Used the libfuse example as a foundation.

The main.c was completely replaced by one of the libfuse examples:
[passthrough_fh.c](https://github.com/libfuse/libfuse/blob/master/example/passthrough_fh.c)
. This choice is made based on that there is little point in spending
time on reinventing the wheel by reimplementing passthrough all over
again. Also, the [passthrough_hp.cc](https://github.com/libfuse/libfuse/blob/master/example/passthrough_hp.cc) wasn't used because it uses a vastly different and much more comlex API, even though the authors claim it to be faster.

sources/main.c

@@ -1,25 +1,653 @@
+/*
+  FUSE: Filesystem in Userspace
+  Copyright (C) 2001-2007  Miklos Szeredi <miklos@szeredi.hu>
+  Copyright (C) 2011       Sebastian Pipping <sebastian@pipping.org>
+
+  This program can be distributed under the terms of the GNU GPLv2.
+  See the file COPYING.
+*/
+
+/** @file
+ *
+ * This file system mirrors the existing file system hierarchy of the
+ * system, starting at the root file system. This is implemented by
+ * just "passing through" all requests to the corresponding user-space
+ * libc functions. This implementation is a little more sophisticated
+ * than the one in passthrough.c, so performance is not quite as bad.
+ *
+ * Compile with:
+ *
+ *     gcc -Wall passthrough_fh.c `pkg-config fuse3 --cflags --libs` -lulockmgr
+ * -o passthrough_fh
+ *
+ * ## Source code ##
+ * \include passthrough_fh.c
+ */
+
+#define FUSE_USE_VERSION 31
+
+#define _GNU_SOURCE
+
+#include <fuse3/fuse.h>
+
+#ifdef HAVE_LIBULOCKMGR
+#include <ulockmgr.h>
+#endif
+
 #include <dirent.h>
 #include <errno.h>
-#include <stdint.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#define FUSE_USE_VERSION 31
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <unistd.h>
+#ifdef HAVE_SETXATTR
+#include <sys/xattr.h>
+#endif
+#include <sys/file.h> /* flock(2) */
 
 #include "sourcefs.h"
-#include <fuse3/fuse.h>
 
 const char *mountpoint = NULL;
 
