[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>

9 files changed, 379 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);
diff --git a/fs/exec.c b/fs/exec.c
index 10d493fea7ce..ce76b33f25ac 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -48,6 +48,7 @@
 #include <linux/syscalls.h>
 #include <linux/rmap.h>
 #include <linux/acct.h>
+#include <linux/cn_proc.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -1096,6 +1097,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
                                         fput(bprm->file);
                                 bprm->file = NULL;
                                 current->did_exec = 1;
+                                proc_exec_connector(current);
                                 return retval;
                         }
                         read_lock(&binfmt_lock);
diff --git a/include/linux/cn_proc.h b/include/linux/cn_proc.h
new file mode 100644
index 000000000000..70ab56317380
--- /dev/null
+++ b/include/linux/cn_proc.h
@@ -0,0 +1,127 @@
+/*
+ * cn_proc.h - process events connector
+ *
+ * Copyright (C) Matt Helsley, IBM Corp. 2005
+ * Based on cn_fork.h by Nguyen Anh Quynh and Guillaume Thouvenin
+ * Original copyright notice follows:
+ * Copyright (C) 2005 Nguyen Anh Quynh <aquynh@gmail.com>
+ * Copyright (C) 2005 Guillaume Thouvenin <guillaume.thouvenin@bull.net>
+ *
+ * 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
+ */
+
+#ifndef CN_PROC_H
+#define CN_PROC_H
+
+#include <linux/types.h>
+#include <linux/connector.h>
+
+/*
+ * Userspace sends this enum to register with the kernel that it is listening
+ * for events on the connector.
+ */
+enum proc_cn_mcast_op {
+        PROC_CN_MCAST_LISTEN = 1,
+        PROC_CN_MCAST_IGNORE = 2
+};
+
+/*
+ * From the user's point of view, the process
+ * ID is the thread group ID and thread ID is the internal
+ * kernel "pid". So, fields are assigned as follow:
+ *
+ *  In user space     -  In  kernel space
+ *
+ * parent process ID  =  parent->tgid
+ * parent thread  ID  =  parent->pid
+ * child  process ID  =  child->tgid
+ * child  thread  ID  =  child->pid
+ */
+
+struct proc_event {
+        enum what {
+                /* Use successive bits so the enums can be used to record
+                 * sets of events as well
+                 */
+                PROC_EVENT_NONE = 0x00000000,
+                PROC_EVENT_FORK = 0x00000001,
+                PROC_EVENT_EXEC = 0x00000002,
+                PROC_EVENT_UID  = 0x00000004,
+                PROC_EVENT_GID  = 0x00000040,
+                /* "next" should be 0x00000400 */
+                /* "last" is the last process event: exit */
+                PROC_EVENT_EXIT = 0x80000000
+        } what;
+        __u32 cpu;
+        union { /* must be last field of proc_event struct */
+                struct {
+                        __u32 err;
+                } ack;
+
+                struct fork_proc_event {
+                        pid_t parent_pid;
+                        pid_t parent_tgid;
+                        pid_t child_pid;
+                        pid_t child_tgid;
+                } fork;
+
+                struct exec_proc_event {
+                        pid_t process_pid;
+                        pid_t process_tgid;
+                } exec;
+
+                struct id_proc_event {
+                        pid_t process_pid;
+                        pid_t process_tgid;
+                        union {
+                                uid_t ruid; /* current->uid */
+                                gid_t rgid; /* current->gid */
+                        } r;
+                        union {
+                                uid_t euid;
+                                gid_t egid;
+                        } e;
+                } id;
+
+                struct exit_proc_event {
+                        pid_t process_pid;
+                        pid_t process_tgid;
+                        __u32 exit_code, exit_signal;
+                } exit;
+        } event_data;
+};
+
+#ifdef __KERNEL__
+#ifdef CONFIG_PROC_EVENTS
+void proc_fork_connector(struct task_struct *task);
+void proc_exec_connector(struct task_struct *task);
+void proc_id_connector(struct task_struct *task, int which_id);
+void proc_exit_connector(struct task_struct *task);
+#else
+static inline void proc_fork_connector(struct task_struct *task)
+{}
+
+static inline void proc_exec_connector(struct task_struct *task)
+{}
+
+static inline void proc_id_connector(struct task_struct *task,
+                                     int which_id)
+{}
+
+static inline void proc_exit_connector(struct task_struct *task)
+{}
+#endif  /* CONFIG_PROC_EVENTS */
+#endif  /* __KERNEL__ */
+#endif  /* CN_PROC_H */
diff --git a/include/linux/connector.h b/include/linux/connector.h
index 95952cc1f525..c5769c6585f4 100644
--- a/include/linux/connector.h
+++ b/include/linux/connector.h
@@ -27,6 +27,12 @@
 #define CN_IDX_CONNECTOR                0xffffffff
 #define CN_VAL_CONNECTOR                0xffffffff
 
