linux/drivers/connector/cn_proc.c
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   1/*
   2 * cn_proc.c - process events connector
   3 *
   4 * Copyright (C) Matt Helsley, IBM Corp. 2005
   5 * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
   6 * Original copyright notice follows:
   7 * Copyright (C) 2005 BULL SA.
   8 *
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License as published by
  12 * the Free Software Foundation; either version 2 of the License, or
  13 * (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with this program; if not, write to the Free Software
  22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23 */
  24
  25#include <linux/module.h>
  26#include <linux/kernel.h>
  27#include <linux/ktime.h>
  28#include <linux/init.h>
  29#include <linux/connector.h>
  30#include <asm/atomic.h>
  31#include <asm/unaligned.h>
  32
  33#include <linux/cn_proc.h>
  34
  35#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))
  36
  37static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
  38static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
  39
  40/* proc_event_counts is used as the sequence number of the netlink message */
  41static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
  42
  43static inline void get_seq(__u32 *ts, int *cpu)
  44{
  45        *ts = get_cpu_var(proc_event_counts)++;
  46        *cpu = smp_processor_id();
  47        put_cpu_var(proc_event_counts);
  48}
  49
  50void proc_fork_connector(struct task_struct *task)
  51{
  52        struct cn_msg *msg;
  53        struct proc_event *ev;
  54        __u8 buffer[CN_PROC_MSG_SIZE];
  55        struct timespec ts;
  56
  57        if (atomic_read(&proc_event_num_listeners) < 1)
  58                return;
  59
  60        msg = (struct cn_msg*)buffer;
  61        ev = (struct proc_event*)msg->data;
  62        get_seq(&msg->seq, &ev->cpu);
  63        ktime_get_ts(&ts); /* get high res monotonic timestamp */
  64        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
  65        ev->what = PROC_EVENT_FORK;
  66        ev->event_data.fork.parent_pid = task->real_parent->pid;
  67        ev->event_data.fork.parent_tgid = task->real_parent->tgid;
  68        ev->event_data.fork.child_pid = task->pid;
  69        ev->event_data.fork.child_tgid = task->tgid;
  70
  71        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  72        msg->ack = 0; /* not used */
  73        msg->len = sizeof(*ev);
  74        /*  If cn_netlink_send() failed, the data is not sent */
  75        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  76}
  77
  78void proc_exec_connector(struct task_struct *task)
  79{
  80        struct cn_msg *msg;
  81        struct proc_event *ev;
  82        struct timespec ts;
  83        __u8 buffer[CN_PROC_MSG_SIZE];
  84
  85        if (atomic_read(&proc_event_num_listeners) < 1)
  86                return;
  87
  88        msg = (struct cn_msg*)buffer;
  89        ev = (struct proc_event*)msg->data;
  90        get_seq(&msg->seq, &ev->cpu);
  91        ktime_get_ts(&ts); /* get high res monotonic timestamp */
  92        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
  93        ev->what = PROC_EVENT_EXEC;
  94        ev->event_data.exec.process_pid = task->pid;
  95        ev->event_data.exec.process_tgid = task->tgid;
  96
  97        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  98        msg->ack = 0; /* not used */
  99        msg->len = sizeof(*ev);
 100        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 101}
 102
 103void proc_id_connector(struct task_struct *task, int which_id)
 104{
 105        struct cn_msg *msg;
 106        struct proc_event *ev;
 107        __u8 buffer[CN_PROC_MSG_SIZE];
 108        struct timespec ts;
 109        const struct cred *cred;
 110
 111        if (atomic_read(&proc_event_num_listeners) < 1)
 112                return;
 113
 114        msg = (struct cn_msg*)buffer;
 115        ev = (struct proc_event*)msg->data;
 116        ev->what = which_id;
 117        ev->event_data.id.process_pid = task->pid;
 118        ev->event_data.id.process_tgid = task->tgid;
 119        rcu_read_lock();
 120        cred = __task_cred(task);
 121        if (which_id == PROC_EVENT_UID) {
 122                ev->event_data.id.r.ruid = cred->uid;
