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cn_proc.c

/*
 * cn_proc.c - process events connector
 *
 * Copyright (C) Matt Helsley, IBM Corp. 2005
 * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
 * Original copyright notice follows:
 * Copyright (C) 2005 BULL SA.
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/init.h>
#include <linux/connector.h>
#include <asm/atomic.h>
#include <asm/unaligned.h>

#include <linux/cn_proc.h>

#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))

static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };

/* proc_event_counts is used as the sequence number of the netlink message */
static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };

static inline void get_seq(__u32 *ts, int *cpu)
{
      *ts = get_cpu_var(proc_event_counts)++;
      *cpu = smp_processor_id();
      put_cpu_var(proc_event_counts);
}

void proc_fork_connector(struct task_struct *task)
{
      struct cn_msg *msg;
      struct proc_event *ev;
      __u8 buffer[CN_PROC_MSG_SIZE];
      struct timespec ts;

      if (atomic_read(&proc_event_num_listeners) < 1)
            return;

      msg = (struct cn_msg*)buffer;
      ev = (struct proc_event*)msg->data;
      get_seq(&msg->seq, &ev->cpu);
      ktime_get_ts(&ts); /* get high res monotonic timestamp */
      put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
      ev->what = PROC_EVENT_FORK;
      ev->event_data.fork.parent_pid = task->real_parent->pid;
      ev->event_data.fork.parent_tgid = task->real_parent->tgid;
      ev->event_data.fork.child_pid = task->pid;
      ev->event_data.fork.child_tgid = task->tgid;

      memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
      msg->ack = 0; /* not used */
      msg->len = sizeof(*ev);
      /*  If cn_netlink_send() failed, the data is not sent */
      cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
}

void proc_exec_connector(struct task_struct *task)
{
      struct cn_msg *msg;
      struct proc_event *ev;
      struct timespec ts;
      __u8 buffer[CN_PROC_MSG_SIZE];

      if (atomic_read(&proc_event_num_listeners) < 1)
            return;

      msg = (struct cn_msg*)buffer;
      ev = (struct proc_event*)msg->data;
      get_seq(&msg->seq, &ev->cpu);
      ktime_get_ts(&ts); /* get high res monotonic timestamp */
      put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
      ev->what = PROC_EVENT_EXEC;
      ev->event_data.exec.process_pid = task->pid;
      ev->event_data.exec.process_tgid = task->tgid;

      memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
      msg->ack = 0; /* not used */
      msg->len = sizeof(*ev);
      cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
}

void proc_id_connector(struct task_struct *task, int which_id)
{
      struct cn_msg *msg;
      struct proc_event *ev;
      __u8 buffer[CN_PROC_MSG_SIZE];
      struct timespec ts;

      if (atomic_read(&proc_event_num_listeners) < 1)
            return;

      msg = (struct cn_msg*)buffer;
      ev = (struct proc_event*)msg->data;
      ev->what = which_id;
      ev->event_data.id.process_pid = task->pid;
      ev->event_data.id.process_tgid = task->tgid;
      if (which_id == PROC_EVENT_UID) {
            ev->event_data.id.r.ruid = task->uid;
            ev->event_data.id.e.euid = task->euid;
      } else if (which_id == PROC_EVENT_GID) {
            ev->event_data.id.r.rgid = task->gid;
            ev->event_data.id.e.egid = task->egid;
      } else
            return;
      get_seq(&msg->seq, &ev->cpu);
      ktime_get_ts(&ts); /* get high res monotonic timestamp */
      put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);

      memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
      msg->ack = 0; /* not used */
      msg->len = sizeof(*ev);
      cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
}

void proc_exit_connector(struct task_struct *task)
{
      struct cn_msg *msg;
      struct proc_event *ev;
      __u8 buffer[CN_PROC_MSG_SIZE];
      struct timespec ts;

      if (atomic_read(&proc_event_num_listeners) < 1)
            return;

      msg = (struct cn_msg*)buffer;
      ev = (struct proc_event*)msg->data;
      get_seq(&msg->seq, &ev->cpu);
      ktime_get_ts(&ts); /* get high res monotonic timestamp */
      put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
      ev->what = PROC_EVENT_EXIT;
      ev->event_data.exit.process_pid = task->pid;
      ev->event_data.exit.process_tgid = task->tgid;
      ev->event_data.exit.exit_code = task->exit_code;
      ev->event_data.exit.exit_signal = task->exit_signal;

      memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
      msg->ack = 0; /* not used */
      msg->len = sizeof(*ev);
      cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
}

/*
 * Send an acknowledgement message to userspace
 *
 * Use 0 for success, EFOO otherwise.
 * Note: this is the negative of conventional kernel error
 * values because it's not being returned via syscall return
 * mechanisms.
 */
static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
{
      struct cn_msg *msg;
      struct proc_event *ev;
      __u8 buffer[CN_PROC_MSG_SIZE];
      struct timespec ts;

      if (atomic_read(&proc_event_num_listeners) < 1)
            return;

      msg = (struct cn_msg*)buffer;
      ev = (struct proc_event*)msg->data;
      msg->seq = rcvd_seq;
      ktime_get_ts(&ts); /* get high res monotonic timestamp */
      put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
      ev->cpu = -1;
      ev->what = PROC_EVENT_NONE;
      ev->event_data.ack.err = err;
      memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
      msg->ack = rcvd_ack + 1;
      msg->len = sizeof(*ev);
      cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
}

/**
 * cn_proc_mcast_ctl
 * @data: message sent from userspace via the connector
 */
static void cn_proc_mcast_ctl(void *data)
{
      struct cn_msg *msg = data;
      enum proc_cn_mcast_op *mc_op = NULL;
      int err = 0;

      if (msg->len != sizeof(*mc_op))
            return;

      mc_op = (enum proc_cn_mcast_op*)msg->data;
      switch (*mc_op) {
      case PROC_CN_MCAST_LISTEN:
            atomic_inc(&proc_event_num_listeners);
            break;
      case PROC_CN_MCAST_IGNORE:
            atomic_dec(&proc_event_num_listeners);
            break;
      default:
            err = EINVAL;
            break;
      }
      cn_proc_ack(err, msg->seq, msg->ack);
}

/*
 * cn_proc_init - initialization entry point
 *
 * Adds the connector callback to the connector driver.
 */
static int __init cn_proc_init(void)
{
      int err;

      if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
                           &cn_proc_mcast_ctl))) {
            printk(KERN_WARNING "cn_proc failed to register\n");
            return err;
      }
      return 0;
}

module_init(cn_proc_init);

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