[PATCH] Process Events Connector

This patch adds a connector that reports fork, exec, id change, and exit
events for all processes to userspace.  It replaces the fork_advisor patch
that ELSA is currently using.  Applications that may find these events
useful include accounting/auditing (e.g.  ELSA), system activity monitoring
(e.g.  top), security, and resource management (e.g.  CKRM).

Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 231 insertions, 0 deletions

diff --git a/drivers/connector/Kconfig b/drivers/connector/Kconfig
index 0bc2059c1e08..e0bdc0db9640 100644
--- a/drivers/connector/Kconfig
+++ b/drivers/connector/Kconfig
@@ -10,4 +10,12 @@ config CONNECTOR
           Connector support can also be built as a module.  If so, the module
           will be called cn.ko.
 
+config PROC_EVENTS
+        boolean "Report process events to userspace"
+        depends on CONNECTOR=y
+        default y
+        ---help---
+          Provide a connector that reports process events to userspace. Send
+          events such as fork, exec, id change (uid, gid, suid, etc), and exit.
+
 endmenu
diff --git a/drivers/connector/Makefile b/drivers/connector/Makefile
index 12ca79e8234d..1f255e46e916 100644
--- a/drivers/connector/Makefile
+++ b/drivers/connector/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_CONNECTOR)         += cn.o
+obj-$(CONFIG_PROC_EVENTS)       += cn_proc.o
 
