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