* mu-maildir: some refactoring, fix clearlinks issue

src/mu-maildir.c

@@ -37,6 +37,19 @@
 #define MU_MAILDIR_NOINDEX_FILE       ".noindex"
 #define MU_MAILDIR_CACHE_FILE         ".mu.cache"
 
+/* note: this function is *not* re-entrant, it returns a static buffer */
+const char*
+fullpath_s (const char* path, const char* name)
+{
+	static char buf[4096];
+	
+	snprintf (buf, sizeof(buf), "%s%c%s",
+		  path, G_DIR_SEPARATOR,
+		  name ? name : "");
+
+	return buf;
+}
+
 
 static gboolean
 create_maildir (const char *path, int mode)
@@ -54,17 +67,16 @@ create_maildir (const char *path, int mode)
 	
 	for (i = 0; i != G_N_ELEMENTS(subdirs); ++i) {
 
-		gchar *fullpath;
+		const char *fullpath;
 		int rv;
+
+		/* static buffer */
+		fullpath = fullpath_s (path, subdirs[i]);
 		
-		fullpath = g_strdup_printf ("%s%c%s", path,
-					    G_DIR_SEPARATOR,
-					    subdirs[i]);
 		rv = g_mkdir_with_parents (fullpath, mode);
-		g_free (fullpath);
-		
 		if (rv != 0) {
-			g_warning ("%s", strerror (errno));
+			g_warning ("g_mkdir_with_parents failed: %s",
+				   strerror (errno));
 			return FALSE;
 		}
 	}
@@ -77,14 +89,16 @@ create_noindex (const char *path)
 {	
 	/* create a noindex file if requested */
 	int fd;
-	gchar *noindexpath;
+	const char *noindexpath;
-	noindexpath = g_strdup_printf ("%s%c%s", path,
+
-					       G_DIR_SEPARATOR,
+	/* static buffer */
-					       MU_MAILDIR_NOINDEX_FILE);
+	noindexpath = fullpath_s (path, MU_MAILDIR_NOINDEX_FILE);
+
 	fd = creat (noindexpath, 0644);
-	g_free (noindexpath);
+
 	if (fd < 0 || close (fd) != 0) {
-		g_warning ("%s", strerror (errno));
+		g_warning ("error in create_noindex: %s",
+			   strerror (errno));
 		return FALSE;
 	}
 	
@@ -193,7 +207,8 @@ mu_maildir_link (const char* src, const char *targetpath)
 }
 
 
-static MuResult process_dir (const char* path, MuMaildirWalkMsgCallback msg_cb, 
+static MuResult process_dir (const char* path,
+			     MuMaildirWalkMsgCallback msg_cb, 
 			     MuMaildirWalkDirCallback dir_cb, void *data);
 
 static MuResult 
@@ -206,7 +221,8 @@ process_file (const char* fullpath, MuMaildirWalkMsgCallback cb, void *data)
 		return MU_OK;
 
 	if (G_UNLIKELY(access(fullpath, R_OK) != 0)) {
-		g_warning ("cannot access %s: %s", fullpath, strerror(errno));
+		g_warning ("cannot access %s: %s", fullpath,
+			   strerror(errno));
 		return MU_ERROR;
 	}
 	
@@ -267,53 +283,67 @@ is_maildir_new_or_cur (const char *path)
 static gboolean
 has_noindex_file (const char *path)
 {
-	char *fname;
+	const char* noindexpath;
 
-	fname = g_newa (char, strlen(path) + 1 +
+	/* static buffer */
-			strlen(MU_MAILDIR_NOINDEX_FILE) + 1);
+	noindexpath = fullpath_s (path, MU_MAILDIR_NOINDEX_FILE);
-	g_sprintf (fname, "%s%c%s", path, G_DIR_SEPARATOR,
-		   MU_MAILDIR_NOINDEX_FILE);
 
-	if (access (fname, F_OK) == 0)
+	if (access (noindexpath, F_OK) == 0)
 		return TRUE;
+	
 	else if (errno != ENOENT)
-		g_warning ("error testing for noindex file: %s",
+		g_warning ("error testing for noindex file %s: %s",
-			   strerror(errno));
+			   noindexpath, strerror(errno));
 
 	return FALSE;
 }
 
-/* if the file system does not support entry->d_type, we add it ourselves
+
- * this is slower (extra stat) but at least it works
+/* do readdir, and of file systems that do not support ->_dtype, fill it
- */
+ * using stat -- much slower, but it works.
-static gboolean
+ */ 
-set_dtype (const char* path, struct dirent *entry)
+static struct dirent*
+readdir_with_stat_fallback (DIR* dir, const char* path)
 {
-	struct stat statbuf;
+	struct dirent *entry;
-	char fullpath[4096];
-	
-	snprintf (fullpath, sizeof(fullpath), "%s%c%s",
-		  path, G_DIR_SEPARATOR, entry->d_name);
 
-	if (stat (fullpath, &statbuf) != 0) {
+	errno = 0;
-		g_warning ("stat failed on %s: %s", fullpath,
+	entry = readdir (dir);
-			   strerror(errno));
+	
-		return FALSE;
+	if (!entry) {
+		if (errno) 
+			g_warning ("readdir failed in %s: %s",
+				   path, strerror (errno));
+		return NULL;
 	}
-
-	/* we only care about dirs, regular files and links */
-	if (S_ISREG (statbuf.st_mode))
-		entry->d_type = DT_REG;
-	else if (S_ISDIR (statbuf.st_mode))
-		entry->d_type = DT_DIR;
-	else if (S_ISLNK (statbuf.st_mode))
-		entry->d_type = DT_LNK;
 	
