/hphp/runtime/ext_zend_compat/php-src/TSRM/tsrm_virtual_cwd.cpp

#include "hphp/runtime/ext_zend_compat/php-src/TSRM/tsrm_virtual_cwd.h"

#include "hphp/runtime/ext/std/ext_std_file.h"

#define CWD_STATE_COPY(d, s)                       \
  (d)->cwd_length = (s)->cwd_length;               \
  (d)->cwd = (char *) malloc((s)->cwd_length+1);   \
  memcpy((d)->cwd, (s)->cwd, (s)->cwd_length+1);

#define CWD_STATE_FREE(s)                          \
  free((s)->cwd);

#ifdef ZTS
ts_rsrc_id cwd_globals_id;
#else
virtual_cwd_globals cwd_globals;
#endif

CWD_API char *tsrm_realpath(const char *path, char *real_path TSRMLS_DC) {
  HPHP::Variant rp = HPHP::HHVM_FN(realpath)(path);
  if (rp.isBoolean()) {
    assert(!rp.toBoolean());
    return nullptr;
  }

  HPHP::StringData *ret = rp.getStringData();

  if (real_path) {
    int copy_len = ret->size();
    memcpy(real_path, ret->data(), copy_len);
    real_path[copy_len] = '\0';
    return real_path;
  } else {
    return strndup(ret->data(), ret->size());
  }
}

#ifdef PHP_WIN32
static inline unsigned long realpath_cache_key(const char *path, int path_len TSRMLS_DC) /* {{{ */
{
  register unsigned long h;
  char *bucket_key_start = tsrm_win32_get_path_sid_key(path TSRMLS_CC);
  char *bucket_key = (char *)bucket_key_start;
  const char *e = bucket_key + strlen(bucket_key);

  if (!bucket_key) {
    return 0;
  }

  for (h = 2166136261U; bucket_key < e;) {
    h *= 16777619;
    h ^= *bucket_key++;
  }
  HeapFree(GetProcessHeap(), 0, (LPVOID)bucket_key_start);
  return h;
}
/* }}} */
#else
static inline unsigned long realpath_cache_key(const char *path, int path_len) /* {{{ */
{
  register unsigned long h;
  const char *e = path + path_len;

  for (h = 2166136261U; path < e;) {
    h *= 16777619;
    h ^= *path++;
  }

  return h;
}
/* }}} */
#endif /* defined(PHP_WIN32) */


static inline void realpath_cache_add(const char *path, int path_len, const char *realpath, int realpath_len, int is_dir, time_t t TSRMLS_DC) /* {{{ */
{
  long size = sizeof(realpath_cache_bucket) + path_len + 1;
  int same = 1;

  if (realpath_len != path_len ||
      memcmp(path, realpath, path_len) != 0) {
    size += realpath_len + 1;
    same = 0;
  }

  if (CWDG(realpath_cache_size) + size <= CWDG(realpath_cache_size_limit)) {
    realpath_cache_bucket *bucket = (realpath_cache_bucket*) malloc(size);
    unsigned long n;

    if (bucket == NULL) {
      return;
    }

#ifdef PHP_WIN32
    bucket->key = realpath_cache_key(path, path_len TSRMLS_CC);
#else
    bucket->key = realpath_cache_key(path, path_len);
#endif
    bucket->path = (char*)bucket + sizeof(realpath_cache_bucket);
    memcpy(bucket->path, path, path_len+1);
    bucket->path_len = path_len;
    if (same) {
      bucket->realpath = bucket->path;
    } else {
      bucket->realpath = bucket->path + (path_len + 1);
      memcpy(bucket->realpath, realpath, realpath_len+1);
    }
    bucket->realpath_len = realpath_len;
    bucket->is_dir = is_dir;
#ifdef PHP_WIN32
    bucket->is_rvalid   = 0;
    bucket->is_readable = 0;
    bucket->is_wvalid   = 0;
    bucket->is_writable = 0;
#endif
    bucket->expires = t + CWDG(realpath_cache_ttl);
    n = bucket->key % (sizeof(CWDG(realpath_cache)) / sizeof(CWDG(realpath_cache)[0]));
    bucket->next = CWDG(realpath_cache)[n];
    CWDG(realpath_cache)[n] = bucket;
    CWDG(realpath_cache_size) += size;
  }
}
/* }}} */


