2008-01-15 10:12:55

by Clifford Wolf

[permalink] [raw]
Subject: [PATCH] rlim in proc/<pid>/status

Hi,

because I needed it already twice in two different projects this week: the
following patch adds rlim (ulimits) output to /proc/<pid>/status.

Please let me know if there is another (already existing) way of accessing
this information easy (i.e. connecting with gdb to the process in question
and 'injecting' a getrlimit() call does not count.. ;-).

yours,
- clifford

Signed-off-by: Clifford Wolf <[email protected]>

--- linux/fs/proc/array.c (revision 757)
+++ linux/fs/proc/array.c (working copy)
@@ -239,6 +239,55 @@
}
}

+static char *rlim_names[RLIM_NLIMITS] = {
+ [RLIMIT_CPU] = "CPU",
+ [RLIMIT_FSIZE] = "FSize",
+ [RLIMIT_DATA] = "Data",
+ [RLIMIT_STACK] = "Stack",
+ [RLIMIT_CORE] = "Core",
+ [RLIMIT_RSS] = "RSS",
+ [RLIMIT_NPROC] = "NProc",
+ [RLIMIT_NOFILE] = "NoFile",
+ [RLIMIT_MEMLOCK] = "MemLock",
+ [RLIMIT_AS] = "AddrSpace",
+ [RLIMIT_LOCKS] = "Locks",
+ [RLIMIT_SIGPENDING] = "SigPending",
+ [RLIMIT_MSGQUEUE] = "MsgQueue",
+ [RLIMIT_NICE] = "Nice",
+ [RLIMIT_RTPRIO] = "RTPrio"
+};
+
+static inline char *task_rlim(struct task_struct *p, char *buffer)
+{
+ unsigned long flags;
+ struct rlimit rlim[RLIM_NLIMITS];
+ int i;
+
+ rcu_read_lock();
+ if (lock_task_sighand(p, &flags)) {
+ for (i=0; i<RLIM_NLIMITS; i++)
+ rlim[i] = p->signal->rlim[i];
+ }
+ rcu_read_unlock();
+
+ for (i=0; i<RLIM_NLIMITS; i++) {
+ if (rlim_names[i])
+ buffer += sprintf(buffer, "Rlim%s:\t", rlim_names[i]);
+ else
+ buffer += sprintf(buffer, "Rlim%d:\t", i);
+ if (rlim[i].rlim_cur != ~0)
+ buffer += sprintf(buffer, "%lu\t", rlim[i].rlim_cur);
+ else
+ buffer += sprintf(buffer, "-\t");
+ if (rlim[i].rlim_max != ~0)
+ buffer += sprintf(buffer, "%lu\n", rlim[i].rlim_max);
+ else
+ buffer += sprintf(buffer, "-\n");
+ }
+
+ return buffer;
+}
+
static inline char *task_sig(struct task_struct *p, char *buffer)
{
unsigned long flags;
@@ -310,6 +359,7 @@
buffer = task_mem(mm, buffer);
mmput(mm);
}
+ buffer = task_rlim(task, buffer);
buffer = task_sig(task, buffer);
buffer = task_cap(task, buffer);
buffer = cpuset_task_status_allowed(task, buffer);

--
[..] If it still doesn't work, re-write it in assembler. This won't fix the
bug, but it will make sure no one else finds it and makes you look bad.


2008-01-15 10:47:18

by KOSAKI Motohiro

[permalink] [raw]
Subject: Re: rlim in proc/<pid>/status

Hi

sound good for me.
a few question please.

> + for (i=0; i<RLIM_NLIMITS; i++) {
> + if (rlim_names[i])
> + buffer += sprintf(buffer, "Rlim%s:\t", rlim_names[i]);
> + else
> + buffer += sprintf(buffer, "Rlim%d:\t", i);

this else is really necessary?

> + if (rlim[i].rlim_cur != ~0)
> + buffer += sprintf(buffer, "%lu\t", rlim[i].rlim_cur);
> + else
> + buffer += sprintf(buffer, "-\t");
> + if (rlim[i].rlim_max != ~0)
> + buffer += sprintf(buffer, "%lu\n", rlim[i].rlim_max);
> + else
> + buffer += sprintf(buffer, "-\n");

Why do you don't use RLIM_INFINITY?

- kosaki

2008-01-15 12:21:41

by Clifford Wolf

[permalink] [raw]
Subject: Re: rlim in proc/<pid>/status

Hi,

On Tue, Jan 15, 2008 at 07:47:22PM +0900, KOSAKI Motohiro wrote:
> sound good for me.
> a few question please.
>
> > + for (i=0; i<RLIM_NLIMITS; i++) {
> > + if (rlim_names[i])
> > + buffer += sprintf(buffer, "Rlim%s:\t", rlim_names[i]);
> > + else
> > + buffer += sprintf(buffer, "Rlim%d:\t", i);
>
> this else is really necessary?

no. not with the current sources. maybe something like the following would
be better:

#if RLIM_NLIMITS != 15
# error New RLIM_NLIMITS add mising entries to rlim_names[]
#endif

> > + if (rlim[i].rlim_cur != ~0)
> > + buffer += sprintf(buffer, "%lu\t", rlim[i].rlim_cur);
> > + else
> > + buffer += sprintf(buffer, "-\t");
> > + if (rlim[i].rlim_max != ~0)
> > + buffer += sprintf(buffer, "%lu\n", rlim[i].rlim_max);
> > + else
> > + buffer += sprintf(buffer, "-\n");
>
> Why do you don't use RLIM_INFINITY?

because I'm blind and didn't see it... ;-)

maybe it would also be better to output 'inf' instead of '-' in this case?

yours,
- clifford

--
The number of the beast - vi vi vi.

