Messages in this thread Patch in this message | | | Date | Fri, 10 Aug 2012 22:43:59 +0400 | From | Stanislav Kinsbursky <> | Subject | Re: [RFC PATCH 1/2] unix sockets: add ability for search for peer from passed root |
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10.08.2012 22:10, J. Bruce Fields пишет: > On Fri, Aug 10, 2012 at 04:57:30PM +0400, Stanislav Kinsbursky wrote: >> This helper is used stream sockets yet. >> All is simple: if non-NULL struct path was passed to unix_find_other(), then >> vfs_path_lookup() is called instead of kern_path(). > I'm having some trouble parsing the changelog. Maybe something like?: > > unix sockets: add ability to look up using passed-in root > > Export a unix_stream_connect_root() helper that allows a caller > to optionally pass in a root path, in which case the lookup will > be done relative to the given path instead of the current > working directory.
Yep, your variant is much better. Thanks.
> > I guess this is a question for the networking people, but: will it cause > problems to have sunrpc calling directly into the unix socket code? > > (And if so, what would be the alternative: define some variant of > sockaddr_un that includes the root path? Something better?)
That was my first idea. But there are problems with this solution (add root path to sockaddr_un) : 1) sockaddr_un size will change. I don't know, how this will affect user-space. Of course, we can introduce something like:
struct sockaddr_un_kern { struct sockaddr_un un; struct path *path; }
But even in this case we need to color this structure somehow (for example, set path to NULL for simple connect or bind call) . And to add this color, we have to separate sys_connect () from our sock->ops->connect() call. And I don't really know how to do it since we don't have any info about socket type in sys_connect () in hands. I.e. we have it, but then we have to add some specific UNIX socket logic to completely generic sys_connect () and sys_bind () .
> --b. > >> Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com> >> --- >> include/net/af_unix.h | 2 ++ >> net/unix/af_unix.c | 25 ++++++++++++++++++------- >> 2 files changed, 20 insertions(+), 7 deletions(-) >> >> diff --git a/include/net/af_unix.h b/include/net/af_unix.h >> index 2ee33da..559467e 100644 >> --- a/include/net/af_unix.h >> +++ b/include/net/af_unix.h >> @@ -67,6 +67,8 @@ struct unix_sock { >> >> long unix_inq_len(struct sock *sk); >> long unix_outq_len(struct sock *sk); >> +int unix_stream_connect_root(struct path *root, struct socket *sock, >> + struct sockaddr *uaddr, int addr_len, int flags); >> >> #ifdef CONFIG_SYSCTL >> extern int unix_sysctl_register(struct net *net); >> diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c >> index 641f2e4..a790ebc 100644 >> --- a/net/unix/af_unix.c >> +++ b/net/unix/af_unix.c >> @@ -759,7 +759,7 @@ out: mutex_unlock(&u->readlock); >> return err; >> } >> >> -static struct sock *unix_find_other(struct net *net, >> +static struct sock *unix_find_other(struct net *net, struct path *root, >> struct sockaddr_un *sunname, int len, >> int type, unsigned int hash, int *error) >> { >> @@ -769,7 +769,11 @@ static struct sock *unix_find_other(struct net *net, >> >> if (sunname->sun_path[0]) { >> struct inode *inode; >> - err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path); >> + >> + if (root) >> + err = vfs_path_lookup(root->dentry, root->mnt, sunname->sun_path, LOOKUP_FOLLOW, &path); >> + else >> + err = kern_path(sunname->sun_path, LOOKUP_FOLLOW, &path); >> if (err) >> goto fail; >> inode = path.dentry->d_inode; >> @@ -979,7 +983,7 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr, >> goto out; >> >> restart: >> - other = unix_find_other(net, sunaddr, alen, sock->type, hash, &err); >> + other = unix_find_other(net, NULL, sunaddr, alen, sock->type, hash, &err); >> if (!other) >> goto out; >> >> @@ -1053,8 +1057,8 @@ static long unix_wait_for_peer(struct sock *other, long timeo) >> return timeo; >> } >> >> -static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, >> - int addr_len, int flags) >> +int unix_stream_connect_root(struct path *root, struct socket *sock, >> + struct sockaddr *uaddr, int addr_len, int flags) >> { >> struct sockaddr_un *sunaddr = (struct sockaddr_un *)uaddr; >> struct sock *sk = sock->sk; >> @@ -1098,7 +1102,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, >> >> restart: >> /* Find listening sock. */ >> - other = unix_find_other(net, sunaddr, addr_len, sk->sk_type, hash, &err); >> + other = unix_find_other(net, root, sunaddr, addr_len, sk->sk_type, hash, &err); >> if (!other) >> goto out; >> >> @@ -1227,6 +1231,13 @@ out: >> sock_put(other); >> return err; >> } >> +EXPORT_SYMBOL_GPL(unix_stream_connect_root); >> + >> +static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, >> + int addr_len, int flags) >> +{ >> + return unix_stream_connect_root(NULL, sock, uaddr, addr_len, flags); >> +} >> >> static int unix_socketpair(struct socket *socka, struct socket *sockb) >> { >> @@ -1508,7 +1519,7 @@ restart: >> if (sunaddr == NULL) >> goto out_free; >> >> - other = unix_find_other(net, sunaddr, namelen, sk->sk_type, >> + other = unix_find_other(net, NULL, sunaddr, namelen, sk->sk_type, >> hash, &err); >> if (other == NULL) >> goto out_free; >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html
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