 cn-y                            += cn_queue.o connector.o
diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c
new file mode 100644
index 000000000000..fcdf0fff13a6
--- /dev/null
+++ b/drivers/connector/cn_proc.c
@@ -0,0 +1,222 @@
+/*
+ * cn_proc.c - process events connector
+ *
+ * Copyright (C) Matt Helsley, IBM Corp. 2005
+ * Based on cn_fork.c by Guillaume Thouvenin <guillaume.thouvenin@bull.net>
+ * Original copyright notice follows:
+ * Copyright (C) 2005 BULL SA.
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <asm/atomic.h>
+
+#include <linux/cn_proc.h>
+
+#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))
+
+static atomic_t proc_event_num_listeners = ATOMIC_INIT(0);
+static struct cb_id cn_proc_event_id = { CN_IDX_PROC, CN_VAL_PROC };
+
+/* proc_counts is used as the sequence number of the netlink message */
+static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
+
+static inline void get_seq(__u32 *ts, int *cpu)
+{
+        *ts = get_cpu_var(proc_event_counts)++;
+        *cpu = smp_processor_id();
+        put_cpu_var(proc_counts);
+}
+
+void proc_fork_connector(struct task_struct *task)
+{
+        struct cn_msg *msg;
+        struct proc_event *ev;
+        __u8 buffer[CN_PROC_MSG_SIZE];
+
+        if (atomic_read(&proc_event_num_listeners) < 1)
+                return;
+
+        msg = (struct cn_msg*)buffer;
+        ev = (struct proc_event*)msg->data;
+        get_seq(&msg->seq, &ev->cpu);
+        ev->what = PROC_EVENT_FORK;
+        ev->event_data.fork.parent_pid = task->real_parent->pid;
+        ev->event_data.fork.parent_tgid = task->real_parent->tgid;
+        ev->event_data.fork.child_pid = task->pid;
+        ev->event_data.fork.child_tgid = task->tgid;
+
+        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+        msg->ack = 0; /* not used */
+        msg->len = sizeof(*ev);
+        /*  If cn_netlink_send() failed, the data is not sent */
+        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
+}
+
+void proc_exec_connector(struct task_struct *task)
+{
+        struct cn_msg *msg;
+        struct proc_event *ev;
+        __u8 buffer[CN_PROC_MSG_SIZE];
+
+        if (atomic_read(&proc_event_num_listeners) < 1)
+                return;
+
+        msg = (struct cn_msg*)buffer;
+        ev = (struct proc_event*)msg->data;
+        get_seq(&msg->seq, &ev->cpu);
+        ev->what = PROC_EVENT_EXEC;
+        ev->event_data.exec.process_pid = task->pid;
+        ev->event_data.exec.process_tgid = task->tgid;
+
+        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+        msg->ack = 0; /* not used */
+        msg->len = sizeof(*ev);
+        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
+}
+
+void proc_id_connector(struct task_struct *task, int which_id)
+{
+        struct cn_msg *msg;
+        struct proc_event *ev;
+        __u8 buffer[CN_PROC_MSG_SIZE];
+
+        if (atomic_read(&proc_event_num_listeners) < 1)
+                return;
+
+        msg = (struct cn_msg*)buffer;
+        ev = (struct proc_event*)msg->data;
+        ev->what = which_id;
+        ev->event_data.id.process_pid = task->pid;
+        ev->event_data.id.process_tgid = task->tgid;
+        if (which_id == PROC_EVENT_UID) {
+                ev->event_data.id.r.ruid = task->uid;
+                ev->event_data.id.e.euid = task->euid;
+        } else if (which_id == PROC_EVENT_GID) {
+                ev->event_data.id.r.rgid = task->gid;
+                ev->event_data.id.e.egid = task->egid;
+        } else
+                return;
+        get_seq(&msg->seq, &ev->cpu);
+
+        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+        msg->ack = 0; /* not used */
+        msg->len = sizeof(*ev);
+        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
+}
+
+void proc_exit_connector(struct task_struct *task)
+{
+        struct cn_msg *msg;
+        struct proc_event *ev;
+        __u8 buffer[CN_PROC_MSG_SIZE];
+
+        if (atomic_read(&proc_event_num_listeners) < 1)
+                return;
+
+        msg = (struct cn_msg*)buffer;
+        ev = (struct proc_event*)msg->data;
+        get_seq(&msg->seq, &ev->cpu);
+        ev->what = PROC_EVENT_EXIT;
+        ev->event_data.exit.process_pid = task->pid;
+        ev->event_data.exit.process_tgid = task->tgid;
+        ev->event_data.exit.exit_code = task->exit_code;
+        ev->event_data.exit.exit_signal = task->exit_signal;
+
+        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+        msg->ack = 0; /* not used */
+        msg->len = sizeof(*ev);
+        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
+}
+
+/*
+ * Send an acknowledgement message to userspace
+ *
+ * Use 0 for success, EFOO otherwise.
+ * Note: this is the negative of conventional kernel error
+ * values because it's not being returned via syscall return
+ * mechanisms.
+ */
+static void cn_proc_ack(int err, int rcvd_seq, int rcvd_ack)
+{
+        struct cn_msg *msg;
+        struct proc_event *ev;
+        __u8 buffer[CN_PROC_MSG_SIZE];
+
+        if (atomic_read(&proc_event_num_listeners) < 1)
+                return;
+
+        msg = (struct cn_msg*)buffer;
+        ev = (struct proc_event*)msg->data;
+        msg->seq = rcvd_seq;
+        ev->cpu = -1;
+        ev->what = PROC_EVENT_NONE;
+        ev->event_data.ack.err = err;
+        memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
+        msg->ack = rcvd_ack + 1;
+        msg->len = sizeof(*ev);
+        cn_netlink_send(msg, CN_IDX_PROC, GFP_KERNEL);
+}
+
+/**
+ * cn_proc_mcast_ctl
+ * @data: message sent from userspace via the connector
+ */
+static void cn_proc_mcast_ctl(void *data)
+{
+        struct cn_msg *msg = data;
+        enum proc_cn_mcast_op *mc_op = NULL;
+        int err = 0;
+
+        if (msg->len != sizeof(*mc_op))
+                return;
+
+        mc_op = (enum proc_cn_mcast_op*)msg->data;
+        switch (*mc_op) {
+        case PROC_CN_MCAST_LISTEN:
+                atomic_inc(&proc_event_num_listeners);
+                break;
+        case PROC_CN_MCAST_IGNORE:
+                atomic_dec(&proc_event_num_listeners);
+                break;
+        default:
+                err = EINVAL;
+                break;
+        }
+        cn_proc_ack(err, msg->seq, msg->ack);
+}
+
+/*
+ * cn_proc_init - initialization entry point
+ *
+ * Adds the connector callback to the connector driver.
+ */
+static int __init cn_proc_init(void)
+{
+        int err;
+
+        if ((err = cn_add_callback(&cn_proc_event_id, "cn_proc",
+                                   &cn_proc_mcast_ctl))) {
+                printk(KERN_WARNING "cn_proc failed to register\n");
+                return err;
+        }
+        return 0;
+}
+
+module_init(cn_proc_init);