X-Git-Url: http://www.project-moonshot.org/gitweb/?p=trust_router.git;a=blobdiff_plain;f=mon%2Fmons.c;fp=mon%2Fmons.c;h=1df11f2e06050c8b0fedc43c529edce18b03b8fe;hp=0000000000000000000000000000000000000000;hb=6f65c9cce86719147d0b4dcc9823b25443c2d185;hpb=eaa1a8ceed54fbfadc2638cf383aaa12ab446a57

diff --git a/mon/mons.c b/mon/mons.c
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+++ b/mon/mons.c
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+/*
+ * Copyright (c) 2018, JANET(UK)
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of JANET(UK) nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <talloc.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <netdb.h>
+
+#include <tr.h>
+#include <tr_debug.h>
+#include <mon_internal.h>
+#include <tr_socket.h>
+#include <sys/wait.h>
+#include <sys/resource.h>
+#include <tr_gss.h>
+
+#include "mons_handlers.h"
+
+static void mons_sweep_procs(MONS_INSTANCE *mons);
+
+static int mons_destructor(void *object)
+{
+  MONS_INSTANCE *mons = talloc_get_type_abort(object, MONS_INSTANCE);
+  if (mons->handlers)
+    g_ptr_array_unref(mons->handlers);
+
+  if (mons->pids)
+    g_array_unref(mons->pids);
+
+  return 0;
+}
+
+/**
+ * Allocate a new MONS_INSTANCE
+ *
+ * @param mem_ctx talloc context for allocation
+ * @return new MONS_INSTANCE or null on failure
+ */
+MONS_INSTANCE *mons_new(TALLOC_CTX *mem_ctx)
+{
+  MONS_INSTANCE *mons = talloc(mem_ctx, MONS_INSTANCE);
+
+  if (mons) {
+    mons->hostname = NULL;
+    mons->mon_port = 0;
+    mons->tids = NULL;
+    mons->trps = NULL;
+    mons->req_handler = NULL;
+    mons->auth_handler = NULL;
+    mons->cookie = NULL;
+
+    /* Before any steps that may fail, install the destructor */
+    talloc_set_destructor((void *)mons, mons_destructor);
+
+    mons->authorized_gss_names = tr_gss_names_new(mons);
+    if (mons->authorized_gss_names == NULL) {
+      talloc_free(mons);
+      return NULL;
+    }
+
+    mons->handlers = g_ptr_array_new();
+    if (mons->handlers == NULL) {
+      talloc_free(mons);
+      return NULL;
+    }
+
+    mons->pids = g_array_new(FALSE, FALSE, sizeof(pid_t));
+    if (mons->pids == NULL) {
+      talloc_free(mons);
+      return NULL;
+    }
+  }
+  return mons;
+}
+
+/**
+ * Callback to process a request and produce a response
+ *
+ * @param req_str JSON-encoded request
+ * @param data pointer to a MONS_INSTANCE
+ * @return pointer to the response string or null to send no response
+ */
+static TR_GSS_RC mons_req_cb(TALLOC_CTX *mem_ctx, TR_MSG *req_msg, TR_MSG **resp_msg, void *data)
+{
+  TALLOC_CTX *tmp_ctx = talloc_new(NULL);
+  MONS_INSTANCE *mons = talloc_get_type_abort(data, MONS_INSTANCE);
+  MON_REQ *req = NULL;
+  MON_RESP *resp = NULL;
+  TR_GSS_RC rc = TR_GSS_ERROR;
+
+  /* Validate inputs */
+  if (req_msg == NULL)
+    goto cleanup;
+
+  req = tr_msg_get_mon_req(req_msg);
+  if (req == NULL) {
+    /* this is an internal error */
+    tr_err("mons_req_cb: Received incorrect message type (was %d, expected %d)",
+           tr_msg_get_msg_type(req_msg),
+           MON_REQUEST);
+    /* TODO send an error response */
+    goto cleanup;
+  }
+
+  /* Allocate a response message */
+  *resp_msg = talloc(tmp_ctx, TR_MSG);
+  if (*resp_msg == NULL) {
+    /* can't return a message, just emit an error */
+    tr_crit("mons_req_cb: Error allocating response message.");
+    goto cleanup;
+  }
+
+  /* Handle the request */
+  resp = mons_handle_request(*resp_msg, mons, req);
+  if (resp == NULL) {
+    /* error processing the request */
+    /* TODO send back an error */
+    *resp_msg = NULL; /* null this out so the caller doesn't mistake it for valid */
+    goto cleanup;
+  }
+
+  /* Set the response message payload */
+  tr_msg_set_mon_resp(*resp_msg, resp);
+
+  /* Put the response message in the caller's context so it does not get freed when we exit */
+  talloc_steal(mem_ctx, *resp_msg);
+  rc = TR_GSS_SUCCESS;
+
+cleanup:
+  talloc_free(tmp_ctx);
+  return rc;
+}
+
+/**
+ * Create a listener for monitoring requests
+ *
+ * Accept connections with mons_accept()
+ *
+ * @param mons monitoring server instance
+ * @param req_handler
+ * @param auth_handler
+ * @param hostname
+ * @param port
+ * @param cookie
+ * @param fd_out
+ * @param max_fd
+ * @return
+ */
+int mons_get_listener(MONS_INSTANCE *mons,
+                      MONS_REQ_FUNC *req_handler,
+                      MONS_AUTH_FUNC *auth_handler,
+                      const char *hostname,
+                      int port,
