Driver core: add CONFIG_UEVENT_HELPER_PATH
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / futex_compat.c
blob2c2e2954b713b2681a5bf120c0097cb2c2affc8c
1 /*
2 * linux/kernel/futex_compat.c
4 * Futex compatibililty routines.
6 * Copyright 2006, Red Hat, Inc., Ingo Molnar
7 */
9 #include <linux/linkage.h>
10 #include <linux/compat.h>
11 #include <linux/futex.h>
13 #include <asm/uaccess.h>
17 * Fetch a robust-list pointer. Bit 0 signals PI futexes:
19 static inline int
20 fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
21 compat_uptr_t __user *head, int *pi)
23 if (get_user(*uentry, head))
24 return -EFAULT;
26 *entry = compat_ptr((*uentry) & ~1);
27 *pi = (unsigned int)(*uentry) & 1;
29 return 0;
33 * Walk curr->robust_list (very carefully, it's a userspace list!)
34 * and mark any locks found there dead, and notify any waiters.
36 * We silently return on any sign of list-walking problem.
38 void compat_exit_robust_list(struct task_struct *curr)
40 struct compat_robust_list_head __user *head = curr->compat_robust_list;
41 struct robust_list __user *entry, *next_entry, *pending;
42 unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip;
43 compat_uptr_t uentry, next_uentry, upending;
44 compat_long_t futex_offset;
45 int rc;
48 * Fetch the list head (which was registered earlier, via
49 * sys_set_robust_list()):
51 if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
52 return;
54 * Fetch the relative futex offset:
56 if (get_user(futex_offset, &head->futex_offset))
57 return;
59 * Fetch any possibly pending lock-add first, and handle it
60 * if it exists:
62 if (fetch_robust_entry(&upending, &pending,
63 &head->list_op_pending, &pip))
64 return;
66 next_entry = NULL; /* avoid warning with gcc */
67 while (entry != (struct robust_list __user *) &head->list) {
69 * Fetch the next entry in the list before calling
70 * handle_futex_death:
72 rc = fetch_robust_entry(&next_uentry, &next_entry,
73 (compat_uptr_t __user *)&entry->next, &next_pi);
75 * A pending lock might already be on the list, so
76 * dont process it twice:
78 if (entry != pending)
79 if (handle_futex_death((void __user *)entry + futex_offset,
80 curr, pi))
81 return;
83 if (rc)
84 return;
85 uentry = next_uentry;
86 entry = next_entry;
87 pi = next_pi;
89 * Avoid excessively long or circular lists:
91 if (!--limit)
92 break;
94 cond_resched();
96 if (pending)
97 handle_futex_death((void __user *)pending + futex_offset,
98 curr, pip);
101 asmlinkage long
102 compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
103 compat_size_t len)
105 if (unlikely(len != sizeof(*head)))
106 return -EINVAL;
108 current->compat_robust_list = head;
110 return 0;
113 asmlinkage long
114 compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,
115 compat_size_t __user *len_ptr)
117 struct compat_robust_list_head __user *head;
118 unsigned long ret;
120 if (!pid)
121 head = current->compat_robust_list;
122 else {
123 struct task_struct *p;
125 ret = -ESRCH;
126 read_lock(&tasklist_lock);
127 p = find_task_by_pid(pid);
128 if (!p)
129 goto err_unlock;
130 ret = -EPERM;
131 if ((current->euid != p->euid) && (current->euid != p->uid) &&
132 !capable(CAP_SYS_PTRACE))
133 goto err_unlock;
134 head = p->compat_robust_list;
135 read_unlock(&tasklist_lock);
138 if (put_user(sizeof(*head), len_ptr))
139 return -EFAULT;
140 return put_user(ptr_to_compat(head), head_ptr);
142 err_unlock:
143 read_unlock(&tasklist_lock);
145 return ret;
148 asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
149 struct compat_timespec __user *utime, u32 __user *uaddr2,
150 u32 val3)
152 struct timespec ts;
153 ktime_t t, *tp = NULL;
154 int val2 = 0;
155 int cmd = op & FUTEX_CMD_MASK;
157 if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI)) {
158 if (get_compat_timespec(&ts, utime))
159 return -EFAULT;
160 if (!timespec_valid(&ts))
161 return -EINVAL;
163 t = timespec_to_ktime(ts);
164 if (cmd == FUTEX_WAIT)
165 t = ktime_add(ktime_get(), t);
166 tp = &t;
168 if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE)
169 val2 = (int) (unsigned long) utime;
171 return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);