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