[PATCH 02/11] Task watchers: Register process events task watcher

From: Matt Helsley
Date: Tue Jun 13 2006 - 20:00:29 EST

This patch makes process events utilize task watchers instead of calling from
fork, exec, exit, and [re][ug]id changes directly.

Signed-off-by: Matt Helsley <matthltc@xxxxxxxxxx>
Cc: Guillaume Thouvenin <guillaume.thouvenin@xxxxxxxx>
--

drivers/connector/cn_proc.c | 65 +++++++++++++++++++++++++++++++++++++-------
fs/exec.c | 2 -
include/linux/cn_proc.h | 22 --------------
kernel/exit.c | 2 -
kernel/fork.c | 7 +---
kernel/sys.c | 8 -----
6 files changed, 57 insertions(+), 49 deletions(-)

Index: linux-2.6.17-rc6-mm2/drivers/connector/cn_proc.c
===================================================================
--- linux-2.6.17-rc6-mm2.orig/drivers/connector/cn_proc.c
+++ linux-2.6.17-rc6-mm2/drivers/connector/cn_proc.c
@@ -25,10 +25,11 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/init.h>
#include <linux/connector.h>
+#include <linux/notifier.h>
#include <asm/atomic.h>

#include <linux/cn_proc.h>

#define CN_PROC_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct proc_event))
@@ -44,11 +45,11 @@ static inline void get_seq(__u32 *ts, in
*ts = get_cpu_var(proc_event_counts)++;
*cpu = smp_processor_id();
put_cpu_var(proc_event_counts);
}

-void proc_fork_connector(struct task_struct *task)
+static void proc_fork_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE];

@@ -67,14 +68,14 @@ void proc_fork_connector(struct task_str

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);
+ cn_netlink_send(msg, CN_IDX_PROC, GFP_ATOMIC);
}

-void proc_exec_connector(struct task_struct *task)
+static void proc_exec_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE];

@@ -90,14 +91,14 @@ void proc_exec_connector(struct task_str
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);
+ cn_netlink_send(msg, CN_IDX_PROC, GFP_ATOMIC);
}

-void proc_id_connector(struct task_struct *task, int which_id)
+static 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];

@@ -121,14 +122,14 @@ void proc_id_connector(struct task_struc
ktime_get_ts(&ev->timestamp);

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);
+ cn_netlink_send(msg, CN_IDX_PROC, GFP_ATOMIC);
}

-void proc_exit_connector(struct task_struct *task)
+static void proc_exit_connector(struct task_struct *task)
{
struct cn_msg *msg;
struct proc_event *ev;
__u8 buffer[CN_PROC_MSG_SIZE];

@@ -146,11 +147,11 @@ void proc_exit_connector(struct task_str
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);
+ cn_netlink_send(msg, CN_IDX_PROC, GFP_ATOMIC);
}

/*
* Send an acknowledgement message to userspace
*
@@ -207,10 +208,49 @@ static void cn_proc_mcast_ctl(void *data
break;
}
cn_proc_ack(err, msg->seq, msg->ack);
}

+
+/*
+ * Dispatch task watcher events to the appropriate process event
+ * generation function.
+ */
+static int cn_proc_watch_task(struct notifier_block *nb, unsigned long val,
+ void *t)
+{
+ struct task_struct *task = t;
+ int rc = NOTIFY_OK;
+
+ switch (get_watch_event(val)) {
+ case WATCH_TASK_CLONE:
+ proc_fork_connector(task);
+ break;
+ case WATCH_TASK_EXEC:
+ proc_exec_connector(task);
+ break;
+ case WATCH_TASK_UID:
+ proc_id_connector(task, PROC_EVENT_UID);
+ break;
+ case WATCH_TASK_GID:
+ proc_id_connector(task, PROC_EVENT_GID);
+ break;
+ case WATCH_TASK_EXIT:
+ proc_exit_connector(task);
+ break;
+ default: /* we don't care about WATCH_TASK_INIT|FREE because we
+ don't keep per-task info */
+ rc = NOTIFY_DONE; /* ignore all other notifications */
+ break;
+ }
+ return rc;
+}
+
+static struct notifier_block __read_mostly cn_proc_nb = {
+ .notifier_call = cn_proc_watch_task,
+};
+
/*
* cn_proc_init - initialization entry point
*
* Adds the connector callback to the connector driver.
*/
@@ -219,11 +259,16 @@ 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;
+ goto out;
}
- return 0;
+
+ err = register_task_watcher(&cn_proc_nb);
+ if (err != 0)
+ cn_del_callback(&cn_proc_event_id);
+out:
+ return err;
}

module_init(cn_proc_init);
Index: linux-2.6.17-rc6-mm2/include/linux/cn_proc.h
===================================================================
--- linux-2.6.17-rc6-mm2.orig/include/linux/cn_proc.h
+++ linux-2.6.17-rc6-mm2/include/linux/cn_proc.h
@@ -93,28 +93,6 @@ struct proc_event {
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 */
Index: linux-2.6.17-rc6-mm2/kernel/exit.c
===================================================================
--- linux-2.6.17-rc6-mm2.orig/kernel/exit.c
+++ linux-2.6.17-rc6-mm2/kernel/exit.c
@@ -31,11 +31,10 @@
#include <linux/delayacct.h>
#include <linux/cpuset.h>
#include <linux/syscalls.h>
#include <linux/signal.h>
#include <linux/posix-timers.h>
-#include <linux/cn_proc.h>
#include <linux/mutex.h>
#include <linux/futex.h>
#include <linux/compat.h>
#include <linux/pipe_fs_i.h>
#include <linux/audit.h> /* for audit_free() */
@@ -941,11 +940,10 @@ fastcall NORET_TYPE void do_exit(long co

module_put(task_thread_info(tsk)->exec_domain->module);
if (tsk->binfmt)
module_put(tsk->binfmt->module);

