gen/nftw.c

   1 /*      $OpenBSD: nftw.c,v 1.2 2003/07/21 21:15:32 millert Exp $        */
   2
   3 /*
   4  * Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  * Sponsored in part by the Defense Advanced Research Projects
  19  * Agency (DARPA) and Air Force Research Laboratory, Air Force
  20  * Materiel Command, USAF, under agreement number F39502-99-1-0512.
  21  */
  22
  23 #if defined(LIBC_SCCS) && !defined(lint)
  24 static const char rcsid[] = "$OpenBSD: nftw.c,v 1.2 2003/07/21 21:15:32 millert Exp $";
  25 #endif /* LIBC_SCCS and not lint */
  26
  27 #include <stdio.h>
  28 #include <sys/cdefs.h>
  29 #include <sys/types.h>
  30 #include <sys/stat.h>
  31 #include <errno.h>
  32 #include <fts.h>
  33 #include <ftw.h>
  34 #include <limits.h>
  35 #include <fcntl.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38 #include <unistd.h>
  39
  40 static int
  41 both_ftw(const char *path,
  42         int (*ofn)(const char *, const struct stat *, int),
  43         int (*nfn)(const char *, const struct stat *, int, struct FTW *),
  44         int nfds, int ftwflags)
  45 {
  46         const char *paths[2];
  47         struct FTW ftw;
  48         FTSENT *cur;
  49         FTS *ftsp;
  50         int ftsflags, fnflag, error, postorder, sverrno;
  51         int cwd_fd = -1; /* cwd_fd != -1 means call chdir a lot */
  52
  53 #if __DARWIN_UNIX03
  54         /* Macro to skip the mount point itself in UNiX03 mode, in legcy
  55           mode the mount point is returned, but we don't decend into it */
  56 #define SKIP_MOUNT if ((ftwflags & FTW_MOUNT) \
  57       && cur->fts_statp->st_dev != path_stat.st_dev) { \
  58         continue; \
  59     }
  60 #else
  61 #define SKIP_MOUNT
  62 #endif
  63
  64         /* XXX - nfds is currently unused */
  65         if (nfds < 1 || nfds > OPEN_MAX) {
  66                 errno = EINVAL;
  67                 return (-1);
  68         }
  69
  70         ftsflags = FTS_COMFOLLOW;
  71         if (!(ftwflags & FTW_CHDIR))
  72                 ftsflags |= FTS_NOCHDIR;
  73         if (ftwflags & FTW_MOUNT)
  74                 ftsflags |= FTS_XDEV;
  75         if (ftwflags & FTW_PHYS) {
  76                 ftsflags |= FTS_PHYSICAL;
  77         } else {
  78                 ftsflags |= FTS_LOGICAL;
  79         }
  80         postorder = (ftwflags & FTW_DEPTH) != 0;
  81
  82         /* We have been requested to change directories, and fts doesn't
  83           always do it (never for FTS_LOGICAL, and sometimes not for
  84           FTS_PHYSICAL) */
  85         if (ftwflags & FTW_CHDIR) {
  86             cwd_fd = open(".", O_RDONLY, 0);
  87             if (cwd_fd < 0) {
  88                 return -1;
  89             }
  90             /* Prevent problems if fts ever starts using chdir when passed
  91               FTS_PHYSICAL */
  92             ftsflags |= FTS_NOCHDIR;
  93         }
  94
  95 #if __DARWIN_UNIX03
  96         struct stat path_stat;
  97
  98         /* UNIX03 requires us to return -1/errno=ELOOP if path
  99           is a looping symlink; fts_open is succesful and fts_read
 100           gives us FTS_NS which isn't very useful, in fact we get
 101           pretty much the same behaviour for ENAMETOOLONG, ENOENT,
 102           ENOTDIR, and EACCES */
 103         {
 104             int rc = stat(path, &path_stat);
 105             int e = errno;
 106             if (rc < 0
 107               && (errno == ELOOP || errno == ENAMETOOLONG || errno == ENOENT
 108               || errno == ENOTDIR || errno == EACCES)) {
 109                     return -1;
 110             }
 111             if (rc >= 0 && nfn) {
 112                 if (!S_ISDIR(path_stat.st_mode)) {
 113                     errno = ENOTDIR;
 114                     return -1;
 115                 }
 116             }
 117         }
 118 #endif
 119         paths[0] = path;
 120         paths[1] = NULL;
 121         ftsp = fts_open((char * const *)paths, ftsflags, NULL);
 122         if (ftsp == NULL) {
 123             return (-1);
 124         }
 125         error = 0;
 126         while ((cur = fts_read(ftsp)) != NULL) {
 127                 switch (cur->fts_info) {
 128                 case FTS_D:
 129                         if (postorder)
 130                                 continue;
 131                         SKIP_MOUNT;
 132                         /* we will get FTS_DNR next (this is not an issue for
 133                           FTS_DP, only FTS_D) */
 134                         if (access(cur->fts_path, R_OK) != 0)
 135                             continue;
 136                         fnflag = FTW_D;
 137                         break;
 138                 case FTS_DNR:
 139                         fnflag = FTW_DNR;
 140                         break;
 141                 case FTS_DP:
 142                         if (!postorder)
 143                                 continue;
 144                         SKIP_MOUNT;
