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 <asm/atomic.h>
  30
  31 #include <linux/cn_proc.h>
  32
  33 #define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))
  34
  35 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
  36 static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
  37
  38 /* proc_event_counts is used as the sequence number of the netlink message */
  39 static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
  40
  41 static inline void get_seq(__u32 *ts, int *cpu)
  42 {
  43         *ts = get_cpu_var(proc_event_counts)++;
  44         *cpu = smp_processor_id();
  45         put_cpu_var(proc_event_counts);
  46 }
  47
  48 void proc_fork_connector(struct task_struct *task)
  49 {
  50         struct cn_msg *msg;
  51         struct proc_event *ev;
  52         __u8 buffer[CN_PROC_MSG_SIZE];
  53
  54         if (atomic_read(&proc_event_num_listeners) < 1)
  55                 return;
  56
  57         msg = (struct cn_msg*)buffer;
  58         ev = (struct proc_event*)msg->data;
  59         get_seq(&msg->seq, &ev->cpu);
  60         ktime_get_ts(&ev->timestamp); /* get high res monotonic timestamp */
  61         ev->what = PROC_EVENT_FORK;
  62         ev->event_data.fork.parent_pid = task->real_parent->pid;
  63         ev->event_data.fork.parent_tgid = task->real_parent->tgid;
  64         ev->event_data.fork.child_pid = task->pid;
  65         ev->event_data.fork.child_tgid = task->tgid;
  66
  67         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  68         msg->ack = 0; /* not used */
  69         msg->len = sizeof(*ev);
  70         /*  If cn_netlink_send() failed, the data is not sent */
  71         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  72 }
  73
  74 void proc_exec_connector(struct task_struct *task)
  75 {
  76         struct cn_msg *msg;
  77         struct proc_event *ev;
  78         __u8 buffer[CN_PROC_MSG_SIZE];
  79
  80         if (atomic_read(&proc_event_num_listeners) < 1)
  81                 return;
  82
  83         msg = (struct cn_msg*)buffer;
  84         ev = (struct proc_event*)msg->data;
  85         get_seq(&msg->seq, &ev->cpu);
  86         ktime_get_ts(&ev->timestamp);
  87         ev->what = PROC_EVENT_EXEC;
  88         ev->event_data.exec.process_pid = task->pid;
  89         ev->event_data.exec.process_tgid = task->tgid;
  90
  91         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  92         msg->ack = 0; /* not used */
  93         msg->len = sizeof(*ev);
  94         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  95 }
  96
  97 void proc_id_connector(struct task_struct *task, int which_id)
  98 {
  99         struct cn_msg *msg;
 100         struct proc_event *ev;
 101         __u8 buffer[CN_PROC_MSG_SIZE];
 102
 103         if (atomic_read(&proc_event_num_listeners) < 1)
 104                 return;
 105
 106         msg = (struct cn_msg*)buffer;
 107         ev = (struct proc_event*)msg->data;
 108         ev->what = which_id;
 109         ev->event_data.id.process_pid = task->pid;
 110         ev->event_data.id.process_tgid = task->tgid;
 111         if (which_id == PROC_EVENT_UID) {
 112                 ev->event_data.id.r.ruid = task->uid;
 113                 ev->event_data.id.e.euid = task->euid;
 114         } else if (which_id == PROC_EVENT_GID) {
 115                 ev->event_data.id.r.rgid = task->gid;
 116                 ev->event_data.id.e.egid = task->egid;
 117         } else
 118                 return;
 119         get_seq(&msg->seq, &ev->cpu);
 120         ktime_get_ts(&ev->timestamp);
 121
 122         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 123         msg->ack = 0; /* not used */
 124         msg->len = sizeof(*ev);
 125         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 126 }
 127
 128 void proc_exit_connector(struct task_struct *task)
 129 {
 130         struct cn_msg *msg;
 131         struct proc_event *ev;
 132         __u8 buffer[CN_PROC_MSG_SIZE];
 133
 134         if (atomic_read(&proc_event_num_listeners) < 1)
 135                 return;
 136
 137         msg = (struct cn_msg*)buffer;
 138         ev = (struct proc_event*)msg->data;
 139         get_seq(&msg->seq, &ev->cpu);
 140         ktime_get_ts(&ev->timestamp);
 141         ev->what = PROC_EVENT_EXIT;
 142         ev->event_data.exit.process_pid = task->pid;
 143         ev->event_data.exit.process_tgid = task->tgid;
 144         ev->event_data.exit.exit_code = task->exit_code;
 145         ev->event_data.exit.exit_signal = task->exit_signal;
 146
 147         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 148         msg->ack = 0; /* not used */
 149         msg->len = sizeof(*ev);
 150         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 151 }
 152
 153 /*
 154  * Send an acknowledgement message to userspace
 155  *
 156  * Use 0 for success, EFOO otherwise.
 157  * Note: this is the negative of conventional kernel error
 158  * values because it's not being returned via syscall return
 159  * mechanisms.
 160  */
 161 static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 162 {
 163         struct cn_msg *msg;
 164         struct proc_event *ev;
 165         __u8 buffer[CN_PROC_MSG_SIZE];
 166
 167         if (atomic_read(&proc_event_num_listeners) < 1)
 168                 return;
 169
 170         msg = (struct cn_msg*)buffer;
 171         ev = (struct proc_event*)msg->data;
 172         msg->seq = rcvd_seq;
 173         ktime_get_ts(&ev->timestamp);
 174         ev->cpu = -1;
 175         ev->what = PROC_EVENT_NONE;
 176         ev->event_data.ack.err = err;
 177         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 178         msg->ack = rcvd_ack + 1;
 179         msg->len = sizeof(*ev);
 180         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 181 }
 182
 183 /**
 184  * cn_proc_mcast_ctl
 185  * @data: message sent from userspace via the connector
 186  */
 187 static void cn_proc_mcast_ctl(void *data)
 188 {
 189         struct cn_msg *msg = data;
 190         enum proc_cn_mcast_op *mc_op = NULL;
 191         int err = 0;
 192
 193         if (msg->len != sizeof(*mc_op))
 194                 return;
 195
 196         mc_op = (enum proc_cn_mcast_op*)msg->data;
 197         switch (*mc_op) {
 198         case PROC_CN_MCAST_LISTEN:
 199                 atomic_inc(&proc_event_num_listeners);
 200                 break;
 201         case PROC_CN_MCAST_IGNORE:
 202                 atomic_dec(&proc_event_num_listeners);
 203                 break;
 204         default:
 205                 err = EINVAL;
 206                 break;
 207         }
 208         cn_proc_ack(err, msg->seq, msg->ack);
 209 }
 210
 211 /*
 212  * cn_proc_init - initialization entry point
 213  *
 214  * Adds the connector callback to the connector driver.
 215  */
 216 static int __init cn_proc_init(void)
 217 {
 218         int err;
 219
 220         if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
 221                                    &cn_proc_mcast_ctl))) {
 222                 printk(KERN_WARNING "cn_proc failed to register\n");
 223                 return err;
 224         }
 225         return 0;
 226 }
 227
 228 module_init(cn_proc_init);