9p: attach-per-user

index 15e05a1..b16b14b 100644
@@ -1,6 +1,7 @@
 /*
  * V9FS FID Management
  *
+ *  Copyright (C) 2007 by Latchesar Ionkov <[email protected]>
  *  Copyright (C) 2005, 2006 by Eric Van Hensbergen <[email protected]>
  *
  *  This program is free software; you can redistribute it and/or modify

@@ -34,9 +35,9 @@
 #include "fid.h"
 
 /**
- * v9fs_fid_insert - add a fid to a dentry
+ * v9fs_fid_add - add a fid to a dentry
+ * @dentry: dentry that the fid is being added to
  * @fid: fid to add
- * @dentry: dentry that it is being added to
  *
  */
 

@@ -66,52 +67,144 @@ int v9fs_fid_add(struct dentry *dentry, struct p9_fid *fid)
 }
 
 /**
- * v9fs_fid_lookup - return a locked fid from a dentry
+ * v9fs_fid_find - retrieve a fid that belongs to the specified uid
  * @dentry: dentry to look for fid in
- *
- * find a fid in the dentry, obtain its semaphore and return a reference to it.
- * code calling lookup is responsible for releasing lock
- *
- * TODO: only match fids that have the same uid as current user
+ * @uid: return fid that belongs to the specified user
+ * @any: if non-zero, return any fid associated with the dentry
  *
  */
 
-struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
+static struct p9_fid *v9fs_fid_find(struct dentry *dentry, u32 uid, int any)
 {
 	struct v9fs_dentry *dent;
-	struct p9_fid *fid;
-
-	P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
-	dent = dentry->d_fsdata;
-	if (dent)
-		fid = list_entry(dent->fidlist.next, struct p9_fid, dlist);
-	else
-		fid = ERR_PTR(-EBADF);
+	struct p9_fid *fid, *ret;
+
+	P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p) uid %d any %d\n",
+		dentry->d_iname, dentry, uid, any);
+	dent = (struct v9fs_dentry *) dentry->d_fsdata;
+	ret = NULL;
+	if (dent) {
+		spin_lock(&dent->lock);
+		list_for_each_entry(fid, &dent->fidlist, dlist) {
+			if (any || fid->uid == uid) {
+				ret = fid;
+				break;
+			}
+		}
+		spin_unlock(&dent->lock);
+	}
 
-	P9_DPRINTK(P9_DEBUG_VFS, " fid: %p\n", fid);
-	return fid;
+	return ret;
 }
 
 /**
- * v9fs_fid_clone - lookup the fid for a dentry, clone a private copy and
- * 	release it
+ * v9fs_fid_lookup - lookup for a fid, try to walk if not found
  * @dentry: dentry to look for fid in
  *
- * find a fid in the dentry and then clone to a new private fid
- *
- * TODO: only match fids that have the same uid as current user
- *
+ * Look for a fid in the specified dentry for the current user.
+ * If no fid is found, try to create one walking from a fid from the parent
+ * dentry (if it has one), or the root dentry. If the user haven't accessed
+ * the fs yet, attach now and walk from the root.
  */
 
-struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
+struct p9_fid *v9fs_fid_lookup(struct dentry *dentry)
 {
-	struct p9_fid *ofid, *fid;
+	int i, n, l, clone, any, access;
+	u32 uid;
+	struct p9_fid *fid;
+	struct dentry *d, *ds;
+	struct v9fs_session_info *v9ses;
+	char **wnames, *uname;
+
+	v9ses = v9fs_inode2v9ses(dentry->d_inode);
+	access = v9ses->flags & V9FS_ACCESS_MASK;
+	switch (access) {
+	case V9FS_ACCESS_SINGLE:
+	case V9FS_ACCESS_USER:
+		uid = current->fsuid;
+		any = 0;
+		break;
+
+	case V9FS_ACCESS_ANY:
+		uid = v9ses->uid;
+		any = 1;
+		break;
+
+	default:
+		uid = ~0;
+		any = 0;
+		break;
+	}
 
