[PATCH v2 1/5] dix: Add facilities for client ID tracking.
Vignatti Tiago (Nokia-MS/Helsinki)
tiago.vignatti at nokia.com
Tue Sep 14 10:19:42 PDT 2010
On Fri, Sep 10, 2010 at 06:58:38PM +0200, ext Rami Ylimäki wrote:
> 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 at vincit.fi>
> ---
> dix/Makefile.am | 1 +
> dix/client.c | 338 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> include/client.h | 54 +++++++++
> include/os.h | 2 +
> os/access.c | 46 ++++++++
> 5 files changed, 441 insertions(+), 0 deletions(-)
> create mode 100644 dix/client.c
> create mode 100644 include/client.h
>
> diff --git a/dix/Makefile.am b/dix/Makefile.am
> index 5e2dad7..bc87da5 100644
> --- a/dix/Makefile.am
> +++ b/dix/Makefile.am
> @@ -7,6 +7,7 @@ libmain_la_SOURCES = \
>
> libdix_la_SOURCES = \
> atom.c \
> + client.c \
> colormap.c \
> cursor.c \
> deprecated.c \
> diff --git a/dix/client.c b/dix/client.c
> new file mode 100644
> index 0000000..99152a4
> --- /dev/null
> +++ b/dix/client.c
> @@ -0,0 +1,338 @@
> +/*
> + * 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 at vincit.fi>
> + *
> + * 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. Use GetClient* to query information and
> + * GetClientIds*Cbs to register for notifications.
> + */
doxygen's @file directive maybe could be used here?
> +
> +#include <stdlib.h>
> +#include <unistd.h>
I pretty much think that those two system header files are already indirected
included (by misc.h -> os.h or something like that)
> +#include "os.h"
> +#include "client.h"
> +#include "dixstruct.h"
> +
> +/* Key for identifying ID information for a client. */
> +static DevPrivateKeyRec ClientIdsPrivKeyRec;
> +static DevPrivateKey ClientIdsPrivKey = &ClientIdsPrivKeyRec;
> +
> +/**
> + * @return Client private holding PID and command line string. Error
> + * (NULL) if PID is not available for the client.
> + */
> +ClientIdsPrivatePtr GetClientIds(ClientPtr client)
> +{
> + PrivatePtr *privates = &(client)->devPrivates;
> + pointer priv = dixLookupPrivate(privates, ClientIdsPrivKey);
> + return (ClientIdsPrivatePtr) priv;
> +}
> +
> +/* Called after PID and command line string have been determined for a
> + * client (all clients, including remote clients, except server
> + * client). You may call GetClientPid and GetClientCmd after this
> + * notification. */
> +static CallbackListPtr ClientIdsReservedCbs = NULL;
> +
> +/**
> + * @return Publisher of client ID allocation notifications.
> + *
> + * @see AddCallback
> + */
> +CallbackListPtr *GetClientIdsReservedCbs(void)
> +{
> + return &ClientIdsReservedCbs;
> +}
> +
> +/* Called before PID and command line string will be invalidated for a
> + * client (all clients, including remote clients, except server
> + * client). GetClientPid and GetClientCmd will return errors when
> + * called after this notification. */
> +static CallbackListPtr ClientIdsReleasedCbs = NULL;
> +
> +/**
> + * @return Publisher of client ID deallocation notifications.
> + *
> + * @see AddCallback
> + */
> +CallbackListPtr *GetClientIdsReleasedCbs(void)
> +{
> + return &ClientIdsReleasedCbs;
> +}
> +
> +/**
> + * 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
> + */
> +static pid_t DetermineClientPid(ClientPtr 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;
For me makes sense to put everything that uses type pid_t inside os/ somehow.
So you would staff things inside os/access.c removing mostly of the references
on this file.
> +/**
> + * 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 GetClientCmd to determine the string at
> + * other times.
> + *
> + * @param[in] pid Process ID of a client.
> + *
> + * @return Client command line string. Error (NULL) if command line
> + * string can't be determined for the client. You must release
> + * the string by calling free when it's not used anymore.
> + *
> + * @see GetClientCmd
> + */
> +static const char *DetermineClientCmd(pid_t pid)
> +{
> + return GetCommandFromPid(pid);
> +}
> +
> +/**
> + * Called when a new client connects. Allocates a private for the
> + * client and fills it with ID information.
> + *
> + * @param[in] client Recently connected client.
