main: split the code in multiple files

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

Makefile.am

@@ -11,7 +11,7 @@ CLEANFILES = fuse-overlayfs.1
 fuse_overlayfs_CFLAGS = -I . -I $(abs_srcdir)/lib $(FUSE_CFLAGS)
 fuse_overlayfs_LDFLAGS =
 fuse_overlayfs_LDADD = lib/libgnu.a $(FUSE_LIBS)
-fuse_overlayfs_SOURCES = main.c
+fuse_overlayfs_SOURCES = main.c direct.c utils.c
 
 WD := $(shell pwd)
 

direct.c

@@ -0,0 +1,170 @@
+/* fuse-overlayfs: Overlay Filesystem in Userspace
+
+   Copyright (C) 2018 Giuseppe Scrivano <giuseppe@scrivano.org>
+   Copyright (C) 2018-2019 Red Hat Inc.
+   Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#define _GNU_SOURCE
+
+#include <config.h>
+
+#include "fuse-overlayfs.h"
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include <sys/xattr.h>
+
+#include "utils.h"
+
+static int
+direct_file_exists (struct ovl_layer *l, const char *pathname)
+{
+  return file_exists_at (l->fd, pathname);
+}
+
+static int
+direct_listxattr (struct ovl_layer *l, const char *path, char *buf, size_t size)
+{
+  cleanup_close int fd = -1;
+  char full_path[PATH_MAX];
+  int ret;
+
+  full_path[0] = '\0';
+  ret = open_fd_or_get_path (l, path, full_path, &fd, O_RDONLY);
+  if (ret < 0)
+    return ret;
+
+  if (fd >= 0)
+    return flistxattr (fd, buf, size);
+
+  return llistxattr (full_path, buf, size);
+}
+
+static int
+direct_getxattr (struct ovl_layer *l, const char *path, const char *name, char *buf, size_t size)
+{
+  cleanup_close int fd = -1;
+  char full_path[PATH_MAX];
+  int ret;
+
+  full_path[0] = '\0';
+  ret = open_fd_or_get_path (l, path, full_path, &fd, O_RDONLY);
+  if (ret < 0)
+    return ret;
+
+  if (fd >= 0)
+    return fgetxattr (fd, name, buf, size);
+
+  return lgetxattr (full_path, name, buf, size);
+}
+
+static int
+direct_fstat (struct ovl_layer *l, int fd, const char *path, struct stat *st)
+{
+  return fstat (fd, st);
+}
+
+static int
+direct_statat (struct ovl_layer *l, const char *path, struct stat *st, int flags)
+{
+  return TEMP_FAILURE_RETRY (fstatat (l->fd, path, st, flags));
+}
+
+static struct dirent *
+direct_readdir (void *dirp)
+{
+  return readdir (dirp);
+}
+
+static void *
+direct_opendir (struct ovl_layer *l, const char *path)
+{
+  cleanup_close int cleanup_fd = -1;
+  DIR *dp = NULL;
+
+  cleanup_fd = TEMP_FAILURE_RETRY (openat (l->fd, path, O_DIRECTORY));
+  if (cleanup_fd < 0)
+    return NULL;
+
+  dp = fdopendir (cleanup_fd);
+  if (dp == NULL)
+    return NULL;
+
+  cleanup_fd = -1;
+
+  return dp;
+}
+
+static int
+direct_closedir (void *dirp)
+{
+  return closedir (dirp);
+}
+
+static int
+direct_openat (struct ovl_layer *l, const char *path, int flags, mode_t mode)
+{
+  return TEMP_FAILURE_RETRY (openat (l->fd, path, flags, mode));
+}
+
+static ssize_t
+direct_readlinkat (struct ovl_layer *l, const char *path, char *buf, size_t bufsiz)
+{
+  return TEMP_FAILURE_RETRY (readlinkat (l->fd, path, buf, bufsiz));
+}
+
+static int
+direct_load_data_source (struct ovl_layer *l, const char *opaque)
+{
+  l->path = realpath (opaque, NULL);
+  if (l->path == NULL)
+    return -1;
+
+  l->fd = open (l->path, O_DIRECTORY);
+  if (l->fd < 0)
+    {
+      free (l->path);
+      l->path = NULL;
+      return l->fd;
+    }
+
+  return 0;
+}
+
+static int
+direct_cleanup (struct ovl_layer *l)
+{
+  return 0;
+}
+
+struct data_source direct_access_ds =
+  {
+   .load_data_source = direct_load_data_source,
+   .cleanup = direct_cleanup,
+   .file_exists = direct_file_exists,
+   .statat = direct_statat,
+   .fstat = direct_fstat,
+   .opendir = direct_opendir,
+   .readdir = direct_readdir,
+   .closedir = direct_closedir,
+   .openat = direct_openat,
+   .getxattr = direct_getxattr,
+   .listxattr = direct_listxattr,
+   .readlinkat = direct_readlinkat,
+  };

