2 * linux/kernel/futex_compat.c
4 * Futex compatibililty routines.
6 * Copyright 2006, Red Hat, Inc., Ingo Molnar
9 #include <linux/linkage.h>
10 #include <linux/compat.h>
11 #include <linux/futex.h>
12 #include <linux/vs_cvirt.h>
14 #include <asm/uaccess.h>
17 * Walk curr->robust_list (very carefully, it's a userspace list!)
18 * and mark any locks found there dead, and notify any waiters.
20 * We silently return on any sign of list-walking problem.
22 void compat_exit_robust_list(struct task_struct *curr)
24 struct compat_robust_list_head __user *head = curr->compat_robust_list;
25 struct robust_list __user *entry, *pending;
26 compat_uptr_t uentry, upending;
27 unsigned int limit = ROBUST_LIST_LIMIT;
28 compat_long_t futex_offset;
31 * Fetch the list head (which was registered earlier, via
32 * sys_set_robust_list()):
34 if (get_user(uentry, &head->list.next))
36 entry = compat_ptr(uentry);
38 * Fetch the relative futex offset:
40 if (get_user(futex_offset, &head->futex_offset))
43 * Fetch any possibly pending lock-add first, and handle it
46 if (get_user(upending, &head->list_op_pending))
48 pending = compat_ptr(upending);
50 handle_futex_death((void *)pending + futex_offset, curr);
52 while (compat_ptr(uentry) != &head->list) {
54 * A pending lock might already be on the list, so
55 * dont process it twice:
58 if (handle_futex_death((void *)entry + futex_offset,
63 * Fetch the next entry in the list:
65 if (get_user(uentry, (compat_uptr_t *)&entry->next))
67 entry = compat_ptr(uentry);
69 * Avoid excessively long or circular lists:
79 compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
82 if (unlikely(len != sizeof(*head)))
85 current->compat_robust_list = head;
91 compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr,
92 compat_size_t __user *len_ptr)
94 struct compat_robust_list_head *head;
98 head = current->compat_robust_list;
100 struct task_struct *p;
103 read_lock(&tasklist_lock);
104 p = find_task_by_pid(pid);
108 if ((current->euid != p->euid) && (current->euid != p->uid) &&
109 !capable(CAP_SYS_PTRACE))
111 head = p->compat_robust_list;
112 read_unlock(&tasklist_lock);
115 if (put_user(sizeof(*head), len_ptr))
117 return put_user(ptr_to_compat(head), head_ptr);
120 read_unlock(&tasklist_lock);
125 asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
126 struct compat_timespec __user *utime, u32 __user *uaddr2,
130 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
133 if (utime && (op == FUTEX_WAIT)) {
134 if (get_compat_timespec(&t, utime))
136 if (!timespec_valid(&t))
138 timeout = timespec_to_jiffies(&t) + 1;
140 if (op >= FUTEX_REQUEUE)
141 val2 = (int) (unsigned long) utime;
143 return do_futex((unsigned long)uaddr, op, val, timeout,
144 (unsigned long)uaddr2, val2, val3);