static inline realpath_cache_bucket* realpath_cache_find(const char *path, int path_len, time_t t TSRMLS_DC) /* {{{ */
{
#ifdef PHP_WIN32
  unsigned long key = realpath_cache_key(path, path_len TSRMLS_CC);
#else
  unsigned long key = realpath_cache_key(path, path_len);
#endif

  unsigned long n = key % (sizeof(CWDG(realpath_cache)) / sizeof(CWDG(realpath_cache)[0]));
  realpath_cache_bucket **bucket = &CWDG(realpath_cache)[n];

  while (*bucket != NULL) {
    if (CWDG(realpath_cache_ttl) && (*bucket)->expires < t) {
      realpath_cache_bucket *r = *bucket;
      *bucket = (*bucket)->next;

      /* if the pointers match then only subtract the length of the path */
      if(r->path == r->realpath) {
        CWDG(realpath_cache_size) -= sizeof(realpath_cache_bucket) + r->path_len + 1;
      } else {
        CWDG(realpath_cache_size) -= sizeof(realpath_cache_bucket) + r->path_len + 1 + r->realpath_len + 1;
      }
      free(r);
    } else if (key == (*bucket)->key && path_len == (*bucket)->path_len &&
        memcmp(path, (*bucket)->path, path_len) == 0) {
      return *bucket;
    } else {
      bucket = &(*bucket)->next;
    }
  }
  return NULL;
}
/* }}} */

CWD_API realpath_cache_bucket* realpath_cache_lookup(const char *path, int path_len, time_t t TSRMLS_DC) /* {{{ */
{
  return realpath_cache_find(path, path_len, t TSRMLS_CC);
}
/* }}} */

CWD_API int realpath_cache_size(TSRMLS_D)
{
  return CWDG(realpath_cache_size);
}

CWD_API int realpath_cache_max_buckets(TSRMLS_D)
{
  return (sizeof(CWDG(realpath_cache)) / sizeof(CWDG(realpath_cache)[0]));
}

CWD_API realpath_cache_bucket** realpath_cache_get_buckets(TSRMLS_D)
{
  return CWDG(realpath_cache);
}


#undef LINK_MAX
#define LINK_MAX 32

static int tsrm_realpath_r(char *path, int start, int len, int *ll, time_t *t, int use_realpath, int is_dir, int *link_is_dir TSRMLS_DC) /* {{{ */
{
  int i, j, save;
  int directory = 0;
#ifdef TSRM_WIN32
  WIN32_FIND_DATA data;
  HANDLE hFind;
  TSRM_ALLOCA_FLAG(use_heap_large)
#else
  struct stat st;
#endif
  realpath_cache_bucket *bucket;
  char *tmp;
  TSRM_ALLOCA_FLAG(use_heap)

  while (1) {
    if (len <= start) {
      if (link_is_dir) {
        *link_is_dir = 1;
      }
      return start;
    }

