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/init.h>
  28 #include <asm/atomic.h>
  29
  30 #include <linux/cn_proc.h>
  31
  32 #define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))
  33
  34 static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
  35 static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
  36
  37 /* proc_event_counts is used as the sequence number of the netlink message */
  38 static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
  39
  40 static inline void get_seq(__u32 *ts, int *cpu)
  41 {
  42         *ts = get_cpu_var(proc_event_counts)++;
  43         *cpu = smp_processor_id();
  44         put_cpu_var(proc_event_counts);
  45 }
  46
  47 void proc_fork_connector(struct task_struct *task)
  48 {
  49         struct cn_msg *msg;
  50         struct proc_event *ev;
  51         __u8 buffer[CN_PROC_MSG_SIZE];
  52
  53         if (atomic_read(&proc_event_num_listeners) < 1)
  54                 return;
  55
  56         msg = (struct cn_msg*)buffer;
  57         ev = (struct proc_event*)msg->data;
  58         get_seq(&msg->seq, &ev->cpu);
  59         getnstimestamp(&ev->timestamp);
  60         ev->what = PROC_EVENT_FORK;
  61         ev->event_data.fork.parent_pid = task->real_parent->pid;
  62         ev->event_data.fork.parent_tgid = task->real_parent->tgid;
  63         ev->event_data.fork.child_pid = task->pid;
  64         ev->event_data.fork.child_tgid = task->tgid;
  65
  66         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  67         msg->ack = 0; /* not used */
  68         msg->len = sizeof(*ev);
  69         /*  If cn_netlink_send() failed, the data is not sent */
  70         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  71 }
  72
  73 void proc_exec_connector(struct task_struct *task)
  74 {
  75         struct cn_msg *msg;
  76         struct proc_event *ev;
  77         __u8 buffer[CN_PROC_MSG_SIZE];
  78
  79         if (atomic_read(&proc_event_num_listeners) < 1)
  80                 return;
  81
  82         msg = (struct cn_msg*)buffer;
  83         ev = (struct proc_event*)msg->data;
  84         get_seq(&msg->seq, &ev->cpu);
  85         getnstimestamp(&ev->timestamp);
  86         ev->what = PROC_EVENT_EXEC;
  87         ev->event_data.exec.process_pid = task->pid;
  88         ev->event_data.exec.process_tgid = task->tgid;
  89
  90         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
  91         msg->ack = 0; /* not used */
  92         msg->len = sizeof(*ev);
  93         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
  94 }
  95
  96 void proc_id_connector(struct task_struct *task, int which_id)
  97 {
  98         struct cn_msg *msg;
  99         struct proc_event *ev;
 100         __u8 buffer[CN_PROC_MSG_SIZE];
 101
 102         if (atomic_read(&proc_event_num_listeners) < 1)
 103                 return;
 104
 105         msg = (struct cn_msg*)buffer;
 106         ev = (struct proc_event*)msg->data;
 107         ev->what = which_id;
 108         ev->event_data.id.process_pid = task->pid;
 109         ev->event_data.id.process_tgid = task->tgid;
 110         if (which_id == PROC_EVENT_UID) {
 111                 ev->event_data.id.r.ruid = task->uid;
 112                 ev->event_data.id.e.euid = task->euid;
 113         } else if (which_id == PROC_EVENT_GID) {
 114                 ev->event_data.id.r.rgid = task->gid;
 115                 ev->event_data.id.e.egid = task->egid;
 116         } else
 117                 return;
 118         get_seq(&msg->seq, &ev->cpu);
 119         getnstimestamp(&ev->timestamp);
 120
 121         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 122         msg->ack = 0; /* not used */
 123         msg->len = sizeof(*ev);
 124         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 125 }
 126
 127 void proc_exit_connector(struct task_struct *task)
 128 {
 129         struct cn_msg *msg;
 130         struct proc_event *ev;
 131         __u8 buffer[CN_PROC_MSG_SIZE];
 132
 133         if (atomic_read(&proc_event_num_listeners) < 1)
 134                 return;
 135
 136         msg = (struct cn_msg*)buffer;
 137         ev = (struct proc_event*)msg->data;
 138         get_seq(&msg->seq, &ev->cpu);
 139         getnstimestamp(&ev->timestamp);
 140         ev->what = PROC_EVENT_EXIT;
 141         ev->event_data.exit.process_pid = task->pid;
 142         ev->event_data.exit.process_tgid = task->tgid;
 143         ev->event_data.exit.exit_code = task->exit_code;
 144         ev->event_data.exit.exit_signal = task->exit_signal;
 145
 146         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 147         msg->ack = 0; /* not used */
 148         msg->len = sizeof(*ev);
 149         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 150 }
 151
 152 /*
 153  * Send an acknowledgement message to userspace
 154  *
 155  * Use 0 for success, EFOO otherwise.
 156  * Note: this is the negative of conventional kernel error
 157  * values because it's not being returned via syscall return
 158  * mechanisms.
 159  */
 160 static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
 161 {
 162         struct cn_msg *msg;
 163         struct proc_event *ev;
 164         __u8 buffer[CN_PROC_MSG_SIZE];
 165
 166         if (atomic_read(&proc_event_num_listeners) < 1)
 167                 return;
 168
 169         msg = (struct cn_msg*)buffer;
 170         ev = (struct proc_event*)msg->data;
 171         msg->seq = rcvd_seq;
 172         getnstimestamp(&ev->timestamp);
 173         ev->cpu = -1;
 174         ev->what = PROC_EVENT_NONE;
 175         ev->event_data.ack.err = err;
 176         memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
 177         msg->ack = rcvd_ack + 1;
 178         msg->len = sizeof(*ev);
 179         cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
 180 }
 181
 182 /**
 183  * cn_proc_mcast_ctl
 184  * @data: message sent from userspace via the connector
 185  */
 186 static void cn_proc_mcast_ctl(void *data)
 187 {
 188         struct cn_msg *msg = data;
 189         enum proc_cn_mcast_op *mc_op = NULL;
 190         int err = 0;
 191
 192         if (msg->len != sizeof(*mc_op))
 193                 return;
 194
 195         mc_op = (enum proc_cn_mcast_op*)msg->data;
 196         switch (*mc_op) {
 197         case PROC_CN_MCAST_LISTEN:
 198                 atomic_inc(&proc_event_num_listeners);
 199                 break;
 200         case PROC_CN_MCAST_IGNORE:
 201                 atomic_dec(&proc_event_num_listeners);
 202                 break;
 203         default:
 204                 err = EINVAL;
 205                 break;
 206         }
 207         cn_proc_ack(err, msg->seq, msg->ack);
 208 }
 209
 210 /*
 211  * cn_proc_init - initialization entry point
 212  *
 213  * Adds the connector callback to the connector driver.
 214  */
 215 static int __init cn_proc_init(void)
 216 {
 217         int err;
 218
 219         if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
 220                                    &cn_proc_mcast_ctl))) {
 221                 printk(KERN_WARNING "cn_proc failed to register\n");
 222                 return err;
 223         }
 224         return 0;
 225 }
 226
 227 module_init(cn_proc_init);