Revision 7f453c24b95a085fc7bd35d53b33abc4dc5a048b authored by Peter Zijlstra on 21 July 2009, 11:19:40 UTC, committed by Peter Zijlstra on 22 July 2009, 16:05:56 UTC
Anton noted that for inherited counters the counter-id as provided by PERF_SAMPLE_ID isn't mappable to the id found through PERF_RECORD_ID because each inherited counter gets its own id. His suggestion was to always return the parent counter id, since that is the primary counter id as exposed. However, these inherited counters have a unique identifier so that events like PERF_EVENT_PERIOD and PERF_EVENT_THROTTLE can be specific about which counter gets modified, which is important when trying to normalize the sample streams. This patch removes PERF_EVENT_PERIOD in favour of PERF_SAMPLE_PERIOD, which is more useful anyway, since changing periods became a lot more common than initially thought -- rendering PERF_EVENT_PERIOD the less useful solution (also, PERF_SAMPLE_PERIOD reports the more accurate value, since it reports the value used to trigger the overflow, whereas PERF_EVENT_PERIOD simply reports the requested period changed, which might only take effect on the next cycle). This still leaves us PERF_EVENT_THROTTLE to consider, but since that _should_ be a rare occurrence, and linking it to a primary id is the most useful bit to diagnose the problem, we introduce a PERF_SAMPLE_STREAM_ID, for those few cases where the full reconstruction is important. [Does change the ABI a little, but I see no other way out] Suggested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1248095846.15751.8781.camel@twins>
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root_plug.c
/*
* Root Plug sample LSM module
*
* Originally written for a Linux Journal.
*
* Copyright (C) 2002 Greg Kroah-Hartman <greg@kroah.com>
*
* Prevents any programs running with egid == 0 if a specific USB device
* is not present in the system. Yes, it can be gotten around, but is a
* nice starting point for people to play with, and learn the LSM
* interface.
*
* If you want to turn this into something with a semblance of security,
* you need to hook the task_* functions also.
*
* See http://www.linuxjournal.com/article.php?sid=6279 for more information
* about this code.
*
* 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, version 2 of the
* License.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/security.h>
#include <linux/usb.h>
#include <linux/moduleparam.h>
/* default is a generic type of usb to serial converter */
static int vendor_id = 0x0557;
static int product_id = 0x2008;
module_param(vendor_id, uint, 0400);
module_param(product_id, uint, 0400);
/* should we print out debug messages */
static int debug = 0;
module_param(debug, bool, 0600);
#define MY_NAME "root_plug"
#define root_dbg(fmt, arg...) \
do { \
if (debug) \
printk(KERN_DEBUG "%s: %s: " fmt , \
MY_NAME , __func__ , \
## arg); \
} while (0)
static int rootplug_bprm_check_security (struct linux_binprm *bprm)
{
struct usb_device *dev;
root_dbg("file %s, e_uid = %d, e_gid = %d\n",
bprm->filename, bprm->cred->euid, bprm->cred->egid);
if (bprm->cred->egid == 0) {
dev = usb_find_device(vendor_id, product_id);
if (!dev) {
root_dbg("e_gid = 0, and device not found, "
"task not allowed to run...\n");
return -EPERM;
}
usb_put_dev(dev);
}
return 0;
}
static struct security_operations rootplug_security_ops = {
.bprm_check_security = rootplug_bprm_check_security,
};
static int __init rootplug_init (void)
{
/* register ourselves with the security framework */
if (register_security (&rootplug_security_ops)) {
printk (KERN_INFO
"Failure registering Root Plug module with the kernel\n");
return -EINVAL;
}
printk (KERN_INFO "Root Plug module initialized, "
"vendor_id = %4.4x, product id = %4.4x\n", vendor_id, product_id);
return 0;
}
security_initcall (rootplug_init);
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