-	P9_DPRINTK(P9_DEBUG_VFS, " dentry: %s (%p)\n", dentry->d_iname, dentry);
-	ofid = v9fs_fid_lookup(dentry);
-	if (IS_ERR(ofid))
-		return ofid;
+	fid = v9fs_fid_find(dentry, uid, any);
+	if (fid)
+		return fid;
+
+	ds = dentry->d_parent;
+	fid = v9fs_fid_find(ds, uid, any);
+	if (!fid) { /* walk from the root */
+		n = 0;
+		for(ds = dentry; !IS_ROOT(ds); ds = ds->d_parent)
+			n++;
+
+		fid = v9fs_fid_find(ds, uid, any);
+		if (!fid) { /* the user is not attached to the fs yet */
+			if (access == V9FS_ACCESS_SINGLE)
+				return ERR_PTR(-EPERM);
+
+			if (v9fs_extended(v9ses))
+				uname = NULL;
+			else
+				uname = v9ses->uname;
+
+			fid = p9_client_attach(v9ses->clnt, NULL, uname, uid,
+				v9ses->aname);
+
+			if (IS_ERR(fid))
+				return fid;
+
+			v9fs_fid_add(ds, fid);
+		}
+	} else /* walk from the parent */
+		n = 1;
+
+	if (ds == dentry)
+		return fid;
+
+	wnames = kmalloc(sizeof(char *) * n, GFP_KERNEL);
+	if (!wnames)
+		return ERR_PTR(-ENOMEM);
+
+	for(d = dentry, i = n; i >= 0; i--, d = d->d_parent)
+		wnames[i] = (char *) d->d_name.name;
+
+	clone = 1;
+	i = 0;
+	while (i < n) {
+		l = min(n - i, P9_MAXWELEM);
+		fid = p9_client_walk(fid, l, &wnames[i], clone);
+		if (!fid) {
+			kfree(wnames);
+			return fid;
+		}
+
+		i += l;
+		clone = 0;
+	}
 
-	fid = p9_client_walk(ofid, 0, NULL, 1);
+	kfree(wnames);
+	v9fs_fid_add(dentry, fid);
 	return fid;
 }
+
+struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
+{
+	struct p9_fid *fid, *ret;
+
+	fid = v9fs_fid_lookup(dentry);
+	if (IS_ERR(fid))
+		return fid;
+
+	ret = p9_client_walk(fid, 0, NULL, 1);
+	return ret;
+}

178 lines not on this page · raw message

index 7eb135c..280dbd4 100644
@@ -29,22 +29,32 @@
 struct v9fs_session_info {
 	/* options */
 	unsigned int maxdata;
-	unsigned char extended;	/* set to 1 if we are using UNIX extensions */
+	unsigned char flags;	/* session flags */
 	unsigned char nodev;	/* set to 1 if no disable device mapping */
 	unsigned short debug;	/* debug level */
 	unsigned int afid;	/* authentication fid */
 	unsigned int cache;	/* cache mode */
 
 	char *options;		/* copy of mount options */
-	char *name;		/* user name to mount as */
-	char *remotename;	/* name of remote hierarchy being mounted */
-	unsigned int uid;	/* default uid/muid for legacy support */
-	unsigned int gid;	/* default gid for legacy support */
+	char *uname;		/* user name to mount as */
+	char *aname;		/* name of remote hierarchy being mounted */
+	unsigned int dfltuid;	/* default uid/muid for legacy support */
+	unsigned int dfltgid;	/* default gid for legacy support */
+	u32 uid;		/* if ACCESS_SINGLE, the uid that has access */
 	struct p9_trans_module *trans; /* 9p transport */
 	struct p9_client *clnt;	/* 9p client */
 	struct dentry *debugfs_dir;
 };
 
