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