 123                ev->event_data.id.e.euid = cred->euid;
 124        } else if (which_id == PROC_EVENT_GID) {
 125                ev->event_data.id.r.rgid = cred->gid;
 126                ev->event_data.id.e.egid = cred->egid;
 127        } else {
 128                rcu_read_unlock();
 129                return;
 130        }
 131        rcu_read_unlock();
 132        get_seq(&msg->seq, &ev->cpu);
 133        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 134        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 135
 136        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 137        msg->ack = 0; /* not used */
 138        msg->len = sizeof(*ev);
 139        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 140}
 141
 142void proc_exit_connector(struct task_struct *task)
 143{
 144        struct cn_msg *msg;
 145        struct proc_event *ev;
 146        __u8 buffer[CN_PROC_MSG_SIZE];
 147        struct timespec ts;
 148
 149        if (atomic_read(&proc_event_num_listeners) < 1)
 150                return;
 151
 152        msg = (struct cn_msg*)buffer;
 153        ev = (struct proc_event*)msg->data;
 154        get_seq(&msg->seq, &ev->cpu);
 155        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 156        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 157        ev->what = PROC_EVENT_EXIT;
 158        ev->event_data.exit.process_pid = task->pid;
 159        ev->event_data.exit.process_tgid = task->tgid;
 160        ev->event_data.exit.exit_code = task->exit_code;
 161        ev->event_data.exit.exit_signal = task->exit_signal;
 162
 163        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 164        msg->ack = 0; /* not used */
 165        msg->len = sizeof(*ev);
 166        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 167}
 168
 169/*
 170 * Send an acknowledgement message to userspace
 171 *
 172 * Use 0 for success, EFOO otherwise.
 173 * Note: this is the negative of conventional kernel error
 174 * values because it's not being returned via syscall return
 175 * mechanisms.
 176 */
 177static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 178{
 179        struct cn_msg *msg;
 180        struct proc_event *ev;
 181        __u8 buffer[CN_PROC_MSG_SIZE];
 182        struct timespec ts;
 183
 184        if (atomic_read(&proc_event_num_listeners) < 1)
 185                return;
 186
 187        msg = (struct cn_msg*)buffer;
 188        ev = (struct proc_event*)msg->data;
 189        msg->seq = rcvd_seq;
 190        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 191        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 192        ev->cpu = -1;
 193        ev->what = PROC_EVENT_NONE;
 194        ev->event_data.ack.err = err;
 195        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 196        msg->ack = rcvd_ack + 1;
 197        msg->len = sizeof(*ev);
 198        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 199}
 200
 201/**
 202 * cn_proc_mcast_ctl
 203 * @data: message sent from userspace via the connector
 204 */
 205static void cn_proc_mcast_ctl(void *data)
 206{
 207        struct cn_msg *msg = data;
 208        enum proc_cn_mcast_op *mc_op = NULL;
 209        int err = 0;
 210
 211        if (msg->len != sizeof(*mc_op))
 212                return;
 213
 214        mc_op = (enum proc_cn_mcast_op*)msg->data;
 215        switch (*mc_op) {
 216        case PROC_CN_MCAST_LISTEN:
 217                atomic_inc(&proc_event_num_listeners);
 218                break;
 219        case PROC_CN_MCAST_IGNORE:
 220                atomic_dec(&proc_event_num_listeners);
 221                break;
 222        default:
 223                err = EINVAL;
 224                break;
 225        }
 226        cn_proc_ack(err, msg->seq, msg->ack);
 227}
 228
 229/*
 230 * cn_proc_init - initialization entry point
 231 *
 232 * Adds the connector callback to the connector driver.
 233 */
 234static int __init cn_proc_init(void)
 235{
 236        int err;
 237
 238        if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
 239                                   &cn_proc_mcast_ctl))) {
 240                printk(KERN_WARNING "cn_proc failed to register\n");
 241                return err;
 242        }
 243        return 0;
 244}
 245
 246module_init(cn_proc_init);
 247