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 <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
  37 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
  38 static 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 */
  41 static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
  42
  43 static 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
  50 void 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
  78 void 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
 103 void 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
 142 void 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  */
 177 static 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  */
 205 static void cn_proc_mcast_ctl(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 206 {
 207         enum proc_cn_mcast_op *mc_op = NULL;
 208         int err = 0;
 209
 210         if (msg->len != sizeof(*mc_op))
 211                 return;
 212
 213         mc_op = (enum proc_cn_mcast_op*)msg->data;
 214         switch (*mc_op) {
 215         case PROC_CN_MCAST_LISTEN:
 216                 atomic_inc(&proc_event_num_listeners);
 217                 break;
 218         case PROC_CN_MCAST_IGNORE:
 219                 atomic_dec(&proc_event_num_listeners);
 220                 break;
 221         default:
 222                 err = EINVAL;
 223                 break;
 224         }
 225         cn_proc_ack(err, msg->seq, msg->ack);
 226 }
 227
 228 /*
 229  * cn_proc_init - initialization entry point
 230  *
 231  * Adds the connector callback to the connector driver.
 232  */
 233 static int __init cn_proc_init(void)
 234 {
 235         int err;
 236
 237         if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
 238                                    &cn_proc_mcast_ctl))) {
 239                 printk(KERN_WARNING "cn_proc failed to register\n");
 240                 return err;
 241         }
 242         return 0;
 243 }
 244
 245 module_init(cn_proc_init);