2008-01-15 20:38:57

by Serge E. Hallyn

[permalink] [raw]
Subject: Re: [PATCH] rlim in proc/<pid>/status

Quoting Clifford Wolf ([email protected]):
> Hi,
>
> because I needed it already twice in two different projects this week: the
> following patch adds rlim (ulimits) output to /proc/<pid>/status.
>
> Please let me know if there is another (already existing) way of accessing
> this information easy (i.e. connecting with gdb to the process in question
> and 'injecting' a getrlimit() call does not count.. ;-).
>
> yours,
> - clifford
>
> Signed-off-by: Clifford Wolf <[email protected]>
>
> --- linux/fs/proc/array.c (revision 757)
> +++ linux/fs/proc/array.c (working copy)
> @@ -239,6 +239,55 @@
> }
> }
>
> +static char *rlim_names[RLIM_NLIMITS] = {
> + [RLIMIT_CPU] = "CPU",
> + [RLIMIT_FSIZE] = "FSize",
> + [RLIMIT_DATA] = "Data",
> + [RLIMIT_STACK] = "Stack",
> + [RLIMIT_CORE] = "Core",
> + [RLIMIT_RSS] = "RSS",
> + [RLIMIT_NPROC] = "NProc",
> + [RLIMIT_NOFILE] = "NoFile",
> + [RLIMIT_MEMLOCK] = "MemLock",
> + [RLIMIT_AS] = "AddrSpace",
> + [RLIMIT_LOCKS] = "Locks",
> + [RLIMIT_SIGPENDING] = "SigPending",
> + [RLIMIT_MSGQUEUE] = "MsgQueue",
> + [RLIMIT_NICE] = "Nice",
> + [RLIMIT_RTPRIO] = "RTPrio"
> +};
> +
> +static inline char *task_rlim(struct task_struct *p, char *buffer)
> +{
> + unsigned long flags;
> + struct rlimit rlim[RLIM_NLIMITS];
> + int i;
> +
> + rcu_read_lock();
> + if (lock_task_sighand(p, &flags)) {
> + for (i=0; i<RLIM_NLIMITS; i++)
> + rlim[i] = p->signal->rlim[i];

I'm confused - where do you unlock_task_sighand()?

> + }
> + rcu_read_unlock();
> +
> + for (i=0; i<RLIM_NLIMITS; i++) {
> + if (rlim_names[i])
> + buffer += sprintf(buffer, "Rlim%s:\t", rlim_names[i]);
> + else
> + buffer += sprintf(buffer, "Rlim%d:\t", i);
> + if (rlim[i].rlim_cur != ~0)
> + buffer += sprintf(buffer, "%lu\t", rlim[i].rlim_cur);
> + else
> + buffer += sprintf(buffer, "-\t");
> + if (rlim[i].rlim_max != ~0)
> + buffer += sprintf(buffer, "%lu\n", rlim[i].rlim_max);
> + else
> + buffer += sprintf(buffer, "-\n");
> + }
> +
> + return buffer;
> +}
> +
> static inline char *task_sig(struct task_struct *p, char *buffer)
> {
> unsigned long flags;
> @@ -310,6 +359,7 @@
> buffer = task_mem(mm, buffer);
> mmput(mm);
> }
> + buffer = task_rlim(task, buffer);
> buffer = task_sig(task, buffer);
> buffer = task_cap(task, buffer);
> buffer = cpuset_task_status_allowed(task, buffer);
>
> --
> [..] If it still doesn't work, re-write it in assembler. This won't fix the
> bug, but it will make sure no one else finds it and makes you look bad.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/

2008-01-16 07:10:23

by Clifford Wolf

[permalink] [raw]
Subject: Re: [PATCH] rlim in proc/<pid>/status (2nd rev.)

Hi,

On Tue, Jan 15, 2008 at 02:36:59PM -0600, [email protected] wrote:
> > + rcu_read_lock();
> > + if (lock_task_sighand(p, &flags)) {
> > + for (i=0; i<RLIM_NLIMITS; i++)
> > + rlim[i] = p->signal->rlim[i];
>
> I'm confused - where do you unlock_task_sighand()?

oh fsck! thanks for that pointer..