    i = len;
    while (i > start && !IS_SLASH(path[i-1])) {
      i--;
    }

    if (i == len ||
      (i == len - 1 && path[i] == '.')) {
      /* remove double slashes and '.' */
      len = i - 1;
      is_dir = 1;
      continue;
    } else if (i == len - 2 && path[i] == '.' && path[i+1] == '.') {
      /* remove '..' and previous directory */
      is_dir = 1;
      if (link_is_dir) {
        *link_is_dir = 1;
      }
      if (i - 1 <= start) {
        return start ? start : len;
      }
      j = tsrm_realpath_r(path, start, i-1, ll, t, use_realpath, 1, NULL TSRMLS_CC);
      if (j > start) {
        j--;
        while (j > start && !IS_SLASH(path[j])) {
          j--;
        }
        if (!start) {
          /* leading '..' must not be removed in case of relative path */
          if (j == 0 && path[0] == '.' && path[1] == '.' &&
              IS_SLASH(path[2])) {
            path[3] = '.';
            path[4] = '.';
            path[5] = DEFAULT_SLASH;
            j = 5;
          } else if (j > 0 &&
              path[j+1] == '.' && path[j+2] == '.' &&
              IS_SLASH(path[j+3])) {
            j += 4;
            path[j++] = '.';
            path[j++] = '.';
            path[j] = DEFAULT_SLASH;
          }
        }
      } else if (!start && !j) {
        /* leading '..' must not be removed in case of relative path */
        path[0] = '.';
        path[1] = '.';
        path[2] = DEFAULT_SLASH;
        j = 2;
      }
      return j;
    }

    path[len] = 0;

    save = (use_realpath != CWD_EXPAND);

    if (start && save && CWDG(realpath_cache_size_limit)) {
      /* cache lookup for absolute path */
      if (!*t) {
        *t = time(0);
      }
      if ((bucket = realpath_cache_find(path, len, *t TSRMLS_CC)) != NULL) {
        if (is_dir && !bucket->is_dir) {
          /* not a directory */
          return -1;
        } else {
          if (link_is_dir) {
            *link_is_dir = bucket->is_dir;
          }
          memcpy(path, bucket->realpath, bucket->realpath_len + 1);
          return bucket->realpath_len;
        }
      }
    }

#ifdef TSRM_WIN32
    if (save && (hFind = FindFirstFile(path, &data)) == INVALID_HANDLE_VALUE) {
      if (use_realpath == CWD_REALPATH) {
        /* file not found */
        return -1;
      }
      /* continue resolution anyway but don't save result in the cache */
      save = 0;
    }

    if (save) {
      FindClose(hFind);
    }

    tmp = tsrm_do_alloca(len+1, use_heap);
    memcpy(tmp, path, len+1);

    if(save &&
        !(IS_UNC_PATH(path, len) && len >= 3 && path[2] != '?') &&
        (data.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)) {
      /* File is a reparse point. Get the target */
      HANDLE hLink = NULL;
      REPARSE_DATA_BUFFER * pbuffer;
      unsigned int retlength = 0;
      int bufindex = 0, isabsolute = 0;
      wchar_t * reparsetarget;
      BOOL isVolume = FALSE;
      char printname[MAX_PATH];
      char substitutename[MAX_PATH];
      int printname_len, substitutename_len;
      int substitutename_off = 0;

      if(++(*ll) > LINK_MAX) {
        return -1;
      }

      hLink = CreateFile(path, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT|FILE_FLAG_BACKUP_SEMANTICS, NULL);
      if(hLink == INVALID_HANDLE_VALUE) {
        return -1;
      }

      pbuffer = (REPARSE_DATA_BUFFER *)tsrm_do_alloca(MAXIMUM_REPARSE_DATA_BUFFER_SIZE, use_heap_large);
      if (pbuffer == NULL) {
        return -1;
      }
      if(!DeviceIoControl(hLink, FSCTL_GET_REPARSE_POINT, NULL, 0, pbuffer,  MAXIMUM_REPARSE_DATA_BUFFER_SIZE, &retlength, NULL)) {
        tsrm_free_alloca(pbuffer, use_heap_large);
        CloseHandle(hLink);
        return -1;
      }