fuse-overlayfs.h

@@ -109,6 +109,8 @@ struct ovl_layer
 /* a data_source defines the methods for accessing a lower layer.  */
 struct data_source
 {
+  int (*load_data_source)(struct ovl_layer *l, const char *opaque);
+  int (*cleanup)(struct ovl_layer *l);
   int (*file_exists)(struct ovl_layer *l, const char *pathname);
   int (*statat)(struct ovl_layer *l, const char *path, struct stat *st, int flags);
   int (*fstat)(struct ovl_layer *l, int fd, const char *path, struct stat *st);

main.c

@@ -141,12 +141,6 @@ open_by_handle_at (int mount_fd, struct file_handle *handle, int flags)
 }
 #endif
 
-static int
-file_exists_at (int dirfd, const char *pathname)
-{
-  return faccessat (dirfd, pathname, F_OK, AT_SYMLINK_NOFOLLOW|AT_EACCESS);
-}
-
 #ifndef RENAME_EXCHANGE
 # define RENAME_EXCHANGE (1 << 1)
 # define RENAME_NOREPLACE (1 << 2)
@@ -274,52 +268,6 @@ inode_to_node (struct ovl_data *lo, ino_t n)
   return lookup_inode (lo, n)->node;
 }
 
-static int
-strconcat3 (char *dest, size_t size, const char *s1, const char *s2, const char *s3)
-{
-  size_t t;
-  char *current = dest;
-
-  size--;
-
-  if (s1)
-    {
-      t = strlen (s1);
-      if (t > size)
-        t = size;
-
-      memcpy (current, s1, t);
-      current += t;
-
-      size -= t;
-    }
-  if (s2)
-    {
-      t = strlen (s2);
-      if (t > size)
-        t = size;
-
-      memcpy (current, s2, t);
-      current += t;
-
-      size -= t;
-    }
-  if (s3)
-    {
-      t = strlen (s3);
-      if (t > size)
-        t = size;
-
-      memcpy (current, s3, t);
-      current += t;
-
-      size -= t;
-    }
-  *current = '\0';
-
-  return current - dest;
-}
-
 static void
 check_can_mknod (struct ovl_data *lo)
 {
@@ -1602,14 +1550,10 @@ read_dirs (struct ovl_data *lo, char *path, bool low, struct ovl_layer *layers)
 
       l->ovl_data = lo;
 
+      l->path = NULL;
       l->fd = -1;
 
-      l->path = realpath (it, NULL);
+      if (l->ds->load_data_source (l, it) < 0)
-      if (l->path == NULL)
-        return NULL;
-
-      l->fd = open (l->path, O_DIRECTORY);
-      if (l->fd < 0)
         return NULL;
 
       l->low = low;
@@ -2912,23 +2856,6 @@ ovl_rmdir (fuse_req_t req, fuse_ino_t parent, const char *name)
   do_rm (req, parent, name, true);
 }
 
