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