      CloseHandle(hLink);

      if(pbuffer->ReparseTag == IO_REPARSE_TAG_SYMLINK) {
        reparsetarget = pbuffer->SymbolicLinkReparseBuffer.ReparseTarget;
        printname_len = pbuffer->MountPointReparseBuffer.PrintNameLength / sizeof(WCHAR);
        isabsolute = (pbuffer->SymbolicLinkReparseBuffer.Flags == 0) ? 1 : 0;
        if (!WideCharToMultiByte(CP_THREAD_ACP, 0,
          reparsetarget + pbuffer->MountPointReparseBuffer.PrintNameOffset  / sizeof(WCHAR),
          printname_len + 1,
          printname, MAX_PATH, NULL, NULL
        )) {
          tsrm_free_alloca(pbuffer, use_heap_large);
          return -1;
        };
        printname_len = pbuffer->MountPointReparseBuffer.PrintNameLength / sizeof(WCHAR);
        printname[printname_len] = 0;

        substitutename_len = pbuffer->MountPointReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
        if (!WideCharToMultiByte(CP_THREAD_ACP, 0,
          reparsetarget + pbuffer->MountPointReparseBuffer.SubstituteNameOffset / sizeof(WCHAR),
          substitutename_len + 1,
          substitutename, MAX_PATH, NULL, NULL
        )) {
          tsrm_free_alloca(pbuffer, use_heap_large);
          return -1;
        };
        substitutename[substitutename_len] = 0;
      }
      else if(pbuffer->ReparseTag == IO_REPARSE_TAG_MOUNT_POINT) {
        isabsolute = 1;
        reparsetarget = pbuffer->MountPointReparseBuffer.ReparseTarget;
        printname_len = pbuffer->MountPointReparseBuffer.PrintNameLength / sizeof(WCHAR);
        if (!WideCharToMultiByte(CP_THREAD_ACP, 0,
          reparsetarget + pbuffer->MountPointReparseBuffer.PrintNameOffset  / sizeof(WCHAR),
          printname_len + 1,
          printname, MAX_PATH, NULL, NULL
        )) {
          tsrm_free_alloca(pbuffer, use_heap_large);
          return -1;
        };
        printname[pbuffer->MountPointReparseBuffer.PrintNameLength / sizeof(WCHAR)] = 0;

        substitutename_len = pbuffer->MountPointReparseBuffer.SubstituteNameLength / sizeof(WCHAR);
        if (!WideCharToMultiByte(CP_THREAD_ACP, 0,
          reparsetarget + pbuffer->MountPointReparseBuffer.SubstituteNameOffset / sizeof(WCHAR),
          substitutename_len + 1,
          substitutename, MAX_PATH, NULL, NULL
        )) {
          tsrm_free_alloca(pbuffer, use_heap_large);
          return -1;
        };
        substitutename[substitutename_len] = 0;
      }
      else if (pbuffer->ReparseTag == IO_REPARSE_TAG_DEDUP) {
        isabsolute = 1;
        memcpy(substitutename, path, len + 1);
        substitutename_len = len;
      } else {
        tsrm_free_alloca(pbuffer, use_heap_large);
        return -1;
      }

      if(isabsolute && substitutename_len > 4) {
        /* Do not resolve volumes (for now). A mounted point can
           target a volume without a drive, it is not certain that
           all IO functions we use in php and its deps support
           path with volume GUID instead of the DOS way, like:
           d:\test\mnt\foo
           \\?\Volume{62d1c3f8-83b9-11de-b108-806e6f6e6963}\foo
        */
        if (strncmp(substitutename, "\\??\\Volume{",11) == 0
          || strncmp(substitutename, "\\\\?\\Volume{",11) == 0
          || strncmp(substitutename, "\\??\\UNC\\", 8) == 0
          ) {
          isVolume = TRUE;
          substitutename_off = 0;
        } else
          /* do not use the \??\ and \\?\ prefix*/
          if (strncmp(substitutename, "\\??\\", 4) == 0
            || strncmp(substitutename, "\\\\?\\", 4) == 0) {
          substitutename_off = 4;
        }
      }

      if (!isVolume) {
        char * tmp2 = substitutename + substitutename_off;
        for(bufindex = 0; bufindex < (substitutename_len - substitutename_off); bufindex++) {
          *(path + bufindex) = *(tmp2 + bufindex);
        }

        *(path + bufindex) = 0;
        j = bufindex;
      } else {
        j = len;
      }