-/*
+static void *xmp_init(struct fuse_conn_info *conn, struct fuse_config *cfg) {
- * #In this function we need to:
+  (void)conn;
- *
+  cfg->use_ino = 1;
- * * Open the folder we are mounting over (and remember it).
+  cfg->nullpath_ok = 1;
- * * Initialize the process table.
+
+  /* parallel_direct_writes feature depends on direct_io features.
+     To make parallel_direct_writes valid, need either set cfg->direct_io
+     in current function (recommended in high level API) or set fi->direct_io
+     in xmp_create() or xmp_open(). */
+  // cfg->direct_io = 1;
+  // cfg->parallel_direct_writes = 1;
+
+  /* Pick up changes from lower filesystem right away. This is
+     also necessary for better hardlink support. When the kernel
+     calls the unlink() handler, it does not know the inode of
+     the to-be-removed entry and can therefore not invalidate
+     the cache of the associated inode - resulting in an
+     incorrect st_nlink value being reported for any remaining
+     hardlinks to this inode. */
+  cfg->entry_timeout = 0;
+  cfg->attr_timeout = 0;
+  cfg->negative_timeout = 0;
+
+  return NULL;
+}
+
+static int xmp_getattr(const char *path, struct stat *stbuf,
+                       struct fuse_file_info *fi) {
+  int res;
+
+  (void)path;
+
+  if (fi)
+    res = fstat(fi->fh, stbuf);
+  else
+    res = source_stat(path, stbuf);
+  if (res == -1) {
+    perror("Stat failed");
+    return -errno;
+  }
+
+  return 0;
+}
+
+static int xmp_access(const char *path, int mask) {
+  int res;
+
+  res = access(path, mask);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_readlink(const char *path, char *buf, size_t size) {
+  int res;
+
+  res = readlink(path, buf, size - 1);
+  if (res == -1)
+    return -errno;
+
+  buf[res] = '\0';
+  return 0;
+}
+
+struct xmp_dirp {
+  DIR *dp;
+  struct dirent *entry;
+  off_t offset;
+};
+
+static int xmp_opendir(const char *path, struct fuse_file_info *fi) {
+  int res;
+  struct xmp_dirp *d = malloc(sizeof(struct xmp_dirp));
+  if (d == NULL)
+    return -ENOMEM;
+
+  d->dp = source_opendir(path);
+  if (d->dp == NULL) {
+    perror("Opendir failed");
+    res = -errno;
+    free(d);
+    return res;
+  }
+  d->offset = 0;
+  d->entry = NULL;
+
+  fi->fh = (unsigned long)d;
+  return 0;
+}
+
+static inline struct xmp_dirp *get_dirp(struct fuse_file_info *fi) {
+  return (struct xmp_dirp *)(uintptr_t)fi->fh;
+}
+
+/* Complete copy of the example method(no need to modify anything so far) */
+static int xmp_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
+                       off_t offset, struct fuse_file_info *fi,
+                       enum fuse_readdir_flags flags) {
+  struct xmp_dirp *d = get_dirp(fi);
+
+  (void)path;
+  if (offset != d->offset) {
+#ifndef __FreeBSD__
+    seekdir(d->dp, offset);
+#else
+    /* Subtract the one that we add when calling
+       telldir() below */
+    seekdir(d->dp, offset - 1);
+#endif
+    d->entry = NULL;
+    d->offset = offset;
+  }
+  while (1) {
+    struct stat st;
+    off_t nextoff;
+    // enum fuse_fill_dir_flags fill_flags = FUSE_FILL_DIR_DEFAULTS;
+    enum fuse_fill_dir_flags fill_flags = 0;
+
+    if (!d->entry) {
+      d->entry = readdir(d->dp);
+      if (!d->entry)
+        break;
+    }
+#ifdef HAVE_FSTATAT
+    if (flags & FUSE_READDIR_PLUS) {
+      int res;
+
+      res = fstatat(dirfd(d->dp), d->entry->d_name, &st, AT_SYMLINK_NOFOLLOW);
+      if (res != -1)
+        fill_flags |= FUSE_FILL_DIR_PLUS;
+    }
+#endif
+    if (!(fill_flags & FUSE_FILL_DIR_PLUS)) {
+      memset(&st, 0, sizeof(st));
+      st.st_ino = d->entry->d_ino;
+      st.st_mode = d->entry->d_type << 12;
+    }
+    nextoff = telldir(d->dp);
+#ifdef __FreeBSD__
+    /* Under FreeBSD, telldir() may return 0 the first time
+       it is called. But for libfuse, an offset of zero
+       means that offsets are not supported, so we shift
+       everything by one. */
+    nextoff++;
+#endif
+    if (filler(buf, d->entry->d_name, &st, nextoff, fill_flags))
+      break;
+
+    d->entry = NULL;
+    d->offset = nextoff;
+  }
+
+  return 0;
+}
+
+/* Complete copy of the example method(no need to modify anything so far) */
+static int xmp_releasedir(const char *path, struct fuse_file_info *fi) {
+  struct xmp_dirp *d = get_dirp(fi);
+  (void)path;
+  closedir(d->dp);
+  free(d);
+  return 0;
+}
+
+// TODO: make this work
+static int xmp_mknod(const char *path, mode_t mode, dev_t rdev) {
+  int res;
+
+  if (S_ISFIFO(mode))
+    res = mkfifo(path, mode);
+  else
+    res = mknod(path, mode, rdev);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_mkdir(const char *path, mode_t mode) {
+  int res;
+
