1 files changed, 56 insertions, 24 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 2b332d170327..2567de3487bd 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);