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 = NULL;
  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                 error = -1;
  68                 goto done;
  69         }
  70
  71         ftsflags = FTS_COMFOLLOW;
  72         if (!(ftwflags & FTW_CHDIR))
  73                 ftsflags |= FTS_NOCHDIR;
  74         if (ftwflags & FTW_MOUNT)
  75                 ftsflags |= FTS_XDEV;
  76         if (ftwflags & FTW_PHYS) {
  77                 ftsflags |= FTS_PHYSICAL;
  78         } else {
  79                 ftsflags |= FTS_LOGICAL;
  80         }
  81         postorder = (ftwflags & FTW_DEPTH) != 0;
  82
  83         /* We have been requested to change directories, and fts doesn't
  84           always do it (never for FTS_LOGICAL, and sometimes not for
  85           FTS_PHYSICAL) */
  86         if (ftwflags & FTW_CHDIR) {
  87             cwd_fd = open(".", O_RDONLY, 0);
  88             if (cwd_fd < 0) {
  89                 error = -1;
  90                 goto done;
  91             }
  92             /* Prevent problems if fts ever starts using chdir when passed
  93               FTS_PHYSICAL */
  94             ftsflags |= FTS_NOCHDIR;
  95         }
  96
  97 #if __DARWIN_UNIX03
  98         struct stat path_stat;
  99
 100         /* UNIX03 requires us to return -1/errno=ELOOP if path
 101           is a looping symlink; fts_open is succesful and fts_read
 102           gives us FTS_NS which isn't very useful, in fact we get
 103           pretty much the same behaviour for ENAMETOOLONG, ENOENT,
 104           ENOTDIR, and EACCES */
 105         {
 106             int rc = stat(path, &path_stat);
 107             if (rc < 0
 108               && (errno == ELOOP || errno == ENAMETOOLONG || errno == ENOENT
 109               || errno == ENOTDIR || errno == EACCES)) {
 110                     error = -1;
 111                     goto done;
 112             }
 113             if (rc >= 0 && nfn) {
 114                 if (!S_ISDIR(path_stat.st_mode)) {
 115                     errno = ENOTDIR;
 116                     error = -1;
 117                     goto done;
 118                 }
 119             }
 120         }
 121 #endif
 122         paths[0] = path;
 123         paths[1] = NULL;
 124         ftsp = fts_open((char * const *)paths, ftsflags, NULL);
 125         if (ftsp == NULL) {
 126             error = -1;
 127             goto done;
 128         }
 129         error = 0;
 130         while ((cur = fts_read(ftsp)) != NULL) {
 131                 switch (cur->fts_info) {
 132                 case FTS_D:
 133                         if (postorder)
 134                                 continue;
 135                         SKIP_MOUNT;
 136                         /* we will get FTS_DNR next (this is not an issue for
 137                           FTS_DP, only FTS_D) */
 138                         if (access(cur->fts_path, R_OK) != 0)
 139                             continue;
 140                         fnflag = FTW_D;
 141                         break;
 142                 case FTS_DNR:
 143                         fnflag = FTW_DNR;
 144                         break;
 145                 case FTS_DP:
 146                         if (!postorder)
 147                                 continue;
 148                         SKIP_MOUNT;
 149                         fnflag = FTW_DP;
 150                         break;
 151                 case FTS_F:
 152                 case FTS_DEFAULT:
 153                         fnflag = FTW_F;
 154                         break;
 155                 case FTS_NS:
 156                 case FTS_NSOK:
 157                         fnflag = FTW_NS;
 158                         break;
 159                 case FTS_SL:
 160                         fnflag = FTW_SL;
 161                         break;
 162                 case FTS_SLNONE:
 163                         fnflag = nfn ? FTW_SLN : FTW_SL;
 164 #if __DARWIN_UNIX03
 165                         {
 166                             /* The legacy behaviour did not signal an error
 167                               on symlink loops unless they ended up causing
 168                               a directory cycle, but the Unix2003 standard
 169                               requires ELOOP to end ftw and nftw walks with
 170                               an error */
 171                             struct stat sb;
