On Fri, 2006-02-24 at 14:44 -0700, Eric W. Biederman wrote:
> We can start on a broad front, looking at several different things.
> But I suggest the first thing we all look at is SYSVIPC. It is
> currently a clearly recognized namespace in the kernel so the scope is
> well defined. SYSVIPC is just complicated enough to have a
> non-trivial implementation while at the same time being simple enough
> that we can go through the code in exhausting detail. Getting the
> group dynamics working properly.
Here's a quick stab at the ipc/msg.c portion of this work. The basic
approach was to move msg_ids, msg_bytes, and msg_hdrs into a structure,
put a pointer to that structure in the task_struct and then dynamically
allocate it.
There is still only one system-wide one of these for now. It can
obviously be extended, though. :)
This is a very simple, brute-force, hack-until-it-compiles-and-boots
approach. (I just realized that I didn't check the return of the alloc
properly.)
Is this the form that we'd like these patches to take? Any comments
about the naming? Do we want to keep the _namespace nomenclature, or
does the "context" that I used here make more sense
-- Dave
work-dave/include/linux/ipc.h | 12 +++
work-dave/include/linux/sched.h | 1
work-dave/ipc/msg.c | 152 ++++++++++++++++++++++------------------
work-dave/ipc/util.c | 7 +
work-dave/ipc/util.h | 2
work-dave/kernel/fork.c | 5 +
6 files changed, 108 insertions(+), 71 deletions(-)
--- work/ipc/msg.c~sysv-container 2006-02-27 09:30:23.000000000 -0800
+++ work-dave/ipc/msg.c 2006-02-27 09:32:18.000000000 -0800
@@ -60,35 +60,44 @@ struct msg_sender {
#define SEARCH_NOTEQUAL 3
#define SEARCH_LESSEQUAL 4
-static atomic_t msg_bytes = ATOMIC_INIT(0);
-static atomic_t msg_hdrs = ATOMIC_INIT(0);
+#define msg_lock(ctx, id) ((struct msg_queue*)ipc_lock(&ctx->msg_ids,id))
+#define msg_unlock(ctx, msq) ipc_unlock(&(msq)->q_perm)
+#define msg_rmid(ctx, id) ((struct msg_queue*)ipc_rmid(&ctx->msg_ids,id))
+#define msg_checkid(ctx, msq, msgid) \
+ ipc_checkid(&ctx->msg_ids,&msq->q_perm,msgid)
+#define msg_buildid(ctx, id, seq) \
+ ipc_buildid(&ctx->msg_ids, id, seq)
-static struct ipc_ids msg_ids;
-
-#define msg_lock(id) ((struct msg_queue*)ipc_lock(&msg_ids,id))
-#define msg_unlock(msq) ipc_unlock(&(msq)->q_perm)
-#define msg_rmid(id) ((struct msg_queue*)ipc_rmid(&msg_ids,id))
-#define msg_checkid(msq, msgid) \
- ipc_checkid(&msg_ids,&msq->q_perm,msgid)
-#define msg_buildid(id, seq) \
- ipc_buildid(&msg_ids, id, seq)
-
-static void freeque (struct msg_queue *msq, int id);
-static int newque (key_t key, int msgflg);
+static void freeque (struct ipc_msg_context *, struct msg_queue *msq, int id);
+static int newque (struct ipc_msg_context *context, key_t key, int id);
#ifdef CONFIG_PROC_FS
static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
#endif
-void __init msg_init (void)
+struct ipc_msg_context *alloc_ipc_msg_context(gfp_t flags)
+{
+ struct ipc_msg_context *msg_context;
+