-static int
-open_fd_or_get_path (struct ovl_layer *l, const char *path, char *out, int *fd, int flags)
-{
-  int ret;
-
-  out[0] = '\0';
-
-  *fd = l->ds->openat (l, path, O_NONBLOCK|O_NOFOLLOW|flags, 0755);
-  if (*fd < 0 && (errno == ELOOP || errno == EISDIR))
-    {
-      strconcat3 (out, PATH_MAX, l->path, "/", path);
-      return 0;
-    }
-
-  return *fd;
-}
-
 static int
 direct_setxattr (struct ovl_layer *l, const char *path, const char *name, const char *buf, size_t size, int flags)
 {
@@ -4789,117 +4716,6 @@ ovl_copy_file_range (fuse_req_t req, fuse_ino_t ino_in, off_t off_in, struct fus
 }
 #endif
 
-static int
-direct_file_exists (struct ovl_layer *l, const char *pathname)
-{
-  return file_exists_at (l->fd, pathname);
-}
-
-static int
-direct_listxattr (struct ovl_layer *l, const char *path, char *buf, size_t size)
-{
-  cleanup_close int fd = -1;
-  char full_path[PATH_MAX];
-  int ret;
-
-  full_path[0] = '\0';
-  ret = open_fd_or_get_path (l, path, full_path, &fd, O_RDONLY);
-  if (ret < 0)
-    return ret;
-
-  if (fd >= 0)
-    return flistxattr (fd, buf, size);
-
-  return llistxattr (full_path, buf, size);
-}
-
-static int
-direct_getxattr (struct ovl_layer *l, const char *path, const char *name, char *buf, size_t size)
-{
-  cleanup_close int fd = -1;
-  char full_path[PATH_MAX];
-  int ret;
-
-  full_path[0] = '\0';
-  ret = open_fd_or_get_path (l, path, full_path, &fd, O_RDONLY);
-  if (ret < 0)
-    return ret;
-
-  if (fd >= 0)
-    return fgetxattr (fd, name, buf, size);
-
-  return lgetxattr (full_path, name, buf, size);
-}
-
-static int
-direct_fstat (struct ovl_layer *l, int fd, const char *path, struct stat *st)
-{
-  return fstat (fd, st);
-}
-
-static int
-direct_statat (struct ovl_layer *l, const char *path, struct stat *st, int flags)
-{
-  return TEMP_FAILURE_RETRY (fstatat (l->fd, path, st, flags));
-}
-
-static struct dirent *
-direct_readdir (void *dirp)
-{
-  return readdir (dirp);
-}
-
-static void *
-direct_opendir (struct ovl_layer *l, const char *path)
-{
-  cleanup_close int cleanup_fd = -1;
-  DIR *dp = NULL;
-
-  cleanup_fd = TEMP_FAILURE_RETRY (openat (l->fd, path, O_DIRECTORY));
-  if (cleanup_fd < 0)
-    return NULL;
-
-  dp = fdopendir (cleanup_fd);
-  if (dp == NULL)
-    return NULL;
-
-  cleanup_fd = -1;
-
-  return dp;
-}
-
-static int
-direct_closedir (void *dirp)
-{
-  return closedir (dirp);
-}
-
-static int
-direct_openat (struct ovl_layer *l, const char *path, int flags, mode_t mode)
-{
-  return TEMP_FAILURE_RETRY (openat (l->fd, path, flags, mode));
-}
-
-static ssize_t
-direct_readlinkat (struct ovl_layer *l, const char *path, char *buf, size_t bufsiz)
-{
-  return TEMP_FAILURE_RETRY (readlinkat (l->fd, path, buf, bufsiz));
-}
-
-struct data_source direct_access_ds =
-  {
-   .file_exists = direct_file_exists,
-   .statat = direct_statat,
-   .fstat = direct_fstat,
-   .opendir = direct_opendir,
-   .readdir = direct_readdir,
-   .closedir = direct_closedir,
-   .openat = direct_openat,
-   .getxattr = direct_getxattr,
-   .listxattr = direct_listxattr,
-   .readlinkat = direct_readlinkat,
-  };
-
 static struct fuse_lowlevel_ops ovl_oper =
   {
    .statfs = ovl_statfs,
@@ -5228,6 +5044,9 @@ err_out2:
   fuse_session_destroy (se);
 err_out1:
 
