os: Add facilities for client ID tracking.

 commit 6d6d4cb6043905d850834946e9bfc526ed5a9ef7
 Author: Matthieu Herrb <matthieu.herrb@laas.fr>
 Date:   Mon Jan 2 13:23:59 2012 +0000

    Add OpenBSD support to DetermineClientCmd()

    Uses kvm_getargv() from libkvm.

    Signed-off-by: Matthieu Herrb <matthieu.herrb@laas.fr>
    Reviewed-by: Adam Jackson <ajax@redhat.com>
    Signed-off-by: Keith Packard <keithp@keithp.com>

 commit cfc4c3d7fa8bd4da4c08b2ab8e6f85435f75353a
 Author: Alan Coopersmith <alan.coopersmith@oracle.com>
 Date:   Sat Dec 24 10:00:56 2011 -0800

    Add Solaris support to DetermineClientCmd

    Uses /proc/pid/psinfo to read command & partial arguments.

    Moves cmdsize & argsize variables into non-Solaris #else clause
    to avoid unused variable warnings.

    Fixes format mismatch errors when building with DEBUG defined on
    a 64-bit platform (where Mask is defined as CARD32).

    Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
    Reviewed-by: Rami Ylimäki <rami.ylimaki@vincit.fi>
    Signed-off-by: Keith Packard <keithp@keithp.com>

 commit 780133f9ae7fada462714b47e79d26075bbd9abe
 Author: Alan Coopersmith <alan.coopersmith@oracle.com>
 Date:   Fri Oct 28 21:29:50 2011 -0700

    Convert DetermineClientCmd to use strdup instead of malloc+strncpy

    *cmdname is initialized to NULL earlier in the function, so it's
    okay to overwrite it with NULL if strdup fails, don't need that
    extra check.

    Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
    Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>

 commit 2ef4ff45ef1fcfc4967ebe3d550408769e5f6500
 Author: Erkki Seppälä <erkki.seppala@vincit.fi>
 Date:   Fri Mar 25 10:38:23 2011 +0200

    os/client: Prevent rare fd leak in DetermineClientPid

    DetermineClientPid didn't close file descriptor if read on
    /proc/pid/cmdline failed. Adjusted the code to disregard the close
    return value and perform the return after that, if the read failed or
    returned EOF.

    Signed-off-by: Mark Kettenis <mark.kettenis@xs4all.nl>
    Signed-off-by: Erkki Seppälä <erkki.seppala@vincit.fi>
    Reviewed-by: Rami Ylimäki <rami.ylimaki@vincit.fi>
    Signed-off-by: Keith Packard <keithp@keithp.com>

 commit 1e933665bef26c74196bb7c59910e6a78bcacf0e
 Author: Rami Ylimäki <rami.ylimaki@vincit.fi>
 Date:   Wed Dec 22 16:51:09 2010 +0200

    os: Add facilities for client ID tracking.

    An interface is provided for figuring out the PID and process name of
    a client. Make some existing functionality from SELinux and IA
    extensions available for general use.

    Signed-off-by: Rami Ylimäki <rami.ylimaki@vincit.fi>
    Reviewed-by: Tiago Vignatti <tiago.vignatti@nokia.com>

 Backported-to-NX-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>

8 files changed, 485 insertions, 0 deletions

diff --git a/nx-X11/programs/Xserver/Imakefile b/nx-X11/programs/Xserver/Imakefile
index 2af91821d..745b26154 100644
--- a/nx-X11/programs/Xserver/Imakefile
+++ b/nx-X11/programs/Xserver/Imakefile
@@ -323,6 +323,15 @@ NXAGENTNXLIBS = -L../../../nxcomp  \
                 -lXcompshad \
                 -lXrender -lXfixes -lXfont -lXcomposite -lXdmcp \
                 -lNX_X11 -lXext
+#elif defined(OpenBSDArchitecture)
+NXAGENTNXLIBS = -L../../../nxcomp  \
+                -L../../../nx-X11/exports/lib \
+                -L../../../nxcompshad \
+                -lkvm \
+                -lXcomp \
+                -lXcompshad \
+                -lXrender -lXfixes -lXfont -lXcomposite -lXinerama -lXdmcp \
+                -lNX_X11 -lXext
 #else
 NXAGENTNXLIBS = -L../../../nxcomp  \
                 -L../../../nx-X11/exports/lib \
diff --git a/nx-X11/programs/Xserver/dix/dispatch.c b/nx-X11/programs/Xserver/dix/dispatch.c
index 3869ef723..16b94301f 100644
--- a/nx-X11/programs/Xserver/dix/dispatch.c
+++ b/nx-X11/programs/Xserver/dix/dispatch.c
@@ -112,6 +112,7 @@ int ProcInitialConnection();
 #include "inputstr.h"
 #include "xkbsrv.h"
 #endif
+#include "client.h"
 
