#include #include #include #include #include static DEFINE_SPINLOCK(string_tree_lock); static struct rb_root string_tree = RB_ROOT; struct ceph_string *ceph_find_or_create_string(const char* str, size_t len) { struct ceph_string *cs, *exist; struct rb_node **p, *parent; int ret; exist = NULL; spin_lock(&string_tree_lock); p = &string_tree.rb_node; while (*p) { exist = rb_entry(*p, struct ceph_string, node); ret = ceph_compare_string(exist, str, len); if (ret > 0) p = &(*p)->rb_left; else if (ret < 0) p = &(*p)->rb_right; else break; exist = NULL; } if (exist && !kref_get_unless_zero(&exist->kref)) { rb_erase(&exist->node, &string_tree); RB_CLEAR_NODE(&exist->node); exist = NULL; } spin_unlock(&string_tree_lock); if (exist) return exist; cs = kmalloc(sizeof(*cs) + len + 1, GFP_NOFS); if (!cs) return NULL; kref_init(&cs->kref); cs->len = len; memcpy(cs->str, str, len); cs->str[len] = 0; retry: exist = NULL; parent = NULL; p = &string_tree.rb_node; spin_lock(&string_tree_lock); while (*p) { parent = *p; exist = rb_entry(*p, struct ceph_string, node); ret = ceph_compare_string(exist, str, len); if (ret > 0) p = &(*p)->rb_left; else if (ret < 0) p = &(*p)->rb_right; else break; exist = NULL; } ret = 0; if (!exist) { rb_link_node(&cs->node, parent, p); rb_insert_color(&cs->node, &string_tree); } else if (!kref_get_unless_zero(&exist->kref)) { rb_erase(&exist->node, &string_tree); RB_CLEAR_NODE(&exist->node); ret = -EAGAIN; } spin_unlock(&string_tree_lock); if (ret == -EAGAIN) goto retry; if (exist) { kfree(cs); cs = exist; } return cs; } EXPORT_SYMBOL(ceph_find_or_create_string); void ceph_release_string(struct kref *ref) { struct ceph_string *cs = container_of(ref, struct ceph_string, kref); spin_lock(&string_tree_lock); if (!RB_EMPTY_NODE(&cs->node)) { rb_erase(&cs->node, &string_tree); RB_CLEAR_NODE(&cs->node); } spin_unlock(&string_tree_lock); kfree_rcu(cs, rcu); } EXPORT_SYMBOL(ceph_release_string); bool ceph_strings_empty(void) { return RB_EMPTY_ROOT(&string_tree); } d0b38e9575272d4621e6739facfd'/>

path: root/net/unix

Age	Commit message (Collapse)	Author	Files	Lines
2017-02-02	unix: add ioctl to open a unix socket file with O_PATH	Andrey Vagin	1	-0/+41
	This ioctl opens a file to which a socket is bound and returns a file descriptor. The caller has to have CAP_NET_ADMIN in the socket network namespace. Currently it is impossible to get a path and a mount point for a socket file. socket_diag reports address, device ID and inode number for unix sockets. An address can contain a relative path or a file may be moved somewhere. And these properties say nothing about a mount namespace and a mount point of a socket file. With the introduced ioctl, we can get a path by reading /proc/self/fd/X and get mnt_id from /proc/self/fdinfo/X. In CRIU we are going to use this ioctl to dump and restore unix socket. Here is an example how it can be used: $ strace -e socket,bind,ioctl ./test /tmp/test_sock socket(AF_UNIX, SOCK_STREAM, 0) = 3 bind(3, {sa_family=AF_UNIX, sun_path="test_sock"}, 11) = 0 ioctl(3, SIOCUNIXFILE, 0) = 4 ^Z $ ss -a \| grep test_sock u_str LISTEN 0 1 test_sock 17798 * 0 $ ls -l /proc/760/fd/{3,4} lrwx------ 1 root root 64 Feb 1 09:41 3 -> 'socket:[17798]' l--------- 1 root root 64 Feb 1 09:41 4 -> /tmp/test_sock $ cat /proc/760/fdinfo/4 pos: 0 flags: 012000000 mnt_id: 40 $ cat /proc/self/mountinfo \| grep "^40\s" 40 19 0:37 / /tmp rw shared:23 - tmpfs tmpfs rw Signed-off-by: Andrei Vagin <avagin@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>