From 328d192ae37f91d3e19c22eb8f97bf830bfc3933 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Sun, 16 Dec 2007 20:08:26 +0000 Subject: [PATCH] add proper handling for local collisions to example. Clean up the example in some minor other ways. (Closes #178) git-svn-id: file:///home/lennart/svn/public/avahi/trunk@1582 941a03a8-eaeb-0310-b9a0-b1bbd8fe43fe --- examples/client-publish-service.c | 128 ++++++++++++++++++------------ 1 file changed, 76 insertions(+), 52 deletions(-) diff --git a/examples/client-publish-service.c b/examples/client-publish-service.c index db079c1..536c9f0 100644 --- a/examples/client-publish-service.c +++ b/examples/client-publish-service.c @@ -2,17 +2,17 @@ /*** This file is part of avahi. - + avahi is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. - + avahi 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 Lesser General Public License for more details. - + You should have received a copy of the GNU Lesser General Public License along with avahi; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 @@ -45,6 +45,7 @@ static void create_services(AvahiClient *c); static void entry_group_callback(AvahiEntryGroup *g, AvahiEntryGroupState state, AVAHI_GCC_UNUSED void *userdata) { assert(g == group || group == NULL); + group = g; /* Called whenever the entry group state changes */ @@ -56,14 +57,15 @@ static void entry_group_callback(AvahiEntryGroup *g, AvahiEntryGroupState state, case AVAHI_ENTRY_GROUP_COLLISION : { char *n; - - /* A service name collision happened. Let's pick a new name */ + + /* A service name collision with a remote service + * happened. Let's pick a new name */ n = avahi_alternative_service_name(name); avahi_free(name); name = n; - + fprintf(stderr, "Service name collision, renaming service to '%s'\n", name); - + /* And recreate the services */ create_services(avahi_entry_group_get_client(g)); break; @@ -88,40 +90,63 @@ static void create_services(AvahiClient *c) { int ret; assert(c); - /* If this is the first time we're called, let's create a new entry group */ + /* If this is the first time we're called, let's create a new + * entry group if necessary */ + if (!group) if (!(group = avahi_entry_group_new(c, entry_group_callback, NULL))) { fprintf(stderr, "avahi_entry_group_new() failed: %s\n", avahi_strerror(avahi_client_errno(c))); goto fail; } - - fprintf(stderr, "Adding service '%s'\n", name); - - /* Create some random TXT data */ - snprintf(r, sizeof(r), "random=%i", rand()); - - /* Add the service for IPP */ - if ((ret = avahi_entry_group_add_service(group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, name, "_ipp._tcp", NULL, NULL, 651, "test=blah", r, NULL)) < 0) { - fprintf(stderr, "Failed to add _ipp._tcp service: %s\n", avahi_strerror(ret)); - goto fail; - } - /* Add the same service for BSD LPR */ - if ((ret = avahi_entry_group_add_service(group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, name, "_printer._tcp", NULL, NULL, 515, NULL)) < 0) { - fprintf(stderr, "Failed to add _printer._tcp service: %s\n", avahi_strerror(ret)); - goto fail; - } + /* If the group is empty (either because it was just created, or + * because it was reset previously, add our entries. */ - /* Add an additional (hypothetic) subtype */ - if ((ret = avahi_entry_group_add_service_subtype(group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, name, "_printer._tcp", NULL, "_magic._sub._printer._tcp") < 0)) { - fprintf(stderr, "Failed to add subtype _magic._sub._printer._tcp: %s\n", avahi_strerror(ret)); - goto fail; - } - - /* Tell the server to register the service */ - if ((ret = avahi_entry_group_commit(group)) < 0) { - fprintf(stderr, "Failed to commit entry_group: %s\n", avahi_strerror(ret)); - goto fail; + if (avahi_entry_group_is_empty(group)) { + fprintf(stderr, "Adding service '%s'\n", name); + + /* Create some random TXT data */ + snprintf(r, sizeof(r), "random=%i", rand()); + + /* Add the service for IPP */ + if ((ret = avahi_entry_group_add_service(group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, name, "_ipp._tcp", NULL, NULL, 651, "test=blah", r, NULL)) < 0) { + + if (ret == AVAHI_ERR_COLLISION) { + char *n; + + /* A service name collision with a local service + * happened. Let's pick a new name */ + n = avahi_alternative_service_name(name); + avahi_free(name); + name = n; + + fprintf(stderr, "Service name collision, renaming service to '%s'\n", name); + + create_services(c); + return; + } + + fprintf(stderr, "Failed to add _ipp._tcp service: %s\n", avahi_strerror(ret)); + goto fail; + } + + /* Add the same service for BSD LPR */ + if ((ret = avahi_entry_group_add_service(group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, name, "_printer._tcp", NULL, NULL, 515, NULL)) < 0) { + fprintf(stderr, "Failed to add _printer._tcp service: %s\n", avahi_strerror(ret)); + goto fail; + } + + /* Add an additional (hypothetic) subtype */ + if ((ret = avahi_entry_group_add_service_subtype(group, AVAHI_IF_UNSPEC, AVAHI_PROTO_UNSPEC, 0, name, "_printer._tcp", NULL, "_magic._sub._printer._tcp") < 0)) { + fprintf(stderr, "Failed to add subtype _magic._sub._printer._tcp: %s\n", avahi_strerror(ret)); + goto fail; + } + + /* Tell the server to register the service */ + if ((ret = avahi_entry_group_commit(group)) < 0) { + fprintf(stderr, "Failed to commit entry group: %s\n", avahi_strerror(ret)); + goto fail; + } } return; @@ -137,36 +162,35 @@ static void client_callback(AvahiClient *c, AvahiClientState state, AVAHI_GCC_UN switch (state) { case AVAHI_CLIENT_S_RUNNING: - + /* The server has startup successfully and registered its host * name on the network, so it's time to create our services */ - if (!group) - create_services(c); + create_services(c); break; case AVAHI_CLIENT_FAILURE: - + fprintf(stderr, "Client failure: %s\n", avahi_strerror(avahi_client_errno(c))); avahi_simple_poll_quit(simple_poll); - + break; case AVAHI_CLIENT_S_COLLISION: - + /* Let's drop our registered services. When the server is back * in AVAHI_SERVER_RUNNING state we will register them * again with the new host name. */ - + case AVAHI_CLIENT_S_REGISTERING: /* The server records are now being established. This * might be caused by a host name change. We need to wait * for our own records to register until the host name is * properly esatblished. */ - + if (group) avahi_entry_group_reset(group); - + break; case AVAHI_CLIENT_CONNECTING: @@ -179,8 +203,8 @@ static void modify_callback(AVAHI_GCC_UNUSED AvahiTimeout *e, void *userdata) { fprintf(stderr, "Doing some weird modification\n"); - avahi_free(name); - name = avahi_strdup("Modified MegaPrinter"); + avahi_free(name); + name = avahi_strdup("Modified MegaPrinter"); /* If the server is currently running, we need to remove our * service and create it anew */ @@ -200,13 +224,13 @@ int main(AVAHI_GCC_UNUSED int argc, AVAHI_GCC_UNUSED char*argv[]) { int error; int ret = 1; struct timeval tv; - + /* Allocate main loop object */ if (!(simple_poll = avahi_simple_poll_new())) { fprintf(stderr, "Failed to create simple poll object.\n"); goto fail; } - + name = avahi_strdup("MegaPrinter"); /* Allocate a new client */ @@ -224,14 +248,14 @@ int main(AVAHI_GCC_UNUSED int argc, AVAHI_GCC_UNUSED char*argv[]) { avahi_elapse_time(&tv, 1000*10, 0), modify_callback, client); - + /* Run the main loop */ avahi_simple_poll_loop(simple_poll); - + ret = 0; - + fail: - + /* Cleanup things */ if (client) @@ -241,6 +265,6 @@ fail: avahi_simple_poll_free(simple_poll); avahi_free(name); - + return ret; } -- 2.39.5