> + */
> +static void ReserveClientIds(ClientPtr client)
> +{
> + ClientIdsPrivatePtr priv = NULL;
> + pid_t pid = -1;
> +
> + if (client == NullClient)
> + return;
> +
> + /* Allocate private structure only if PID is available. */
> + pid = DetermineClientPid(client);
> + if (pid != -1)
> + {
> + priv = malloc(sizeof(ClientIdsPrivateRec));
> + if (priv)
> + {
> + priv->pid = pid;
> + priv->cmdline = DetermineClientCmd(pid);
> + }
> + }
> +
> + DebugF("client(%lx): Reserved pid(%d).\n",
> + client->clientAsMask, priv ? priv->pid : -1);
> + DebugF("client(%lx): Reserved cmdline(%s).\n",
> + client->clientAsMask, (priv && priv->cmdline) ? priv->cmdline : "NULL");
> +
> + dixSetPrivate(&(client)->devPrivates, ClientIdsPrivKey, priv);
> +}
> +
> +/**
> + * Called when an existing client disconnects. Frees client ID
> + * information as well as the client private.
> + *
> + * @param[in] client Recently disconnected client.
> + */
> +static void ReleaseClientIds(ClientPtr client)
> +{
> + ClientIdsPrivatePtr priv = NULL;
> +
> + if (client == NullClient)
> + return;
> +
> + priv = GetClientIds(client);
> + if (!priv)
> + return;
> +
> + DebugF("client(%lx): Released pid(%d).\n",
> + client->clientAsMask, priv ? priv->pid : -1);
> + DebugF("client(%lx): Released cmdline(%s).\n",
> + client->clientAsMask, (priv && priv->cmdline) ? priv->cmdline : "NULL");
> +
> + free((void *) priv->cmdline); /* const char * */
> + free(priv);
> + dixSetPrivate(&(client)->devPrivates, ClientIdsPrivKey, NULL);
> +}
> +
> +/**
> + * Called when new client connects or existing client disconnects.
> + *
> + * @param[in] pcbl Publisher of client state change notifications.
> + * @param[in] nulldata Unused private callback data.
> + * @param[in] calldata Information about client whose state changed.
> + *
> + * @see GetClientIdsReservedCbs
> + * @see GetClientIdsReleasedCbs
> + */
> +static void ClientIdsChanged(CallbackListPtr *pcbl, pointer nulldata, pointer calldata)
> +{
> + NewClientInfoRec *pci = (NewClientInfoRec *)calldata;
> + ClientPtr client = pci->client;
> +
> + switch (client->clientState)
> + {
> + case ClientStateGone:
> + case ClientStateRetained:
> + /* Notify subscribers that client IDs will be released before
> + * they are actually released. */
> + CallCallbacks(&ClientIdsReleasedCbs, client);
> + ReleaseClientIds(client);
> + break;
> + case ClientStateInitial:
> + /* Reserve client IDs and notify subscribers about new IDs
> + * afterwards. */
> + ReserveClientIds(client);
> + CallCallbacks(&ClientIdsReservedCbs, client);
> + break;
> + default:
> + break;
> + }
> +}
> +
> +/**
> + * Starts tracking of client connections and disconnections. After
> + * initialization, PID and command line strings are determined and
> + * cached for each connected client. Call this before any clients have
> + * connected.
> + *
> + * @param[in] server Recently initialized server client.
> + */
> +void InitClientIds(ClientPtr server)
> +{
> + if (!dixRegisterPrivateKey(ClientIdsPrivKey, PRIVATE_CLIENT, 0))
> + FatalError("Can't register client IDs private.\n");
> +
> + if (!AddCallback(&ClientStateCallback, ClientIdsChanged, NULL))
> + FatalError("Can't track client IDs.\n");
> +
> + ReserveClientIds(server);
> +}
> +
> +/**
> + * Stops tracking clients. Call this after all clients have
> + * disconnected.
> + *
> + * @param[in] server Server client that is about to be cleaned up.
> + */
> +void CloseClientIds(ClientPtr server)
> +{
> + if (!DeleteCallback(&ClientStateCallback, ClientIdsChanged, NULL))
> + LogMessage(X_ERROR, "Can't stop tracking client IDs.\n");
> +
> + DeleteCallbackList(&ClientIdsReservedCbs);
> + DeleteCallbackList(&ClientIdsReleasedCbs);
> +
> + ReleaseClientIds(server);
> +}
> +
> +/**
> + * 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 ClientIdsReservedCbs notification
> + * - after ClientIdsReleasedCbs notification
> + * - for remote clients
> + *
> + * @see DetermineClientPid
> + */
> +pid_t GetClientPid(ClientPtr client)
> +{
> + ClientIdsPrivatePtr priv = NULL;
> +
> + if (client == NullClient)
> + return -1;
> +
> + priv = GetClientIds(client);
> + if (!priv)
> + return -1;
> +
> + return priv->pid;
> +}
> +
> +/**
> + * Get cached command line string of a client.
> + *
> + * param[in] client Client whose command line string caching has been
> + * attempted previously.
