sys_ia32.c

linux 内核源代码

	gid_t a, b, c;
	int ret;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	ret = sys_getresgid((gid_t __user *) &a, (gid_t __user *) &b, (gid_t __user *) &c);
	set_fs(old_fs);

	if (ret)
		return ret;

	return put_user(a, rgid) | put_user(b, egid) | put_user(c, sgid);
}

asmlinkage long
sys32_lseek (unsigned int fd, int offset, unsigned int whence)
{
	/* Sign-extension of "offset" is important here... */
	return sys_lseek(fd, offset, whence);
}

static int
groups16_to_user(short __user *grouplist, struct group_info *group_info)
{
	int i;
	short group;

	for (i = 0; i < group_info->ngroups; i++) {
		group = (short)GROUP_AT(group_info, i);
		if (put_user(group, grouplist+i))
			return -EFAULT;
	}

	return 0;
}

static int
groups16_from_user(struct group_info *group_info, short __user *grouplist)
{
	int i;
	short group;

	for (i = 0; i < group_info->ngroups; i++) {
		if (get_user(group, grouplist+i))
			return  -EFAULT;
		GROUP_AT(group_info, i) = (gid_t)group;
	}

	return 0;
}

asmlinkage long
sys32_getgroups16 (int gidsetsize, short __user *grouplist)
{
	int i;

	if (gidsetsize < 0)
		return -EINVAL;

	get_group_info(current->group_info);
	i = current->group_info->ngroups;
	if (gidsetsize) {
		if (i > gidsetsize) {
			i = -EINVAL;
			goto out;
		}
		if (groups16_to_user(grouplist, current->group_info)) {
			i = -EFAULT;
			goto out;
		}
	}
out:
	put_group_info(current->group_info);
	return i;
}

asmlinkage long
sys32_setgroups16 (int gidsetsize, short __user *grouplist)
{
	struct group_info *group_info;
	int retval;

	if (!capable(CAP_SETGID))
		return -EPERM;
	if ((unsigned)gidsetsize > NGROUPS_MAX)
		return -EINVAL;

	group_info = groups_alloc(gidsetsize);
	if (!group_info)
		return -ENOMEM;
	retval = groups16_from_user(group_info, grouplist);
	if (retval) {
		put_group_info(group_info);
		return retval;
	}

	retval = set_current_groups(group_info);
	put_group_info(group_info);

	return retval;
}

asmlinkage long
sys32_truncate64 (unsigned int path, unsigned int len_lo, unsigned int len_hi)
{
	return sys_truncate(compat_ptr(path), ((unsigned long) len_hi << 32) | len_lo);
}

asmlinkage long
sys32_ftruncate64 (int fd, unsigned int len_lo, unsigned int len_hi)
{
	return sys_ftruncate(fd, ((unsigned long) len_hi << 32) | len_lo);
}

static int
putstat64 (struct stat64 __user *ubuf, struct kstat *kbuf)
{
	int err;
	u64 hdev;

	if (clear_user(ubuf, sizeof(*ubuf)))
		return -EFAULT;

	hdev = huge_encode_dev(kbuf->dev);
	err  = __put_user(hdev, (u32 __user*)&ubuf->st_dev);
	err |= __put_user(hdev >> 32, ((u32 __user*)&ubuf->st_dev) + 1);
	err |= __put_user(kbuf->ino, &ubuf->__st_ino);
	err |= __put_user(kbuf->ino, &ubuf->st_ino_lo);
	err |= __put_user(kbuf->ino >> 32, &ubuf->st_ino_hi);
	err |= __put_user(kbuf->mode, &ubuf->st_mode);
	err |= __put_user(kbuf->nlink, &ubuf->st_nlink);
	err |= __put_user(kbuf->uid, &ubuf->st_uid);
	err |= __put_user(kbuf->gid, &ubuf->st_gid);
	hdev = huge_encode_dev(kbuf->rdev);
	err  = __put_user(hdev, (u32 __user*)&ubuf->st_rdev);
	err |= __put_user(hdev >> 32, ((u32 __user*)&ubuf->st_rdev) + 1);
	err |= __put_user(kbuf->size, &ubuf->st_size_lo);
	err |= __put_user((kbuf->size >> 32), &ubuf->st_size_hi);
	err |= __put_user(kbuf->atime.tv_sec, &ubuf->st_atime);
	err |= __put_user(kbuf->atime.tv_nsec, &ubuf->st_atime_nsec);
	err |= __put_user(kbuf->mtime.tv_sec, &ubuf->st_mtime);
	err |= __put_user(kbuf->mtime.tv_nsec, &ubuf->st_mtime_nsec);
	err |= __put_user(kbuf->ctime.tv_sec, &ubuf->st_ctime);
	err |= __put_user(kbuf->ctime.tv_nsec, &ubuf->st_ctime_nsec);
	err |= __put_user(kbuf->blksize, &ubuf->st_blksize);
	err |= __put_user(kbuf->blocks, &ubuf->st_blocks);
	return err;
}

