Implement getxattr, setxattr, removexattr ops.

Also, two cleanups:
- move key, val memset(3) closer to other key, val initialization
- simplify expression 'rc ? -rc : 0'

3 files changed, 170 insertions, 17 deletions

diff --git a/dbfs-backend.c b/dbfs-backend.c
index 34c9fc3..14eeb2b 100644
--- a/dbfs-backend.c
+++ b/dbfs-backend.c
@@ -6,6 +6,7 @@
 #include <errno.h>
 #include <unistd.h>
 #include <time.h>
+#include <attr/xattr.h>
 #include <glib.h>
 #include <db.h>
 #include "dbfs.h"
@@ -108,14 +109,13 @@ int dbfs_inode_read(guint64 ino_n, struct dbfs_inode **ino_out)
 	size_t ex_sz;
 	guint32 mode;
 
-	memset(&key, 0, sizeof(key));
-	memset(&val, 0, sizeof(val));
-
 	sprintf(key_str, "/inode/%Lu", (unsigned long long) ino_n);
 
+	memset(&key, 0, sizeof(key));
 	key.data = key_str;
 	key.size = strlen(key_str);
 
+	memset(&val, 0, sizeof(val));
 	val.flags = DB_DBT_MALLOC;
 
 	rc = gfs->meta->get(gfs->meta, NULL, &key, &val, 0);
@@ -197,14 +197,13 @@ int dbfs_dir_read(guint64 ino, DBT *val)
 	char key_str[32];
 	int rc;
 
-	memset(&key, 0, sizeof(key));
-	memset(val, 0, sizeof(*val));
-
 	sprintf(key_str, "/dir/%Lu", (unsigned long long) ino);
 
+	memset(&key, 0, sizeof(key));
 	key.data = key_str;
 	key.size = strlen(key_str);
 
+	memset(val, 0, sizeof(*val));
 	val->flags = DB_DBT_MALLOC;
 
 	rc = gfs->meta->get(gfs->meta, NULL, &key, val, 0);
@@ -431,14 +430,13 @@ int dbfs_symlink_read(guint64 ino, DBT *val)
 	char key_str[32];
 	int rc;
 
-	memset(&key, 0, sizeof(key));
-	memset(val, 0, sizeof(*val));
-
 	sprintf(key_str, "/symlink/%Lu", (unsigned long long) ino);
 
+	memset(&key, 0, sizeof(key));
 	key.data = key_str;
 	key.size = strlen(key_str);
 
+	memset(val, 0, sizeof(*val));
 	val->flags = DB_DBT_MALLOC;
 
 	rc = gfs->meta->get(gfs->meta, NULL, &key, val, 0);
@@ -452,14 +450,13 @@ int dbfs_symlink_write(guint64 ino, const char *link)
 	DBT key, val;
 	char key_str[32];
 
-	memset(&key, 0, sizeof(key));
-	memset(&val, 0, sizeof(val));
-
 	sprintf(key_str, "/symlink/%Lu", (unsigned long long) ino);
 
+	memset(&key, 0, sizeof(key));
 	key.data = key_str;
 	key.size = strlen(key_str);
 
+	memset(&val, 0, sizeof(val));
 	val.data = (void *) link;
 	val.size = strlen(link);
 
@@ -584,3 +581,108 @@ err_out:
 	return rc;
 }
 
+static int dbfs_xattr_read(guint64 ino, const char *name, DBT *val)
+{
+	char key_str[DBFS_XATTR_NAME_LEN + 32];
+	DBT key;
+	int rc;
+
+	snprintf(key_str, sizeof(key_str),
+		 "/xattr/%Lu/%s", (unsigned long long) ino, name);
+
+	memset(&key, 0, sizeof(key));
+	key.data = key_str;
+	key.size = strlen(key_str);
+
+	memset(val, 0, sizeof(*val));
+	val->flags = DB_DBT_MALLOC;
+
+	rc = gfs->meta->get(gfs->meta, NULL, &key, val, 0);
+	if (rc == DB_NOTFOUND)
+		return -EINVAL;
+	return rc ? -EIO : 0;
+}
+
+static int dbfs_xattr_write(guint64 ino, const char *name,
+			    const char *buf, size_t buflen)
+{
+	char key_str[DBFS_XATTR_NAME_LEN + 32];
+	DBT key, val;
+
+	snprintf(key_str, sizeof(key_str),
+		 "/xattr/%Lu/%s", (unsigned long long) ino, name);
+
+	memset(&key, 0, sizeof(key));
+	key.data = key_str;
+	key.size = strlen(key_str);
+
+	memset(&val, 0, sizeof(val));
+	val.data = (void *) buf;
+	val.size = buflen;
+
+	return gfs->meta->put(gfs->meta, NULL, &key, &val, 0) ? -EIO : 0;
+}
+
+int dbfs_xattr_get(guint64 ino_n, const char *name,
+		   char **buf_out, size_t *buflen_out)
+{
+	int rc;
+	DBT val;
+
+	rc = dbfs_xattr_read(ino_n, name, &val);
+	if (rc)
+		return rc;
+	
+	*buf_out = val.data;
+	*buflen_out = val.size;
+
+	return 0;
+}
+
+int dbfs_xattr_set(guint64 ino_n, const char *name, const char *buf,
+		   size_t buflen, int flags)
+{
+	char *current = NULL;
+	size_t current_len = 0;
+	int rc, exists;
+
+	rc = dbfs_xattr_get(ino_n, name, &current, &current_len);
+	if (rc && (rc != -EINVAL))
+		return rc;
+
+	exists = (current == NULL);
+	free(current);
+
+	if (exists && (flags & XATTR_CREATE))
+		return -EEXIST;
+	if (!exists && (flags & XATTR_REPLACE))
+		return -ENOATTR;
+	if (buflen > DBFS_XATTR_MAX_LEN)
+		return -ENOSPC;		/* TODO: return value sane? */
+
+	/* FIXME: update list of xattrs for this inode */
+
+	return dbfs_xattr_write(ino_n, name, buf, buflen);
+}
+
+int dbfs_xattr_remove(guint64 ino_n, const char *name)
+{
+	char key_str[DBFS_XATTR_NAME_LEN + 32];
+	DBT key;
+	int rc;
+
+	snprintf(key_str, sizeof(key_str),
+		 "/xattr/%Lu/%s", (unsigned long long) ino_n, name);
+
+	memset(&key, 0, sizeof(key));
+	key.data = key_str;
+	key.size = strlen(key_str);
+
+	/* FIXME: update list of xattrs for this inode */
+
+	rc = gfs->meta->del(gfs->meta, NULL, &key, 0);
+	if (rc == DB_NOTFOUND)
+		return -ENOENT;
+	return rc ? -EIO : 0;
+}
+
diff --git a/dbfs.c b/dbfs.c
index 10a7906..d665cf0 100644
--- a/dbfs.c
+++ b/dbfs.c
@@ -212,7 +212,7 @@ static void dbfs_op_mkdir(fuse_req_t req, fuse_ino_t parent, const char *name,
 static void dbfs_op_unlink(fuse_req_t req, fuse_ino_t parent, const char *name)
 {
 	int rc = dbfs_unlink(parent, name, 0);
-	fuse_reply_err(req, rc ? -rc : 0);
+	fuse_reply_err(req, -rc);
 }
 