+  res = source_mkdir(path, mode);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_unlink(const char *path) {
+  int res;
+
+  res = source_unlink(path);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_rmdir(const char *path) {
+  int res;
+
+  res = source_rmdir(path);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_symlink(const char *from, const char *to) {
+  int res;
+
+  res = source_symlink(from, to);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_rename(const char *from, const char *to, unsigned int flags) {
+  int res;
+
+  /* When we have renameat2() in libc, then we can implement flags */
+  if (flags)
+    return -EINVAL;
+
+  res = source_rename(from, to);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_link(const char *from, const char *to) {
+  int res;
+
+  res = link(from, to);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_chmod(const char *path, mode_t mode, struct fuse_file_info *fi) {
+  int res;
+
+  if (fi)
+    res = fchmod(fi->fh, mode);
+  else
+    res = chmod(path, mode);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_chown(const char *path, uid_t uid, gid_t gid,
+                     struct fuse_file_info *fi) {
+  int res;
+
+  if (fi)
+    res = fchown(fi->fh, uid, gid);
+  else
+    res = lchown(path, uid, gid);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_truncate(const char *path, off_t size,
+                        struct fuse_file_info *fi) {
+  int res;
+
+  if (fi)
+    res = ftruncate(fi->fh, size);
+  else
+    res = truncate(path, size);
+
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+#ifdef HAVE_UTIMENSAT
+static int xmp_utimens(const char *path, const struct timespec ts[2],
+                       struct fuse_file_info *fi) {
+  int res;
+
+  /* don't use utime/utimes since they follow symlinks */
+  if (fi)
+    res = futimens(fi->fh, ts);
+  else
+    res = utimensat(0, path, ts, AT_SYMLINK_NOFOLLOW);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+#endif
+
+static int xmp_create(const char *path, mode_t mode,
+                      struct fuse_file_info *fi) {
+  int fd;
+
+  fd = open(path, fi->flags, mode);
+  if (fd == -1)
+    return -errno;
+
+  fi->fh = fd;
+  return 0;
+}
+
+static int xmp_open(const char *path, struct fuse_file_info *fi) {
+  int fd;
+
+  fd = open(path, fi->flags);
+  if (fd == -1)
+    return -errno;
+
+  /* Enable direct_io when open has flags O_DIRECT to enjoy the feature
+     parallel_direct_writes (i.e., to get a shared lock, not exclusive lock,
+     for writes to the same file).
+  if (fi->flags & O_DIRECT) {
+    fi->direct_io = 1;
+    fi->parallel_direct_writes = 1;
+  }
   */
-static void *icfs_init(struct fuse_conn_info *conn, struct fuse_config *cfg) {
+
-  (void)conn; /* Explicit way to tell we ignore these arguments. */
+  fi->fh = fd;
-  (void)cfg;  /* This also silences the compiler warnings. */
+  return 0;
+}
+
+static int xmp_read(const char *path, char *buf, size_t size, off_t offset,
+                    struct fuse_file_info *fi) {
+  int res;
+
+  (void)path;
+  res = pread(fi->fh, buf, size, offset);
+  if (res == -1)
+    res = -errno;
+
+  return res;
+}
+
+static int xmp_read_buf(const char *path, struct fuse_bufvec **bufp,
+                        size_t size, off_t offset, struct fuse_file_info *fi) {
+  struct fuse_bufvec *src;
+
+  (void)path;
+
+  src = malloc(sizeof(struct fuse_bufvec));
+  if (src == NULL)
+    return -ENOMEM;
+
+  *src = FUSE_BUFVEC_INIT(size);
+
+  src->buf[0].flags = FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK;
+  src->buf[0].fd = fi->fh;
+  src->buf[0].pos = offset;
+
+  *bufp = src;
+
+  return 0;
+}
+
+static int xmp_write(const char *path, const char *buf, size_t size,
+                     off_t offset, struct fuse_file_info *fi) {
+  int res;
+
+  (void)path;
+  res = pwrite(fi->fh, buf, size, offset);
+  if (res == -1)
+    res = -errno;
+
+  return res;
+}
+
+static int xmp_write_buf(const char *path, struct fuse_bufvec *buf,
+                         off_t offset, struct fuse_file_info *fi) {
+  struct fuse_bufvec dst = FUSE_BUFVEC_INIT(fuse_buf_size(buf));
+
+  (void)path;
+
+  dst.buf[0].flags = FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK;
+  dst.buf[0].fd = fi->fh;
+  dst.buf[0].pos = offset;
+
+  return fuse_buf_copy(&dst, buf, FUSE_BUF_SPLICE_NONBLOCK);
+}
+
+static int xmp_statfs(const char *path, struct statvfs *stbuf) {
+  int res;
+
+  res = statvfs(path, stbuf);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_flush(const char *path, struct fuse_file_info *fi) {
+  int res;
+
+  (void)path;
+  /* This is called from every close on an open file, so call the
+     close on the underlying filesystem.	But since flush may be