> + *
> + * @return Cached client command line. Error (NULL) if called:
> + * - before ClientIdsReservedCbs notification
> + * - after ClientIdsReleasedCbs notification
> + * - for remote clients
> + * - on OS that doesn't support mapping of PID to command line
> + *
> + * @see DetermineClientCmd
> + */
> +const char *GetClientCmd(ClientPtr client)
> +{
> + ClientIdsPrivatePtr priv = NULL;
> +
> + if (client == NullClient)
> + return NULL;
> +
> + priv = GetClientIds(client);
> + if (!priv)
> + return NULL;
> +
> + return priv->cmdline;
> +}
> diff --git a/include/client.h b/include/client.h
> new file mode 100644
> index 0000000..6c15b2b
> --- /dev/null
> +++ b/include/client.h
> @@ -0,0 +1,54 @@
> +/*
> + * 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 at vincit.fi>
> + */
> +
> +#ifndef CLIENT_IDS_H
> +#define CLIENT_IDS_H
> +
> +#include <sys/types.h>
> +
> +#include "dix.h"
> +
> +/* Client specific ID information. The corresponding client private
> + * will be NULL if PID is not available for the client. */
> +typedef struct
> +{
> + pid_t pid; /* always zero or positive */
> + const char *cmdline; /* NULL if not available */
> +} ClientIdsPrivateRec, *ClientIdsPrivatePtr;
> +
> +/* Initialize and clean up. */
> +void InitClientIds(ClientPtr server);
> +void CloseClientIds(ClientPtr server);
> +
> +/* Register to notifications. */
> +extern _X_EXPORT CallbackListPtr *GetClientIdsReservedCbs(void);
> +extern _X_EXPORT CallbackListPtr *GetClientIdsReleasedCbs(void);
> +
> +/* Query client IDs. */
> +extern _X_EXPORT ClientIdsPrivatePtr GetClientIds(ClientPtr client);
> +extern _X_EXPORT pid_t GetClientPid(ClientPtr client);
> +extern _X_EXPORT const char *GetClientCmd(ClientPtr client);
> +
> +#endif /* CLIENT_IDS_H */
> diff --git a/include/os.h b/include/os.h
> index efa202c..22c22a7 100644
> --- a/include/os.h
> +++ b/include/os.h
> @@ -51,6 +51,7 @@ SOFTWARE.
>
> #include "misc.h"
> #include <stdarg.h>
> +#include <sys/types.h> /* pid_t */
>
> #define SCREEN_SAVER_ON 0
> #define SCREEN_SAVER_OFF 1
> @@ -369,6 +370,7 @@ typedef struct {
>
> extern _X_EXPORT int GetLocalClientCreds(ClientPtr, LocalClientCredRec **);
> extern _X_EXPORT void FreeLocalClientCreds(LocalClientCredRec *);
> +extern _X_EXPORT const char *GetCommandFromPid(pid_t pid);
>
> extern _X_EXPORT int ChangeAccessControl(ClientPtr /*client*/, int /*fEnabled*/);
>
> diff --git a/os/access.c b/os/access.c
> index 0279259..ce96436 100644
> --- a/os/access.c
> +++ b/os/access.c
> @@ -1297,6 +1297,52 @@ FreeLocalClientCreds(LocalClientCredRec *lcc)
> }
> }
>
> +/**
> + * Map a client PID to a command line string. Currently only systems
> + * with /proc/pid/cmdline are supported.
> + *
> + * @param[in] pid Process ID of a client.
> + *
> + * @return Command line string of the given process. Error (NULL) if
> + * the command line string can't be determined from the
> + * PID. You must release the string by calling free when it's
> + * not used anymore.
> + */
> +const char *GetCommandFromPid(pid_t pid)
> +{
> + char path[PATH_MAX + 1];
> + char *cmd = NULL;
> + int fd = 0;
> + int bytes = 0;
> +
> + if (pid == -1)
> + return NULL;
> +
> + if (snprintf(path, sizeof(path), "/proc/%d/cmdline", pid) < 0)
> + return NULL;
> +
> + fd = open(path, O_RDONLY);
> + if (fd < 0)
> + return NULL;
> + bytes = read(fd, path, sizeof(path));
> + if (bytes <= 0)
> + return NULL;
> + if (close(fd) < 0)
> + return NULL;
> +
> + /* We are only interested in the process name. We don't care about
> + * its arguments. Allocate space only for the process name. */
> + path[bytes - 1] = '\0';
> + bytes = strlen(path) + 1;
> + cmd = malloc(bytes);
> + if (cmd == NULL)
> + return NULL;
> + strncpy(cmd, path, bytes);
> + cmd[bytes - 1] = '\0';
> +
> + return cmd;
> +}
> +
> static int
> AuthorizedClient(ClientPtr client)
> {
Given those minor changes I pointed, for me the patch is quite in nice shape:
Acked-by: Tiago Vignatti <tiago.vignatti at nokia.com>
Cheers,
Tiago
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