+                      void *cookie,
+                      int *fd_out,
+                      size_t max_fd)
+{
+  size_t n_fd=0;
+  size_t ii=0;
+
+  mons->mon_port = port;
+  n_fd = tr_sock_listen_all(port, fd_out, max_fd);
+  if (n_fd<=0)
+    tr_err("mons_get_listener: Error opening port %d", port);
+  else {
+    /* opening port succeeded */
+    tr_info("mons_get_listener: Opened port %d.", port);
+
+    /* make this socket non-blocking */
+    for (ii=0; ii<n_fd; ii++) {
+      if (0 != fcntl(fd_out[ii], F_SETFL, O_NONBLOCK)) {
+        tr_err("mons_get_listener: Error setting O_NONBLOCK.");
+        for (ii=0; ii<n_fd; ii++) {
+          close(fd_out[ii]);
+          fd_out[ii]=-1;
+        }
+        n_fd=0;
+        break;
+      }
+    }
+  }
+
+  if (n_fd>0) {
+    /* store the caller's request handler & cookie */
+    mons->req_handler = req_handler;
+    mons->auth_handler = auth_handler;
+    mons->hostname = hostname;
+    mons->cookie = cookie;
+  }
+
+  return (int) n_fd;
+}
+
+/**
+ * Process to handle an incoming monitoring request
+ *
+ * This should be run in a child process after fork(). Handles the request
+ * and terminates. Never returns to the caller.
+ *
+ * @param mons the monitoring server instance
+ * @param conn_fd file descriptor for the incoming connection
+ */
+static void mons_handle_proc(MONS_INSTANCE *mons, int conn_fd)
+{
+  struct rlimit rlim; /* for disabling core dump */
+
+  switch(tr_gss_handle_connection(conn_fd,
+                                  "trustmonitor", mons->hostname, /* acceptor name */
+                                  mons->auth_handler, mons->cookie, /* auth callback and cookie */
+                                  mons_req_cb, mons /* req callback and cookie */
+  )) {
+    case TR_GSS_SUCCESS:
+      /* do nothing */
+      break;
+
+    case TR_GSS_ERROR:
+      tr_debug("mons_accept: Error returned by tr_gss_handle_connection()");
+      break;
+
+    default:
+      tr_err("mons_accept: Unexpected value returned by tr_gss_handle_connection()");
+      break;
+  }
+  close(conn_fd);
+
+  /* This ought to be an exit(0), but log4shib does not play well with fork() due to
+   * threading issues. To ensure we do not get stuck in the exit handler, we will
+   * abort. First disable core dump for this subprocess (the main process will still
+   * dump core if the environment allows). */
+  rlim.rlim_cur = 0; /* max core size of 0 */
+  rlim.rlim_max = 0; /* prevent the core size limit from being raised later */
+  setrlimit(RLIMIT_CORE, &rlim);
+  abort(); /* exit hard */
+}
+
+/**
+ * Accept and process a connection on a port opened with mons_get_listener()
+ *
+ * @param mons monitoring interface instance
+ * @param listen FD of the connection socket
+ * @return 0 on success
+ */
+int mons_accept(MONS_INSTANCE *mons, int listen)
+{
+  int conn=-1;
+  int pid=-1;
+
+  if (0 > (conn = tr_sock_accept(listen))) {
+    tr_debug("mons_accept: Error accepting connection");
+    return 1;
+  }
+
+  if (0 > (pid = fork())) {
+    perror("Error on fork()");
+    return 1;
+  }
+
+  if (pid == 0) {
+    /* Only the child process gets here */
+    close(listen); /* this belongs to the parent */
+    mons_handle_proc(mons, conn); /* never returns */
+  }
+
+  /* Only the parent process gets here */
+  close(conn); /* this belongs to the child */
+  g_array_append_val(mons->pids, pid);
+
+  /* clean up any processes that have completed */
+  mons_sweep_procs(mons);
+
+  return 0;
+}
+
+void mons_sweep_procs(MONS_INSTANCE *mons)
+{
+  guint ii;
+  pid_t pid;
+  int status;
+
+  /* loop backwards over the array so we can remove elements as we go */
+  for (ii=mons->pids->len; ii > 0; ii--) {
+    /* ii-1 is the current index */
+    pid = g_array_index(mons->pids, pid_t, ii-1);
+    if (waitpid(pid, &status, WNOHANG) > 0) {
+      /* the process exited */
+      tr_debug("mons_sweep_procs: monitoring process %d terminated.", pid);
+
+      g_array_remove_index_fast(mons->pids, ii-1); /* disturbs only indices >= ii-1 which we've already handled */
+      if (WIFEXITED(status)) {
+        if (WEXITSTATUS(status) == 0)
+          tr_debug("mons_sweep_procs: monitoring process %d succeeded.", pid);
+        else
+          tr_debug("mons_sweep_procs: monitoring process %d exited with status %d.", pid, WTERMSIG(status));
+      } else if (WIFSIGNALED(status)) {
+        tr_debug("mons_sweep_procs: monitoring process %d terminated by signal %d.", pid, WTERMSIG(status));
+      }
+    }
+  }
+}