ftp.c

一个从网络上自动下载文件的自由工具

                  logprintf (LOG_VERBOSE, _("\
Remote file no newer than local file `%s' -- not retrieving.\n"), con->target);
                  dlthis = false;
                }
              else if (eq_size)
                {
                  /* Remote file is newer or sizes cannot be matched */
                  logprintf (LOG_VERBOSE, _("\
Remote file is newer than local file `%s' -- retrieving.\n\n"),
                             con->target);
                }
              else
                {
                  /* Sizes do not match */
                  logprintf (LOG_VERBOSE, _("\
The sizes do not match (local %s) -- retrieving.\n\n"),
                             number_to_static_string (local_size));
                }
            }
        }       /* opt.timestamping && f->type == FT_PLAINFILE */
      switch (f->type)
        {
        case FT_SYMLINK:
          /* If opt.retr_symlinks is defined, we treat symlinks as
             if they were normal files.  There is currently no way
             to distinguish whether they might be directories, and
             follow them.  */
          if (!opt.retr_symlinks)
            {
#ifdef HAVE_SYMLINK
              if (!f->linkto)
                logputs (LOG_NOTQUIET,
                         _("Invalid name of the symlink, skipping.\n"));
              else
                {
                  struct_stat st;
                  /* Check whether we already have the correct
                     symbolic link.  */
                  int rc = lstat (con->target, &st);
                  if (rc == 0)
                    {
                      size_t len = strlen (f->linkto) + 1;
                      if (S_ISLNK (st.st_mode))
                        {
                          char *link_target = (char *)alloca (len);
                          size_t n = readlink (con->target, link_target, len);
                          if ((n == len - 1)
                              && (memcmp (link_target, f->linkto, n) == 0))
                            {
                              logprintf (LOG_VERBOSE, _("\
Already have correct symlink %s -> %s\n\n"),
                                         con->target, escnonprint (f->linkto));
                              dlthis = false;
                              break;
                            }
                        }
                    }
                  logprintf (LOG_VERBOSE, _("Creating symlink %s -> %s\n"),
                             con->target, escnonprint (f->linkto));
                  /* Unlink before creating symlink!  */
                  unlink (con->target);
                  if (symlink (f->linkto, con->target) == -1)
                    logprintf (LOG_NOTQUIET, "symlink: %s\n", strerror (errno));
                  logputs (LOG_VERBOSE, "\n");
                } /* have f->linkto */
#else  /* not HAVE_SYMLINK */
              logprintf (LOG_NOTQUIET,
                         _("Symlinks not supported, skipping symlink `%s'.\n"),
                         con->target);
#endif /* not HAVE_SYMLINK */
            }
          else                /* opt.retr_symlinks */
            {
              if (dlthis)
                err = ftp_loop_internal (u, f, con);
            } /* opt.retr_symlinks */
          break;
        case FT_DIRECTORY:
          if (!opt.recursive)
            logprintf (LOG_NOTQUIET, _("Skipping directory `%s'.\n"),
                       escnonprint (f->name));
          break;
        case FT_PLAINFILE:
          /* Call the retrieve loop.  */
          if (dlthis)
            err = ftp_loop_internal (u, f, con);
          break;
        case FT_UNKNOWN:
          logprintf (LOG_NOTQUIET, _("%s: unknown/unsupported file type.\n"),
                     escnonprint (f->name));
          break;
        }       /* switch */

      /* Set the time-stamp information to the local file.  Symlinks
         are not to be stamped because it sets the stamp on the
         original.  :( */
      if (!(f->type == FT_SYMLINK && !opt.retr_symlinks)
          && f->tstamp != -1
          && dlthis
          && file_exists_p (con->target))
        {
          /* #### This code repeats in http.c and ftp.c.  Move it to a
             function!  */
          const char *fl = NULL;
          if (opt.output_document)
            {
              if (output_stream_regular)
                fl = opt.output_document;
            }
          else
            fl = con->target;
          if (fl)
            touch (fl, f->tstamp);
        }
      else if (f->tstamp == -1)
        logprintf (LOG_NOTQUIET, _("%s: corrupt time-stamp.\n"), con->target);

      if (f->perms && f->type == FT_PLAINFILE && dlthis)
        {
          if (opt.preserve_perm)
            chmod (con->target, f->perms);
        }
      else
        DEBUGP (("Unrecognized permissions for %s.\n", con->target));

      xfree (con->target);
      con->target = old_target;

      url_set_file (u, ofile);
      xfree (ofile);

      /* Break on fatals.  */
      if (err == QUOTEXC || err == HOSTERR || err == FWRITEERR)
        break;
      con->cmd &= ~ (DO_CWD | DO_LOGIN);
      f = f->next;
    }

