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 <linux/gfp.h>
  31#include <linux/ptrace.h>
  32#include <linux/atomic.h>
  33
  34#include <asm/unaligned.h>
  35
  36#include <linux/cn_proc.h>
  37
  38#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))
  39
  40static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
  41static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
  42
  43/* proc_event_counts is used as the sequence number of the netlink message */
  44static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
  45
  46static inline void get_seq(__u32 *ts, int *cpu)
  47{
  48        preempt_disable();
  49        *ts = __this_cpu_inc_return(proc_event_counts) - 1;
  50        *cpu = smp_processor_id();
  51        preempt_enable();
  52}
  53
  54void proc_fork_connector(struct task_struct *task)
  55{
  56        struct cn_msg *msg;
  57        struct proc_event *ev;
  58        __u8 buffer[CN_PROC_MSG_SIZE];
  59        struct timespec ts;
  60        struct task_struct *parent;
  61
  62        if (atomic_read(&proc_event_num_listeners) < 1)
  63                return;
  64
  65        msg = (struct cn_msg *)buffer;
  66        ev = (struct proc_event *)msg->data;
  67        get_seq(&msg->seq, &ev->cpu);
  68        ktime_get_ts(&ts); /* get high res monotonic timestamp */
  69        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
  70        ev->what = PROC_EVENT_FORK;
  71        rcu_read_lock();
  72        parent = rcu_dereference(task->real_parent);
  73        ev->event_data.fork.parent_pid = parent->pid;
  74        ev->event_data.fork.parent_tgid = parent->tgid;
  75        rcu_read_unlock();
  76        ev->event_data.fork.child_pid = task->pid;
  77        ev->event_data.fork.child_tgid = task->tgid;
  78
  79        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  80        msg->ack = 0; /* not used */
  81        msg->len = sizeof(*ev);
  82        /*  If cn_netlink_send() failed, the data is not sent */
  83        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  84}
  85
  86void proc_exec_connector(struct task_struct *task)
  87{
  88        struct cn_msg *msg;
  89        struct proc_event *ev;
  90        struct timespec ts;
  91        __u8 buffer[CN_PROC_MSG_SIZE];
  92
  93        if (atomic_read(&proc_event_num_listeners) < 1)
  94                return;
  95
  96        msg = (struct cn_msg *)buffer;
  97        ev = (struct proc_event *)msg->data;
  98        get_seq(&msg->seq, &ev->cpu);
  99        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 100        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 101        ev->what = PROC_EVENT_EXEC;
 102        ev->event_data.exec.process_pid = task->pid;
 103        ev->event_data.exec.process_tgid = task->tgid;
 104
 105        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 106        msg->ack = 0; /* not used */
 107        msg->len = sizeof(*ev);
 108        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 109}
 110
 111void proc_id_connector(struct task_struct *task, int which_id)
 112{
 113        struct cn_msg *msg;
 114        struct proc_event *ev;
 115        __u8 buffer[CN_PROC_MSG_SIZE];
 116        struct timespec ts;
 117        const struct cred *cred;
 118
 119        if (atomic_read(&proc_event_num_listeners) < 1)
 120                return;
 121
 122        msg = (struct cn_msg *)buffer;
 123        ev = (struct proc_event *)msg->data;
 124        ev->what = which_id;
 125        ev->event_data.id.process_pid = task->pid;
 126        ev->event_data.id.process_tgid = task->tgid;
 127        rcu_read_lock();
 128        cred = __task_cred(task);
 129        if (which_id == PROC_EVENT_UID) {
 130                ev->event_data.id.r.ruid = cred->uid;
 131                ev->event_data.id.e.euid = cred->euid;
 132        } else if (which_id == PROC_EVENT_GID) {
 133                ev->event_data.id.r.rgid = cred->gid;
 134                ev->event_data.id.e.egid = cred->egid;
 135        } else {
 136                rcu_read_unlock();
 137                return;
 138        }
 139        rcu_read_unlock();
 140        get_seq(&msg->seq, &ev->cpu);
 141        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 142        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 143
 144        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 145        msg->ack = 0; /* not used */
 146        msg->len = sizeof(*ev);
 147        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 148}
 149
 150void proc_sid_connector(struct task_struct *task)
 151{
 152        struct cn_msg *msg;
 153        struct proc_event *ev;
 154        struct timespec ts;
 155        __u8 buffer[CN_PROC_MSG_SIZE];
 156
 157        if (atomic_read(&proc_event_num_listeners) < 1)
 158                return;
 159
 160        msg = (struct cn_msg *)buffer;
 161        ev = (struct proc_event *)msg->data;
 162        get_seq(&msg->seq, &ev->cpu);
 163        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 164        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 165        ev->what = PROC_EVENT_SID;
 166        ev->event_data.sid.process_pid = task->pid;
 167        ev->event_data.sid.process_tgid = task->tgid;
 168
 169        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 170        msg->ack = 0; /* not used */
 171        msg->len = sizeof(*ev);
 172        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 173}
 174
 175void proc_ptrace_connector(struct task_struct *task, int ptrace_id)
 176{
 177        struct cn_msg *msg;
 178        struct proc_event *ev;
 179        struct timespec ts;
 180        __u8 buffer[CN_PROC_MSG_SIZE];
 181
 182        if (atomic_read(&proc_event_num_listeners) < 1)