asmlinkage long
sys32_stat64 (char __user *filename, struct stat64 __user *statbuf)
{
	struct kstat s;
	long ret = vfs_stat(filename, &s);
	if (!ret)
		ret = putstat64(statbuf, &s);
	return ret;
}

asmlinkage long
sys32_lstat64 (char __user *filename, struct stat64 __user *statbuf)
{
	struct kstat s;
	long ret = vfs_lstat(filename, &s);
	if (!ret)
		ret = putstat64(statbuf, &s);
	return ret;
}

asmlinkage long
sys32_fstat64 (unsigned int fd, struct stat64 __user *statbuf)
{
	struct kstat s;
	long ret = vfs_fstat(fd, &s);
	if (!ret)
		ret = putstat64(statbuf, &s);
	return ret;
}

asmlinkage long
sys32_sched_rr_get_interval (pid_t pid, struct compat_timespec __user *interval)
{
	mm_segment_t old_fs = get_fs();
	struct timespec t;
	long ret;

	set_fs(KERNEL_DS);
	ret = sys_sched_rr_get_interval(pid, (struct timespec __user *) &t);
	set_fs(old_fs);
	if (put_compat_timespec(&t, interval))
		return -EFAULT;
	return ret;
}

asmlinkage long
sys32_pread (unsigned int fd, void __user *buf, unsigned int count, u32 pos_lo, u32 pos_hi)
{
	return sys_pread64(fd, buf, count, ((unsigned long) pos_hi << 32) | pos_lo);
}

asmlinkage long
sys32_pwrite (unsigned int fd, void __user *buf, unsigned int count, u32 pos_lo, u32 pos_hi)
{
	return sys_pwrite64(fd, buf, count, ((unsigned long) pos_hi << 32) | pos_lo);
}

asmlinkage long
sys32_sendfile (int out_fd, int in_fd, int __user *offset, unsigned int count)
{
	mm_segment_t old_fs = get_fs();
	long ret;
	off_t of;

	if (offset && get_user(of, offset))
		return -EFAULT;

	set_fs(KERNEL_DS);
	ret = sys_sendfile(out_fd, in_fd, offset ? (off_t __user *) &of : NULL, count);
	set_fs(old_fs);

	if (offset && put_user(of, offset))
		return -EFAULT;

	return ret;
}

asmlinkage long
sys32_personality (unsigned int personality)
{
	long ret;

	if (current->personality == PER_LINUX32 && personality == PER_LINUX)
		personality = PER_LINUX32;
	ret = sys_personality(personality);
	if (ret == PER_LINUX32)
		ret = PER_LINUX;
	return ret;
}

asmlinkage unsigned long
sys32_brk (unsigned int brk)
{
	unsigned long ret, obrk;
	struct mm_struct *mm = current->mm;

	obrk = mm->brk;
	ret = sys_brk(brk);
	if (ret < obrk)
		clear_user(compat_ptr(ret), PAGE_ALIGN(ret) - ret);
	return ret;
}

/* Structure for ia32 emulation on ia64 */
struct epoll_event32
{
	u32 events;
	u32 data[2];
};

asmlinkage long
sys32_epoll_ctl(int epfd, int op, int fd, struct epoll_event32 __user *event)
{
	mm_segment_t old_fs = get_fs();
	struct epoll_event event64;
	int error;
	u32 data_halfword;

	if (!access_ok(VERIFY_READ, event, sizeof(struct epoll_event32)))
		return -EFAULT;