  /* We do not want to call ftp_retrieve_dirs here */
  if (opt.recursive &&
      !(opt.reclevel != INFINITE_RECURSION && depth >= opt.reclevel))
    err = ftp_retrieve_dirs (u, orig, con);
  else if (opt.recursive)
    DEBUGP ((_("Will not retrieve dirs since depth is %d (max %d).\n"),
             depth, opt.reclevel));
  --depth;
  return err;
}

/* Retrieve the directories given in a file list.  This function works
   by simply going through the linked list and calling
   ftp_retrieve_glob on each directory entry.  The function knows
   about excluded directories.  */
static uerr_t
ftp_retrieve_dirs (struct url *u, struct fileinfo *f, ccon *con)
{
  char *container = NULL;
  int container_size = 0;

  for (; f; f = f->next)
    {
      int size;
      char *odir, *newdir;

      if (opt.quota && total_downloaded_bytes > opt.quota)
        break;
      if (f->type != FT_DIRECTORY)
        continue;

      /* Allocate u->dir off stack, but reallocate only if a larger
         string is needed.  It's a pity there's no "realloca" for an
         item on the bottom of the stack.  */
      size = strlen (u->dir) + 1 + strlen (f->name) + 1;
      if (size > container_size)
        container = (char *)alloca (size);
      newdir = container;

      odir = u->dir;
      if (*odir == '\0'
          || (*odir == '/' && *(odir + 1) == '\0'))
        /* If ODIR is empty or just "/", simply append f->name to
           ODIR.  (In the former case, to preserve u->dir being
           relative; in the latter case, to avoid double slash.)  */
        sprintf (newdir, "%s%s", odir, f->name);
      else
        /* Else, use a separator. */
        sprintf (newdir, "%s/%s", odir, f->name);

      DEBUGP (("Composing new CWD relative to the initial directory.\n"));
      DEBUGP (("  odir = '%s'\n  f->name = '%s'\n  newdir = '%s'\n\n",
               odir, f->name, newdir));
      if (!accdir (newdir))
        {
          logprintf (LOG_VERBOSE, _("\
Not descending to `%s' as it is excluded/not-included.\n"),
                     escnonprint (newdir));
          continue;
        }

      con->st &= ~DONE_CWD;

      odir = xstrdup (u->dir);  /* because url_set_dir will free
                                   u->dir. */
      url_set_dir (u, newdir);
      ftp_retrieve_glob (u, con, GLOB_GETALL);
      url_set_dir (u, odir);
      xfree (odir);

      /* Set the time-stamp?  */
    }

  if (opt.quota && total_downloaded_bytes > opt.quota)
    return QUOTEXC;
  else
    return RETROK;
}

/* Return true if S has a leading '/'  or contains '../' */
static bool
has_insecure_name_p (const char *s)
{
  if (*s == '/')
    return true;

  if (strstr (s, "../") != 0)
    return true;

  return false;
}

/* A near-top-level function to retrieve the files in a directory.
   The function calls ftp_get_listing, to get a linked list of files.
   Then it weeds out the file names that do not match the pattern.
   ftp_retrieve_list is called with this updated list as an argument.

   If the argument ACTION is GLOB_GETONE, just download the file (but
   first get the listing, so that the time-stamp is heeded); if it's
   GLOB_GLOBALL, use globbing; if it's GLOB_GETALL, download the whole
   directory.  */
static uerr_t
ftp_retrieve_glob (struct url *u, ccon *con, int action)
{
  struct fileinfo *f, *start;
  uerr_t res;

  con->cmd |= LEAVE_PENDING;

  res = ftp_get_listing (u, con, &start);
  if (res != RETROK)
    return res;
  /* First: weed out that do not conform the global rules given in
     opt.accepts and opt.rejects.  */
  if (opt.accepts || opt.rejects)
    {
      f = start;
      while (f)
        {
          if (f->type != FT_DIRECTORY && !acceptable (f->name))
            {
              logprintf (LOG_VERBOSE, _("Rejecting `%s'.\n"),
                         escnonprint (f->name));
              f = delelement (f, &start);
            }
          else
            f = f->next;
        }
    }
  /* Remove all files with possible harmful names */
  f = start;
  while (f)
    {
      if (has_insecure_name_p (f->name))
        {
          logprintf (LOG_VERBOSE, _("Rejecting `%s'.\n"),
                     escnonprint (f->name));
          f = delelement (f, &start);
        }
      else
        f = f->next;
    }
  /* Now weed out the files that do not match our globbing pattern.
     If we are dealing with a globbing pattern, that is.  */
  if (*u->file && (action == GLOB_GLOBALL || action == GLOB_GETONE))
    {
      int (*matcher) (const char *, const char *, int)
        = opt.ignore_case ? fnmatch_nocase : fnmatch;
      int matchres = 0;

