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+/*
+ * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). All
+ * rights reserved.
+ * Copyright (c) 1993, 2010, Oracle and/or its affiliates. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/**
+ * @file
+ *
+ * This file contains functionality for identifying clients by various
+ * means. The primary purpose of identification is to simply aid in
+ * finding out which clients are using X server and how they are using
+ * it. For example, it's often necessary to monitor what requests
+ * clients are executing (to spot bad behaviour) and how they are
+ * allocating resources in X server (to spot excessive resource
+ * usage).
+ *
+ * This framework automatically allocates information, that can be
+ * used for client identification, when a client connects to the
+ * server. The information is freed when the client disconnects. The
+ * allocated information is just a collection of various IDs, such as
+ * PID and process name for local clients, that are likely to be
+ * useful in analyzing X server usage.
+ *
+ * Users of the framework can query ID information about clients at
+ * any time. To avoid repeated polling of IDs the users can also
+ * subscribe for notifications about the availability of ID
+ * information. IDs have been allocated before ClientStateCallback is
+ * called with ClientStateInitial state. Similarly the IDs will be
+ * released after ClientStateCallback is called with ClientStateGone
+ * state.
+ *
+ * Author: Rami Ylimäki <rami.ylimaki@vincit.fi>
+ */
+
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "client.h"
+#include "os.h"
+#include "dixstruct.h"
+
+/**
+ * Try to determine a PID for a client from its connection
+ * information. This should be called only once when new client has
+ * connected, use GetClientPid to determine the PID at other times.
+ *
+ * @param[in] client Connection linked to some process.
+ *
+ * @return PID of the client. Error (-1) if PID can't be determined
+ * for the client.
+ *
+ * @see GetClientPid
+ */
+pid_t DetermineClientPid(struct _Client *client)
+{
+ LocalClientCredRec *lcc = NULL;
+ pid_t pid = -1;
+
+ if (client == NullClient)
+ return pid;
+
+ if (client == serverClient)
+ return getpid();
+
+ if (GetLocalClientCreds(client, &lcc) != -1)
+ {
+ if (lcc->fieldsSet & LCC_PID_SET)
+ pid = lcc->pid;
+ FreeLocalClientCreds(lcc);
+ }
+
+ return pid;
+}
+
+/**
+ * Try to determine a command line string for a client based on its
+ * PID. Note that mapping PID to a command hasn't been implemented for
+ * some operating systems. This should be called only once when a new
+ * client has connected, use GetClientCmdName/Args to determine the
+ * string at other times.
+ *
+ * @param[in] pid Process ID of a client.
+
+ * @param[out] cmdname Client process name without arguments. You must
+ * release this by calling free. On error NULL is
+ * returned. Pass NULL if you aren't interested in
+ * this value.
+ * @param[out] cmdargs Arguments to client process. Useful for
+ * identifying a client that is executed from a
+ * launcher program. You must release this by
+ * calling free. On error NULL is returned. Pass
+ * NULL if you aren't interested in this value.
+ *
+ * @see GetClientCmdName/Args
+ */
+void DetermineClientCmd(pid_t pid, const char **cmdname, const char **cmdargs)
+{
+ char path[PATH_MAX + 1];
+ int totsize = 0;
+ int cmdsize = 0;
+ int argsize = 0;
+ int fd = 0;
+
+ if (cmdname)
+ *cmdname = NULL;
+ if (cmdargs)
+ *cmdargs = NULL;
+
+ if (pid == -1)
+ return;
+
+ /* Check if /proc/pid/cmdline exists. It's not supported on all
+ * operating systems. */
+ if (snprintf(path, sizeof(path), "/proc/%d/cmdline", pid) < 0)
+ return;
+ fd = open(path, O_RDONLY);
+ if (fd < 0)
+ return;
+
+ /* Read the contents of /proc/pid/cmdline. It should contain the
+ * process name and arguments. */
+ totsize = read(fd, path, sizeof(path));
+ if (totsize <= 0)
+ return;
+ if (close(fd) < 0)
+ return;
+ path[totsize - 1] = '\0';
+
+ /* Contruct the process name without arguments. */
+ cmdsize = strlen(path) + 1;
+ if (cmdname)
+ {
+ char *name = malloc(cmdsize);
+ if (name)
+ {
+ strncpy(name, path, cmdsize);
+ name[cmdsize - 1] = '\0';
+ *cmdname = name;
+ }
+ }
+
+ /* Construct the arguments for client process. */
+ argsize = totsize - cmdsize;
+ if (cmdargs && (argsize > 0))
+ {
+ char *args = malloc(argsize);
+ if (args)
+ {
+ int i = 0;
+ for (i = 0; i < (argsize - 1); ++i)
+ {
+ const char c = path[cmdsize + i];
+ args[i] = (c == '\0') ? ' ' : c;
+ }
+ args[argsize - 1] = '\0';
+ *cmdargs = args;
+ }
+ }
+}
+
+/**
+ * Called when a new client connects. Allocates client ID information.
