Commit ce72a16f authored by Al Viro's avatar Al Viro
Browse files

wait4(2)/waitid(2): separate copying rusage to userland 



New helpers: kernel_waitid() and kernel_wait4().  sys_waitid(),
sys_wait4() and their compat variants switched to those.  Copying
struct rusage to userland is left to syscall itself.  For
compat_sys_wait4() that eliminates the use of set_fs() completely.
For compat_sys_waitid() it's still needed (for siginfo handling);
that will change shortly.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 7e95a225

include/linux/resource.h

+1 −1
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ 


struct task_struct;



int getrusage(struct task_struct *p, int who, struct rusage __user *ru);

void getrusage(struct task_struct *p, int who, struct rusage *ru);

int do_prlimit(struct task_struct *tsk, unsigned int resource,

		struct rlimit *new_rlim, struct rlimit *old_rlim);

kernel/exit.c

+52 −37
Original line number Diff line number Diff line
@@ -1003,7 +1003,7 @@ struct wait_opts { 


	struct siginfo __user	*wo_info;

	int __user		*wo_stat;

	struct rusage __user	*wo_rusage;

	struct rusage		*wo_rusage;



	wait_queue_t		child_wait;

	int			notask_error;
@@ -1054,8 +1054,10 @@ static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p, 
				pid_t pid, uid_t uid, int why, int status)

{

	struct siginfo __user *infop;

	int retval = wo->wo_rusage

		? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

	int retval = 0;



	if (wo->wo_rusage)

		getrusage(p, RUSAGE_BOTH, wo->wo_rusage);



	put_task_struct(p);

	infop = wo->wo_info;
@@ -1182,8 +1184,9 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) 
		spin_unlock_irq(&current->sighand->siglock);

	}



	retval = wo->wo_rusage

		? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

	if (wo->wo_rusage)

		getrusage(p, RUSAGE_BOTH, wo->wo_rusage);

	retval = 0;

	status = (p->signal->flags & SIGNAL_GROUP_EXIT)

		? p->signal->group_exit_code : p->exit_code;

	if (!retval && wo->wo_stat)
@@ -1316,8 +1319,9 @@ unlock_sig: 
	if (unlikely(wo->wo_flags & WNOWAIT))

		return wait_noreap_copyout(wo, p, pid, uid, why, exit_code);



	retval = wo->wo_rusage

		? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

	if (wo->wo_rusage)

		getrusage(p, RUSAGE_BOTH, wo->wo_rusage);

	retval = 0;

	if (!retval && wo->wo_stat)

		retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat);
@@ -1377,8 +1381,9 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p) 
	sched_annotate_sleep();



	if (!wo->wo_info) {

		retval = wo->wo_rusage

			? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0;

		if (wo->wo_rusage)

			getrusage(p, RUSAGE_BOTH, wo->wo_rusage);

		retval = 0;

		put_task_struct(p);

		if (!retval && wo->wo_stat)

			retval = put_user(0xffff, wo->wo_stat);
@@ -1618,8 +1623,8 @@ end: 
	return retval;

}



SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,

		infop, int, options, struct rusage __user *, ru)

static long kernel_waitid(int which, pid_t upid, struct siginfo __user *infop,

			  int options, struct rusage *ru)

{

	struct wait_opts wo;

	struct pid *pid = NULL;
@@ -1687,8 +1692,21 @@ SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, 
	return ret;

}



SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,

		int, options, struct rusage __user *, ru)

SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,

		infop, int, options, struct rusage __user *, ru)

{

	struct rusage r;

	long err = kernel_waitid(which, upid, infop, options, ru ? &r : NULL);



	if (!err) {

		if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))

			return -EFAULT;

	}

	return err;

}



static long kernel_wait4(pid_t upid, int __user *stat_addr,

			int options, struct rusage *ru)

{

	struct wait_opts wo;

	struct pid *pid = NULL;
@@ -1724,6 +1742,19 @@ SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr, 
	return ret;

}



SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,

		int, options, struct rusage __user *, ru)

{

	struct rusage r;

	long err = kernel_wait4(upid, stat_addr, options, ru ? &r : NULL);



	if (err > 0) {

		if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))

			return -EFAULT;

	}

	return err;

}



#ifdef __ARCH_WANT_SYS_WAITPID



/*
@@ -1744,29 +1775,13 @@ COMPAT_SYSCALL_DEFINE4(wait4, 
	int, options,

	struct compat_rusage __user *, ru)

{

	if (!ru) {

		return sys_wait4(pid, stat_addr, options, NULL);

	} else {

	struct rusage r;

		int ret;

		unsigned int status;

		mm_segment_t old_fs = get_fs();



		set_fs (KERNEL_DS);

		ret = sys_wait4(pid,

				(stat_addr ?

				 (unsigned int __user *) &status : NULL),

				options, (struct rusage __user *) &r);

		set_fs (old_fs);



		if (ret > 0) {

			if (put_compat_rusage(&r, ru))

				return -EFAULT;

			if (stat_addr && put_user(status, stat_addr))

	long err = kernel_wait4(pid, stat_addr, options, ru ? &r : NULL);

	if (err > 0) {

		if (ru && put_compat_rusage(&r, ru))

			return -EFAULT;

	}

		return ret;

	}

	return err;

}



COMPAT_SYSCALL_DEFINE5(waitid,
@@ -1782,8 +1797,8 @@ COMPAT_SYSCALL_DEFINE5(waitid, 
	memset(&info, 0, sizeof(info));



	set_fs(KERNEL_DS);

	ret = sys_waitid(which, pid, (siginfo_t __user *)&info, options,

			 uru ? (struct rusage __user *)&ru : NULL);

	ret = kernel_waitid(which, pid, (siginfo_t __user *)&info, options,

			 uru ? &ru : NULL);

	set_fs(old_fs);



	if ((ret < 0) || (info.si_signo == 0))

kernel/sys.c

+6 −10
Original line number Diff line number Diff line
@@ -1552,7 +1552,7 @@ static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r) 
	r->ru_oublock += task_io_get_oublock(t);

}



static void k_getrusage(struct task_struct *p, int who, struct rusage *r)

void getrusage(struct task_struct *p, int who, struct rusage *r)

{

	struct task_struct *t;

	unsigned long flags;
@@ -1626,20 +1626,16 @@ out: 
	r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */

}



int getrusage(struct task_struct *p, int who, struct rusage __user *ru)

SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)

{

	struct rusage r;



	k_getrusage(p, who, &r);

	return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;

}



SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru)

{

	if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN &&

	    who != RUSAGE_THREAD)

		return -EINVAL;

	return getrusage(current, who, ru);



	getrusage(current, who, &r);

	return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0;

}



#ifdef CONFIG_COMPAT
@@ -1651,7 +1647,7 @@ COMPAT_SYSCALL_DEFINE2(getrusage, int, who, struct compat_rusage __user *, ru) 
	    who != RUSAGE_THREAD)

		return -EINVAL;



	k_getrusage(current, who, &r);

	getrusage(current, who, &r);

	return put_compat_rusage(&r, ru);

}

#endif

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