#if VIRTUAL_CWD_DEBUG
      fprintf(stderr, "reparse: print: %s ", printname);
      fprintf(stderr, "sub: %s ", substitutename);
      fprintf(stderr, "resolved: %s ", path);
#endif
      tsrm_free_alloca(pbuffer, use_heap_large);

      if(isabsolute == 1) {
        if (!((j == 3) && (path[1] == ':') && (path[2] == '\\'))) {
          /* use_realpath is 0 in the call below coz path is absolute*/
          j = tsrm_realpath_r(path, 0, j, ll, t, 0, is_dir, &directory TSRMLS_CC);
          if(j < 0) {
            tsrm_free_alloca(tmp, use_heap);
            return -1;
          }
        }
      }
      else {
        if(i + j >= MAXPATHLEN - 1) {
          tsrm_free_alloca(tmp, use_heap);
          return -1;
        }

        memmove(path+i, path, j+1);
        memcpy(path, tmp, i-1);
        path[i-1] = DEFAULT_SLASH;
        j  = tsrm_realpath_r(path, start, i + j, ll, t, use_realpath, is_dir, &directory TSRMLS_CC);
        if(j < 0) {
          tsrm_free_alloca(tmp, use_heap);
          return -1;
        }
      }
      directory = (data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY);

      if(link_is_dir) {
        *link_is_dir = directory;
      }
    }
    else {
      if (save) {
        directory = (data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;
        if (is_dir && !directory) {
          /* not a directory */
          return -1;
        }
      }

#elif defined(NETWARE)
    save = 0;
    tmp = tsrm_do_alloca(len+1, use_heap);
    memcpy(tmp, path, len+1);
#else
    if (save && php_sys_lstat(path, &st) < 0) {
      if (use_realpath == CWD_REALPATH) {
        /* file not found */
        return -1;
      }
      /* continue resolution anyway but don't save result in the cache */
      save = 0;
    }

    tmp = (char*) tsrm_do_alloca(len+1, use_heap);
    memcpy(tmp, path, len+1);

    if (save && S_ISLNK(st.st_mode)) {
      if (++(*ll) > LINK_MAX || (j = php_sys_readlink(tmp, path, MAXPATHLEN)) < 0) {
        /* too many links or broken symlinks */
        tsrm_free_alloca(tmp, use_heap);
        return -1;
      }
      path[j] = 0;
      if (IS_ABSOLUTE_PATH(path, j)) {
        j = tsrm_realpath_r(path, 1, j, ll, t, use_realpath, is_dir, &directory TSRMLS_CC);
        if (j < 0) {
          tsrm_free_alloca(tmp, use_heap);
          return -1;
        }
      } else {
        if (i + j >= MAXPATHLEN-1) {
          tsrm_free_alloca(tmp, use_heap);
          return -1; /* buffer overflow */
        }
        memmove(path+i, path, j+1);
        memcpy(path, tmp, i-1);
        path[i-1] = DEFAULT_SLASH;
        j = tsrm_realpath_r(path, start, i + j, ll, t, use_realpath, is_dir, &directory TSRMLS_CC);
        if (j < 0) {
          tsrm_free_alloca(tmp, use_heap);
          return -1;
        }
      }
      if (link_is_dir) {
        *link_is_dir = directory;
      }
    } else {
      if (save) {
        directory = S_ISDIR(st.st_mode);
        if (link_is_dir) {
          *link_is_dir = directory;
        }
        if (is_dir && !directory) {
          /* not a directory */
          tsrm_free_alloca(tmp, use_heap);
          return -1;
        }
      }
#endif
      if (i - 1 <= start) {
        j = start;
      } else {
        /* some leading directories may be unaccessable */
        j = tsrm_realpath_r(path, start, i-1, ll, t, save ? CWD_FILEPATH : use_realpath, 1, NULL TSRMLS_CC);
        if (j > start) {
          path[j++] = DEFAULT_SLASH;
        }
      }
#ifdef TSRM_WIN32
      if (j < 0 || j + len - i >= MAXPATHLEN-1) {
        tsrm_free_alloca(tmp, use_heap);
        return -1;
      }
      if (save) {
        i = strlen(data.cFileName);
        memcpy(path+j, data.cFileName, i+1);
        j += i;
      } else {
        /* use the original file or directory name as it wasn't found */
        memcpy(path+j, tmp+i, len-i+1);
        j += (len-i);
      }
    }
#else
      if (j < 0 || j + len - i >= MAXPATHLEN-1) {
        tsrm_free_alloca(tmp, use_heap);
        return -1;
      }
      memcpy(path+j, tmp+i, len-i+1);
      j += (len-i);
    }
#endif

