1 files changed, 56 insertions, 24 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 2b332d1..2567de3 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1090,20 +1090,23 @@ asmlinkage void sys_exit_group(int error_code)
 	do_group_exit((error_code & 0xff) << 8);
 }
 
-static int eligible_child(pid_t pid, int options, struct task_struct *p)
+static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
+{
+	struct pid *pid = NULL;
+	if (type == PIDTYPE_PID)
+		pid = task->pids[type].pid;
+	else if (type < PIDTYPE_MAX)
+		pid = task->group_leader->pids[type].pid;
+	return pid;
+}
+
+static int eligible_child(enum pid_type type, struct pid *pid, int options,
+			  struct task_struct *p)
 {
 	int err;
-	struct pid_namespace *ns;
 
-	ns = current->nsproxy->pid_ns;
-	if (pid > 0) {
-		if (task_pid_nr_ns(p, ns) != pid)
-			return 0;
-	} else if (!pid) {
-		if (task_pgrp_nr_ns(p, ns) != task_pgrp_vnr(current))
-			return 0;
-	} else if (pid != -1) {
-		if (task_pgrp_nr_ns(p, ns) != -pid)
+	if (type < PIDTYPE_MAX) {
+		if (task_pid_type(p, type) != pid)
 			return 0;
 	}
 
@@ -1127,7 +1130,7 @@ static int eligible_child(pid_t pid, int options, struct task_struct *p)
 	if (likely(!err))
 		return 1;
 
-	if (pid <= 0)
+	if (type != PIDTYPE_PID)
 		return 0;
 	/* This child was explicitly requested, abort */
 	read_unlock(&tasklist_lock);
@@ -1447,8 +1450,9 @@ static int wait_task_continued(struct task_struct *p, int noreap,
 	return retval;
 }
 
-static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
-		    int __user *stat_addr, struct rusage __user *ru)
+static long do_wait(enum pid_type type, struct pid *pid, int options,
+		    struct siginfo __user *infop, int __user *stat_addr,
+		    struct rusage __user *ru)
 {
 	DECLARE_WAITQUEUE(wait, current);
 	struct task_struct *tsk;
@@ -1456,6 +1460,11 @@ static long do_wait(pid_t pid, int options, struct siginfo __user *infop,
 
 	add_wait_queue(&current->signal->wait_chldexit,&wait);
 repeat:
+	/* If there is nothing that can match our critier just get out */
+	retval = -ECHILD;
+	if ((type < PIDTYPE_MAX) && (!pid || hlist_empty(&pid->tasks[type])))
+		goto end;
+
 	/*
 	 * We will set this flag if we see any child that might later
 	 * match our criteria, even if we are not able to reap it yet.
@@ -1468,7 +1477,7 @@ repeat:
 		struct task_struct *p;
 
 		list_for_each_entry(p, &tsk->children, sibling) {
-			int ret = eligible_child(pid, options, p);
+			int ret = eligible_child(type, pid, options, p);
 			if (!ret)
 				continue;
 
@@ -1515,7 +1524,7 @@ repeat:
 		if (!flag) {
 			list_for_each_entry(p, &tsk->ptrace_children,
 								ptrace_list) {
-				flag = eligible_child(pid, options, p);
+				flag = eligible_child(type, pid, options, p);
 				if (!flag)
 					continue;
 				if (likely(flag > 0))
@@ -1570,10 +1579,12 @@ end:
 	return retval;
 }
 
-asmlinkage long sys_waitid(int which, pid_t pid,
+asmlinkage long sys_waitid(int which, pid_t upid,
 			   struct siginfo __user *infop, int options,
 			   struct rusage __user *ru)
 {
+	struct pid *pid = NULL;
+	enum pid_type type;
 	long ret;
 
 	if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED))
@@ -1583,37 +1594,58 @@ asmlinkage long sys_waitid(int which, pid_t pid,
 
 	switch (which) {
 	case P_ALL:
-		pid = -1;
+		type = PIDTYPE_MAX;
 		break;
 	case P_PID:
-		if (pid <= 0)
+		type = PIDTYPE_PID;
+		if (upid <= 0)
 			return -EINVAL;
 		break;
 	case P_PGID:
-		if (pid <= 0)
+		type = PIDTYPE_PGID;
+		if (upid <= 0)
 			return -EINVAL;
-		pid = -pid;
 		break;
 	default:
 		return -EINVAL;
 	}
 
-	ret = do_wait(pid, options, infop, NULL, ru);
+	if (type < PIDTYPE_MAX)
+		pid = find_get_pid(upid);
+	ret = do_wait(type, pid, options, infop, NULL, ru);
+	put_pid(pid);
 
 	/* avoid REGPARM breakage on x86: */
 	prevent_tail_call(ret);
 	return ret;
 }
 
-asmlinkage long sys_wait4(pid_t pid, int __user *stat_addr,
+asmlinkage long sys_wait4(pid_t upid, int __user *stat_addr,
 			  int options, struct rusage __user *ru)
 {
+	struct pid *pid = NULL;
+	enum pid_type type;
 	long ret;
 
 	if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
 			__WNOTHREAD|__WCLONE|__WALL))
 		return -EINVAL;
-	ret = do_wait(pid, options | WEXITED, NULL, stat_addr, ru);
+
+	if (upid == -1)
+		type = PIDTYPE_MAX;
+	else if (upid < 0) {
+		type = PIDTYPE_PGID;
+		pid = find_get_pid(-upid);
+	} else if (upid == 0) {
+		type = PIDTYPE_PGID;
+		pid = get_pid(task_pgrp(current));
+	} else /* upid > 0 */ {
+		type = PIDTYPE_PID;
+		pid = find_get_pid(upid);
+	}
+
+	ret = do_wait(type, pid, options | WEXITED, NULL, stat_addr, ru);
+	put_pid(pid);
 
 	/* avoid REGPARM breakage on x86: */
 	prevent_tail_call(ret);