-	return TRUE;
+	/* XFS, ReiserFS and some other FSs don't support d_type, and
+	 * always set it to NULL; we use (slow) stat instead then */
+	if (G_UNLIKELY(entry->d_type == DT_UNKNOWN)) {
+
+		struct stat statbuf;
+		const char* fullpath;
+
+		/* note, fullpath_s returns a static buffer */
+		fullpath = fullpath_s (path, entry->d_name);
+		if (stat (fullpath, &statbuf) != 0) {
+			g_warning ("stat failed on %s: %s", fullpath,
+				   strerror(errno));
+			return FALSE;
+		}
+
+		/* we only care about dirs, regular files and links */
+		if (S_ISREG (statbuf.st_mode))
+			entry->d_type = DT_REG;
+		else if (S_ISDIR (statbuf.st_mode))
+			entry->d_type = DT_DIR;
+		else if (S_ISLNK (statbuf.st_mode))
+			entry->d_type = DT_LNK;
+	}
+	
+	return entry;
 }
 
-
-
 static gboolean
 ignore_dir_entry (struct dirent *entry)
 {
@@ -353,16 +383,19 @@ process_dir_entry (const char* path, struct dirent *entry,
 		   MuMaildirWalkDirCallback cb_dir, 
 		   void *data)
 {
+	const char *fp;
 	char* fullpath;
 	
 	/* ignore special dirs: */
 	if (ignore_dir_entry (entry)) 
 		return MU_OK;
-
-	fullpath = g_newa (char, strlen(path) + strlen(entry->d_name) + 1);
-	sprintf (fullpath, "%s%c%s", path, G_DIR_SEPARATOR,
-		 entry->d_name);
 	
+	/* we have to copy the buffer from fullpath_s, because it
+	 * returns a static buffer */
+	fp = fullpath_s (path, entry->d_name);
+	fullpath = g_newa (char, strlen(fp) + 1);
+	strcpy (fullpath, fp);
+
 	switch (entry->d_type) {
 	case DT_REG:
 		/* we only want files in cur/ and new/ */
@@ -421,8 +454,9 @@ process_dir (const char* path, MuMaildirWalkMsgCallback msg_cb,
 	
 	dir = opendir (path);		
 	if (G_UNLIKELY(!dir)) {
-		g_warning ("failed to open %s: %s", path, strerror(errno));
+		g_warning ("%s: ignoring  %s: %s", path,
-		return MU_ERROR;
+			   __FUNCTION__, strerror(errno));
+		return MU_OK;
 	}
 	
 	if (dir_cb) {
@@ -433,17 +467,16 @@ process_dir (const char* path, MuMaildirWalkMsgCallback msg_cb,
 		}
 	}
 	
-	/* we sort the inodes, which makes file-access much faster on 
+	/* we sort the inodes if the FS's dirent has them. It makes
-	   some filesystems, such as ext3fs */
+	 * file-access much faster on some filesystems, such as
+	 * ext3,4. readdir_with_stat_fallback is a wrapper for readdir
+	 * that falls back to (slow) stats if the FS does not support
+	 * entry->d_type
+	 */
 	lst = NULL;
-	while ((entry = readdir (dir))) {
+	while ((entry = readdir_with_stat_fallback (dir, path)))
-
-		/* handle FSs that don't support entry->d_type */
-		if (entry->d_type == DT_UNKNOWN) 
-			set_dtype (path, entry);
-		
 		lst = g_list_prepend (lst, dirent_copy(entry));
-	}
+	
 #if HAVE_STRUCT_DIRENT_D_INO		
 	c = lst = g_list_sort (lst, (GCompareFunc)dirent_cmp);
 #endif /*HAVE_STRUCT_DIRENT_D_INO*/	
@@ -506,37 +539,35 @@ clear_links (const gchar* dirname, DIR *dir)
 	gboolean rv;
 	
 	rv = TRUE;
-	while ((entry = readdir (dir)) && rv) {
+	while ((entry = readdir_with_stat_fallback (dir, dirname))) {
 		
-		char fullpath[4096];
+		const char *fp;
-		size_t len;
+		char *fullpath;
 
-		/* ignore dot thingies */
+		/* ignore empty, dot thingies */
-		if (entry->d_name && entry->d_name[0] == '.')
+		if (!entry->d_name || entry->d_name[0] == '.')
 			continue;
-
-		/* handle FSs that don't support entry->d_type */
-		if (entry->d_type == DT_UNKNOWN) 
-			set_dtype (dirname, entry);
 		
 		/* ignore non-links / non-dirs */
 		if (entry->d_type != DT_LNK && entry->d_type != DT_DIR)
 			continue; 
 
-		len = snprintf (fullpath, sizeof(fullpath), "%s%c%s",
+		/* we have to copy the buffer from fullpath_s, because it
-				dirname, G_DIR_SEPARATOR, entry->d_name);
+		 * returns a static buffer and we are recursive*/
-		if (len == sizeof(fullpath)) {
+		fp = fullpath_s (dirname, entry->d_name);
-			g_warning ("name is too long: %s", fullpath);
+		fullpath = g_newa (char, strlen(fp) + 1);
-			continue;
+		strcpy (fullpath, fp);
-		}
+				
-
+		if (entry->d_type == DT_LNK) {
-		if (entry->d_type == DT_LNK && unlink (fullpath) != 0) {
+			if (unlink (fullpath) != 0) {
-			g_warning ("error unlinking %s: %s",
+				g_warning ("error unlinking %s: %s",
-				   fullpath, strerror(errno));
+					   fullpath, strerror(errno));
-			rv = FALSE;
+				rv = FALSE;
-		} else /* == DT_DIR, see check before*/
+			}
+		} else /* DT_DIR, see check before*/
 			rv = mu_maildir_clear_links (fullpath);
 	}
+	
 	return rv;
 }