Support unix domain sockets in -yy option
This change extends -yy option to handle unix domain sockets:
their peer addresses will be printed, similar to inet sockets.
For a listening socket, its socket inode and socket path are printed.
For an accepted socket, its socket inode, the peer inode, and the
socket path are printed.
For a client socket, its socket inode and the peer inode are printed.
An example of a server side communication using netcat:
$ ./strace -yy -e network nc -l -U /tmp/example.sock
socket(PF_LOCAL, SOCK_STREAM, 0) = 3
setsockopt(3<UNIX:[14728348]>, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
bind(3<UNIX:[14728348]>, {sa_family=AF_LOCAL, sun_path="/tmp/example.sock"}, 19) = 0
listen(3<UNIX:[14728348,"/tmp/example.sock"]>, 10) = 0
accept(3<UNIX:[14728348,"/tmp/example.sock"]>, {sa_family=AF_LOCAL, NULL}, [2]) = 4<UNIX:[14727246->14727245,"/tmp/example.sock"]>
recvfrom(4<UNIX:[14727246->14727245,"/tmp/example.sock"]>, "INPUT\n", 8192, 0, NULL, NULL) = 6
INPUT
An example of a client side communication using netcat:
$ ./strace -yy -e network nc -U /tmp/example.sock
socket(PF_LOCAL, SOCK_STREAM, 0) = 3
connect(3<UNIX:[14727245]>, {sa_family=AF_LOCAL, sun_path="/tmp/example.sock"}, 19) = 0
getsockopt(3<UNIX:[14727245]>, SOL_SOCKET, SO_ERROR, [0], [4]) = 0
INPUT
...
sendto(3<UNIX:[14727245->14727246]>, "INPUT\n", 6, 0, NULL, 0) = 6
* linux/unix_diag.h: New file.
* socketutils.c (send_query): Rename to inet_send_query.
(parse_response): Rename to inet_parse_response.
(unix_print, unix_send_query, unix_parse_response): New functions.
(receive_responses): Add a new argument named parser: a function for
handling protocol specific data parts of diag messages.
(print_sockaddr_by_inode): Call unix_print.
Replace NETLINK_INET_DIAG with NETLINK_SOCK_DIAG, they are equal
but NETLINK_SOCK_DIAG looks more generic.
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
diff --git a/socketutils.c b/socketutils.c
index f57c304..8b0d615 100644
--- a/socketutils.c
+++ b/socketutils.c
@@ -5,9 +5,16 @@
#include <linux/netlink.h>
#include <linux/sock_diag.h>
#include <linux/inet_diag.h>
+#include <linux/unix_diag.h>
+#include <linux/rtnetlink.h>
+
+#include <sys/un.h>
+#ifndef UNIX_PATH_MAX
+# define UNIX_PATH_MAX sizeof(((struct sockaddr_un *) 0)->sun_path)
+#endif
static bool
-send_query(const int fd, const int family, const int proto)
+inet_send_query(const int fd, const int family, const int proto)
{
struct sockaddr_nl nladdr = {
.nl_family = AF_NETLINK
@@ -49,8 +56,9 @@
}
static bool
-parse_response(const struct inet_diag_msg *diag_msg, const unsigned long inode)
+inet_parse_response(const void *data, int data_len, const unsigned long inode)
{
+ const struct inet_diag_msg *diag_msg = data;
static const char zero_addr[sizeof(struct in6_addr)];
socklen_t addr_size, text_size;
@@ -95,7 +103,8 @@
}
static bool
-receive_responses(const int fd, const unsigned long inode)
+receive_responses(const int fd, const unsigned long inode,
+ bool (* parser) (const void*, int, const unsigned long))
{
static char buf[8192];
struct sockaddr_nl nladdr = {
@@ -132,7 +141,7 @@
case NLMSG_ERROR:
return false;
}
- if (parse_response(NLMSG_DATA(h), inode))
+ if (parser(NLMSG_DATA(h), h->nlmsg_len, inode))
return true;
}
}
@@ -141,8 +150,119 @@
static bool