	__get_user(event64.events, &event->events);
	__get_user(data_halfword, &event->data[0]);
	event64.data = data_halfword;
	__get_user(data_halfword, &event->data[1]);
 	event64.data |= (u64)data_halfword << 32;

	set_fs(KERNEL_DS);
	error = sys_epoll_ctl(epfd, op, fd, (struct epoll_event __user *) &event64);
	set_fs(old_fs);

	return error;
}

asmlinkage long
sys32_epoll_wait(int epfd, struct epoll_event32 __user * events, int maxevents,
		 int timeout)
{
	struct epoll_event *events64 = NULL;
	mm_segment_t old_fs = get_fs();
	int numevents, size;
	int evt_idx;
	int do_free_pages = 0;

	if (maxevents <= 0) {
		return -EINVAL;
	}

	/* Verify that the area passed by the user is writeable */
	if (!access_ok(VERIFY_WRITE, events, maxevents * sizeof(struct epoll_event32)))
		return -EFAULT;

	/*
 	 * Allocate space for the intermediate copy.  If the space needed
	 * is large enough to cause kmalloc to fail, then try again with
	 * __get_free_pages.
	 */
	size = maxevents * sizeof(struct epoll_event);
	events64 = kmalloc(size, GFP_KERNEL);
	if (events64 == NULL) {
		events64 = (struct epoll_event *)
				__get_free_pages(GFP_KERNEL, get_order(size));
		if (events64 == NULL)
			return -ENOMEM;
		do_free_pages = 1;
	}

	/* Do the system call */
	set_fs(KERNEL_DS); /* copy_to/from_user should work on kernel mem*/
	numevents = sys_epoll_wait(epfd, (struct epoll_event __user *) events64,
				   maxevents, timeout);
	set_fs(old_fs);

	/* Don't modify userspace memory if we're returning an error */
	if (numevents > 0) {
		/* Translate the 64-bit structures back into the 32-bit
		   structures */
		for (evt_idx = 0; evt_idx < numevents; evt_idx++) {
			__put_user(events64[evt_idx].events,
				   &events[evt_idx].events);
			__put_user((u32)events64[evt_idx].data,
				   &events[evt_idx].data[0]);
			__put_user((u32)(events64[evt_idx].data >> 32),
				   &events[evt_idx].data[1]);
		}
	}

	if (do_free_pages)
		free_pages((unsigned long) events64, get_order(size));
	else
		kfree(events64);
	return numevents;
}

/*
 * Get a yet unused TLS descriptor index.
 */
static int
get_free_idx (void)
{
	struct thread_struct *t = &current->thread;
	int idx;

	for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
		if (desc_empty(t->tls_array + idx))
			return idx + GDT_ENTRY_TLS_MIN;
	return -ESRCH;
}

/*
 * Set a given TLS descriptor:
 */
asmlinkage int
sys32_set_thread_area (struct ia32_user_desc __user *u_info)
{
	struct thread_struct *t = &current->thread;
	struct ia32_user_desc info;
	struct desc_struct *desc;
	int cpu, idx;

	if (copy_from_user(&info, u_info, sizeof(info)))
		return -EFAULT;
	idx = info.entry_number;

	/*
	 * index -1 means the kernel should try to find and allocate an empty descriptor:
	 */
	if (idx == -1) {
		idx = get_free_idx();
		if (idx < 0)
			return idx;
		if (put_user(idx, &u_info->entry_number))
			return -EFAULT;
	}

	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
		return -EINVAL;

	desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN;

	cpu = smp_processor_id();

	if (LDT_empty(&info)) {
		desc->a = 0;
		desc->b = 0;
	} else {
		desc->a = LDT_entry_a(&info);
		desc->b = LDT_entry_b(&info);
	}
	load_TLS(t, cpu);
	return 0;
}

/*
 * Get the current Thread-Local Storage area:
 */

#define GET_BASE(desc) (			\
	(((desc)->a >> 16) & 0x0000ffff) |	\
	(((desc)->b << 16) & 0x00ff0000) |	\
	( (desc)->b        & 0xff000000)   )