+/*
+ * Process Events connector unique ids -- used for message routing
+ */
+#define CN_IDX_PROC                     0x1
+#define CN_VAL_PROC                     0x1
+
 #define CN_NETLINK_USERS                1
 
 /*
diff --git a/kernel/exit.c b/kernel/exit.c
index 537394b25e8d..452a1d116178 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -28,6 +28,7 @@
 #include <linux/cpuset.h>
 #include <linux/syscalls.h>
 #include <linux/signal.h>
+#include <linux/cn_proc.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -863,6 +864,7 @@ fastcall NORET_TYPE void do_exit(long code)
                 module_put(tsk->binfmt->module);
 
         tsk->exit_code = code;
+        proc_exit_connector(tsk);
         exit_notify(tsk);
 #ifdef CONFIG_NUMA
         mpol_free(tsk->mempolicy);
diff --git a/kernel/fork.c b/kernel/fork.c
index 8a069612eac3..efac2c58ec7d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -42,6 +42,7 @@
 #include <linux/profile.h>
 #include <linux/rmap.h>
 #include <linux/acct.h>
+#include <linux/cn_proc.h>
 
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -1143,6 +1144,7 @@ static task_t *copy_process(unsigned long clone_flags,
                         __get_cpu_var(process_counts)++;
         }
 
+        proc_fork_connector(p);
         if (!current->signal->tty && p->signal->tty)
                 p->signal->tty = NULL;
 
diff --git a/kernel/sys.c b/kernel/sys.c
index 2fa1ed18123c..1e1f41b3fdf6 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -28,6 +28,7 @@
 #include <linux/suspend.h>
 #include <linux/tty.h>
 #include <linux/signal.h>
+#include <linux/cn_proc.h>
 
 #include <linux/compat.h>
 #include <linux/syscalls.h>
@@ -623,6 +624,7 @@ asmlinkage long sys_setregid(gid_t rgid, gid_t egid)
         current->egid = new_egid;
         current->gid = new_rgid;
         key_fsgid_changed(current);
+        proc_id_connector(current, PROC_EVENT_GID);
         return 0;
 }
 
@@ -662,6 +664,7 @@ asmlinkage long sys_setgid(gid_t gid)
                 return -EPERM;
 
         key_fsgid_changed(current);
+        proc_id_connector(current, PROC_EVENT_GID);
         return 0;
 }
   
@@ -751,6 +754,7 @@ asmlinkage long sys_setreuid(uid_t ruid, uid_t euid)
         current->fsuid = current->euid;
 
         key_fsuid_changed(current);
+        proc_id_connector(current, PROC_EVENT_UID);
 
         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
 }
@@ -798,6 +802,7 @@ asmlinkage long sys_setuid(uid_t uid)
         current->suid = new_suid;
 
         key_fsuid_changed(current);
+        proc_id_connector(current, PROC_EVENT_UID);
 
         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
 }
@@ -846,6 +851,7 @@ asmlinkage long sys_setresuid(uid_t ruid, uid_t euid, uid_t suid)
                 current->suid = suid;
 
         key_fsuid_changed(current);
+        proc_id_connector(current, PROC_EVENT_UID);
 
         return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
 }
@@ -898,6 +904,7 @@ asmlinkage long sys_setresgid(gid_t rgid, gid_t egid, gid_t sgid)
                 current->sgid = sgid;
 
         key_fsgid_changed(current);
+        proc_id_connector(current, PROC_EVENT_GID);
         return 0;
 }
 
@@ -940,6 +947,7 @@ asmlinkage long sys_setfsuid(uid_t uid)
         }
 
         key_fsuid_changed(current);
+        proc_id_connector(current, PROC_EVENT_UID);
 
         security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
 
@@ -968,6 +976,7 @@ asmlinkage long sys_setfsgid(gid_t gid)
                 }
                 current->fsgid = gid;
                 key_fsgid_changed(current);
+                proc_id_connector(current, PROC_EVENT_GID);
         }
         return old_fsgid;
 }