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
  32 #include <linux/cn_proc.h>
  33
  34 #define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))
  35
  36 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
  37 static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
  38
  39 /* proc_event_counts is used as the sequence number of the netlink message */
  40 static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
  41
  42 static inline void get_seq(__u32 *ts, int *cpu)
  43 {
  44         *ts = get_cpu_var(proc_event_counts)++;
  45         *cpu = smp_processor_id();
  46         put_cpu_var(proc_event_counts);
  47 }
  48
  49 void proc_fork_connector(struct task_struct *task)
  50 {
  51         struct cn_msg *msg;
  52         struct proc_event *ev;
  53         __u8 buffer[CN_PROC_MSG_SIZE];
  54         struct timespec ts;
  55
  56         if (atomic_read(&proc_event_num_listeners) < 1)
  57                 return;
  58
  59         msg = (struct cn_msg*)buffer;
  60         ev = (struct proc_event*)msg->data;
  61         get_seq(&msg->seq, &ev->cpu);
  62         ktime_get_ts(&ts); /* get high res monotonic timestamp */
  63         ev->timestamp_ns = timespec_to_ns(&ts);
  64         ev->what = PROC_EVENT_FORK;
  65         ev->event_data.fork.parent_pid = task->real_parent->pid;
  66         ev->event_data.fork.parent_tgid = task->real_parent->tgid;
  67         ev->event_data.fork.child_pid = task->pid;
  68         ev->event_data.fork.child_tgid = task->tgid;
  69
  70         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  71         msg->ack = 0; /* not used */
  72         msg->len = sizeof(*ev);
  73         /*  If cn_netlink_send() failed, the data is not sent */
  74         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  75 }
  76
  77 void proc_exec_connector(struct task_struct *task)
  78 {
  79         struct cn_msg *msg;
  80         struct proc_event *ev;
  81         struct timespec ts;
  82         __u8 buffer[CN_PROC_MSG_SIZE];
  83
  84         if (atomic_read(&proc_event_num_listeners) < 1)
  85                 return;
  86
  87         msg = (struct cn_msg*)buffer;
  88         ev = (struct proc_event*)msg->data;
  89         get_seq(&msg->seq, &ev->cpu);
  90         ktime_get_ts(&ts); /* get high res monotonic timestamp */
  91         ev->timestamp_ns = timespec_to_ns(&ts);
  92         ev->what = PROC_EVENT_EXEC;
  93         ev->event_data.exec.process_pid = task->pid;
  94         ev->event_data.exec.process_tgid = task->tgid;
  95
  96         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  97         msg->ack = 0; /* not used */
  98         msg->len = sizeof(*ev);
  99         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 100 }
 101
 102 void proc_id_connector(struct task_struct *task, int which_id)
 103 {
 104         struct cn_msg *msg;
 105         struct proc_event *ev;
 106         __u8 buffer[CN_PROC_MSG_SIZE];
 107         struct timespec ts;
 108
 109         if (atomic_read(&proc_event_num_listeners) < 1)
 110                 return;
 111
 112         msg = (struct cn_msg*)buffer;
 113         ev = (struct proc_event*)msg->data;
 114         ev->what = which_id;
 115         ev->event_data.id.process_pid = task->pid;
 116         ev->event_data.id.process_tgid = task->tgid;
 117         if (which_id == PROC_EVENT_UID) {
 118                 ev->event_data.id.r.ruid = task->uid;
 119                 ev->event_data.id.e.euid = task->euid;
 120         } else if (which_id == PROC_EVENT_GID) {
 121                 ev->event_data.id.r.rgid = task->gid;
 122                 ev->event_data.id.e.egid = task->egid;
 123         } else
 124                 return;
 125         get_seq(&msg->seq, &ev->cpu);
 126         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 127         ev->timestamp_ns = timespec_to_ns(&ts);
 128
 129         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 130         msg->ack = 0; /* not used */
 131         msg->len = sizeof(*ev);
 132         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 133 }
 134
 135 void proc_exit_connector(struct task_struct *task)
 136 {
 137         struct cn_msg *msg;
 138         struct proc_event *ev;
 139         __u8 buffer[CN_PROC_MSG_SIZE];
 140         struct timespec ts;
 141
 142         if (atomic_read(&proc_event_num_listeners) < 1)
 143                 return;
 144
 145         msg = (struct cn_msg*)buffer;
 146         ev = (struct proc_event*)msg->data;
 147         get_seq(&msg->seq, &ev->cpu);
 148         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 149         ev->timestamp_ns = timespec_to_ns(&ts);
 150         ev->what = PROC_EVENT_EXIT;
 151         ev->event_data.exit.process_pid = task->pid;
 152         ev->event_data.exit.process_tgid = task->tgid;
 153         ev->event_data.exit.exit_code = task->exit_code;
 154         ev->event_data.exit.exit_signal = task->exit_signal;
 155
 156         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 157         msg->ack = 0; /* not used */
 158         msg->len = sizeof(*ev);
 159         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 160 }
 161
 162 /*
 163  * Send an acknowledgement message to userspace
 164  *
 165  * Use 0 for success, EFOO otherwise.
 166  * Note: this is the negative of conventional kernel error
 167  * values because it's not being returned via syscall return
 168  * mechanisms.
 169  */
 170 static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 171 {
 172         struct cn_msg *msg;
 173         struct proc_event *ev;
 174         __u8 buffer[CN_PROC_MSG_SIZE];
 175         struct timespec ts;
 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         msg->seq = rcvd_seq;
 183         ktime_get_ts(&ts); /* get high res monotonic timestamp */
 184         ev->timestamp_ns = timespec_to_ns(&ts);
 185         ev->cpu = -1;
 186         ev->what = PROC_EVENT_NONE;
 187         ev->event_data.ack.err = err;
 188         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 189         msg->ack = rcvd_ack + 1;
 190         msg->len = sizeof(*ev);
 191         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 192 }
 193
 194 /**
 195  * cn_proc_mcast_ctl
 196  * @data: message sent from userspace via the connector
 197  */
 198 static void cn_proc_mcast_ctl(void *data)
 199 {
 200         struct cn_msg *msg = data;
 201         enum proc_cn_mcast_op *mc_op = NULL;
 202         int err = 0;
 203
 204         if (msg->len != sizeof(*mc_op))
 205                 return;
 206
 207         mc_op = (enum proc_cn_mcast_op*)msg->data;
 208         switch (*mc_op) {
 209         case PROC_CN_MCAST_LISTEN:
 210                 atomic_inc(&proc_event_num_listeners);
 211                 break;
 212         case PROC_CN_MCAST_IGNORE:
 213                 atomic_dec(&proc_event_num_listeners);
 214                 break;
 215         default:
 216                 err = EINVAL;
 217                 break;
 218         }
 219         cn_proc_ack(err, msg->seq, msg->ack);
 220 }
 221
 222 /*
 223  * cn_proc_init - initialization entry point
 224  *
 225  * Adds the connector callback to the connector driver.
 226  */
 227 static int __init cn_proc_init(void)
 228 {
 229         int err;
 230
 231         if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
 232                                    &cn_proc_mcast_ctl))) {
 233                 printk(KERN_WARNING "cn_proc failed to register\n");
 234                 return err;
 235         }
 236         return 0;
 237 }
 238
 239 module_init(cn_proc_init);