+ msg_context = kzalloc(sizeof(*msg_context), flags);
+ if (!msg_context)
+ return NULL;
+
+ atomic_set(&msg_context->msg_bytes, 0);
+ atomic_set(&msg_context->msg_hdrs, 0);
+
+ return msg_context;
+}
+
+void __init msg_init (struct ipc_msg_context *context)
{
- ipc_init_ids(&msg_ids,msg_ctlmni);
+ ipc_init_ids(&context->msg_ids,msg_ctlmni);
ipc_init_proc_interface("sysvipc/msg",
" key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
- &msg_ids,
+ &context->msg_ids,
sysvipc_msg_proc_show);
}
-static int newque (key_t key, int msgflg)
+static int newque (struct ipc_msg_context *context, key_t key, int msgflg)
{
int id;
int retval;
@@ -108,14 +117,14 @@ static int newque (key_t key, int msgflg
return retval;
}
- id = ipc_addid(&msg_ids, &msq->q_perm, msg_ctlmni);
+ id = ipc_addid(&context->msg_ids, &msq->q_perm, msg_ctlmni);
if(id == -1) {
security_msg_queue_free(msq);
ipc_rcu_putref(msq);
return -ENOSPC;
}
- msq->q_id = msg_buildid(id,msq->q_perm.seq);
+ msq->q_id = msg_buildid(context,id,msq->q_perm.seq);
msq->q_stime = msq->q_rtime = 0;
msq->q_ctime = get_seconds();
msq->q_cbytes = msq->q_qnum = 0;
@@ -124,7 +133,7 @@ static int newque (key_t key, int msgflg
INIT_LIST_HEAD(&msq->q_messages);
INIT_LIST_HEAD(&msq->q_receivers);
INIT_LIST_HEAD(&msq->q_senders);
- msg_unlock(msq);
+ msg_unlock(context, msq);
return msq->q_id;
}
@@ -182,23 +191,24 @@ static void expunge_all(struct msg_queue
* msg_ids.sem and the spinlock for this message queue is hold
* before freeque() is called. msg_ids.sem remains locked on exit.
*/
-static void freeque (struct msg_queue *msq, int id)
+static void freeque (struct ipc_msg_context *context,
+ struct msg_queue *msq, int id)
{
struct list_head *tmp;
expunge_all(msq,-EIDRM);
ss_wakeup(&msq->q_senders,1);
- msq = msg_rmid(id);
- msg_unlock(msq);
+ msq = msg_rmid(context, id);
+ msg_unlock(context, msq);
tmp = msq->q_messages.next;
while(tmp != &msq->q_messages) {
struct msg_msg* msg = list_entry(tmp,struct msg_msg,m_list);
tmp = tmp->next;
- atomic_dec(&msg_hdrs);
+ atomic_dec(&context->msg_hdrs);
free_msg(msg);
}
- atomic_sub(msq->q_cbytes, &msg_bytes);
+ atomic_sub(msq->q_cbytes, &context->msg_bytes);
security_msg_queue_free(msq);
ipc_rcu_putref(msq);
}
@@ -207,32 +217,34 @@ asmlinkage long sys_msgget (key_t key, i
{
int id, ret = -EPERM;
struct msg_queue *msq;
-
- down(&msg_ids.sem);
+ struct ipc_msg_context *context = current->ipc_msg_context;
+
+ down(&context->msg_ids.sem);
if (key == IPC_PRIVATE)
- ret = newque(key, msgflg);
- else if ((id = ipc_findkey(&msg_ids, key)) == -1) { /* key not used */
+ ret = newque(context, key, msgflg);
+ else if ((id = ipc_findkey(&context->msg_ids, key)) == -1) {
+ /* key not used */
if (!(msgflg & IPC_CREAT))
ret = -ENOENT;
else
- ret = newque(key, msgflg);
+ ret = newque(context, key, msgflg);
} else if (msgflg & IPC_CREAT && msgflg & IPC_EXCL) {
ret = -EEXIST;
} else {
- msq = msg_lock(id);
+ msq = msg_lock(context, id);
if(msq==NULL)
BUG();
if (ipcperms(&msq->q_perm, msgflg))
ret = -EACCES;
