1 /*
2 * linux/kernel/futex_compat.c
3 *
4 * Futex compatibililty routines.
5 *
6 * Copyright 2006, Red Hat, Inc., Ingo Molnar
7 */
8
9 #include <linux/linkage.h>
10 #include <linux/compat.h>
11 #include <linux/futex.h>
12
13 #include <asm/uaccess.h>
14
15 /*
16 * Walk curr->robust_list (very carefully, it's a userspace list!)
17 * and mark any locks found there dead, and notify any waiters.
18 *
19 * We silently return on any sign of list-walking problem.
20 */
21 void compat_exit_robust_list(struct task_struct *curr)
22 {
23 struct compat_robust_list_head __user *head = curr->compat_robust_list;
24 struct robust_list __user *entry, *pending;
25 compat_uptr_t uentry, upending;
26 unsigned int limit = ROBUST_LIST_LIMIT;
27 compat_long_t futex_offset;
28
29 /*
30 * Fetch the list head (which was registered earlier, via
31 * sys_set_robust_list()):
32 */
33 if (get_user(uentry, &head->list.next))
34 return;
35 entry = compat_ptr(uentry);
36 /*
37 * Fetch the relative futex offset:
38 */
39 if (get_user(futex_offset, &head->futex_offset))
40 return;
41 /*
42 * Fetch any possibly pending lock-add first, and handle it
43 * if it exists:
44 */
45 if (get_user(upending, &head->list_op_pending))
46 return;
47 pending = compat_ptr(upending);
48 if (upending)
49 handle_futex_death((void *)pending + futex_offset, curr);
50
51 while (compat_ptr(uentry) != &head->list) {
52 /*
53 * A pending lock might already be on the list, so
54 * dont process it twice:
55 */
56 if (entry != pending)
57 if (handle_futex_death((void *)entry + futex_offset,
58 curr))
59 return;
60
61 /*
62 * Fetch the next entry in the list:
63 */
64 if (get_user(uentry, (compat_uptr_t *)&entry->next))
65 return;
66 entry = compat_ptr(uentry);
67 /*
68 * Avoid excessively long or circular lists:
69 */
70 if (!--limit)
71 break;
72
73 cond_resched();
74 }
75 }
76
77 asmlinkage long
78 compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
79 compat_size_t len)
80 {
81 if (unlikely(len != sizeof(*head)))
82 return -EINVAL;
83
84 current->compat_robust_list = head;
85
86 return 0;
87 }
88
89 asmlinkage long
90 compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr,
91 compat_size_t __user *len_ptr)
92 {
93 struct compat_robust_list_head *head;
94 unsigned long ret;
95
96 if (!pid)
97 head = current->compat_robust_list;
98 else {
99 struct task_struct *p;
100
101 ret = -ESRCH;
102 read_lock(&tasklist_lock);
103 p = find_task_by_pid(pid);
104 if (!p)
105 goto err_unlock;
106 ret = -EPERM;
107 if ((current->euid != p->euid) && (current->euid != p->uid) &&
108 !capable(CAP_SYS_PTRACE))
109 goto err_unlock;
110 head = p->compat_robust_list;
111 read_unlock(&tasklist_lock);
112 }
113
114 if (put_user(sizeof(*head), len_ptr))
115 return -EFAULT;
116 return put_user(ptr_to_compat(head), head_ptr);
117
118 err_unlock:
119 read_unlock(&tasklist_lock);
120
121 return ret;
122 }
123
124 asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
125 struct compat_timespec __user *utime, u32 __user *uaddr2,
126 u32 val3)
127 {
128 struct timespec t;
129 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
130 int val2 = 0;
131
132 if (utime && (op == FUTEX_WAIT)) {
133 if (get_compat_timespec(&t, utime))
134 return -EFAULT;
135 if (!timespec_valid(&t))
136 return -EINVAL;
137 timeout = timespec_to_jiffies(&t) + 1;
138 }
139 if (op >= FUTEX_REQUEUE)
140 val2 = (int) (unsigned long) utime;
141
142 return do_futex((unsigned long)uaddr, op, val, timeout,
143 (unsigned long)uaddr2, val2, val3);
144 }
145
This page was automatically generated by the
LXR engine.
Visit the LXR main site for more
information.