      f = start;
      while (f)
        {
          matchres = matcher (u->file, f->name, 0);
          if (matchres == -1)
            {
              logprintf (LOG_NOTQUIET, "%s: %s\n", con->target,
                         strerror (errno));
              break;
            }
          if (matchres == FNM_NOMATCH)
            f = delelement (f, &start); /* delete the element from the list */
          else
            f = f->next;        /* leave the element in the list */
        }
      if (matchres == -1)
        {
          freefileinfo (start);
          return RETRBADPATTERN;
        }
    }
  if (start)
    {
      /* Just get everything.  */
      ftp_retrieve_list (u, start, con);
    }
  else if (!start)
    {
      if (action == GLOB_GLOBALL)
        {
          /* No luck.  */
          /* #### This message SUCKS.  We should see what was the
             reason that nothing was retrieved.  */
          logprintf (LOG_VERBOSE, _("No matches on pattern `%s'.\n"),
                     escnonprint (u->file));
        }
      else /* GLOB_GETONE or GLOB_GETALL */
        {
          /* Let's try retrieving it anyway.  */
          con->st |= ON_YOUR_OWN;
          res = ftp_loop_internal (u, NULL, con);
          return res;
        }
    }
  freefileinfo (start);
  if (opt.quota && total_downloaded_bytes > opt.quota)
    return QUOTEXC;
  else
    /* #### Should we return `res' here?  */
    return RETROK;
}

/* The wrapper that calls an appropriate routine according to contents
   of URL.  Inherently, its capabilities are limited on what can be
   encoded into a URL.  */
uerr_t
ftp_loop (struct url *u, int *dt, struct url *proxy, bool recursive, bool glob)
{
  ccon con;                     /* FTP connection */
  uerr_t res;

  *dt = 0;

  xzero (con);

  con.csock = -1;
  con.st = ON_YOUR_OWN;
  con.rs = ST_UNIX;
  con.id = NULL;
  con.proxy = proxy;

  /* If the file name is empty, the user probably wants a directory
     index.  We'll provide one, properly HTML-ized.  Unless
     opt.htmlify is 0, of course.  :-) */
  if (!*u->file && !recursive)
    {
      struct fileinfo *f;
      res = ftp_get_listing (u, &con, &f);

      if (res == RETROK)
        {
          if (opt.htmlify && !opt.spider)
            {
              char *filename = (opt.output_document
                                ? xstrdup (opt.output_document)
                                : (con.target ? xstrdup (con.target)
                                   : url_file_name (u)));
              res = ftp_index (filename, u, f);
              if (res == FTPOK && opt.verbose)
                {
                  if (!opt.output_document)
                    {
                      struct_stat st;
                      wgint sz;
                      if (stat (filename, &st) == 0)
                        sz = st.st_size;
                      else
                        sz = -1;
                      logprintf (LOG_NOTQUIET,
                                 _("Wrote HTML-ized index to `%s' [%s].\n"),
                                 filename, number_to_static_string (sz));
                    }
                  else
                    logprintf (LOG_NOTQUIET,
                               _("Wrote HTML-ized index to `%s'.\n"),
                               filename);
                }
              xfree (filename);
            }
          freefileinfo (f);
        }
    }
  else
    {
      bool ispattern = false;
      if (glob)
        {
          /* Treat the URL as a pattern if the file name part of the
             URL path contains wildcards.  (Don't check for u->file
             because it is unescaped and therefore doesn't leave users
             the option to escape literal '*' as %2A.)  */
          char *file_part = strrchr (u->path, '/');
          if (!file_part)
            file_part = u->path;
          ispattern = has_wildcards_p (file_part);
        }
      if (ispattern || recursive || opt.timestamping)
        {
          /* ftp_retrieve_glob is a catch-all function that gets called
             if we need globbing, time-stamping or recursion.  Its
             third argument is just what we really need.  */
          res = ftp_retrieve_glob (u, &con,
                                   ispattern ? GLOB_GLOBALL : GLOB_GETONE);
        }
      else
        res = ftp_loop_internal (u, NULL, &con);
    }
  if (res == FTPOK)
    res = RETROK;
  if (res == RETROK)
    *dt |= RETROKF;
  /* If a connection was left, quench it.  */
  if (con.csock != -1)
    fd_close (con.csock);
  xfree_null (con.id);
  con.id = NULL;
  xfree_null (con.target);
  con.target = NULL;
  return res;
}

/* Delete an element from the fileinfo linked list.  Returns the
   address of the next element, or NULL if the list is exhausted.  It
   can modify the start of the list.  */
static struct fileinfo *
delelement (struct fileinfo *f, struct fileinfo **start)
{
  struct fileinfo *prev = f->prev;
  struct fileinfo *next = f->next;

  xfree (f->name);
  xfree_null (f->linkto);
  xfree (f);

  if (next)
    next->prev = prev;
  if (prev)
    prev->next = next;
  else
    *start = next;
  return next;
}

/* Free the fileinfo linked list of files.  */
static void
freefileinfo (struct fileinfo *f)
{
  while (f)
    {
      struct fileinfo *next = f->next;
      xfree (f->name);
      if (f->linkto)
        xfree (f->linkto);
      xfree (f);
      f = next;
    }
}