 183                return;
 184
 185        msg = (struct cn_msg *)buffer;
 186        ev = (struct proc_event *)msg->data;
 187        get_seq(&msg->seq, &ev->cpu);
 188        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 189        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 190        ev->what = PROC_EVENT_PTRACE;
 191        ev->event_data.ptrace.process_pid  = task->pid;
 192        ev->event_data.ptrace.process_tgid = task->tgid;
 193        if (ptrace_id == PTRACE_ATTACH) {
 194                ev->event_data.ptrace.tracer_pid  = current->pid;
 195                ev->event_data.ptrace.tracer_tgid = current->tgid;
 196        } else if (ptrace_id == PTRACE_DETACH) {
 197                ev->event_data.ptrace.tracer_pid  = 0;
 198                ev->event_data.ptrace.tracer_tgid = 0;
 199        } else
 200                return;
 201
 202        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 203        msg->ack = 0; /* not used */
 204        msg->len = sizeof(*ev);
 205        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 206}
 207
 208void proc_comm_connector(struct task_struct *task)
 209{
 210        struct cn_msg *msg;
 211        struct proc_event *ev;
 212        struct timespec ts;
 213        __u8 buffer[CN_PROC_MSG_SIZE];
 214
 215        if (atomic_read(&proc_event_num_listeners) < 1)
 216                return;
 217
 218        msg = (struct cn_msg *)buffer;
 219        ev = (struct proc_event *)msg->data;
 220        get_seq(&msg->seq, &ev->cpu);
 221        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 222        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 223        ev->what = PROC_EVENT_COMM;
 224        ev->event_data.comm.process_pid  = task->pid;
 225        ev->event_data.comm.process_tgid = task->tgid;
 226        get_task_comm(ev->event_data.comm.comm, task);
 227
 228        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 229        msg->ack = 0; /* not used */
 230        msg->len = sizeof(*ev);
 231        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 232}
 233
 234void proc_exit_connector(struct task_struct *task)
 235{
 236        struct cn_msg *msg;
 237        struct proc_event *ev;
 238        __u8 buffer[CN_PROC_MSG_SIZE];
 239        struct timespec ts;
 240
 241        if (atomic_read(&proc_event_num_listeners) < 1)
 242                return;
 243
 244        msg = (struct cn_msg *)buffer;
 245        ev = (struct proc_event *)msg->data;
 246        get_seq(&msg->seq, &ev->cpu);
 247        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 248        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 249        ev->what = PROC_EVENT_EXIT;
 250        ev->event_data.exit.process_pid = task->pid;
 251        ev->event_data.exit.process_tgid = task->tgid;
 252        ev->event_data.exit.exit_code = task->exit_code;
 253        ev->event_data.exit.exit_signal = task->exit_signal;
 254
 255        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 256        msg->ack = 0; /* not used */
 257        msg->len = sizeof(*ev);
 258        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 259}
 260
 261/*
 262 * Send an acknowledgement message to userspace
 263 *
 264 * Use 0 for success, EFOO otherwise.
 265 * Note: this is the negative of conventional kernel error
 266 * values because it's not being returned via syscall return
 267 * mechanisms.
 268 */
 269static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 270{
 271        struct cn_msg *msg;
 272        struct proc_event *ev;
 273        __u8 buffer[CN_PROC_MSG_SIZE];
 274        struct timespec ts;
 275
 276        if (atomic_read(&proc_event_num_listeners) < 1)
 277                return;
 278
 279        msg = (struct cn_msg *)buffer;
 280        ev = (struct proc_event *)msg->data;
 281        msg->seq = rcvd_seq;
 282        ktime_get_ts(&ts); /* get high res monotonic timestamp */
 283        put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 284        ev->cpu = -1;
 285        ev->what = PROC_EVENT_NONE;
 286        ev->event_data.ack.err = err;
 287        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 288        msg->ack = rcvd_ack + 1;
 289        msg->len = sizeof(*ev);
 290        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 291}
 292
 293/**
 294 * cn_proc_mcast_ctl
 295 * @data: message sent from userspace via the connector
 296 */
 297static void cn_proc_mcast_ctl(struct cn_msg *msg,
 298                              struct netlink_skb_parms *nsp)
 299{
 300        enum proc_cn_mcast_op *mc_op = NULL;
 301        int err = 0;
 302
 303        if (msg->len != sizeof(*mc_op))
 304                return;
 305
 306        mc_op = (enum proc_cn_mcast_op *)msg->data;
 307        switch (*mc_op) {
 308        case PROC_CN_MCAST_LISTEN:
 309                atomic_inc(&proc_event_num_listeners);
 310                break;
 311        case PROC_CN_MCAST_IGNORE:
 312                atomic_dec(&proc_event_num_listeners);
 313                break;
 314        default:
 315                err = EINVAL;
 316                break;
 317        }
 318        cn_proc_ack(err, msg->seq, msg->ack);
 319}
 320
 321/*
 322 * cn_proc_init - initialization entry point
 323 *
 324 * Adds the connector callback to the connector driver.
 325 */
 326static int __init cn_proc_init(void)
 327{
 328        int err = cn_add_callback(&cn_proc_event_id,
 329                                  "cn_proc",
 330                                  &cn_proc_mcast_ctl);
 331        if (err) {
 332                pr_warn("cn_proc failed to register\n");
 333                return err;
 334        }
 335        return 0;
 336}
 337
 338module_init(cn_proc_init);
 339
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