Implement server side afs callbacks.
authorAndre Noll <maan@systemlinux.org>
Sat, 8 Sep 2007 16:34:37 +0000 (18:34 +0200)
committerAndre Noll <maan@systemlinux.org>
Sat, 8 Sep 2007 16:34:37 +0000 (18:34 +0200)
Not yet working as the code for contacting afs is still missing.

afs.c

diff --git a/afs.c b/afs.c
index 71a9f1c..b5cf9f7 100644 (file)
--- a/afs.c
+++ b/afs.c
@@ -4,7 +4,7 @@
 #include <dirent.h> /* readdir() */
 #include <sys/mman.h>
 #include <sys/time.h>
-
+//#include <inttypes.h>
 
 #include "net.h"
 #include "afs.h"
@@ -17,8 +17,6 @@
 
 /** \file afs.c Paraslash's audio file selector. */
 
-static uint32_t socket_cookie;
-
 /**
  * Compare two osl objects of string type.
  *
@@ -71,6 +69,18 @@ enum afs_table_num {
 
 static struct table_info afs_tables[NUM_AFS_TABLES];
 
+struct command_task {
+       /** The file descriptor for the local socket. */
+       int fd;
+       /**
+        * Value sent by the command handlers to identify themselves as
+        * children of the running para_server.
+        */
+       uint32_t cookie;
+       /** The associated task structure. */
+       struct task task;
+};
+
 
 /**
  * A wrapper for strtol(3).
@@ -134,6 +144,18 @@ struct callback_data {
        int sma_ret;
 };
 
+struct callback_query {
+       /** The function to be called. */
+       callback_function *handler;
+       /** The number of bytes of the query */
+       size_t query_size;
+};
+
+struct callback_result {
+       /** The number of bytes of the result. */
+       size_t result_size;
+};
+
 static struct callback_data *shm_callback_data;
 static int callback_mutex;
 static int child_mutex;
@@ -463,9 +485,7 @@ static enum play_mode init_admissible_files(void)
        return PLAY_MODE_MOOD;
 }
 
-int command_socket;
-
-static void setup_command_socket(void)
+static int setup_command_socket_or_die(void)
 {
        int ret;
        char *socket_name = "/tmp/afs_command_socket";
@@ -476,13 +496,13 @@ static void setup_command_socket(void)
                S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IWOTH);
        if (ret < 0)
                exit(EXIT_FAILURE);
-       command_socket = ret;
-       if (listen(command_socket , 5) < 0) {
+       if (listen(ret , 5) < 0) {
                PARA_EMERG_LOG("%s", "can not listen on socket\n");
                exit(EXIT_FAILURE);
        }
        PARA_INFO_LOG("listening on command socket %s (fd %d)\n", socket_name,
-               command_socket);
+               ret);
+       return ret;
 }
 
 static int server_socket;
@@ -546,9 +566,142 @@ static void register_signal_task(void)
        register_task(&st->task);
 }
 
