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![Randy.Dunlap](/assets/img/avatar_default.png)
- Move capable() from sched.h to capability.h; - Use <linux/capability.h> where capable() is used (in include/, block/, ipc/, kernel/, a few drivers/, mm/, security/, & sound/; many more drivers/ to go) Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
254 lines
5.3 KiB
C
254 lines
5.3 KiB
C
/*
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* linux/mm/mlock.c
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*
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* (C) Copyright 1995 Linus Torvalds
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* (C) Copyright 2002 Christoph Hellwig
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*/
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#include <linux/capability.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/mempolicy.h>
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#include <linux/syscalls.h>
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static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
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unsigned long start, unsigned long end, unsigned int newflags)
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{
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struct mm_struct * mm = vma->vm_mm;
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pgoff_t pgoff;
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int pages;
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int ret = 0;
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if (newflags == vma->vm_flags) {
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*prev = vma;
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goto out;
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}
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pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
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*prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
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vma->vm_file, pgoff, vma_policy(vma));
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if (*prev) {
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vma = *prev;
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goto success;
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}
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*prev = vma;
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if (start != vma->vm_start) {
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ret = split_vma(mm, vma, start, 1);
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if (ret)
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goto out;
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}
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if (end != vma->vm_end) {
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ret = split_vma(mm, vma, end, 0);
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if (ret)
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goto out;
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}
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success:
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/*
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* vm_flags is protected by the mmap_sem held in write mode.
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* It's okay if try_to_unmap_one unmaps a page just after we
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* set VM_LOCKED, make_pages_present below will bring it back.
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*/
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vma->vm_flags = newflags;
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/*
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* Keep track of amount of locked VM.
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*/
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pages = (end - start) >> PAGE_SHIFT;
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if (newflags & VM_LOCKED) {
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pages = -pages;
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if (!(newflags & VM_IO))
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ret = make_pages_present(start, end);
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}
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vma->vm_mm->locked_vm -= pages;
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out:
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if (ret == -ENOMEM)
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ret = -EAGAIN;
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return ret;
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}
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static int do_mlock(unsigned long start, size_t len, int on)
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{
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unsigned long nstart, end, tmp;
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struct vm_area_struct * vma, * prev;
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int error;
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len = PAGE_ALIGN(len);
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end = start + len;
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if (end < start)
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return -EINVAL;
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if (end == start)
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return 0;
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vma = find_vma_prev(current->mm, start, &prev);
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if (!vma || vma->vm_start > start)
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return -ENOMEM;
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if (start > vma->vm_start)
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prev = vma;
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for (nstart = start ; ; ) {
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unsigned int newflags;
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/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
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newflags = vma->vm_flags | VM_LOCKED;
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if (!on)
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newflags &= ~VM_LOCKED;
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tmp = vma->vm_end;
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if (tmp > end)
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tmp = end;
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error = mlock_fixup(vma, &prev, nstart, tmp, newflags);
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if (error)
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break;
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nstart = tmp;
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if (nstart < prev->vm_end)
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nstart = prev->vm_end;
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if (nstart >= end)
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break;
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vma = prev->vm_next;
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if (!vma || vma->vm_start != nstart) {
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error = -ENOMEM;
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break;
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}
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}
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return error;
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}
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asmlinkage long sys_mlock(unsigned long start, size_t len)
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{
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unsigned long locked;
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unsigned long lock_limit;
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int error = -ENOMEM;
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if (!can_do_mlock())
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return -EPERM;
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down_write(¤t->mm->mmap_sem);
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len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
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start &= PAGE_MASK;
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locked = len >> PAGE_SHIFT;
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locked += current->mm->locked_vm;
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lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
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lock_limit >>= PAGE_SHIFT;
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/* check against resource limits */
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if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
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error = do_mlock(start, len, 1);
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up_write(¤t->mm->mmap_sem);
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return error;
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}
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asmlinkage long sys_munlock(unsigned long start, size_t len)
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{
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int ret;
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down_write(¤t->mm->mmap_sem);
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len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
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start &= PAGE_MASK;
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ret = do_mlock(start, len, 0);
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up_write(¤t->mm->mmap_sem);
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return ret;
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}
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static int do_mlockall(int flags)
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{
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struct vm_area_struct * vma, * prev = NULL;
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unsigned int def_flags = 0;
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if (flags & MCL_FUTURE)
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def_flags = VM_LOCKED;
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current->mm->def_flags = def_flags;
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if (flags == MCL_FUTURE)
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goto out;
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for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
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unsigned int newflags;
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newflags = vma->vm_flags | VM_LOCKED;
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if (!(flags & MCL_CURRENT))
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newflags &= ~VM_LOCKED;
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/* Ignore errors */
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mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
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}
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out:
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return 0;
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}
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asmlinkage long sys_mlockall(int flags)
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{
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unsigned long lock_limit;
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int ret = -EINVAL;
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if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
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goto out;
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ret = -EPERM;
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if (!can_do_mlock())
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goto out;
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down_write(¤t->mm->mmap_sem);
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lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
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lock_limit >>= PAGE_SHIFT;
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ret = -ENOMEM;
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if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
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capable(CAP_IPC_LOCK))
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ret = do_mlockall(flags);
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up_write(¤t->mm->mmap_sem);
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out:
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return ret;
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}
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asmlinkage long sys_munlockall(void)
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{
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int ret;
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down_write(¤t->mm->mmap_sem);
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ret = do_mlockall(0);
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up_write(¤t->mm->mmap_sem);
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return ret;
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}
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/*
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* Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
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* shm segments) get accounted against the user_struct instead.
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*/
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static DEFINE_SPINLOCK(shmlock_user_lock);
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int user_shm_lock(size_t size, struct user_struct *user)
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{
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unsigned long lock_limit, locked;
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int allowed = 0;
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locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
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lock_limit >>= PAGE_SHIFT;
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spin_lock(&shmlock_user_lock);
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if (locked + user->locked_shm > lock_limit && !capable(CAP_IPC_LOCK))
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goto out;
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get_uid(user);
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user->locked_shm += locked;
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allowed = 1;
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out:
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spin_unlock(&shmlock_user_lock);
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return allowed;
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}
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void user_shm_unlock(size_t size, struct user_struct *user)
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{
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spin_lock(&shmlock_user_lock);
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user->locked_shm -= (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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spin_unlock(&shmlock_user_lock);
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free_uid(user);
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}
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