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>
1 parent 573402d
Raw File
uid16.c
/*
 *	Wrapper functions for 16bit uid back compatibility. All nicely tied
 *	together in the faint hope we can take the out in five years time.
 */

#include <linux/mm.h>
#include <linux/utsname.h>
#include <linux/mman.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/prctl.h>
#include <linux/capability.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/security.h>
#include <linux/syscalls.h>

#include <asm/uaccess.h>

SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
{
	long ret = sys_chown(filename, low2highuid(user), low2highgid(group));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(3, ret, filename, user, group);
	return ret;
}

SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
{
	long ret = sys_lchown(filename, low2highuid(user), low2highgid(group));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(3, ret, filename, user, group);
	return ret;
}

SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
{
	long ret = sys_fchown(fd, low2highuid(user), low2highgid(group));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(3, ret, fd, user, group);
	return ret;
}

SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
{
	long ret = sys_setregid(low2highgid(rgid), low2highgid(egid));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(2, ret, rgid, egid);
	return ret;
}

SYSCALL_DEFINE1(setgid16, old_gid_t, gid)
{
	long ret = sys_setgid(low2highgid(gid));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(1, ret, gid);
	return ret;
}

SYSCALL_DEFINE2(setreuid16, old_uid_t, ruid, old_uid_t, euid)
{
	long ret = sys_setreuid(low2highuid(ruid), low2highuid(euid));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(2, ret, ruid, euid);
	return ret;
}

SYSCALL_DEFINE1(setuid16, old_uid_t, uid)
{
	long ret = sys_setuid(low2highuid(uid));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(1, ret, uid);
	return ret;
}

SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
{
	long ret = sys_setresuid(low2highuid(ruid), low2highuid(euid),
				 low2highuid(suid));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(3, ret, ruid, euid, suid);
	return ret;
}

SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruid, old_uid_t __user *, euid, old_uid_t __user *, suid)
{
	const struct cred *cred = current_cred();
	int retval;

	if (!(retval   = put_user(high2lowuid(cred->uid),  ruid)) &&
	    !(retval   = put_user(high2lowuid(cred->euid), euid)))
		retval = put_user(high2lowuid(cred->suid), suid);

	return retval;
}

SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
{
	long ret = sys_setresgid(low2highgid(rgid), low2highgid(egid),
				 low2highgid(sgid));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(3, ret, rgid, egid, sgid);
	return ret;
}


SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgid, old_gid_t __user *, egid, old_gid_t __user *, sgid)
{
	const struct cred *cred = current_cred();
	int retval;

	if (!(retval   = put_user(high2lowgid(cred->gid),  rgid)) &&
	    !(retval   = put_user(high2lowgid(cred->egid), egid)))
		retval = put_user(high2lowgid(cred->sgid), sgid);

	return retval;
}

SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
{
	long ret = sys_setfsuid(low2highuid(uid));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(1, ret, uid);
	return ret;
}

SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
{
	long ret = sys_setfsgid(low2highgid(gid));
	/* avoid REGPARM breakage on x86: */
	asmlinkage_protect(1, ret, gid);
	return ret;
}

static int groups16_to_user(old_gid_t __user *grouplist,
    struct group_info *group_info)
{
	int i;
	old_gid_t group;

	for (i = 0; i < group_info->ngroups; i++) {
		group = high2lowgid(GROUP_AT(group_info, i));
		if (put_user(group, grouplist+i))
			return -EFAULT;
	}

	return 0;
}

static int groups16_from_user(struct group_info *group_info,
    old_gid_t __user *grouplist)
{
	int i;
	old_gid_t group;

	for (i = 0; i < group_info->ngroups; i++) {
		if (get_user(group, grouplist+i))
			return  -EFAULT;
		GROUP_AT(group_info, i) = low2highgid(group);
	}

	return 0;
}

SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
{
	const struct cred *cred = current_cred();
	int i;

	if (gidsetsize < 0)
		return -EINVAL;

	i = cred->group_info->ngroups;
	if (gidsetsize) {
		if (i > gidsetsize) {
			i = -EINVAL;
			goto out;
		}
		if (groups16_to_user(grouplist, cred->group_info)) {
			i = -EFAULT;
			goto out;
		}
	}
out:
	return i;
}

SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
{
	struct group_info *group_info;
	int retval;

	if (!capable(CAP_SETGID))
		return -EPERM;
	if ((unsigned)gidsetsize > NGROUPS_MAX)
		return -EINVAL;

	group_info = groups_alloc(gidsetsize);
	if (!group_info)
		return -ENOMEM;
	retval = groups16_from_user(group_info, grouplist);
	if (retval) {
		put_group_info(group_info);
		return retval;
	}

	retval = set_current_groups(group_info);
	put_group_info(group_info);

	return retval;
}

SYSCALL_DEFINE0(getuid16)
{
	return high2lowuid(current_uid());
}

SYSCALL_DEFINE0(geteuid16)
{
	return high2lowuid(current_euid());
}

SYSCALL_DEFINE0(getgid16)
{
	return high2lowgid(current_gid());
}

SYSCALL_DEFINE0(getegid16)
{
	return high2lowgid(current_egid());
}
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