ss: simplify code

Rather than copy-pasting code using sendmsg/recvmsg, use the simpler
send() and recv() system calls.

diff --git a/misc/ss.c b/misc/ss.c
index 2caac4af0afe15d91895024e3d7ff2b3633cf11c..5414f7557ab8c92dd6ba9541021778bd2b766f5f 100644 (file)
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -2061,67 +2061,38 @@ static int unix_show_sock(struct nlmsghdr *nlh, struct filter *f)
 static int unix_show_netlink(struct filter *f, FILE *dump_fp)
 {
        int fd;
-       struct sockaddr_nl nladdr;
        struct {
                struct nlmsghdr nlh;
                struct unix_diag_req r;
        } req;
-       struct msghdr msg;
        char    buf[8192];
-       struct iovec iov[3];
 
        if ((fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_INET_DIAG)) < 0)
                return -1;
 
-       memset(&nladdr, 0, sizeof(nladdr));
-       nladdr.nl_family = AF_NETLINK;
-
+       memset(&req, 0, sizeof(req));
        req.nlh.nlmsg_len = sizeof(req);
        req.nlh.nlmsg_type = SOCK_DIAG_BY_FAMILY;
        req.nlh.nlmsg_flags = NLM_F_ROOT|NLM_F_MATCH|NLM_F_REQUEST;
-       req.nlh.nlmsg_pid = 0;
        req.nlh.nlmsg_seq = 123456;
-       memset(&req.r, 0, sizeof(req.r));
+
        req.r.sdiag_family = AF_UNIX;
-       req.r.sdiag_protocol = 0; /* ignored */
        req.r.udiag_states = f->states;
        req.r.udiag_show = UDIAG_SHOW_NAME | UDIAG_SHOW_PEER | UDIAG_SHOW_RQLEN;
 
-       iov[0] = (struct iovec){
-               .iov_base = &req,
-               .iov_len = sizeof(req)
-       };
-
-       msg = (struct msghdr) {
-               .msg_name = (void*)&nladdr,
-               .msg_namelen = sizeof(nladdr),
-               .msg_iov = iov,
-               .msg_iovlen = f->f ? 3 : 1,
-       };
-
-       if (sendmsg(fd, &msg, 0) < 0) {
+       if (send(fd, &req, sizeof(req), 0) < 0) {
                close(fd);
                return -1;
        }
 
-       iov[0] = (struct iovec){
-               .iov_base = buf,
-               .iov_len = sizeof(buf)
-       };
-
        while (1) {
-               int status;
+               ssize_t status;
                struct nlmsghdr *h;
+               struct sockaddr_nl nladdr;
+               socklen_t slen = sizeof(nladdr);
 
-               msg = (struct msghdr) {
-                       (void*)&nladdr, sizeof(nladdr),
-                       iov,    1,
-                       NULL,   0,
-                       0
-               };
-
-               status = recvmsg(fd, &msg, 0);
-
+               status = recvfrom(fd, buf, sizeof(buf), 0,
+                                 (struct sockaddr *) &nladdr, &slen);
                if (status < 0) {
                        if (errno == EINTR)
                                continue;
@@ -2130,8 +2101,7 @@ static int unix_show_netlink(struct filter *f, FILE *dump_fp)
                }
                if (status == 0) {
                        fprintf(stderr, "EOF on netlink\n");
-                       close(fd);
-                       return 0;
+                       goto close_it;
                }
 
                if (dump_fp)
@@ -2145,10 +2115,9 @@ static int unix_show_netlink(struct filter *f, FILE *dump_fp)
                            h->nlmsg_seq != 123456)
                                goto skip_it;
 
-                       if (h->nlmsg_type == NLMSG_DONE) {
-                               close(fd);
-                               return 0;
-                       }
+                       if (h->nlmsg_type == NLMSG_DONE)
+                               goto close_it;
+
                        if (h->nlmsg_type == NLMSG_ERROR) {
                                struct nlmsgerr *err = (struct nlmsgerr*)NLMSG_DATA(h);
                                if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr))) {
@@ -2172,15 +2141,14 @@ static int unix_show_netlink(struct filter *f, FILE *dump_fp)
 skip_it:
                        h = NLMSG_NEXT(h, status);
                }
-               if (msg.msg_flags & MSG_TRUNC) {
-                       fprintf(stderr, "Message truncated\n");
-                       continue;
-               }
+
                if (status) {
-                       fprintf(stderr, "!!!Remnant of size %d\n", status);
+                       fprintf(stderr, "!!!Remnant of size %zd\n", status);
                        exit(1);
                }
        }
+
+close_it:
        close(fd);
        return 0;
 }