145 строки
3.2 KiB
C
145 строки
3.2 KiB
C
/*
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* linux/kernel/futex_compat.c
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*
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* Futex compatibililty routines.
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*
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* Copyright 2006, Red Hat, Inc., Ingo Molnar
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*/
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#include <linux/linkage.h>
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#include <linux/compat.h>
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#include <linux/futex.h>
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#include <asm/uaccess.h>
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/*
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* Walk curr->robust_list (very carefully, it's a userspace list!)
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* and mark any locks found there dead, and notify any waiters.
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*
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* We silently return on any sign of list-walking problem.
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*/
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void compat_exit_robust_list(struct task_struct *curr)
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{
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struct compat_robust_list_head __user *head = curr->compat_robust_list;
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struct robust_list __user *entry, *pending;
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compat_uptr_t uentry, upending;
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unsigned int limit = ROBUST_LIST_LIMIT;
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compat_long_t futex_offset;
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/*
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* Fetch the list head (which was registered earlier, via
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* sys_set_robust_list()):
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*/
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if (get_user(uentry, &head->list.next))
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return;
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entry = compat_ptr(uentry);
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/*
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* Fetch the relative futex offset:
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*/
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if (get_user(futex_offset, &head->futex_offset))
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return;
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/*
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* Fetch any possibly pending lock-add first, and handle it
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* if it exists:
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*/
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if (get_user(upending, &head->list_op_pending))
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return;
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pending = compat_ptr(upending);
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if (upending)
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handle_futex_death((void *)pending + futex_offset, curr);
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while (compat_ptr(uentry) != &head->list) {
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/*
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* A pending lock might already be on the list, so
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* dont process it twice:
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*/
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if (entry != pending)
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if (handle_futex_death((void *)entry + futex_offset,
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curr))
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return;
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/*
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* Fetch the next entry in the list:
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*/
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if (get_user(uentry, (compat_uptr_t *)&entry->next))
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return;
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entry = compat_ptr(uentry);
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/*
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* Avoid excessively long or circular lists:
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*/
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if (!--limit)
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break;
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cond_resched();
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}
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}
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asmlinkage long
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compat_sys_set_robust_list(struct compat_robust_list_head __user *head,
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compat_size_t len)
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{
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if (unlikely(len != sizeof(*head)))
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return -EINVAL;
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current->compat_robust_list = head;
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return 0;
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}
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asmlinkage long
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compat_sys_get_robust_list(int pid, compat_uptr_t *head_ptr,
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compat_size_t __user *len_ptr)
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{
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struct compat_robust_list_head *head;
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unsigned long ret;
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if (!pid)
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head = current->compat_robust_list;
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else {
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struct task_struct *p;
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ret = -ESRCH;
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read_lock(&tasklist_lock);
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p = find_task_by_pid(pid);
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if (!p)
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goto err_unlock;
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ret = -EPERM;
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if ((current->euid != p->euid) && (current->euid != p->uid) &&
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!capable(CAP_SYS_PTRACE))
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goto err_unlock;
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head = p->compat_robust_list;
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read_unlock(&tasklist_lock);
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}
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if (put_user(sizeof(*head), len_ptr))
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return -EFAULT;
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return put_user(ptr_to_compat(head), head_ptr);
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err_unlock:
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read_unlock(&tasklist_lock);
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return ret;
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}
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asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,
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struct compat_timespec __user *utime, u32 __user *uaddr2,
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u32 val3)
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{
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struct timespec t;
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unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
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int val2 = 0;
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if (utime && (op == FUTEX_WAIT)) {
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if (get_compat_timespec(&t, utime))
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return -EFAULT;
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if (!timespec_valid(&t))
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return -EINVAL;
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timeout = timespec_to_jiffies(&t) + 1;
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}
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if (op >= FUTEX_REQUEUE)
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val2 = (int) (unsigned long) utime;
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return do_futex((unsigned long)uaddr, op, val, timeout,
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(unsigned long)uaddr2, val2, val3);
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}
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