 static void dbfs_op_link(fuse_req_t req, fuse_ino_t ino_n, fuse_ino_t parent,
@@ -278,7 +278,7 @@ static void dbfs_op_rmdir(fuse_req_t req, fuse_ino_t parent, const char *name)
 	rc = dbfs_unlink(parent, name, DBFS_UNLINK_DIR);
 
 out:
-	fuse_reply_err(req, rc ? -rc : 0);
+	fuse_reply_err(req, -rc);
 }
 
 static void dbfs_op_symlink(fuse_req_t req, const char *link,
@@ -402,6 +402,48 @@ static void dbfs_op_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,
 	free(b.p);
 }
 
+static void dbfs_op_setxattr(fuse_req_t req, fuse_ino_t ino,
+			     const char *name, const char *value,
+			     size_t size, int flags)
+{
+	int rc = dbfs_xattr_set(ino, name, value, size, flags);
+	fuse_reply_err(req, -rc);
+}
+
+static void dbfs_op_getxattr(fuse_req_t req, fuse_ino_t ino,
+			     const char *name, size_t size)
+{
+	char *buf = NULL;
+	size_t buflen = 0;
+	int rc;
+
+	rc = dbfs_xattr_get(ino, name, &buf, &buflen);
+	if (rc)
+		goto err_out;
+
+	if (size == 0)
+		fuse_reply_xattr(req, buflen);
+	else if (buflen <= size)
+		fuse_reply_buf(req, buf, buflen);
+	else {
+		rc = -ERANGE;
+		goto err_out;
+	}
+
+	free(buf);
+	return;
+
+err_out:
+	fuse_reply_err(req, -rc);
+}
+
+static void dbfs_op_removexattr(fuse_req_t req, fuse_ino_t ino,
+				const char *name)
+{
+	int rc = dbfs_xattr_remove(ino, name);
+	fuse_reply_err(req, -rc);
+}
+
 static struct fuse_lowlevel_ops dbfs_ops = {
 	.init		= dbfs_op_init,
 	.destroy	= dbfs_op_destroy,
@@ -428,10 +470,10 @@ static struct fuse_lowlevel_ops dbfs_ops = {
 	.releasedir	= dbfs_op_releasedir,
 	.fsyncdir	= NULL,
 	.statfs		= NULL,
-	.setxattr	= NULL,
-	.getxattr	= NULL,
+	.setxattr	= dbfs_op_setxattr,
+	.getxattr	= dbfs_op_getxattr,
 	.listxattr	= NULL,
-	.removexattr	= NULL,
+	.removexattr	= dbfs_op_removexattr,
 	.access		= NULL,
 	.create		= NULL,
 };
diff --git a/dbfs.h b/dbfs.h
index 220a02f..5e22788 100644
--- a/dbfs.h
+++ b/dbfs.h
@@ -13,6 +13,9 @@ enum {
 	DBFS_ROOT_INO		= 1,
 
 	DBFS_DIRENT_ALIGN	= 8,
+
+	DBFS_XATTR_NAME_LEN	= 256,
+	DBFS_XATTR_MAX_LEN	= (1024 * 1024),
 };
 
 enum {
@@ -95,6 +98,12 @@ extern int dbfs_mknod(guint64 parent, const char *name,
 		      struct dbfs_inode **ino);
 extern int dbfs_symlink_write(guint64 ino, const char *link);
 extern int dbfs_inode_del(struct dbfs_inode *ino);
+extern int dbfs_xattr_get(guint64 ino_n, const char *name,
+			  char **buf_out, size_t *buflen_out);
+extern int dbfs_xattr_set(guint64 ino_n, const char *name,
+			  const char *buf, size_t buflen,
+			  int flags);
+extern int dbfs_xattr_remove(guint64 ino_n, const char *name);
 
 /* libdbfs.c */
 extern int dbfs_open(struct dbfs *fs);