+/* session flags */
+enum {
+	V9FS_EXTENDED		= 0x01,	/* 9P2000.u */
+	V9FS_ACCESS_MASK	= 0x06,	/* access mask */
+	V9FS_ACCESS_SINGLE	= 0x02,	/* only one user can access the files */
+	V9FS_ACCESS_USER	= 0x04,	/* attache per user */
+	V9FS_ACCESS_ANY		= 0x06,	/* use the same attach for all users */
+};
+
 /* possible values of ->cache */
 /* eventually support loose, tight, time, session, default always none */
 enum {

@@ -65,8 +75,15 @@ void v9fs_session_cancel(struct v9fs_session_info *v9ses);
 #define V9FS_PORT		564
 #define V9FS_DEFUSER	"nobody"
 #define V9FS_DEFANAME	""
+#define V9FS_DEFUID	(0)
+#define V9FS_DEFGID	(0)
 
 static inline struct v9fs_session_info *v9fs_inode2v9ses(struct inode *inode)
 {
 	return (inode->i_sb->s_fs_info);
 }
+
+static inline int v9fs_extended(struct v9fs_session_info *v9ses)
+{
+	return v9ses->flags & V9FS_EXTENDED;
+}

175 lines not on this page · raw message

index 88884d3..cd693e3 100644
@@ -216,6 +216,7 @@ struct p9_tauth {
 	u32 afid;
 	struct p9_str uname;
 	struct p9_str aname;
+	u32 n_uname;		/* 9P2000.u extensions */
 };
 
 struct p9_rauth {

@@ -239,6 +240,7 @@ struct p9_tattach {
 	u32 afid;
 	struct p9_str uname;
 	struct p9_str aname;
+	u32 n_uname;		/* 9P2000.u extensions */
 };
 
 struct p9_rattach {

@@ -382,8 +384,9 @@ int p9_deserialize_fcall(void *buf, u32 buflen, struct p9_fcall *fc, int dotu);
 void p9_set_tag(struct p9_fcall *fc, u16 tag);
 struct p9_fcall *p9_create_tversion(u32 msize, char *version);
 struct p9_fcall *p9_create_tattach(u32 fid, u32 afid, char *uname,
-	char *aname);
-struct p9_fcall *p9_create_tauth(u32 afid, char *uname, char *aname);
+	char *aname, u32 n_uname, int dotu);
+struct p9_fcall *p9_create_tauth(u32 afid, char *uname, char *aname,
+	u32 n_uname, int dotu);
 struct p9_fcall *p9_create_tflush(u16 oldtag);
 struct p9_fcall *p9_create_twalk(u32 fid, u32 newfid, u16 nwname,
 	char **wnames);

index 0adafdb..9b9221a 100644
@@ -57,8 +57,9 @@ struct p9_client *p9_client_create(struct p9_trans *trans, int msize,
 void p9_client_destroy(struct p9_client *clnt);
 void p9_client_disconnect(struct p9_client *clnt);
 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
-						     char *uname, char *aname);
-struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname, char *aname);
+					char *uname, u32 n_uname, char *aname);
+struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname,
+						u32 n_uname, char *aname);
 struct p9_fid *p9_client_walk(struct p9_fid *oldfid, int nwname, char **wnames,
 								int clone);
 int p9_client_open(struct p9_fid *fid, int mode);

index e161012..d83cc12 100644
@@ -146,7 +146,7 @@ void p9_client_disconnect(struct p9_client *clnt)
 EXPORT_SYMBOL(p9_client_disconnect);
 
 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
-	char *uname, char *aname)
+	char *uname, u32 n_uname, char *aname)
 {
 	int err;
 	struct p9_fcall *tc, *rc;

@@ -165,7 +165,8 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 		goto error;
 	}
 
-	tc = p9_create_tattach(fid->fid, afid?afid->fid:P9_NOFID, uname, aname);
+	tc = p9_create_tattach(fid->fid, afid?afid->fid:P9_NOFID, uname, aname,
+		n_uname, clnt->dotu);
 	if (IS_ERR(tc)) {
 		err = PTR_ERR(tc);
 		tc = NULL;

