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