drivers/connector/cn_proc.c

   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
  40 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
  41 static 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 */
  44 static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
  45
  46 static 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
  54 void 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
  86 void 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
 111 void 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
 150 void 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
 175 void 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
 208 void proc_exit_connector(struct task_struct *task)
 209 {
 210         struct cn_msg *msg;
 211         struct proc_event *ev;
 212         __u8 buffer[CN_PROC_MSG_SIZE];
 213         struct timespec ts;
 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_EXIT;
 224         ev->event_data.exit.process_pid = task->pid;
 225         ev->event_data.exit.process_tgid = task->tgid;
 226         ev->event_data.exit.exit_code = task->exit_code;
 227         ev->event_data.exit.exit_signal = task->exit_signal;
 228
 229         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 230         msg->ack = 0; /* not used */
 231         msg->len = sizeof(*ev);
 232         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 233 }
 234
 235 /*
 236  * Send an acknowledgement message to userspace
 237  *
 238  * Use 0 for success, EFOO otherwise.
 239  * Note: this is the negative of conventional kernel error
 240  * values because it's not being returned via syscall return
 241  * mechanisms.
 242  */
 243 static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 244 {
 245         struct cn_msg *msg;
 246         struct proc_event *ev;
 247         __u8 buffer[CN_PROC_MSG_SIZE];
 248         struct timespec ts;
 249
 250         if (atomic_read(&proc_event_num_listeners) < 1)
 251                 return;
 252
 253         msg = (struct cn_msg*)buffer;
 254         ev = (struct proc_event*)msg->data;
 255         msg->seq = rcvd_seq;
 256         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 257         put_unaligned(timespec_to_ns(&ts), (__u64 *)&ev->timestamp_ns);
 258         ev->cpu = -1;
 259         ev->what = PROC_EVENT_NONE;
 260         ev->event_data.ack.err = err;
 261         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 262         msg->ack = rcvd_ack + 1;
 263         msg->len = sizeof(*ev);
 264         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 265 }
 266
 267 /**
 268  * cn_proc_mcast_ctl
 269  * @data: message sent from userspace via the connector
 270  */
 271 static void cn_proc_mcast_ctl(struct cn_msg *msg,
 272                               struct netlink_skb_parms *nsp)
 273 {
 274         enum proc_cn_mcast_op *mc_op = NULL;
 275         int err = 0;
 276
 277         if (msg->len != sizeof(*mc_op))
 278                 return;
 279
 280         mc_op = (enum proc_cn_mcast_op*)msg->data;
 281         switch (*mc_op) {
 282         case PROC_CN_MCAST_LISTEN:
 283                 atomic_inc(&proc_event_num_listeners);
 284                 break;
 285         case PROC_CN_MCAST_IGNORE:
 286                 atomic_dec(&proc_event_num_listeners);
 287                 break;
 288         default:
 289                 err = EINVAL;
 290                 break;
 291         }
 292         cn_proc_ack(err, msg->seq, msg->ack);
 293 }
 294
 295 /*
 296  * cn_proc_init - initialization entry point
 297  *
 298  * Adds the connector callback to the connector driver.
 299  */
 300 static int __init cn_proc_init(void)
 301 {
 302         int err;
 303
 304         if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
 305                                    &cn_proc_mcast_ctl))) {
 306                 printk(KERN_WARNING "cn_proc failed to register\n");
 307                 return err;
 308         }
 309         return 0;
 310 }
 311
 312 module_init(cn_proc_init);