@@ -190,7 +191,8 @@ error:
 }
 EXPORT_SYMBOL(p9_client_attach);
 
-struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname, char *aname)
+struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname,
+	u32 n_uname, char *aname)
 {
 	int err;
 	struct p9_fcall *tc, *rc;

@@ -209,7 +211,7 @@ struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname, char *aname)
 		goto error;
 	}
 
-	tc = p9_create_tauth(fid->fid, uname, aname);
+	tc = p9_create_tauth(fid->fid, uname, aname, n_uname, clnt->dotu);
 	if (IS_ERR(tc)) {
 		err = PTR_ERR(tc);
 		tc = NULL;

index d979d95..aa2aa98 100644
@@ -547,7 +547,8 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tversion);
 
-struct p9_fcall *p9_create_tauth(u32 afid, char *uname, char *aname)
+struct p9_fcall *p9_create_tauth(u32 afid, char *uname, char *aname,
+	u32 n_uname, int dotu)
 {
 	int size;
 	struct p9_fcall *fc;

@@ -555,7 +556,16 @@ struct p9_fcall *p9_create_tauth(u32 afid, char *uname, char *aname)
 	struct cbuf *bufp = &buffer;
 
 	/* afid[4] uname[s] aname[s] */
-	size = 4 + 2 + strlen(uname) + 2 + strlen(aname);
+	size = 4 + 2 + 2;
+	if (uname)
+		size += strlen(uname);
+
+	if (aname)
+		size += strlen(aname);
+
+	if (dotu)
+		size += 4;	/* n_uname */
+
 	fc = p9_create_common(bufp, size, P9_TAUTH);
 	if (IS_ERR(fc))
 		goto error;

@@ -563,6 +573,8 @@ struct p9_fcall *p9_create_tauth(u32 afid, char *uname, char *aname)
 	p9_put_int32(bufp, afid, &fc->params.tauth.afid);
 	p9_put_str(bufp, uname, &fc->params.tauth.uname);
 	p9_put_str(bufp, aname, &fc->params.tauth.aname);
+	if (dotu)
+		p9_put_int32(bufp, n_uname, &fc->params.tauth.n_uname);
 
 	if (buf_check_overflow(bufp)) {
 		kfree(fc);

@@ -574,7 +586,8 @@ error:
 EXPORT_SYMBOL(p9_create_tauth);
 
 struct p9_fcall *
-p9_create_tattach(u32 fid, u32 afid, char *uname, char *aname)
+p9_create_tattach(u32 fid, u32 afid, char *uname, char *aname,
+	u32 n_uname, int dotu)
 {
 	int size;
 	struct p9_fcall *fc;

@@ -582,7 +595,16 @@ p9_create_tattach(u32 fid, u32 afid, char *uname, char *aname)
 	struct cbuf *bufp = &buffer;
 
 	/* fid[4] afid[4] uname[s] aname[s] */
-	size = 4 + 4 + 2 + strlen(uname) + 2 + strlen(aname);
+	size = 4 + 4 + 2 + 2;
+	if (uname)
+		size += strlen(uname);
+
+	if (aname)
+		size += strlen(aname);
+
+	if (dotu)
+		size += 4;	/* n_uname */
+
 	fc = p9_create_common(bufp, size, P9_TATTACH);
 	if (IS_ERR(fc))
 		goto error;

@@ -591,6 +613,8 @@ p9_create_tattach(u32 fid, u32 afid, char *uname, char *aname)
 	p9_put_int32(bufp, afid, &fc->params.tattach.afid);
 	p9_put_str(bufp, uname, &fc->params.tattach.uname);
 	p9_put_str(bufp, aname, &fc->params.tattach.aname);
+	if (dotu)
+		p9_put_int32(bufp, n_uname, &fc->params.tattach.n_uname);
 
 error:
 	return fc;