+     called multiple times for an open file, this must not really
+     close the file.  This is important if used on a network
+     filesystem like NFS which flush the data/metadata on close() */
+  res = close(dup(fi->fh));
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+static int xmp_release(const char *path, struct fuse_file_info *fi) {
+  (void)path;
+  close(fi->fh);
+
+  return 0;
+}
+
+static int xmp_fsync(const char *path, int isdatasync,
+                     struct fuse_file_info *fi) {
+  int res;
+  (void)path;
+
+#ifndef HAVE_FDATASYNC
+  (void)isdatasync;
+#else
+  if (isdatasync)
+    res = fdatasync(fi->fh);
+  else
+#endif
+  res = fsync(fi->fh);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+#ifdef HAVE_POSIX_FALLOCATE
+static int xmp_fallocate(const char *path, int mode, off_t offset, off_t length,
+                         struct fuse_file_info *fi) {
+  (void)path;
+
+  if (mode)
+    return -EOPNOTSUPP;
+
+  return -posix_fallocate(fi->fh, offset, length);
+}
+#endif
+
+#ifdef HAVE_SETXATTR
+/* xattr operations are optional and can safely be left unimplemented */
+static int xmp_setxattr(const char *path, const char *name, const char *value,
+                        size_t size, int flags) {
+  int res = lsetxattr(path, name, value, size, flags);
+  if (res == -1)
+    return -errno;
+  return 0;
+}
+
+static int xmp_getxattr(const char *path, const char *name, char *value,
+                        size_t size) {
+  int res = lgetxattr(path, name, value, size);
+  if (res == -1)
+    return -errno;
+  return res;
+}
+
+static int xmp_listxattr(const char *path, char *list, size_t size) {
+  int res = llistxattr(path, list, size);
+  if (res == -1)
+    return -errno;
+  return res;
+}
+
+static int xmp_removexattr(const char *path, const char *name) {
+  int res = lremovexattr(path, name);
+  if (res == -1)
+    return -errno;
+  return 0;
+}
+#endif /* HAVE_SETXATTR */
+
+#ifdef HAVE_LIBULOCKMGR
+static int xmp_lock(const char *path, struct fuse_file_info *fi, int cmd,
+                    struct flock *lock) {
+  (void)path;
+
+  return ulockmgr_op(fi->fh, cmd, lock, &fi->lock_owner,
+                     sizeof(fi->lock_owner));
+}
+#endif
+
+static int xmp_flock(const char *path, struct fuse_file_info *fi, int op) {
+  int res;
+  (void)path;
+
+  res = flock(fi->fh, op);
+  if (res == -1)
+    return -errno;
+
+  return 0;
+}
+
+#ifdef HAVE_COPY_FILE_RANGE
+static ssize_t xmp_copy_file_range(const char *path_in,
+                                   struct fuse_file_info *fi_in, off_t off_in,
+                                   const char *path_out,
+                                   struct fuse_file_info *fi_out, off_t off_out,
+                                   size_t len, int flags) {
+  ssize_t res;
+  (void)path_in;
+  (void)path_out;
+
+  res = copy_file_range(fi_in->fh, &off_in, fi_out->fh, &off_out, len, flags);
+  if (res == -1)
+    return -errno;
+
+  return res;
+}
+#endif
+
+static off_t xmp_lseek(const char *path, off_t off, int whence,
+                       struct fuse_file_info *fi) {
+  off_t res;
+  (void)path;
+
+  res = lseek(fi->fh, off, whence);
+  if (res == -1)
+    return -errno;
+
+  return res;
+}
+
+static const struct fuse_operations xmp_oper = {
+    .init = xmp_init,
+    .getattr = xmp_getattr,
+    .access = xmp_access,
+    .readlink = xmp_readlink,
+    .opendir = xmp_opendir,
+    .readdir = xmp_readdir,
+    .releasedir = xmp_releasedir,
+    .mknod = xmp_mknod,
+    .mkdir = xmp_mkdir,
+    .symlink = xmp_symlink,
+    .unlink = xmp_unlink,
+    .rmdir = xmp_rmdir,
+    .rename = xmp_rename,
+    .link = xmp_link,
+    .chmod = xmp_chmod,
+    .chown = xmp_chown,
+    .truncate = xmp_truncate,
+#ifdef HAVE_UTIMENSAT
+    .utimens = xmp_utimens,
+#endif
+    .create = xmp_create,
+    .open = xmp_open,
+    .read = xmp_read,
+    .read_buf = xmp_read_buf,
+    .write = xmp_write,
+    .write_buf = xmp_write_buf,
+    .statfs = xmp_statfs,
+    .flush = xmp_flush,
+    .release = xmp_release,
+    .fsync = xmp_fsync,
+#ifdef HAVE_POSIX_FALLOCATE
+    .fallocate = xmp_fallocate,
+#endif
+#ifdef HAVE_SETXATTR
+    .setxattr = xmp_setxattr,
+    .getxattr = xmp_getxattr,
+    .listxattr = xmp_listxattr,
+    .removexattr = xmp_removexattr,
+#endif
+#ifdef HAVE_LIBULOCKMGR
+    .lock = xmp_lock,
+#endif
+    .flock = xmp_flock,
+#ifdef HAVE_COPY_FILE_RANGE
+    .copy_file_range = xmp_copy_file_range,
+#endif
+    .lseek = xmp_lseek,
+};
+
+int main(int argc, char *argv[]) {
+  umask(0);
+
+  // FUSE won't tell us the mountpoint on it's own, so we need to extract it
+  // ourselves.
+  mountpoint = realpath(argv[argc - 1], NULL);
 
