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[92.243.24.172]) by mx.google.com with ESMTPS id bm15sm2680690qab.17.2012.05.08.00.58.30 (version=SSLv3 cipher=OTHER); Tue, 08 May 2012 00:58:32 -0700 (PDT) From: Jani Nikula To: Austin Clements , notmuch@notmuchmail.org Subject: Re: [PATCH v2 2/2] new: Centralize file type stat-ing logic In-Reply-To: <1336429240-1114-3-git-send-email-amdragon@mit.edu> References: <1336414186-15293-1-git-send-email-amdragon@mit.edu> <1336429240-1114-1-git-send-email-amdragon@mit.edu> <1336429240-1114-3-git-send-email-amdragon@mit.edu> User-Agent: Notmuch/0.11.1+222~ga47a98c (http://notmuchmail.org) Emacs/23.1.1 (i686-pc-linux-gnu) Date: Tue, 08 May 2012 07:58:28 +0000 Message-ID: <87r4uvdryz.fsf@nikula.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Gm-Message-State: ALoCoQl9ItXHqbHEak1VBDEU3KqrTo5GO5ue8xuA/6kGn/FOJzkzG/L7EUE8aMGQMSGTOZ6ZMPs7 Cc: Vladimir Marek X-BeenThere: notmuch@notmuchmail.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: "Use and development of the notmuch mail system." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 May 2012 07:58:36 -0000 On Mon, 7 May 2012 18:20:40 -0400, Austin Clements wrote: > This moves our logic to get a file's type into one function. This has > several benefits: we can support OSes and file systems that do not > provide dirent.d_type or always return DT_UNKNOWN, complex > symlink-handling logic has been replaced by a simple stat fall-through > in one place, and the error message for un-stat-able file is more > accurate (previously, the error always mentioned directories, even > though a broken symlink is not a directory). LGTM. > --- > notmuch-new.c | 103 +++++++++++++++++++++++++++++++++++---------------------- > test/new | 2 +- > 2 files changed, 64 insertions(+), 41 deletions(-) > > diff --git a/notmuch-new.c b/notmuch-new.c > index cb720cc..8955677 100644 > --- a/notmuch-new.c > +++ b/notmuch-new.c > @@ -154,6 +154,48 @@ dirent_sort_strcmp_name (const struct dirent **a, const struct dirent **b) > return strcmp ((*a)->d_name, (*b)->d_name); > } > > +/* Return the type of a directory entry relative to path as a stat(2) > + * mode. Like stat, this follows symlinks. Returns -1 and sets errno > + * if the file's type cannot be determined (which includes dangling > + * symlinks). > + */ > +static int > +dirent_type (const char *path, const struct dirent *entry) > +{ > + struct stat statbuf; > + char *abspath; > + int err, saved_errno; > + > +#ifdef _DIRENT_HAVE_D_TYPE > + /* Mapping from d_type to stat mode_t. We omit DT_LNK so that > + * we'll fall through to stat and get the real file type. */ > + static const mode_t modes[] = { > + [DT_BLK] = S_IFBLK, > + [DT_CHR] = S_IFCHR, > + [DT_DIR] = S_IFDIR, > + [DT_FIFO] = S_IFIFO, > + [DT_REG] = S_IFREG, > + [DT_SOCK] = S_IFSOCK > + }; > + if (entry->d_type < ARRAY_SIZE(modes) && modes[entry->d_type]) > + return modes[entry->d_type]; > +#endif > + > + abspath = talloc_asprintf (NULL, "%s/%s", path, entry->d_name); > + if (!abspath) { > + errno = ENOMEM; > + return -1; > + } > + err = stat(abspath, &statbuf); > + saved_errno = errno; > + talloc_free (abspath); > + if (err < 0) { > + errno = saved_errno; > + return -1; > + } > + return statbuf.st_mode & S_IFMT; > +} > + > /* Test if the directory looks like a Maildir directory. > * > * Search through the array of directory entries to see if we can find all > @@ -162,12 +204,12 @@ dirent_sort_strcmp_name (const struct dirent **a, const struct dirent **b) > * Return 1 if the directory looks like a Maildir and 0 otherwise. > */ > static int > -_entries_resemble_maildir (struct dirent **entries, int count) > +_entries_resemble_maildir (const char *path, struct dirent **entries, int count) > { > int i, found = 0; > > for (i = 0; i < count; i++) { > - if (entries[i]->d_type != DT_DIR && entries[i]->d_type != DT_UNKNOWN) > + if (dirent_type (path, entries[i]) != S_IFDIR) > continue; > > if (strcmp(entries[i]->d_name, "new") == 0 || > @@ -250,7 +292,7 @@ add_files_recursive (notmuch_database_t *notmuch, > notmuch_status_t status, ret = NOTMUCH_STATUS_SUCCESS; > notmuch_message_t *message = NULL; > struct dirent **fs_entries = NULL; > - int i, num_fs_entries; > + int i, num_fs_entries, entry_type; > notmuch_directory_t *directory; > notmuch_filenames_t *db_files = NULL; > notmuch_filenames_t *db_subdirs = NULL; > @@ -317,7 +359,7 @@ add_files_recursive (notmuch_database_t *notmuch, > } > > /* Pass 1: Recurse into all sub-directories. */ > - is_maildir = _entries_resemble_maildir (fs_entries, num_fs_entries); > + is_maildir = _entries_resemble_maildir (path, fs_entries, num_fs_entries); > > for (i = 0; i < num_fs_entries; i++) { > if (interrupted) > @@ -325,17 +367,16 @@ add_files_recursive (notmuch_database_t *notmuch, > > entry = fs_entries[i]; > > - /* We only want to descend into directories. > - * But symlinks can be to directories too, of course. > - * > - * And if the filesystem doesn't tell us the file type in the > - * scandir results, then it might be a directory (and if not, > - * then we'll stat and return immediately in the next level of > - * recursion). */ > - if (entry->d_type != DT_DIR && > - entry->d_type != DT_LNK && > - entry->d_type != DT_UNKNOWN) > - { > + /* We only want to descend into directories (and symlinks to > + * directories). */ > + entry_type = dirent_type (path, entry); > + if (entry_type == -1) { > + /* Be pessimistic, e.g. so we don't lose lots of mail just > + * because a user broke a symlink. */ > + fprintf (stderr, "Error reading file %s/%s: %s\n", > + path, entry->d_name, strerror (errno)); > + return NOTMUCH_STATUS_FILE_ERROR; > + } else if (entry_type != S_IFDIR) { > continue; > } > > @@ -425,31 +466,13 @@ add_files_recursive (notmuch_database_t *notmuch, > notmuch_filenames_move_to_next (db_subdirs); > } > > - /* If we're looking at a symlink, we only want to add it if it > - * links to a regular file, (and not to a directory, say). > - * > - * Similarly, if the file is of unknown type (due to filesystem > - * limitations), then we also need to look closer. > - * > - * In either case, a stat does the trick. > - */ > - if (entry->d_type == DT_LNK || entry->d_type == DT_UNKNOWN) { > - int err; > - > - next = talloc_asprintf (notmuch, "%s/%s", path, entry->d_name); > - err = stat (next, &st); > - talloc_free (next); > - next = NULL; > - > - /* Don't emit an error for a link pointing nowhere, since > - * the directory-traversal pass will have already done > - * that. */ > - if (err) > - continue; > - > - if (! S_ISREG (st.st_mode)) > - continue; > - } else if (entry->d_type != DT_REG) { > + /* Only add regular files (and symlinks to regular files). */ > + entry_type = dirent_type (path, entry); > + if (entry_type == -1) { > + fprintf (stderr, "Error reading file %s/%s: %s\n", > + path, entry->d_name, strerror (errno)); > + return NOTMUCH_STATUS_FILE_ERROR; > + } else if (entry_type != S_IFREG) { > continue; > } > > diff --git a/test/new b/test/new > index 26253db..e3900f5 100755 > --- a/test/new > +++ b/test/new > @@ -140,7 +140,7 @@ test_begin_subtest "Broken symlink aborts" > ln -s does-not-exist "${MAIL_DIR}/broken" > output=$(NOTMUCH_NEW 2>&1) > test_expect_equal "$output" \ > -"Error reading directory /run/shm/nm/tmp.new/mail/broken: No such file or directory > +"Error reading file /run/shm/nm/tmp.new/mail/broken: No such file or directory > Note: A fatal error was encountered: Something went wrong trying to read or write a file > No new mail." > rm "${MAIL_DIR}/broken" > -- > 1.7.10 > > _______________________________________________ > notmuch mailing list > notmuch@notmuchmail.org > http://notmuchmail.org/mailman/listinfo/notmuch