix their permissions after making them.  */
 175       if (((parent_mode & WX_USR) != WX_USR)
 176           || ((owner != (uid_t) -1 || group != (gid_t) -1)
 177               && (parent_mode & 07000) != 0))
 178         {
 179           tmp_mode = 0700;
 180           re_protect = 1;
 181         }
 182       else
 183         {
 184           tmp_mode = parent_mode;
 185           re_protect = 0;
 186         }
 187
 188       /* If we can record the current working directory, we may be able
 189          to do the chdir optimization.  */
 190       do_chdir = !save_cwd (&cwd);
 191
 192       /* If we've saved the cwd and DIRPATH is an absolute pathname,
 193          we must chdir to `/' in order to enable the chdir optimization.
 194          So if chdir ("/") fails, turn off the optimization.  */
 195       if (do_chdir && *dirpath == '/' && chdir ("/") < 0)
 196         do_chdir = 0;
 197
 198       slash = dirpath;
 199
 200       /* Skip over leading slashes.  */
 201       while (*slash == '/')
 202         slash++;
 203
 204       while (1)
 205         {
 206           int newly_created_dir = 1;
 207
 208           /* slash points to the leftmost unprocessed component of dirpath.  */
 209           basename_dir = slash;
 210
 211           slash = strchr (slash, '/');
 212           if (slash == NULL)
 213             break;
 214
 215           /* If we're *not* doing chdir before each mkdir, then we have to refer
 216              to the target using the full (multi-component) directory name.  */
 217           if (!do_chdir)
 218             basename_dir = dirpath;
 219
 220           *slash = '\0';
 221           if (mkdir (basename_dir, tmp_mode))
 222             {
 223               if (stat (basename_dir, &stats))
 224                 {
 225                   error (0, errno, "cannot create directory `%s'", dirpath);
 226                   CLEANUP;
 227                   return 1;
 228                 }
 229               else if (!S_ISDIR (stats.st_mode))
 230                 {
 231                   error (0, 0, "`%s' exists but is not a directory", dirpath);
 232                   CLEANUP;
 233                   return 1;
 234                 }
 235               else
 236                 {
 237                   /* DIRPATH already exists and is a directory. */
 238                   newly_created_dir = 0;
 239                 }
 240             }
 241
 242           if (newly_created_dir)
 243             {
 244               if (verbose_fmt_string)
 245                 fprintf (stderr, verbose_fmt_string, dirpath);
 246
 247               if ((owner != (uid_t) -1 || group != (gid_t) -1)
 248                   && chown (basename_dir, owner, group)
 249 #if defined(AFS) && defined (EPERM)
 250                   && errno != EPERM
 251 #endif
 252                   )
 253                 {
 254                   error (0, errno, "%s", dirpath);
 255                   CLEANUP;
 256                   return 1;
 257                 }
 258
 259               if (re_protect)
 260                 {
 261                   struct ptr_list *new = (struct ptr_list *)
 262                     alloca (sizeof (struct ptr_list));
 263                   new->dirname_end = slash;
 264                   new->next = leading_dirs;
 265                   leading_dirs = new;
 266                 }
 267             }
 268
 269           /* If we were able to save the initial working directory,
 270              then we can use chdir to change into each directory before
 271              creating an entry in that directory.  This avoids making
 272              stat and mkdir process O(n^2) file name components.  */
 273           if (do_chdir && chdir (basename_dir) < 0)
 274             {
 275               error (0, errno, "cannot chdir to directory, %s", dirpath);
 276               CLEANUP;
 277               return 1;
 278             }
 279
 280           *slash++ = '/';
 281
 282           /* Avoid unnecessary calls to `stat' when given
 283              pathnames containing multiple adjacent slashes.  */
 284           while (*slash == '/')
 285             slash++;
 286         }
 287
 288       if (!do_chdir)
 289         basename_dir = dirpath;
 290
 291       /* We're done making leading directories.
 292          Create the final component of the path.  */
 293
 294       /* The path could end in "/." or contain "/..", so test
 295          if we really have to create the directory.  */
 296
 297       if (stat (basename_dir, &stats) && mkdir (basename_dir, mode))
 298         {
 299           error (0, errno, "cannot create directory `%s'", dirpath);
 300           CLEANUP;
 301           return 1;
 302         }
 303
 304       /* Done creating directories.  Restore original umask.  */
 305       umask (oldmask);
 306
 307       if (verbose_fmt_string != NULL)
 308         error (0, 0, verbose_fmt_string, dirpath);
 309
 310       if (owner != (uid_t) -1 && group != (gid_t) -1)
 311         {
 312           if (chown (basename_dir, owner, group)
 313 #ifdef AFS
 314               && errno != EPERM
 315 #endif
 316               )
 317             {
 318               error (0, errno, "cannot chown %s", dirpath);
 319               retval = 1;
 320             }
 321           /* chown may have turned off some permission bits we wanted.  */
 322           if ((mode & 07000) != 0 && chmod (basename_dir, mode))
 323             {
 324               error (0, errno, "cannot chmod %s", dirpath);
 325               retval = 1;
 326             }
 327         }
 328
 329       CLEANUP_CWD;
 330
 331       /* If the mode for leading directories didn't include owner "wx"
 332          privileges, we have to reset their protections to the correct
 333          value.  */
 334       for (p = leading_dirs; p != NULL; p = p->next)
 335         {
 336           *(p->dirname_end) = '\0';
 337           if (chmod (dirpath, parent_mode))
 338             {
 339               error (0, errno, "%s", dirpath);
 340               retval = 1;
 341             }
 342         }
 343     }
 344   else
 345     {
 346       /* We get here if the entire path already exists.  */
 347
 348       const char *dirpath = argpath;
 349
 350       if (!S_ISDIR (stats.st_mode))
 351         {
 352           error (0, 0, "`%s' exists but is not a directory", dirpath);
 353           return 1;
 354         }
 355
 356       if (!preserve_existing)
 357         {
 358           /* chown must precede chmod because on some systems,
 359              chown clears the set[ug]id bits for non-superusers,
 360              resulting in incorrect permissions.
 361              On System V, users can give away files with chown and then not
 362              be able to chmod them.  So don't give files away.  */
 363
 364           if ((owner != (uid_t) -1 || group != (gid_t) -1)
 365               && chown (dirpath, owner, group)
 366 #ifdef AFS
 367               && errno != EPERM
 368 #endif
 369               )
 370             {
 371               error (0, errno, "%s", dirpath);
 372               retval = 1;
 373             }
 374           if (chmod (dirpath, mode))
 375             {
 376               error (0, errno, "%s", dirpath);
 377               retval = 1;
 378             }
 379         }
 380     }
 381
 382   return retval;
 383 }