 #define mskcnt ((MAXCLIENTS + 31) / 32)
 #define BITMASK(i) (1U << ((i) & 31))
@@ -3560,6 +3561,9 @@ CloseDownClient(register ClientPtr client)
 	    CallCallbacks((&ClientStateCallback), (void *)&clientinfo);
 	} 	    
 	FreeClientResources(client);
+	/* Disable client ID tracking. This must be done after
+	 * ClientStateCallback. */
+	ReleaseClientIds(client);
 	if (client->index < nextFreeClientID)
 	    nextFreeClientID = client->index;
 	clients[client->index] = NullClient;
@@ -3643,6 +3647,7 @@ void InitClient(ClientPtr client, int i, void * ospriv)
     client->smart_start_tick = SmartScheduleTime;
     client->smart_stop_tick = SmartScheduleTime;
     client->smart_check_tick = SmartScheduleTime;
+    client->clientIds = NULL;
 }
 
 extern int clientPrivateLen;
@@ -3724,6 +3729,11 @@ ClientPtr NextAvailableClient(void * ospriv)
 	currentMaxClients++;
     while ((nextFreeClientID < MAXCLIENTS) && clients[nextFreeClientID])
 	nextFreeClientID++;
+
+    /* Enable client ID tracking. This must be done before
+     * ClientStateCallback. */
+    ReserveClientIds(client);
+
     if (ClientStateCallback)
     {
 	NewClientInfoRec clientinfo;
diff --git a/nx-X11/programs/Xserver/dix/main.c b/nx-X11/programs/Xserver/dix/main.c
index 7bd41d865..50bbeb3dc 100644
--- a/nx-X11/programs/Xserver/dix/main.c
+++ b/nx-X11/programs/Xserver/dix/main.c
@@ -100,6 +100,7 @@ Equipment Corporation.
 #include "site.h"
 #include "dixfont.h"
 #include "extnsionst.h"
+#include "client.h"
 #ifdef PANORAMIX
 #include "panoramiXsrv.h"
 #else
@@ -382,6 +383,7 @@ main(int argc, char *argv[], char *envp[])
 	InitInput(argc, argv);
 	if (InitAndStartDevices() != Success)
 	    FatalError("failed to initialize core devices");
+	ReserveClientIds(serverClient);
 
 	InitFonts();
 	if (loadableFonts) {
@@ -470,6 +472,7 @@ main(int argc, char *argv[], char *envp[])
 #endif
 	FreeAuditTimer();
 
+	ReleaseClientIds(serverClient);
 	free(serverClient->devPrivates);
 	serverClient->devPrivates = NULL;
 
