Add 'dbfs' for Berkeley DB experiments.

3 files changed, 178 insertions, 1 deletions

diff --git a/.gitignore b/.gitignore
index 5267297..567f41c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -21,6 +21,7 @@ stamp-h1
 
 # app-specific
 ndbfs
+dbfs
 dbfs-config.h*
 
 fuse-db-*.tar.gz
diff --git a/Makefile.am b/Makefile.am
index 0389a98..133ec66 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -4,10 +4,13 @@
 
 INCLUDES	= @GNET_CFLAGS@ @FUSE_CFLAGS@
 
-sbin_PROGRAMS	= ndbfs
+sbin_PROGRAMS	= ndbfs dbfs
 
 ndbfs_SOURCES	= ndbfs.c
 ndbfs_LDADD	= @GNET_LIBS@ @FUSE_LIBS@
 
+dbfs_SOURCES	= dbfs.c
+dbfs_LDADD	= @GNET_LIBS@ @FUSE_LIBS@ @DB_LIBS@
+
 EXTRA_DIST	= autogen.sh
 
diff --git a/dbfs.c b/dbfs.c
new file mode 100644
index 0000000..f286eb4
--- /dev/null
+++ b/dbfs.c
@@ -0,0 +1,173 @@
+
+#define FUSE_USE_VERSION 25
+
+#include <fuse_lowlevel.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <assert.h>
+
+static const char *hello_str = "Hello World!\n";
+static const char *hello_name = "hello";
+
+static int hello_stat(fuse_ino_t ino, struct stat *stbuf)
+{
+	stbuf->st_ino = ino;
+	switch (ino) {
+	case 1:
+		stbuf->st_mode = S_IFDIR | 0755;
+		stbuf->st_nlink = 2;
+		break;
+
+	case 2:
+		stbuf->st_mode = S_IFREG | 0444;
+		stbuf->st_nlink = 1;
+		stbuf->st_size = strlen(hello_str);
+		break;
+
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static void hello_ll_getattr(fuse_req_t req, fuse_ino_t ino,
+			     struct fuse_file_info *fi)
+{
+	struct stat stbuf;
+
+	(void)fi;
+
+	memset(&stbuf, 0, sizeof(stbuf));
+	if (hello_stat(ino, &stbuf) == -1)
+		fuse_reply_err(req, ENOENT);
+	else
+		fuse_reply_attr(req, &stbuf, 1.0);
+}
+
+static void hello_ll_lookup(fuse_req_t req, fuse_ino_t parent, const char *name)
+{
+	struct fuse_entry_param e;
+
+	if (parent != 1 || strcmp(name, hello_name) != 0)
+		fuse_reply_err(req, ENOENT);
+	else {
+		memset(&e, 0, sizeof(e));
+		e.ino = 2;
+		e.attr_timeout = 1.0;
+		e.entry_timeout = 1.0;
+		hello_stat(e.ino, &e.attr);
+
+		fuse_reply_entry(req, &e);
+	}
+}
+
+struct dirbuf {
+	char *p;
+	size_t size;
+};
+
+static void dirbuf_add(struct dirbuf *b, const char *name, fuse_ino_t ino)
+{
+	struct stat stbuf;
+	size_t oldsize = b->size;
+	b->size += fuse_dirent_size(strlen(name));
+	b->p = (char *)realloc(b->p, b->size);
+	memset(&stbuf, 0, sizeof(stbuf));
+	stbuf.st_ino = ino;
+	fuse_add_dirent(b->p + oldsize, name, &stbuf, b->size);
+}
+
+#define min(x, y) ((x) < (y) ? (x) : (y))
+
+static int reply_buf_limited(fuse_req_t req, const char *buf, size_t bufsize,
+			     off_t off, size_t maxsize)
+{
+	if (off < bufsize)
+		return fuse_reply_buf(req, buf + off,
+				      min(bufsize - off, maxsize));
+	else
+		return fuse_reply_buf(req, NULL, 0);
+}
+
+static void hello_ll_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
+			     off_t off, struct fuse_file_info *fi)
+{
+	(void)fi;
+
+	if (ino != 1)
+		fuse_reply_err(req, ENOTDIR);
+	else {
+		struct dirbuf b;
+
+		memset(&b, 0, sizeof(b));
+		dirbuf_add(&b, ".", 1);
+		dirbuf_add(&b, "..", 1);
+		dirbuf_add(&b, hello_name, 2);
+		reply_buf_limited(req, b.p, b.size, off, size);
+		free(b.p);
+	}
+}
+
+static void hello_ll_open(fuse_req_t req, fuse_ino_t ino,
+			  struct fuse_file_info *fi)
+{
+	if (ino != 2)
+		fuse_reply_err(req, EISDIR);
+	else if ((fi->flags & 3) != O_RDONLY)
+		fuse_reply_err(req, EACCES);
+	else
+		fuse_reply_open(req, fi);
+}
+
+static void hello_ll_read(fuse_req_t req, fuse_ino_t ino, size_t size,
+			  off_t off, struct fuse_file_info *fi)
+{
+	(void)fi;
+
+	assert(ino == 2);
+	reply_buf_limited(req, hello_str, strlen(hello_str), off, size);
+}
+
+static struct fuse_lowlevel_ops hello_ll_oper = {
+	.lookup = hello_ll_lookup,
+	.getattr = hello_ll_getattr,
+	.readdir = hello_ll_readdir,
+	.open = hello_ll_open,
+	.read = hello_ll_read,
+};
+
+int main(int argc, char *argv[])
+{
+	struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
+	char *mountpoint;
+	int err = -1;
+	int fd;
+
+	if (fuse_parse_cmdline(&args, &mountpoint, NULL, NULL) != -1 &&
+	    (fd = fuse_mount(mountpoint, &args)) != -1) {
+		struct fuse_session *se;
+
+		se = fuse_lowlevel_new(&args, &hello_ll_oper,
+				       sizeof(hello_ll_oper), NULL);
+		if (se != NULL) {
+			if (fuse_set_signal_handlers(se) != -1) {
+				struct fuse_chan *ch = fuse_kern_chan_new(fd);
+				if (ch != NULL) {
+					fuse_session_add_chan(se, ch);
+					err = fuse_session_loop(se);
+				}
+				fuse_remove_signal_handlers(se);
+			}
+			fuse_session_destroy(se);
+		}
+		close(fd);
+	}
+	fuse_unmount(mountpoint);
+	fuse_opt_free_args(&args);
+
+	return err ? 1 : 0;
+}