   int ret = source_init(mountpoint);
   if (ret != 0) {
@@ -27,70 +655,5 @@ static void *icfs_init(struct fuse_conn_info *conn, struct fuse_config *cfg) {
     exit(EXIT_FAILURE);
   }
 
-  return NULL;
+  return fuse_main(argc, argv, &xmp_oper, NULL);
-}
-
-static int icfs_getattr(const char *path, struct stat *stbuf,
-                        struct fuse_file_info *fi) {
-  (void)stbuf;
-  (void)fi;
-
-  int statret = source_stat(path, stbuf);
-  if (statret != 0)
-    perror("Stat failed.");
-
-  return statret;
-}
-
-static int icfs_opendir(const char *path, struct fuse_file_info *fi) {
-  DIR *dir_stream = source_opendir(path);
-
-  if (dir_stream == NULL) {
-    perror("Opendir failed.");
-    return 1;
-  }
-
-  fi->fh = (intptr_t)dir_stream;
-
-  return 0;
-}
-
-static int icfs_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
-                        off_t offset, struct fuse_file_info *fi,
-                        enum fuse_readdir_flags flags) {
-  DIR *dir_stream = (DIR *)fi->fh;
-  struct dirent *dir_entry = source_readdir(dir_stream);
-  if (dir_entry == NULL) {
-    perror("Readdir failed.");
-    return 1;
-  }
-
-  do {
-    int filler_ret = filler(buf, dir_entry->d_name, NULL, 0, 0);
-    if (filler_ret != 0) {
-      return -ENOMEM;
-    }
-  } while ((dir_entry = source_readdir(dir_stream)) != NULL);
-
-  return 0;
-}
-
-static const struct fuse_operations icfs_oper = {
-    .init = icfs_init,
-    .getattr = icfs_getattr,
-    .opendir = icfs_opendir,
-    .readdir = icfs_readdir,
-};
-
-int main(int argc, char *argv[]) {
-
-  int ret;
-
-  // FUSE won't tell us the mountpoint on it's own, so we need to extract it
-  // ourselves.
-  mountpoint = realpath(argv[argc - 1], NULL);
-
-  ret = fuse_main(argc, argv, &icfs_oper, NULL);
-
-  return ret;
 }