diff --git a/nx-X11/programs/Xserver/include/Imakefile b/nx-X11/programs/Xserver/include/Imakefile
index d1d7bd651..53f193ec8 100644
--- a/nx-X11/programs/Xserver/include/Imakefile
+++ b/nx-X11/programs/Xserver/include/Imakefile
@@ -16,6 +16,7 @@ depend::
 InstallDriverSDKNonExecFile(XIstubs.h,$(DRIVERSDKINCLUDEDIR))
 InstallDriverSDKNonExecFile(bstore.h,$(DRIVERSDKINCLUDEDIR))
 InstallDriverSDKNonExecFile(bstorestr.h,$(DRIVERSDKINCLUDEDIR))
+InstallDriverSDKNonExecFile(client.h,$(DRIVERSDKINCLUDEDIR))
 InstallDriverSDKNonExecFile(colormap.h,$(DRIVERSDKINCLUDEDIR))
 InstallDriverSDKNonExecFile(colormapst.h,$(DRIVERSDKINCLUDEDIR))
 InstallDriverSDKNonExecFile(cursor.h,$(DRIVERSDKINCLUDEDIR))
diff --git a/nx-X11/programs/Xserver/include/client.h b/nx-X11/programs/Xserver/include/client.h
new file mode 100644
index 000000000..87f2b1172
--- /dev/null
+++ b/nx-X11/programs/Xserver/include/client.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). 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.
+ */
+
+/* Author: Rami Ylimäki <rami.ylimaki@vincit.fi> */
+
+#ifndef CLIENT_H
+#define CLIENT_H
+
+#ifdef HAVE_DIX_CONFIG_H
+#include <dix-config.h>
+#endif                          /* HAVE_DIX_CONFIG_H */
+#include <X11/Xfuncproto.h>
+#include <sys/types.h>
+
+/* Client IDs. Use GetClientPid, GetClientCmdName and GetClientCmdArgs
+ * instead of accessing the fields directly. */
+typedef struct {
+    pid_t pid;                  /* process ID, -1 if not available */
+    const char *cmdname;        /* process name, NULL if not available */
+    const char *cmdargs;        /* process arguments, NULL if not available */
+} ClientIdRec, *ClientIdPtr;
+
+struct _Client;
+
+/* Initialize and clean up. */
+void ReserveClientIds(struct _Client *client);
+void ReleaseClientIds(struct _Client *client);
+
+/* Determine client IDs for caching. Exported on purpose for
+ * extensions such as SELinux. */
+extern _X_EXPORT pid_t DetermineClientPid(struct _Client *client);
+extern _X_EXPORT void DetermineClientCmd(pid_t, const char **cmdname,
+                                         const char **cmdargs);
+
+/* Query cached client IDs. Exported on purpose for drivers. */
+extern _X_EXPORT pid_t GetClientPid(struct _Client *client);
+extern _X_EXPORT const char *GetClientCmdName(struct _Client *client);
+extern _X_EXPORT const char *GetClientCmdArgs(struct _Client *client);
+
+#endif                          /* CLIENT_H */
diff --git a/nx-X11/programs/Xserver/include/dixstruct.h b/nx-X11/programs/Xserver/include/dixstruct.h
index 1096f5c40..b8ee8e9cf 100644
--- a/nx-X11/programs/Xserver/include/dixstruct.h
+++ b/nx-X11/programs/Xserver/include/dixstruct.h
@@ -24,6 +24,7 @@ SOFTWARE.
 #ifndef DIXSTRUCT_H
 #define DIXSTRUCT_H
 
+#include "client.h"
 #include "dix.h"
 #include "resource.h"
 #include "cursor.h"
@@ -141,6 +142,8 @@ typedef struct _Client {
     long    smart_start_tick;
     long    smart_stop_tick;
     long    smart_check_tick;
+
+    ClientIdPtr  clientIds;
 }           ClientRec;
 
 /*
diff --git a/nx-X11/programs/Xserver/os/Imakefile b/nx-X11/programs/Xserver/os/Imakefile
index 144cb5a55..86f5cd4e6 100644
--- a/nx-X11/programs/Xserver/os/Imakefile
+++ b/nx-X11/programs/Xserver/os/Imakefile
@@ -128,6 +128,7 @@ TMEMCMP_OBJS = timingsafe_memcmp.o
 BOOTSTRAPCFLAGS = 
            SRCS = WaitFor.c		\
                   access.c		\
+                  client.c		\
                   connection.c		\
                   io.c			\
                   $(COLOR_SRCS)		\
@@ -151,6 +152,7 @@ BOOTSTRAPCFLAGS =
 
