[CONNECTOR]: Add userspace example code into Documentation/connector/

I was asked several times to include userspace example code into
Documentation, so if there is no policy against it, consider attached patch
for 2.6.18. This program works with included Documentation/connector/cn_test.c
connector module.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 206 insertions, 0 deletions

diff --git a/Documentation/connector/ucon.c b/Documentation/connector/ucon.c
new file mode 100644
index 000000000000..d738cde2a8d5
--- /dev/null
+++ b/Documentation/connector/ucon.c
@@ -0,0 +1,206 @@
+/*
+ *      ucon.c
+ *
+ * Copyright (c) 2004+ Evgeniy Polyakov <johnpol@2ka.mipt.ru>
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <asm/types.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/poll.h>
+
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+
+#include <arpa/inet.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <time.h>
+
+#include <linux/connector.h>
+
+#define DEBUG
+#define NETLINK_CONNECTOR       11
+
+#ifdef DEBUG
+#define ulog(f, a...) fprintf(stdout, f, ##a)
+#else
+#define ulog(f, a...) do {} while (0)
+#endif
+
+static int need_exit;
+static __u32 seq;
+
+static int netlink_send(int s, struct cn_msg *msg)
+{
+        struct nlmsghdr *nlh;
+        unsigned int size;
+        int err;
+        char buf[128];
+        struct cn_msg *m;
+
+        size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len);
+
+        nlh = (struct nlmsghdr *)buf;
+        nlh->nlmsg_seq = seq++;
+        nlh->nlmsg_pid = getpid();
+        nlh->nlmsg_type = NLMSG_DONE;
+        nlh->nlmsg_len = NLMSG_LENGTH(size - sizeof(*nlh));
+        nlh->nlmsg_flags = 0;
+
+        m = NLMSG_DATA(nlh);
+#if 0
+        ulog("%s: [%08x.%08x] len=%u, seq=%u, ack=%u.\n",
+               __func__, msg->id.idx, msg->id.val, msg->len, msg->seq, msg->ack);
+#endif
+        memcpy(m, msg, sizeof(*m) + msg->len);
+
+        err = send(s, nlh, size, 0);
+        if (err == -1)
+                ulog("Failed to send: %s [%d].\n",
+                        strerror(errno), errno);
+
+        return err;
+}
+
+int main(int argc, char *argv[])
+{
+        int s;
+        char buf[1024];
+        int len;
+        struct nlmsghdr *reply;
+        struct sockaddr_nl l_local;
+        struct cn_msg *data;
+        FILE *out;
+        time_t tm;
+        struct pollfd pfd;
+
+        if (argc < 2)
+                out = stdout;
+        else {
+                out = fopen(argv[1], "a+");
+                if (!out) {
+                        ulog("Unable to open %s for writing: %s\n",
+                                argv[1], strerror(errno));
+                        out = stdout;
+                }
+        }
+
+        memset(buf, 0, sizeof(buf));
+
+        s = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
+        if (s == -1) {
+                perror("socket");
+                return -1;
+        }
+
+        l_local.nl_family = AF_NETLINK;
+        l_local.nl_groups = 0x123; /* bitmask of requested groups */
+        l_local.nl_pid = 0;
+
+        if (bind(s, (struct sockaddr *)&l_local, sizeof(struct sockaddr_nl)) == -1) {
+                perror("bind");
+                close(s);
+                return -1;
+        }
+
+#if 0
+        {
+                int on = 0x57; /* Additional group number */
+                setsockopt(s, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &on, sizeof(on));
+        }
+#endif
+        if (0) {
+                int i, j;
+
+                memset(buf, 0, sizeof(buf));
+
+                data = (struct cn_msg *)buf;
+
+                data->id.idx = 0x123;
+                data->id.val = 0x456;
+                data->seq = seq++;
+                data->ack = 0;
+                data->len = 0;
+
+                for (j=0; j<10; ++j) {
+                        for (i=0; i<1000; ++i) {
+                                len = netlink_send(s, data);
+                        }
+
+                        ulog("%d messages have been sent to %08x.%08x.\n", i, data->id.idx, data->id.val);
+                }
+
+                return 0;
+        }
+
+
+        pfd.fd = s;
+
+        while (!need_exit) {
+                pfd.events = POLLIN;
+                pfd.revents = 0;
+                switch (poll(&pfd, 1, -1)) {
+                        case 0:
+                                need_exit = 1;
+                                break;
+                        case -1:
+                                if (errno != EINTR) {
+                                        need_exit = 1;
+                                        break;
+                                }
+                                continue;
+                }
+                if (need_exit)
+                        break;
+
+                memset(buf, 0, sizeof(buf));
+                len = recv(s, buf, sizeof(buf), 0);
+                if (len == -1) {
+                        perror("recv buf");
+                        close(s);
+                        return -1;
+                }
+                reply = (struct nlmsghdr *)buf;
+
+                switch (reply->nlmsg_type) {
+                case NLMSG_ERROR:
+                        fprintf(out, "Error message received.\n");
+                        fflush(out);
+                        break;
+                case NLMSG_DONE:
+                        data = (struct cn_msg *)NLMSG_DATA(reply);
+
+                        time(&tm);
+                        fprintf(out, "%.24s : [%x.%x] [%08u.%08u].\n",
+                                ctime(&tm), data->id.idx, data->id.val, data->seq, data->ack);
+                        fflush(out);
+                        break;
+                default:
+                        break;
+                }
+        }
+
+        close(s);
+        return 0;
+}