-void register_tasks(void)
+static void command_pre_select(struct sched *s, struct task *t)
+{
+       struct command_task *ct = t->private_data;
+       t->ret = 1;
+       para_fd_set(ct->fd, &s->rfds, &s->max_fileno);
+}
+
+/*
+ * On errors, negative value is written to fd.
+ * On success: If query produced a result, the result_shmid is written to fd.
+ * Otherwise, zero is written.
+ */
+static int call_callback(int fd, int query_shmid)
+{
+       void *query_shm, *result_shm;
+       struct callback_query *cq;
+       struct callback_result *cr;
+       struct osl_object query, result = {.data = NULL};
+       int result_shmid = -1, ret, ret2;
+
+       ret = shm_attach(query_shmid, ATTACH_RO, &query_shm);
+       if (ret < 0)
+               goto out;
+       cq = query_shm;
+       query.data = (char *)query_shm + sizeof(*cq);
+       query.size = cq->query_size;
+       ret = cq->handler(&query, &result);
+       ret2 = shm_detach(query_shm);
+       if (ret2 < 0 && ret >= 0)
+               ret = ret2;
+       if (ret < 0)
+               goto out;
+       ret = 0;
+       if (!result.data || !result.size)
+               goto out;
+       ret = shm_new(result.size + sizeof(struct callback_result));
+       if (ret < 0)
+               goto out;
+       result_shmid = ret;
+       ret = shm_attach(result_shmid, ATTACH_RW, &result_shm);
+       if (ret < 0)
+               goto out;
+       cr = result_shm;
+       cr->result_size = result.size;
+       memcpy(result_shm + sizeof(*cr), result.data, result.size);
+       ret = shm_detach(result_shm);
+       if (ret < 0)
+               goto out;
+       ret = result_shmid;
+out:
+       free(result.data);
+       ret2 = send_bin_buffer(fd, (char *)ret, sizeof(int));
+       if (ret < 0 || ret2 < 0) {
+               if (result_shmid >= 0)
+                       if (shm_destroy(result_shmid) < 0)
+                               PARA_ERROR_LOG("destroy result failed\n");
+               if (ret >= 0)
+                       ret = ret2;
+       }
+       return ret;
+}
+
+static void command_post_select(struct sched *s, struct task *t)
+{
+       struct command_task *ct = t->private_data;
+       struct sockaddr_un unix_addr;
+       char buf[sizeof(uint32_t) + sizeof(int)];
+       uint32_t cookie;
+       int query_shmid, fd;
+
+       t->ret = 1;
+       if (!FD_ISSET(ct->fd, &s->rfds))
+               return;
+       t->ret = para_accept(ct->fd, &unix_addr, sizeof(unix_addr));
+       if (t->ret < 0)
+               return;
+       /*
+        * The following errors may be caused by a malicious local user. So do
+        * not return an error in this case as this would terminate  para_afs
+        * and para_server.
+        */
+       fd = t->ret;
+       t->ret = recv_bin_buffer(ct->fd, buf, sizeof(buf));
+       if (t->ret < 0) {
+               PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-t->ret));
+               t->ret = 1;
+               goto out;
+       }
+       if (t->ret != sizeof(buf)) {
+               PARA_NOTICE_LOG("short read (%d bytes, expected %d)\n",
+                       t->ret, sizeof(buf));
+               t->ret = 1;
+               goto out;
+       }
+       cookie = *(uint32_t *)buf;
+       if (cookie != ct->cookie) {
+               PARA_NOTICE_LOG("received invalid cookie(got %u, expected %u)\n",
+                       (unsigned)cookie, (unsigned)ct->cookie);
+               t->ret = 1;
+               goto out;
+       }
+       query_shmid = *(int *)(buf + sizeof(cookie));
+       if (query_shmid < 0) {
+               PARA_WARNING_LOG("received invalid query shmid %d)\n",
+                       query_shmid);
+               t->ret = 1;
+               goto out;
+       }
+       t->ret = call_callback(fd, query_shmid);
+       if (t->ret < 0) {
+               PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-t->ret));
+               t->ret = 1;
+               goto out;
+       }
+out:
+       close(fd);
+}
+
+static void register_command_task(uint32_t cookie)
+{
+       static struct command_task command_task_struct;
+       struct command_task *ct = &command_task_struct;
+       ct->fd = setup_command_socket_or_die();
+       ct->cookie = cookie;
+
+       ct->task.pre_select = command_pre_select;
+       ct->task.post_select = command_post_select;
+       ct->task.private_data = ct;
+       sprintf(ct->task.status, "command task");
+       register_task(&ct->task);
+}
+
+void register_tasks(uint32_t cookie)
 {
        register_signal_task();
+       register_command_task(cookie);
 }
 
 __noreturn int afs_init(uint32_t cookie, int socket_fd)
@@ -559,10 +712,8 @@ __noreturn int afs_init(uint32_t cookie, int socket_fd)
        struct sched s;
 
        server_socket = socket_fd;
-       socket_cookie = cookie;
        PARA_INFO_LOG("server_socket: %d, afs_socket_cookie: %u\n",
                server_socket, (unsigned) cookie);
-       setup_command_socket();
 
        ret = attribute_init(&afs_tables[TBLNUM_ATTRIBUTES]);
        if (ret < 0)
@@ -587,7 +738,7 @@ __noreturn int afs_init(uint32_t cookie, int socket_fd)
                goto aft_init_error;
 
        current_play_mode = init_admissible_files();
-       register_tasks();
+       register_tasks(cookie);
        s.default_timeout.tv_sec = 0;
        s.default_timeout.tv_usec = 99 * 1000;
        sched(&s);
@@ -672,6 +823,7 @@ static int com_init(__a_unused int fd, int argc, const char **argv)
        }
        return 1;
 }
+
 /** Describes a command of para_server. */
 struct command {
        /** The name of the command. */
@@ -680,7 +832,7 @@ struct command {
        int (*handler)(int fd, int argc, const char **argv);
 };
 
-static struct command cmd[] = {
+static struct command afs_cmds[] = {
 {
        .name = "add",
        .handler = com_add,
@@ -802,6 +954,7 @@ static struct command cmd[] = {
 }
 };
 
+#if 0
 static void call_callback(void)
 {
        struct osl_object query, result = {.data = NULL};
@@ -854,7 +1007,6 @@ out:
        mutex_unlock(result_mutex); /* wake up child */
 }
 
-#if 0
 static int got_sigchld;
 static void server_loop(int child_pid)
 {