[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>

diff --git a/Documentation/connector/ucon.c b/Documentation/connector/ucon.c
new file mode 100644 (file)
index 0000000..d738cde
--- /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;
+}