+ *
+ * @param[in] client Recently connected client.
+ */
+void ReserveClientIds(struct _Client *client)
+{
+#ifdef CLIENTIDS
+ if (client == NullClient)
+ return;
+
+ assert(!client->clientIds);
+ client->clientIds = calloc(1, sizeof(ClientIdRec));
+ if (!client->clientIds)
+ return;
+
+ client->clientIds->pid = DetermineClientPid(client);
+ if (client->clientIds->pid != -1)
+ DetermineClientCmd(client->clientIds->pid, &client->clientIds->cmdname, &client->clientIds->cmdargs);
+
+ DebugF("client(%lx): Reserved pid(%d).\n",
+ client->clientAsMask, client->clientIds->pid);
+ DebugF("client(%lx): Reserved cmdname(%s) and cmdargs(%s).\n",
+ client->clientAsMask,
+ client->clientIds->cmdname ? client->clientIds->cmdname : "NULL",
+ client->clientIds->cmdargs ? client->clientIds->cmdargs : "NULL");
+#endif /* CLIENTIDS */
+}
+
+/**
+ * Called when an existing client disconnects. Frees client ID
+ * information.
+ *
+ * @param[in] client Recently disconnected client.
+ */
+void ReleaseClientIds(struct _Client *client)
+{
+#ifdef CLIENTIDS
+ if (client == NullClient)
+ return;
+
+ if (!client->clientIds)
+ return;
+
+ DebugF("client(%lx): Released pid(%d).\n",
+ client->clientAsMask, client->clientIds->pid);
+ DebugF("client(%lx): Released cmdline(%s) and cmdargs(%s).\n",
+ client->clientAsMask,
+ client->clientIds->cmdname ? client->clientIds->cmdname : "NULL",
+ client->clientIds->cmdargs ? client->clientIds->cmdargs : "NULL");
+
+ free((void *) client->clientIds->cmdname); /* const char * */
+ free((void *) client->clientIds->cmdargs); /* const char * */
+ free(client->clientIds);
+ client->clientIds = NULL;
+#endif /* CLIENTIDS */
+}
+
+/**
+ * Get cached PID of a client.
+ *
+ * param[in] client Client whose PID has been already cached.
+ *
+ * @return Cached client PID. Error (-1) if called:
+ * - before ClientStateInitial client state notification
+ * - after ClientStateGone client state notification
+ * - for remote clients
+ *
+ * @see DetermineClientPid
+ */
+pid_t GetClientPid(struct _Client *client)
+{
+ if (client == NullClient)
+ return -1;
+
+ if (!client->clientIds)
+ return -1;
+
+ return client->clientIds->pid;
+}
+
+/**
+ * Get cached command name string of a client.
+ *
+ * param[in] client Client whose command line string has been already
+ * cached.
+ *
+ * @return Cached client command name. Error (NULL) if called:
+ * - before ClientStateInitial client state notification
+ * - after ClientStateGone client state notification
+ * - for remote clients
+ * - on OS that doesn't support mapping of PID to command line
+ *
+ * @see DetermineClientCmd
+ */
+const char *GetClientCmdName(struct _Client *client)
+{
+ if (client == NullClient)
+ return NULL;
+
+ if (!client->clientIds)
+ return NULL;
+
+ return client->clientIds->cmdname;
+}
+
+/**
+ * Get cached command arguments string of a client.
+ *
+ * param[in] client Client whose command line string has been already
+ * cached.
+ *
+ * @return Cached client command arguments. Error (NULL) if called:
+ * - before ClientStateInitial client state notification
+ * - after ClientStateGone client state notification
+ * - for remote clients
+ * - on OS that doesn't support mapping of PID to command line
+ *
+ * @see DetermineClientCmd
+ */
+const char *GetClientCmdArgs(struct _Client *client)
+{
+ if (client == NullClient)
+ return NULL;
+
+ if (!client->clientIds)
+ return NULL;
+
+ return client->clientIds->cmdargs;
+}