    if (save && start && CWDG(realpath_cache_size_limit)) {
      /* save absolute path in the cache */
      realpath_cache_add(tmp, len, path, j, directory, *t TSRMLS_CC);
    }

    tsrm_free_alloca(tmp, use_heap);
    return j;
  }
}
/* }}} */

/* Resolve path relatively to state and put the real path into state */
/* returns 0 for ok, 1 for error */
CWD_API int virtual_file_ex(cwd_state *state, const char *path, verify_path_func verify_path, int use_realpath TSRMLS_DC) /* {{{ */
{
  int path_length = strlen(path);
  char resolved_path[MAXPATHLEN];
  int start = 1;
  int ll = 0;
  time_t t;
  int ret;
  int add_slash;
  void *tmp;

  if (path_length == 0 || path_length >= MAXPATHLEN-1) {
#ifdef TSRM_WIN32
# if _MSC_VER < 1300
    errno = EINVAL;
# else
    _set_errno(EINVAL);
# endif
#else
    errno = EINVAL;
#endif
    return 1;
  }

#if VIRTUAL_CWD_DEBUG
  fprintf(stderr,"cwd = %s path = %s\n", state->cwd, path);
#endif

  /* cwd_length can be 0 when getcwd() fails.
   * This can happen under solaris when a dir does not have read permissions
   * but *does* have execute permissions */
  if (!IS_ABSOLUTE_PATH(path, path_length)) {
    if (state->cwd_length == 0) {
      /* resolve relative path */
      start = 0;
      memcpy(resolved_path , path, path_length + 1);
    } else {
      int state_cwd_length = state->cwd_length;

#ifdef TSRM_WIN32
      if (IS_SLASH(path[0])) {
        if (state->cwd[1] == ':') {
          /* Copy only the drive name */
          state_cwd_length = 2;
        } else if (IS_UNC_PATH(state->cwd, state->cwd_length)) {
          /* Copy only the share name */
          state_cwd_length = 2;
          while (IS_SLASH(state->cwd[state_cwd_length])) {
            state_cwd_length++;
          }
          while (state->cwd[state_cwd_length] &&
              !IS_SLASH(state->cwd[state_cwd_length])) {
            state_cwd_length++;
          }
          while (IS_SLASH(state->cwd[state_cwd_length])) {
            state_cwd_length++;
          }
          while (state->cwd[state_cwd_length] &&
              !IS_SLASH(state->cwd[state_cwd_length])) {
            state_cwd_length++;
          }
        }
      }
#endif
      if (path_length + state_cwd_length + 1 >= MAXPATHLEN-1) {
        return 1;
      }
      memcpy(resolved_path, state->cwd, state_cwd_length);
      if (resolved_path[state_cwd_length-1] == DEFAULT_SLASH) {
        memcpy(resolved_path + state_cwd_length, path, path_length + 1);
        path_length += state_cwd_length;
      } else {
        resolved_path[state_cwd_length] = DEFAULT_SLASH;
        memcpy(resolved_path + state_cwd_length + 1, path, path_length + 1);
        path_length += state_cwd_length + 1;
      }
    }
  } else {
#ifdef TSRM_WIN32
    if (path_length > 2 && path[1] == ':' && !IS_SLASH(path[2])) {
      resolved_path[0] = path[0];
      resolved_path[1] = ':';
      resolved_path[2] = DEFAULT_SLASH;
      memcpy(resolved_path + 3, path + 2, path_length - 1);
      path_length++;
    } else
#endif
    memcpy(resolved_path, path, path_length + 1);
  }

