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
  55         if (atomic_read(&proc_event_num_listeners) < 1)
  56                 return;
  57
  58         msg = (struct cn_msg*)buffer;
  59         ev = (struct proc_event*)msg->data;
  60         get_seq(&msg->seq, &ev->cpu);
  61         ktime_get_ts(&ev->timestamp); /* get high res monotonic timestamp */
  62         ev->what = PROC_EVENT_FORK;
  63         ev->event_data.fork.parent_pid = task->real_parent->pid;
  64         ev->event_data.fork.parent_tgid = task->real_parent->tgid;
  65         ev->event_data.fork.child_pid = task->pid;
  66         ev->event_data.fork.child_tgid = task->tgid;
  67
  68         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  69         msg->ack = 0; /* not used */
  70         msg->len = sizeof(*ev);
  71         /*  If cn_netlink_send() failed, the data is not sent */
  72         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  73 }
  74
  75 void proc_exec_connector(struct task_struct *task)
  76 {
  77         struct cn_msg *msg;
  78         struct proc_event *ev;
  79         __u8 buffer[CN_PROC_MSG_SIZE];
  80
  81         if (atomic_read(&proc_event_num_listeners) < 1)
  82                 return;
  83
  84         msg = (struct cn_msg*)buffer;
  85         ev = (struct proc_event*)msg->data;
  86         get_seq(&msg->seq, &ev->cpu);
  87         ktime_get_ts(&ev->timestamp);
  88         ev->what = PROC_EVENT_EXEC;
  89         ev->event_data.exec.process_pid = task->pid;
  90         ev->event_data.exec.process_tgid = task->tgid;
  91
  92         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  93         msg->ack = 0; /* not used */
  94         msg->len = sizeof(*ev);
  95         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  96 }
  97
  98 void proc_id_connector(struct task_struct *task, int which_id)
  99 {
 100         struct cn_msg *msg;
 101         struct proc_event *ev;
 102         __u8 buffer[CN_PROC_MSG_SIZE];
 103
 104         if (atomic_read(&proc_event_num_listeners) < 1)
 105                 return;
 106
 107         msg = (struct cn_msg*)buffer;
 108         ev = (struct proc_event*)msg->data;
 109         ev->what = which_id;
 110         ev->event_data.id.process_pid = task->pid;
 111         ev->event_data.id.process_tgid = task->tgid;
 112         if (which_id == PROC_EVENT_UID) {
 113                 ev->event_data.id.r.ruid = task->uid;
 114                 ev->event_data.id.e.euid = task->euid;
 115         } else if (which_id == PROC_EVENT_GID) {
 116                 ev->event_data.id.r.rgid = task->gid;
 117                 ev->event_data.id.e.egid = task->egid;
 118         } else
 119                 return;
 120         get_seq(&msg->seq, &ev->cpu);
 121         ktime_get_ts(&ev->timestamp);
 122
 123         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 124         msg->ack = 0; /* not used */
 125         msg->len = sizeof(*ev);
 126         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 127 }
 128
 129 void proc_exit_connector(struct task_struct *task)
 130 {
 131         struct cn_msg *msg;
 132         struct proc_event *ev;
 133         __u8 buffer[CN_PROC_MSG_SIZE];
 134
 135         if (atomic_read(&proc_event_num_listeners) < 1)
 136                 return;
 137
 138         msg = (struct cn_msg*)buffer;
 139         ev = (struct proc_event*)msg->data;
 140         get_seq(&msg->seq, &ev->cpu);
 141         ktime_get_ts(&ev->timestamp);
 142         ev->what = PROC_EVENT_EXIT;
 143         ev->event_data.exit.process_pid = task->pid;
 144         ev->event_data.exit.process_tgid = task->tgid;
 145         ev->event_data.exit.exit_code = task->exit_code;
 146         ev->event_data.exit.exit_signal = task->exit_signal;
 147
 148         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 149         msg->ack = 0; /* not used */
 150         msg->len = sizeof(*ev);
 151         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 152 }
 153
 154 /*
 155  * Send an acknowledgement message to userspace
 156  *
 157  * Use 0 for success, EFOO otherwise.
 158  * Note: this is the negative of conventional kernel error
 159  * values because it's not being returned via syscall return
 160  * mechanisms.
 161  */
 162 static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 163 {
 164         struct cn_msg *msg;
 165         struct proc_event *ev;
 166         __u8 buffer[CN_PROC_MSG_SIZE];
 167
 168         if (atomic_read(&proc_event_num_listeners) < 1)
 169                 return;
 170
 171         msg = (struct cn_msg*)buffer;
 172         ev = (struct proc_event*)msg->data;
 173         msg->seq = rcvd_seq;
 174         ktime_get_ts(&ev->timestamp);
 175         ev->cpu = -1;
 176         ev->what = PROC_EVENT_NONE;
 177         ev->event_data.ack.err = err;
 178         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 179         msg->ack = rcvd_ack + 1;
 180         msg->len = sizeof(*ev);
 181         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 182 }
 183
 184 /**
 185  * cn_proc_mcast_ctl
 186  * @data: message sent from userspace via the connector
 187  */
 188 static void cn_proc_mcast_ctl(void *data)
 189 {
 190         struct cn_msg *msg = data;
 191         enum proc_cn_mcast_op *mc_op = NULL;
 192         int err = 0;
 193
 194         if (msg->len != sizeof(*mc_op))
 195                 return;
 196
 197         mc_op = (enum proc_cn_mcast_op*)msg->data;
 198         switch (*mc_op) {
 199         case PROC_CN_MCAST_LISTEN:
 200                 atomic_inc(&proc_event_num_listeners);
 201                 break;
 202         case PROC_CN_MCAST_IGNORE:
 203                 atomic_dec(&proc_event_num_listeners);
 204                 break;
 205         default:
 206                 err = EINVAL;
 207                 break;
 208         }
 209         cn_proc_ack(err, msg->seq, msg->ack);
 210 }
 211
 212 /*
 213  * cn_proc_init - initialization entry point
 214  *
 215  * Adds the connector callback to the connector driver.
 216  */
 217 static int __init cn_proc_init(void)
 218 {
 219         int err;
 220
 221         if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
 222                                    &cn_proc_mcast_ctl))) {
 223                 printk(KERN_WARNING "cn_proc failed to register\n");
 224                 return err;
 225         }
 226         return 0;
 227 }
 228
 229 module_init(cn_proc_init);