inet_print(int fd, int family, int protocol, const unsigned long inode)
{
- return send_query(fd, family, protocol)
- && receive_responses(fd, inode);
+ return inet_send_query(fd, family, protocol)
+ && receive_responses(fd, inode, inet_parse_response);
+}
+
+static bool
+unix_send_query(const int fd, const unsigned long inode)
+{
+ struct sockaddr_nl nladdr = {
+ .nl_family = AF_NETLINK
+ };
+ struct {
+ struct nlmsghdr nlh;
+ struct unix_diag_req udr;
+ } req = {
+ .nlh = {
+ .nlmsg_len = sizeof(req),
+ .nlmsg_type = SOCK_DIAG_BY_FAMILY,
+ .nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST
+ },
+ .udr = {
+ .sdiag_family = AF_UNIX,
+ .udiag_ino = inode,
+ .udiag_states = -1,
+ .udiag_show = UDIAG_SHOW_NAME | UDIAG_SHOW_PEER
+ }
+ };
+ struct iovec iov = {
+ .iov_base = &req,
+ .iov_len = sizeof(req)
+ };
+ struct msghdr msg = {
+ .msg_name = (void*)&nladdr,
+ .msg_namelen = sizeof(nladdr),
+ .msg_iov = &iov,
+ .msg_iovlen = 1
+ };
+
+ for (;;) {
+ if (sendmsg(fd, &msg, 0) < 0) {
+ if (errno == EINTR)
+ continue;
+ return false;
+ }
+ return true;
+ }
+}
+
+static bool
+unix_parse_response(const void *data, int data_len, const unsigned long inode)
+{
+ const struct unix_diag_msg *diag_msg = data;
+ struct rtattr *attr;
+ int rta_len = data_len - NLMSG_LENGTH(sizeof(*diag_msg));
+ uint32_t peer = 0;
+ size_t path_len = 0;
+ char path[UNIX_PATH_MAX + 1];
+
+ if (diag_msg->udiag_ino != inode)
+ return false;
+ if (diag_msg->udiag_family != AF_UNIX)
+ return false;
+
+ for (attr = (struct rtattr *) (diag_msg + 1);
+ RTA_OK(attr, rta_len);
+ attr = RTA_NEXT(attr, rta_len)) {
+ switch (attr->rta_type) {
+ case UNIX_DIAG_NAME:
+ if (!path_len) {
+ path_len = RTA_PAYLOAD(attr);
+ if (path_len > UNIX_PATH_MAX)
+ path_len = UNIX_PATH_MAX;
+ memcpy(path, RTA_DATA(attr), path_len);
+ path[path_len] = '\0';
+ }
+ break;
+ case UNIX_DIAG_PEER:
+ if (RTA_PAYLOAD(attr) >= 4)
+ peer = *(uint32_t *)RTA_DATA(attr);
+ break;
+ }
+ }
+
+ /*
+ * print obtained information in the following format:
+ * "UNIX:[" SELF_INODE [ "->" PEER_INODE ][ "," SOCKET_FILE ] "]"
+ */
+ if (peer || path_len) {
+ tprintf("UNIX:[%lu", inode);
+ if (peer)
+ tprintf("->%u", peer);
+ if (path_len) {
+ if (path[0] == '\0') {
+ char *outstr = alloca(4 * path_len - 1);
+ string_quote(path + 1, outstr, -1, path_len);
+ tprintf(",@%s", outstr);
+ } else {
+ char *outstr = alloca(4 * path_len + 3);
+ string_quote(path, outstr, -1, path_len + 1);
+ tprintf(",%s", outstr);
+ }
+ }
+ tprints("]");
+ return true;
+ }
+ else
+ return false;
+}
+
+static bool
+unix_print(int fd, const unsigned long inode)
+{
+ return unix_send_query(fd, inode)
+ && receive_responses(fd, inode, unix_parse_response);
}
/* Given an inode number of a socket, print out the details
@@ -153,7 +273,7 @@
int fd;
bool r = false;
- fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_INET_DIAG);
+ fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
if (fd < 0)
return false;
@@ -166,6 +286,8 @@
r = inet_print(fd, AF_INET6, IPPROTO_TCP, inode);
else if (strcmp(proto_name, "UDPv6") == 0)
r = inet_print(fd, AF_INET6, IPPROTO_UDP, inode);
+ else if (strcmp(proto_name, "UNIX") == 0)
+ r = unix_print(fd, inode);
} else {
const int families[] = {AF_INET, AF_INET6};
const int protocols[] = {IPPROTO_TCP, IPPROTO_UDP};