sources/sourcefs.c

@@ -2,15 +2,24 @@
 
 #include "sourcefs.h"
 #include <dirent.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
+#include <string.h>
 #include <sys/stat.h>
+#include <unistd.h>
 
 static struct source_files_handle {
   int root_fd;
 } handle;
 
-void source_fname_translate(const char *filename) {}
+const char *source_fname_translate(const char *filename) {
+  if (strcmp("/", filename) == 0) {
+    return ".";
+  } else {
+    return filename + 1;
+  }
+}
 
 int source_init(const char *root_path) {
   int root_fd = open(root_path, O_PATH);
@@ -24,17 +33,43 @@ int source_init(const char *root_path) {
   return 0;
 }
 
-// Currently this literally is a fstatat wrapper.
+int source_mkdir(const char *filename, mode_t mode) {
-int source_stat(const char *restrict pathname, struct stat *restrict statbuf) {
+  const char *relative_filename = source_fname_translate(filename);
-  int statret = fstatat(handle.root_fd, pathname, statbuf, 0);
+  return mkdirat(handle.root_fd, relative_filename, mode);
-  return statret;
+}
+
+int source_unlink(const char *filename) {
+  const char *relative_filename = source_fname_translate(filename);
+  return unlinkat(handle.root_fd, relative_filename, 0);
+}
+
+int source_stat(const char *restrict filename, struct stat *restrict statbuf) {
+  const char *relative_filename = source_fname_translate(filename);
+  return fstatat(handle.root_fd, relative_filename, statbuf, 0);
+}
+
+int source_rmdir(const char *filename) {
+  const char *relative_filename = source_fname_translate(filename);
+  return unlinkat(handle.root_fd, relative_filename, AT_REMOVEDIR);
+}
+
+int source_symlink(const char *target, const char *linkpath) {
+  const char *relative_linkpath = source_fname_translate(linkpath);
+  return symlinkat(target, handle.root_fd, relative_linkpath);
 }
 
 DIR *source_opendir(const char *filename) {
-  int fd = openat(handle.root_fd, filename, NULL);
+  const char *relative_filename = source_fname_translate(filename);
+  int fd = openat(handle.root_fd, relative_filename, NULL);
+  if (fd < 0) {
+    perror("Openat failed");
+    return NULL;
+  }
   DIR *dir_pointer = fdopendir(fd);
   return dir_pointer;
 }
 
-// Just regular readdir in disguise.
+int source_rename(const char *oldpath, const char *newpath) {
-struct dirent *source_readdir(DIR *dirp) { return readdir(dirp); }
+  printf("{\"%s\", \"%s\"}\n", oldpath, newpath);
+  return -1;
+}

sources/sourcefs.h

@@ -14,25 +14,23 @@
  */
 int source_init(const char *root_path);
 
-/**
+/* All of the functions below are designed to behave exactly as their non-source
- * `stat()`, but for source files.
+ * counterparts. */
- *
+
- * @see `stat()`
+int source_stat(const char *restrict filename, struct stat *restrict statbuf);
- */
-int source_stat(const char *restrict pathname, struct stat *restrict statbuf);
 
-/**
- * `readdir()`, but for source files.
- *
- * @see `readdir(3)`
- */
 struct dirent *source_readdir(DIR *dirp);
 
-/**
- * `opendir()`, but for source files.
- *
- * @see `opendir()`
- */
 DIR *source_opendir(const char *filename);
 
+int source_unlink(const char *filename);
+
+int source_mkdir(const char *filename, mode_t mode);
+
+int source_rmdir(const char *filename);
+
+int source_symlink(const char *target, const char *linkpath);
+
+int source_rename(const char *oldpath, const char *newpath);
+
 #endif // !SOURCEFS_H