#define GET_LIMIT(desc) (			\
	((desc)->a & 0x0ffff) |			\
	 ((desc)->b & 0xf0000) )

#define GET_32BIT(desc)		(((desc)->b >> 22) & 1)
#define GET_CONTENTS(desc)	(((desc)->b >> 10) & 3)
#define GET_WRITABLE(desc)	(((desc)->b >>  9) & 1)
#define GET_LIMIT_PAGES(desc)	(((desc)->b >> 23) & 1)
#define GET_PRESENT(desc)	(((desc)->b >> 15) & 1)
#define GET_USEABLE(desc)	(((desc)->b >> 20) & 1)

asmlinkage int
sys32_get_thread_area (struct ia32_user_desc __user *u_info)
{
	struct ia32_user_desc info;
	struct desc_struct *desc;
	int idx;

	if (get_user(idx, &u_info->entry_number))
		return -EFAULT;
	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
		return -EINVAL;

	desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;

	info.entry_number = idx;
	info.base_addr = GET_BASE(desc);
	info.limit = GET_LIMIT(desc);
	info.seg_32bit = GET_32BIT(desc);
	info.contents = GET_CONTENTS(desc);
	info.read_exec_only = !GET_WRITABLE(desc);
	info.limit_in_pages = GET_LIMIT_PAGES(desc);
	info.seg_not_present = !GET_PRESENT(desc);
	info.useable = GET_USEABLE(desc);

	if (copy_to_user(u_info, &info, sizeof(info)))
		return -EFAULT;
	return 0;
}

long sys32_fadvise64_64(int fd, __u32 offset_low, __u32 offset_high, 
			__u32 len_low, __u32 len_high, int advice)
{ 
	return sys_fadvise64_64(fd,
			       (((u64)offset_high)<<32) | offset_low,
			       (((u64)len_high)<<32) | len_low,
			       advice); 
} 

#ifdef	NOTYET  /* UNTESTED FOR IA64 FROM HERE DOWN */

asmlinkage long sys32_setreuid(compat_uid_t ruid, compat_uid_t euid)
{
	uid_t sruid, seuid;

	sruid = (ruid == (compat_uid_t)-1) ? ((uid_t)-1) : ((uid_t)ruid);
	seuid = (euid == (compat_uid_t)-1) ? ((uid_t)-1) : ((uid_t)euid);
	return sys_setreuid(sruid, seuid);
}

asmlinkage long
sys32_setresuid(compat_uid_t ruid, compat_uid_t euid,
		compat_uid_t suid)
{
	uid_t sruid, seuid, ssuid;

	sruid = (ruid == (compat_uid_t)-1) ? ((uid_t)-1) : ((uid_t)ruid);
	seuid = (euid == (compat_uid_t)-1) ? ((uid_t)-1) : ((uid_t)euid);
	ssuid = (suid == (compat_uid_t)-1) ? ((uid_t)-1) : ((uid_t)suid);
	return sys_setresuid(sruid, seuid, ssuid);
}

asmlinkage long
sys32_setregid(compat_gid_t rgid, compat_gid_t egid)
{
	gid_t srgid, segid;

	srgid = (rgid == (compat_gid_t)-1) ? ((gid_t)-1) : ((gid_t)rgid);
	segid = (egid == (compat_gid_t)-1) ? ((gid_t)-1) : ((gid_t)egid);
	return sys_setregid(srgid, segid);
}

asmlinkage long
sys32_setresgid(compat_gid_t rgid, compat_gid_t egid,
		compat_gid_t sgid)
{
	gid_t srgid, segid, ssgid;

	srgid = (rgid == (compat_gid_t)-1) ? ((gid_t)-1) : ((gid_t)rgid);
	segid = (egid == (compat_gid_t)-1) ? ((gid_t)-1) : ((gid_t)egid);
	ssgid = (sgid == (compat_gid_t)-1) ? ((gid_t)-1) : ((gid_t)sgid);
	return sys_setresgid(srgid, segid, ssgid);
}
#endif /* NOTYET */