 172                             int rc = stat(cur->fts_path, &sb);
 173                             if (rc < 0 && errno == ELOOP) {
 174                                 error = -1;
 175                                 goto done;
 176                             }
 177                         }
 178 #endif
 179                         break;
 180                 case FTS_DC:
 181 #if __DARWIN_UNIX03
 182                         /* Unix03 says nftw should break cycles and not return
 183                           errors in non-physical mode (which is definitly what it
 184                           says ftw can't do) */
 185                         if (nfn && !(ftwflags & FTW_PHYS)) {
 186                                 /* 4489297 - when FTW_DEPTH is set, skip
 187                                    the link also */
 188                                 if (postorder)
 189                                     continue;
 190                                 fnflag = FTW_D;
 191                                 break;
 192                         }
 193 #endif
 194                         errno = ELOOP;
 195                         /* FALLTHROUGH */
 196                 default:
 197                         error = -1;
 198                         goto done;
 199                 }
 200
 201                 if (cwd_fd >= 0) {
 202                     char *dir, *free_me = NULL;
 203                     if (fnflag == FTW_D) {
 204                         dir = cur->fts_path;
 205                     } else {
 206                         /* we could alloc just enough for the directory,
 207                           and use memmove -- but that is a little more
 208                           error prone, and not noticable in with all the
 209                           extra work... */
 210                         dir = free_me = strdup(cur->fts_path);
 211                         dir[cur->fts_pathlen - cur->fts_namelen] = '\0';
 212                     }
 213                     int rc = chdir(dir);
 214                     if (free_me) {
 215                         free(free_me);
 216                     }
 217                     if (rc < 0) {
 218                         if(cur->fts_pathlen == cur->fts_namelen &&
 219                            fnflag == FTW_DNR) {
 220                             /* If cwd_fd is our last FD, fts_read will give us FTS_DNR
 221                              * and fts_path == fts_name == "."
 222                              * This check results in the correct errno being returned.
 223                              */
 224                             errno = EMFILE;
 225                         }
 226                         error = -1;
 227                         goto done;
 228                     }
 229                 }
 230                 if (nfn) {
 231                     ftw.base = cur->fts_pathlen - cur->fts_namelen;
 232                     ftw.level = cur->fts_level;
 233                     error = nfn(cur->fts_path, cur->fts_statp, fnflag, &ftw);
 234                 } else {
 235                     error = ofn(cur->fts_path, cur->fts_statp, fnflag);
 236                 }
 237                 if (cwd_fd >= 0) {
 238                     if (fchdir(cwd_fd) < 0) {
 239                         error = -1;
 240                         goto done;
 241                     }
 242                 }
 243
 244                 if (error != 0)
 245                         break;
 246         }
 247 done:
 248         sverrno = errno;
 249         if(ftsp != NULL)
 250                 (void) fts_close(ftsp);
 251         if(cwd_fd >= 0)
 252                 (void) close(cwd_fd);
 253         errno = sverrno;
 254         return (error);
 255 }
 256
 257 int
 258 ftw(const char *path, int (*fn)(const char *, const struct stat *, int),
 259     int nfds)
 260 {
 261         /* The legacy implmentation didn't follow symlinks, but Unix03
 262           does - this was likely a bug in the legacy implemtation; JKH
 263           thinks we ought change the legacy behaviour, and I agree; anyone
 264           who doesn't should replace FTW_PHYS with
 265           __DARWIN_UNIX03 ? 0 : FTW_PHYS */
 266         return both_ftw(path, fn, NULL, nfds, FTW_PHYS);
 267 }
 268
 269 int
 270 nftw(const char *path, int (*fn)(const char *, const struct stat *, int,
 271      struct FTW *), int nfds, int ftwflags)
 272 {
 273         return both_ftw(path, NULL, fn, nfds, ftwflags);
 274 }