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os: Add facilities for client ID tracking.

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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>
This commit is contained in:
Rami Ylimäki 2010-12-22 16:51:09 +02:00
commit 1e933665be
10 changed files with 403 additions and 0 deletions
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os/client.c Normal file
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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;
}