Here is a new version of the patch which solves this issue and the issues
adressed earlier in this thread by kosaki.

yours,
- clifford

Signed-off-by: Clifford Wolf <[email protected]>

--- linux/fs/proc/array.c (revision 750)
+++ linux/fs/proc/array.c (revision 764)
@@ -239,6 +239,58 @@
}
}

+static char *rlim_names[RLIM_NLIMITS] = {
+ [RLIMIT_CPU] = "CPU",
+ [RLIMIT_FSIZE] = "FSize",
+ [RLIMIT_DATA] = "Data",
+ [RLIMIT_STACK] = "Stack",
+ [RLIMIT_CORE] = "Core",
+ [RLIMIT_RSS] = "RSS",
+ [RLIMIT_NPROC] = "NProc",
+ [RLIMIT_NOFILE] = "NoFile",
+ [RLIMIT_MEMLOCK] = "MemLock",
+ [RLIMIT_AS] = "AddrSpace",
+ [RLIMIT_LOCKS] = "Locks",
+ [RLIMIT_SIGPENDING] = "SigPending",
+ [RLIMIT_MSGQUEUE] = "MsgQueue",
+ [RLIMIT_NICE] = "Nice",
+ [RLIMIT_RTPRIO] = "RTPrio"
+};
+
+#if RLIM_NLIMITS != 15
+# error Value of RLIM_NLIMITS changed. \
+ Please update rlim_names in fs/proc/array.c
+#endif
+
+static inline char *task_rlim(struct task_struct *p, char *buffer)
+{
+ unsigned long flags;
+ struct rlimit rlim[RLIM_NLIMITS];
+ int i;
+
+ rcu_read_lock();
+ if (lock_task_sighand(p, &flags)) {
+ for (i=0; i<RLIM_NLIMITS; i++)
+ rlim[i] = p->signal->rlim[i];
+ unlock_task_sighand(p, &flags);
+ }
+ rcu_read_unlock();
+
+ for (i=0; i<RLIM_NLIMITS; i++) {
+ buffer += sprintf(buffer, "Rlim%s:\t", rlim_names[i]);
+ if (rlim[i].rlim_cur != RLIM_INFINITY)
+ buffer += sprintf(buffer, "%lu\t", rlim[i].rlim_cur);
+ else
+ buffer += sprintf(buffer, "inf\t");
+ if (rlim[i].rlim_max != RLIM_INFINITY)
+ buffer += sprintf(buffer, "%lu\n", rlim[i].rlim_max);
+ else
+ buffer += sprintf(buffer, "inf\n");
+ }
+
+ return buffer;
+}
+
static inline char *task_sig(struct task_struct *p, char *buffer)
{
unsigned long flags;
@@ -310,6 +362,7 @@
buffer = task_mem(mm, buffer);
mmput(mm);
}
+ buffer = task_rlim(task, buffer);
buffer = task_sig(task, buffer);
buffer = task_cap(task, buffer);
buffer = cpuset_task_status_allowed(task, buffer);

--
perl -le '$_=1;(1x$_)!~/^(11+)\1+$/&&print${_}while$_++<1000'|fmt

2008-01-16 07:33:18

by KOSAKI Motohiro

[permalink] [raw]
Subject: Re: [PATCH] rlim in proc/<pid>/status (2nd rev.)

Hi Clifford,

> +static inline char *task_rlim(struct task_struct *p, char *buffer)
> +{
> + unsigned long flags;
> + struct rlimit rlim[RLIM_NLIMITS];
> + int i;
> +
> + rcu_read_lock();
> + if (lock_task_sighand(p, &flags)) {
> + for (i=0; i<RLIM_NLIMITS; i++)
> + rlim[i] = p->signal->rlim[i];
> + unlock_task_sighand(p, &flags);
> + }

lock_task_sighand is possible return NULL?
if so, rlim is uninitialized when NULL.


- kosaki

2008-01-16 10:10:43

by Clifford Wolf

[permalink] [raw]
Subject: Re: [PATCH] rlim in proc/<pid>/status (2nd rev.)

Hi,

On Wed, Jan 16, 2008 at 04:33:12PM +0900, KOSAKI Motohiro wrote:
> Hi Clifford,
>
> > +static inline char *task_rlim(struct task_struct *p, char *buffer)
> > +{
> > + unsigned long flags;
> > + struct rlimit rlim[RLIM_NLIMITS];
> > + int i;
> > +
> > + rcu_read_lock();
> > + if (lock_task_sighand(p, &flags)) {
> > + for (i=0; i<RLIM_NLIMITS; i++)
> > + rlim[i] = p->signal->rlim[i];
> > + unlock_task_sighand(p, &flags);
> > + }
>
> lock_task_sighand is possible return NULL?
> if so, rlim is uninitialized when NULL.

hmm.. can p->sighand be NULL here? If so, there also is a problem in the
task_sig() function in the same file.

In fact that code is copy&paste from task_sig(). In fact I'm not even sure
if I actually need to lock anything to access p->signal->rlim.. I've
searched the kernel code a bit and it looks like most acesses to the rlimits
are done unlocked, which is no problem imo given the typical change-pattern
of this values..

anyone a clue on this issues?

yours,
- clifford

--
2B OR (NOT 2B) That is the question. The answer is FF.