- proc_exit_connector(tsk);
exit_notify(tsk);
#ifdef CONFIG_NUMA
mpol_free(tsk->mempolicy);
tsk->mempolicy = NULL;
#endif
Index: linux-2.6.17-rc6-mm2/kernel/fork.c
===================================================================
--- linux-2.6.17-rc6-mm2.orig/kernel/fork.c
+++ linux-2.6.17-rc6-mm2/kernel/fork.c
@@ -42,11 +42,10 @@
#include <linux/mount.h>
#include <linux/audit.h>
#include <linux/profile.h>
#include <linux/rmap.h>
#include <linux/acct.h>
-#include <linux/cn_proc.h>
#include <linux/delayacct.h>
#include <linux/notifier.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -1251,14 +1250,12 @@ static task_t *copy_process(unsigned lon

total_forks++;
spin_unlock(&current->sighand->siglock);
write_unlock_irq(&tasklist_lock);
notify_result = notify_watchers(WATCH_TASK_CLONE, p);
- if (notify_result & NOTIFY_STOP_MASK)
- goto bad_fork_cleanup_namespaces;
- proc_fork_connector(p);
- return p;
+ if (!(notify_result & NOTIFY_STOP_MASK))
+ return p;

bad_fork_cleanup_namespaces:
exit_task_namespaces(p);
bad_fork_cleanup_keys:
exit_keys(p);
Index: linux-2.6.17-rc6-mm2/fs/exec.c
===================================================================
--- linux-2.6.17-rc6-mm2.orig/fs/exec.c
+++ linux-2.6.17-rc6-mm2/fs/exec.c
@@ -46,11 +46,10 @@
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/rmap.h>
#include <linux/acct.h>
-#include <linux/cn_proc.h>
#include <linux/audit.h>
#include <linux/notifier.h>

#include <asm/uaccess.h>
#include <asm/mmu_context.h>
@@ -1097,11 +1096,10 @@ int search_binary_handler(struct linux_b
if (bprm->file)
fput(bprm->file);
bprm->file = NULL;
current->did_exec = 1;
notify_watchers(WATCH_TASK_EXEC, current);
- proc_exec_connector(current);
return retval;
}
read_lock(&binfmt_lock);
put_binfmt(fmt);
if (retval != -ENOEXEC || bprm->mm == NULL)
Index: linux-2.6.17-rc6-mm2/kernel/sys.c
===================================================================
--- linux-2.6.17-rc6-mm2.orig/kernel/sys.c
+++ linux-2.6.17-rc6-mm2/kernel/sys.c
@@ -862,11 +862,10 @@ asmlinkage long sys_setregid(gid_t rgid,
current->fsgid = new_egid;
current->egid = new_egid;
current->gid = new_rgid;
key_fsgid_changed(current);
notify_watchers(WATCH_TASK_GID, current);
- proc_id_connector(current, PROC_EVENT_GID);
return 0;
}

/*
* setgid() is implemented like SysV w/ SAVED_IDS
@@ -903,11 +902,10 @@ asmlinkage long sys_setgid(gid_t gid)
else
return -EPERM;

key_fsgid_changed(current);
notify_watchers(WATCH_TASK_GID, current);
- proc_id_connector(current, PROC_EVENT_GID);
return 0;
}

static int set_user(uid_t new_ruid, int dumpclear)
{
@@ -994,11 +992,10 @@ asmlinkage long sys_setreuid(uid_t ruid,
current->suid = current->euid;
current->fsuid = current->euid;

key_fsuid_changed(current);
notify_watchers(WATCH_TASK_UID, current);
- proc_id_connector(current, PROC_EVENT_UID);

return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
}


@@ -1043,11 +1040,10 @@ asmlinkage long sys_setuid(uid_t uid)
current->fsuid = current->euid = uid;
current->suid = new_suid;

key_fsuid_changed(current);
notify_watchers(WATCH_TASK_UID, current);
- proc_id_connector(current, PROC_EVENT_UID);

return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
}


@@ -1093,11 +1089,10 @@ asmlinkage long sys_setresuid(uid_t ruid
if (suid != (uid_t) -1)
current->suid = suid;

key_fsuid_changed(current);
notify_watchers(WATCH_TASK_UID, current);
- proc_id_connector(current, PROC_EVENT_UID);

return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
}

asmlinkage long sys_getresuid(uid_t __user *ruid, uid_t __user *euid, uid_t __user *suid)
@@ -1147,11 +1142,10 @@ asmlinkage long sys_setresgid(gid_t rgid
if (sgid != (gid_t) -1)
current->sgid = sgid;

key_fsgid_changed(current);
notify_watchers(WATCH_TASK_GID, current);
- proc_id_connector(current, PROC_EVENT_GID);
return 0;
}

asmlinkage long sys_getresgid(gid_t __user *rgid, gid_t __user *egid, gid_t __user *sgid)
{
@@ -1191,11 +1185,10 @@ asmlinkage long sys_setfsuid(uid_t uid)
current->fsuid = uid;
}

key_fsuid_changed(current);
notify_watchers(WATCH_TASK_UID, current);
- proc_id_connector(current, PROC_EVENT_UID);

security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);

return old_fsuid;
}
@@ -1221,11 +1214,10 @@ asmlinkage long sys_setfsgid(gid_t gid)
smp_wmb();
}
current->fsgid = gid;
key_fsgid_changed(current);
notify_watchers(WATCH_TASK_GID, current);
- proc_id_connector(current, PROC_EVENT_GID);
}
return old_fsgid;
}

asmlinkage long sys_times(struct tms __user * tbuf)

--

-
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