#ifdef TSRM_WIN32
  if (memchr(resolved_path, '*', path_length) ||
    memchr(resolved_path, '?', path_length)) {
    return 1;
  }
#endif

#ifdef TSRM_WIN32
  if (IS_UNC_PATH(resolved_path, path_length)) {
    /* skip UNC name */
    resolved_path[0] = DEFAULT_SLASH;
    resolved_path[1] = DEFAULT_SLASH;
    start = 2;
    while (!IS_SLASH(resolved_path[start])) {
      if (resolved_path[start] == 0) {
        goto verify;
      }
      resolved_path[start] = toupper(resolved_path[start]);
      start++;
    }
    resolved_path[start++] = DEFAULT_SLASH;
    while (!IS_SLASH(resolved_path[start])) {
      if (resolved_path[start] == 0) {
        goto verify;
      }
      resolved_path[start] = toupper(resolved_path[start]);
      start++;
    }
    resolved_path[start++] = DEFAULT_SLASH;
  } else if (IS_ABSOLUTE_PATH(resolved_path, path_length)) {
    /* skip DRIVE name */
    resolved_path[0] = toupper(resolved_path[0]);
    resolved_path[2] = DEFAULT_SLASH;
    start = 3;
  }
#elif defined(NETWARE)
  if (IS_ABSOLUTE_PATH(resolved_path, path_length)) {
    /* skip VOLUME name */
    start = 0;
    while (start != ':') {
      if (resolved_path[start] == 0) return -1;
      start++;
    }
    start++;
    if (!IS_SLASH(resolved_path[start])) return -1;
    resolved_path[start++] = DEFAULT_SLASH;
  }
#endif

  add_slash = (use_realpath != CWD_REALPATH) && path_length > 0 && IS_SLASH(resolved_path[path_length-1]);
  t = CWDG(realpath_cache_ttl) ? 0 : -1;
  path_length = tsrm_realpath_r(resolved_path, start, path_length, &ll, &t, use_realpath, 0, NULL TSRMLS_CC);

  if (path_length < 0) {
    errno = ENOENT;
    return 1;
  }

  if (!start && !path_length) {
    resolved_path[path_length++] = '.';
  }
  if (add_slash && path_length && !IS_SLASH(resolved_path[path_length-1])) {
    if (path_length >= MAXPATHLEN-1) {
      return -1;
    }
    resolved_path[path_length++] = DEFAULT_SLASH;
  }
  resolved_path[path_length] = 0;

#ifdef TSRM_WIN32
verify:
#endif
  if (verify_path) {
    cwd_state old_state;

    CWD_STATE_COPY(&old_state, state);
    state->cwd_length = path_length;

    tmp = realloc(state->cwd, state->cwd_length+1);
    if (tmp == NULL) {
#if VIRTUAL_CWD_DEBUG
      fprintf (stderr, "Out of memory\n");
#endif
      return 1;
    }
    state->cwd = (char *) tmp;

    memcpy(state->cwd, resolved_path, state->cwd_length+1);
    if (verify_path(state)) {
      CWD_STATE_FREE(state);
      *state = old_state;
      ret = 1;
    } else {
      CWD_STATE_FREE(&old_state);
      ret = 0;
    }
  } else {
    state->cwd_length = path_length;
    tmp = realloc(state->cwd, state->cwd_length+1);
    if (tmp == NULL) {
#if VIRTUAL_CWD_DEBUG
      fprintf (stderr, "Out of memory\n");
#endif
      return 1;
    }
    state->cwd = (char *) tmp;

    memcpy(state->cwd, resolved_path, state->cwd_length+1);
    ret = 0;
  }

#if VIRTUAL_CWD_DEBUG
  fprintf (stderr, "virtual_file_ex() = %s\n",state->cwd);
#endif
  return (ret);
}
/* }}} */