+  for (tmp_layer = lo.layers; tmp_layer; tmp_layer = tmp_layer->next)
+    tmp_layer->ds->cleanup (tmp_layer);
+
   node_mark_all_free (lo.root);
 
   hash_free (lo.inodes);

utils.c

@@ -0,0 +1,124 @@
+/* fuse-overlayfs: Overlay Filesystem in Userspace
+
+   Copyright (C) 2019 Red Hat Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <config.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include "utils.h"
+
+int
+file_exists_at (int dirfd, const char *pathname)
+{
+  return faccessat (dirfd, pathname, F_OK, AT_SYMLINK_NOFOLLOW|AT_EACCESS);
+
+}
+
+int
+strconcat3 (char *dest, size_t size, const char *s1, const char *s2, const char *s3)
+{
+  size_t t;
+  char *current = dest;
+
+  size--;
+
+  if (s1)
+    {
+      t = strlen (s1);
+      if (t > size)
+        t = size;
+
+      memcpy (current, s1, t);
+      current += t;
+
+      size -= t;
+    }
+  if (s2)
+    {
+      t = strlen (s2);
+      if (t > size)
+        t = size;
+
+      memcpy (current, s2, t);
+      current += t;
+
+      size -= t;
+    }
+  if (s3)
+    {
+      t = strlen (s3);
+      if (t > size)
+        t = size;
+
+      memcpy (current, s3, t);
+      current += t;
+
+      size -= t;
+    }
+  *current = '\0';
+
+  return current - dest;
+}
+
+void
+cleanup_freep (void *p)
+{
+  void **pp = (void **) p;
+  free (*pp);
+}
+
+void
+cleanup_filep (FILE **f)
+{
+  FILE *file = *f;
+  if (file)
+    (void) fclose (file);
+}
+
+void
+cleanup_closep (void *p)
+{
+  int *pp = p;
+  if (*pp >= 0)
+    close (*pp);
+}
+
+void
+cleanup_dirp (DIR **p)
+{
+  DIR *dir = *p;
+  if (dir)
+    closedir (dir);
+}
+
+int
+open_fd_or_get_path (struct ovl_layer *l, const char *path, char *out, int *fd, int flags)
+{
+  int ret;
+
+  out[0] = '\0';
+
+  *fd = l->ds->openat (l, path, O_NONBLOCK|O_NOFOLLOW|flags, 0755);
+  if (*fd < 0 && (errno == ELOOP || errno == EISDIR))
+    {
+      strconcat3 (out, PATH_MAX, l->path, "/", path);
+      return 0;
+    }
+
+  return *fd;
+}

utils.h

@@ -18,36 +18,22 @@
 #ifndef UTILS_H
 # define UTILS_H
 
-void
+# include <unistd.h>
-cleanup_freep (void *p)
+# include <stdio.h>
-{
+# include <sys/types.h>
-  void **pp = (void **) p;
+# include <dirent.h>
-  free (*pp);
+# include <stdlib.h>
-}
+# include "fuse-overlayfs.h"
 
-void
+void cleanup_freep (void *p);
-cleanup_filep (FILE **f)
+void cleanup_filep (FILE **f);
-{
+void cleanup_closep (void *p);
-  FILE *file = *f;
+void cleanup_dirp (DIR **p);
-  if (file)
-    (void) fclose (file);
-}
 
-void
+int file_exists_at (int dirfd, const char *pathname);
-cleanup_closep (void *p)
-{
-  int *pp = p;
-  if (*pp >= 0)
-    close (*pp);
-}
 
-void
+int strconcat3 (char *dest, size_t size, const char *s1, const char *s2, const char *s3);
-cleanup_dirp (DIR **p)
+int open_fd_or_get_path (struct ovl_layer *l, const char *path, char *out, int *fd, int flags);
-{
-  DIR *dir = *p;
-  if (dir)
-    closedir (dir);
-}
 
 # define cleanup_file __attribute__((cleanup (cleanup_filep)))
 # define cleanup_free __attribute__((cleanup (cleanup_freep)))