            OBJS = WaitFor.o		\
                   access.o		\
+                  client.o		\
                   connection.o		\
                   io.o			\
                   $(COLOR_OBJS)		\
diff --git a/nx-X11/programs/Xserver/os/client.c b/nx-X11/programs/Xserver/os/client.c
new file mode 100644
index 000000000..ef5e3935d
--- /dev/null
+++ b/nx-X11/programs/Xserver/os/client.c
@@ -0,0 +1,397 @@
+/*
+ * 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"
+
+#ifdef __sun
+#include <errno.h>
+#include <procfs.h>
+#endif
+
+#ifdef __OpenBSD__
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <sys/types.h>
+
+#include <kvm.h>
+#include <limits.h>
+#endif
+
+/**
+ * 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 fd = 0;
+
+    if (cmdname)
+        *cmdname = NULL;
+    if (cmdargs)
+        *cmdargs = NULL;
+
+    if (pid == -1)
+        return;
+
+#ifdef __sun                    /* Solaris */
+    /* Solaris does not support /proc/pid/cmdline, but makes information
+     * similar to what ps shows available in a binary structure in the
+     * /proc/pid/psinfo file. */
+    if (snprintf(path, sizeof(path), "/proc/%d/psinfo", pid) < 0)
+        return;
+    fd = open(path, O_RDONLY);
+    if (fd < 0) {
+        ErrorF("Failed to open %s: %s\n", path, strerror(errno));
+        return;
+    }
+    else {
+        psinfo_t psinfo = { 0 };
+        char *sp;
+
+        totsize = read(fd, &psinfo, sizeof(psinfo_t));
+        close(fd);
+        if (totsize <= 0)
+            return;
+
+        /* pr_psargs is the first PRARGSZ (80) characters of the command
+         * line string - assume up to the first space is the command name,
+         * since it's not delimited.   While there is also pr_fname, that's
+         * more limited, giving only the first 16 chars of the basename of
+         * the file that was exec'ed, thus cutting off many long gnome
+         * command names, or returning "isapython2.6" for all python scripts.
+         */
+        psinfo.pr_psargs[PRARGSZ - 1] = '\0';
+        sp = strchr(psinfo.pr_psargs, ' ');
+        if (sp)
+            *sp++ = '\0';
+
+        if (cmdname)
+            *cmdname = strdup(psinfo.pr_psargs);
+
+        if (cmdargs && sp)
+            *cmdargs = strdup(sp);
+    }
+#elif defined(__OpenBSD__)
+    /* on OpenBSD use kvm_getargv() */
+    {
+        kvm_t *kd;
+        char errbuf[_POSIX2_LINE_MAX];
+        char **argv;
+        struct kinfo_proc *kp;
+        size_t len = 0;
+        int i, n;
+
+        kd = kvm_open(NULL, NULL, NULL, KVM_NO_FILES, errbuf);
+        if (kd == NULL)
+            return;
+        kp = kvm_getprocs(kd, KERN_PROC_PID, pid, sizeof(struct kinfo_proc),
+                          &n);
+        if (n != 1)
+            return;
+        argv = kvm_getargv(kd, kp, 0);
+        *cmdname = strdup(argv[0]);
+        i = 1;
+        while (argv[i] != NULL) {
+            len += strlen(argv[i]) + 1;
+            i++;
+        }
+        *cmdargs = calloc(1, len);
+        i = 1;
+        while (argv[i] != NULL) {
+            strlcat(*cmdargs, argv[i], len);
+            strlcat(*cmdargs, " ", len);
+            i++;
+        }
+        kvm_close(kd);
+    }
+#else                           /* Linux using /proc/pid/cmdline */
+
+    /* 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));
+    close(fd);
+    if (totsize <= 0)
+        return;
+    path[totsize - 1] = '\0';
+
+    /* Contruct the process name without arguments. */
+    if (cmdname) {
+        *cmdname = strdup(path);
+    }
+
+    /* Construct the arguments for client process. */
+    if (cmdargs) {
+        int cmdsize = strlen(path) + 1;
+        int argsize = totsize - cmdsize;
+        char *args = NULL;
+
+        if (argsize > 0)
+            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;
+        }
+    }
+#endif
+}
+
+/**
+ * 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",
+           (unsigned long) client->clientAsMask, client->clientIds->pid);
+    DebugF("client(%lx): Reserved cmdname(%s) and cmdargs(%s).\n",
+           (unsigned long) 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",
+           (unsigned long) client->clientAsMask, client->clientIds->pid);
+    DebugF("client(%lx): Released cmdline(%s) and cmdargs(%s).\n",
+           (unsigned long) 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;
+}