else {
- int qid = msg_buildid(id, msq->q_perm.seq);
+ int qid = msg_buildid(context, id, msq->q_perm.seq);
ret = security_msg_queue_associate(msq, msgflg);
if (!ret)
ret = qid;
}
- msg_unlock(msq);
+ msg_unlock(context, msq);
}
- up(&msg_ids.sem);
+ up(&context->msg_ids.sem);
return ret;
}
@@ -333,6 +345,7 @@ asmlinkage long sys_msgctl (int msqid, i
struct msg_queue *msq;
struct msq_setbuf setbuf;
struct kern_ipc_perm *ipcp;
+ struct ipc_msg_context *context = current->ipc_msg_context;
if (msqid < 0 || cmd < 0)
return -EINVAL;
@@ -362,18 +375,18 @@ asmlinkage long sys_msgctl (int msqid, i
msginfo.msgmnb = msg_ctlmnb;
msginfo.msgssz = MSGSSZ;
msginfo.msgseg = MSGSEG;
- down(&msg_ids.sem);
+ down(&context->msg_ids.sem);
if (cmd == MSG_INFO) {
- msginfo.msgpool = msg_ids.in_use;
- msginfo.msgmap = atomic_read(&msg_hdrs);
- msginfo.msgtql = atomic_read(&msg_bytes);
+ msginfo.msgpool = context->msg_ids.in_use;
+ msginfo.msgmap = atomic_read(&context->msg_hdrs);
+ msginfo.msgtql = atomic_read(&context->msg_bytes);
} else {
msginfo.msgmap = MSGMAP;
msginfo.msgpool = MSGPOOL;
msginfo.msgtql = MSGTQL;
}
- max_id = msg_ids.max_id;
- up(&msg_ids.sem);
+ max_id = context->msg_ids.max_id;
+ up(&context->msg_ids.sem);
if (copy_to_user (buf, &msginfo, sizeof(struct msginfo)))
return -EFAULT;
return (max_id < 0) ? 0: max_id;
@@ -385,20 +398,21 @@ asmlinkage long sys_msgctl (int msqid, i
int success_return;
if (!buf)
return -EFAULT;
- if(cmd == MSG_STAT && msqid >= msg_ids.entries->size)
+ if(cmd == MSG_STAT && msqid >= context->msg_ids.entries->size)
return -EINVAL;
memset(&tbuf,0,sizeof(tbuf));
- msq = msg_lock(msqid);
+ msq = msg_lock(context, msqid);
if (msq == NULL)
return -EINVAL;
if(cmd == MSG_STAT) {
- success_return = msg_buildid(msqid, msq->q_perm.seq);
+ success_return =
+ msg_buildid(context, msqid, msq->q_perm.seq);
} else {
err = -EIDRM;
- if (msg_checkid(msq,msqid))
+ if (msg_checkid(context,msq,msqid))
goto out_unlock;
success_return = 0;
}
@@ -419,7 +433,7 @@ asmlinkage long sys_msgctl (int msqid, i
tbuf.msg_qbytes = msq->q_qbytes;
tbuf.msg_lspid = msq->q_lspid;
tbuf.msg_lrpid = msq->q_lrpid;
- msg_unlock(msq);
+ msg_unlock(context, msq);
if (copy_msqid_to_user(buf, &tbuf, version))
return -EFAULT;
return success_return;
@@ -438,14 +452,14 @@ asmlinkage long sys_msgctl (int msqid, i
return -EINVAL;
}
- down(&msg_ids.sem);
- msq = msg_lock(msqid);
+ down(&context->msg_ids.sem);
+ msq = msg_lock(context, msqid);
err=-EINVAL;
if (msq == NULL)
goto out_up;
err = -EIDRM;
- if (msg_checkid(msq,msqid))
+ if (msg_checkid(context,msq,msqid))
goto out_unlock_up;
ipcp = &msq->q_perm;
err = -EPERM;
@@ -480,22 +494,22 @@ asmlinkage long sys_msgctl (int msqid, i
* due to a larger queue size.
*/
ss_wakeup(&msq->q_senders,0);
- msg_unlock(msq);
+ msg_unlock(context, msq);
break;
}
case IPC_RMID:
- freeque (msq, msqid);
+ freeque (context, msq, msqid);
break;
}
err = 0;
out_up:
- up(&msg_id
...
|
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