 145                         fnflag = FTW_DP;
 146                         break;
 147                 case FTS_F:
 148                 case FTS_DEFAULT:
 149                         fnflag = FTW_F;
 150                         break;
 151                 case FTS_NS:
 152                 case FTS_NSOK:
 153                         fnflag = FTW_NS;
 154                         break;
 155                 case FTS_SL:
 156                         fnflag = FTW_SL;
 157                         break;
 158                 case FTS_SLNONE:
 159                         fnflag = nfn ? FTW_SLN : FTW_SL;
 160 #if __DARWIN_UNIX03
 161                         {
 162                             /* The legacy behaviour did not signal an error
 163                               on symlink loops unless they ended up causing
 164                               a directory cycle, but the Unix2003 standard
 165                               requires ELOOP to end ftw and nftw walks with
 166                               an error */
 167                             struct stat sb;
 168                             int rc = stat(cur->fts_path, &sb);
 169                             if (rc < 0 && errno == ELOOP) {
 170                                 error = -1;
 171                                 goto done;
 172                             }
 173                         }
 174 #endif
 175                         break;
 176                 case FTS_DC:
 177 #if __DARWIN_UNIX03
 178                         /* Unix03 says nftw should break cycles and not return
 179                           errors in non-physical mode (which is definitly what it
 180                           says ftw can't do) */
 181                         if (nfn && !(ftwflags & FTW_PHYS)) {
 182                                 /* 4489297 - when FTW_DEPTH is set, skip
 183                                    the link also */
 184                                 if (postorder)
 185                                     continue;
 186                                 fnflag = FTW_D;
 187                                 break;
 188                         }
 189 #endif
 190                         errno = ELOOP;
 191                         /* FALLTHROUGH */
 192                 default:
 193                         error = -1;
 194                         goto done;
 195                 }
 196
 197                 if (cwd_fd >= 0) {
 198                     char *dir, *free_me = NULL;
 199                     if (fnflag == FTW_D) {
 200                         dir = cur->fts_path;
 201                     } else {
 202                         /* we could alloc just enough for the directory,
 203                           and use memmove -- but that is a little more
 204                           error prone, and not noticable in with all the
 205                           extra work... */
 206                         dir = free_me = strdup(cur->fts_path);
 207                         dir[cur->fts_pathlen - cur->fts_namelen] = '\0';
 208                     }
 209                     int rc = chdir(dir);
 210                     if (free_me) {
 211                         free(free_me);
 212                     }
 213                     if (rc < 0) {
 214                         error = -1;
 215                         goto done;
 216                     }
 217                 }
 218                 if (nfn) {
 219                     ftw.base = cur->fts_pathlen - cur->fts_namelen;
 220                     ftw.level = cur->fts_level;
 221                     error = nfn(cur->fts_path, cur->fts_statp, fnflag, &ftw);
 222                 } else {
 223                     error = ofn(cur->fts_path, cur->fts_statp, fnflag);
 224                 }
 225                 if (cwd_fd >= 0) {
 226                     if (fchdir(cwd_fd) < 0) {
 227                         error = -1;
 228                         goto done;
 229                     }
 230                 }
 231
 232                 if (error != 0)
 233                         break;
 234         }
 235 done:
 236         sverrno = errno;
 237         (void) fts_close(ftsp);
 238         errno = sverrno;
 239         return (error);
 240 }
 241
 242 int
 243 ftw(const char *path, int (*fn)(const char *, const struct stat *, int),
 244     int nfds)
 245 {
 246         /* The legacy implmentation didn't follow symlinks, but Unix03
 247           does - this was likely a bug in the legacy implemtation; JKH
 248           thinks we ought change the legacy behaviour, and I agree; anyone
 249           who doesn't should replace FTW_PHYS with
 250           __DARWIN_UNIX03 ? 0 : FTW_PHYS */
 251         return both_ftw(path, fn, NULL, nfds, FTW_PHYS);
 252 }
 253
 254 int
 255 nftw(const char *path, int (*fn)(const char *, const struct stat *, int,
 256      struct FTW *), int nfds, int ftwflags)
 257 {
 258         return both_ftw(path, NULL, fn, nfds, ftwflags);
 259 }