criu/fsnotify.c

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <signal.h>
#include <string.h>
#include <utime.h>
#include <dirent.h>
#include <limits.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/inotify.h>
#include <sys/vfs.h>
#include <sys/wait.h>
#include <sys/poll.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <aio.h>

#include <linux/fanotify.h>

#include "compiler.h"
#include "asm/types.h"
#include "fsnotify.h"
#include "proc_parse.h"
#include "syscall.h"
#include "crtools.h"
#include "mount.h"
#include "image.h"
#include "util.h"
#include "files.h"
#include "files-reg.h"
#include "file-ids.h"
#include "log.h"
#include "list.h"
#include "lock.h"

#include "protobuf.h"
#include "protobuf/fsnotify.pb-c.h"

#undef	LOG_PREFIX
#define LOG_PREFIX "fsnotify: "

struct fsnotify_mark_info {
	struct list_head		list;
	union {
		InotifyWdEntry		*iwe;
		FanotifyMarkEntry	*fme;
	};
	struct file_remap		*remap;
};

struct fsnotify_file_info {
	struct list_head		list;
	union {
		InotifyFileEntry	*ife;
		FanotifyFileEntry	*ffe;
	};
	struct list_head		marks;
	struct file_desc		d;
};

static LIST_HEAD(inotify_info_head);
static LIST_HEAD(fanotify_info_head);

/* Checks if file descriptor @lfd is inotify */
int is_inotify_link(int lfd)
{
	return is_anon_link_type(lfd, "inotify");
}

/* Checks if file descriptor @lfd is fanotify */
int is_fanotify_link(int lfd)
{
	return is_anon_link_type(lfd, "[fanotify]");
}

void show_inotify_wd(int fd_inotify_wd)
{
	pb_show_plain(fd_inotify_wd, PB_INOTIFY_WD);
}

void show_inotify(int fd_inotify)
{
	pb_show_plain(fd_inotify, PB_INOTIFY);
}

void show_fanotify_mark(int fd)
{
	pb_show_plain(fd, PB_FANOTIFY_MARK);
}

void show_fanotify(int fd)
{
	pb_show_plain(fd, PB_FANOTIFY);
}

static int dump_inotify_entry(union fdinfo_entries *e, void *arg)
{
	InotifyWdEntry *we = &e->ify;

	we->id = *(u32 *)arg;
	pr_info("wd: wd 0x%08x s_dev 0x%08x i_ino 0x%16"PRIx64" mask 0x%08x\n",
			we->wd, we->s_dev, we->i_ino, we->mask);
	pr_info("\t[fhandle] bytes 0x%08x type 0x%08x __handle 0x%016"PRIx64":0x%016"PRIx64"\n",
			we->f_handle->bytes, we->f_handle->type,
			we->f_handle->handle[0], we->f_handle->handle[1]);
	return pb_write_one(fdset_fd(glob_fdset, CR_FD_INOTIFY_WD), we, PB_INOTIFY_WD);
}

static int dump_one_inotify(int lfd, u32 id, const struct fd_parms *p)
{
	InotifyFileEntry ie = INOTIFY_FILE_ENTRY__INIT;

	ie.id = id;
	ie.flags = p->flags;
	ie.fown = (FownEntry *)&p->fown;

	pr_info("id 0x%08x flags 0x%08x\n", ie.id, ie.flags);
	if (pb_write_one(fdset_fd(glob_fdset, CR_FD_INOTIFY), &ie, PB_INOTIFY))
		return -1;

	return parse_fdinfo(lfd, FD_TYPES__INOTIFY, dump_inotify_entry, &id);
}

const struct fdtype_ops inotify_dump_ops = {
	.type		= FD_TYPES__INOTIFY,
	.dump		= dump_one_inotify,
};

static int dump_fanotify_entry(union fdinfo_entries *e, void *arg)
{
	struct fsnotify_params *fsn_params = arg;
	FanotifyMarkEntry *fme = &e->ffy;

	fme->id = fsn_params->id;

	if (fme->type == MARK_TYPE__INODE) {

		BUG_ON(!fme->ie);

		pr_info("mark: s_dev 0x%08x i_ino 0x%016"PRIx64" mask 0x%08x\n",
			fme->s_dev, fme->ie->i_ino, fme->mask);

		pr_info("\t[fhandle] bytes 0x%08x type 0x%08x __handle 0x%016"PRIx64":0x%016"PRIx64"\n",
			fme->ie->f_handle->bytes, fme->ie->f_handle->type,
			fme->ie->f_handle->handle[0], fme->ie->f_handle->handle[1]);
	}

	if (fme->type == MARK_TYPE__MOUNT) {
		struct mount_info *m;

		BUG_ON(!fme->me);

		m = lookup_mnt_id(fme->me->mnt_id);
		if (!m) {
			pr_err("Can't find mnt_id %x\n", fme->me->mnt_id);
			return -1;
		}
		fme->s_dev = m->s_dev;

		pr_info("mark: s_dev 0x%08x mnt_id  0x%08x mask 0x%08x\n",
			fme->s_dev, fme->me->mnt_id, fme->mask);

	}

	return pb_write_one(fdset_fd(glob_fdset, CR_FD_FANOTIFY_MARK), fme, PB_FANOTIFY_MARK);
}

static int dump_one_fanotify(int lfd, u32 id, const struct fd_parms *p)
{
	FanotifyFileEntry fe = FANOTIFY_FILE_ENTRY__INIT;
	struct fsnotify_params fsn_params = { .id = id, };

	fe.id = id;
	fe.flags = p->flags;
	fe.fown = (FownEntry *)&p->fown;

	if (parse_fdinfo(lfd, FD_TYPES__FANOTIFY,
			 dump_fanotify_entry, &fsn_params) < 0)
		return -1;

	pr_info("id 0x%08x flags 0x%08x\n", fe.id, fe.flags);

	fe.faflags = fsn_params.faflags;
	fe.evflags = fsn_params.evflags;

	return pb_write_one(fdset_fd(glob_fdset, CR_FD_FANOTIFY), &fe, PB_FANOTIFY);
}

const struct fdtype_ops fanotify_dump_ops = {
	.type		= FD_TYPES__FANOTIFY,
	.dump		= dump_one_fanotify,
};

static char *get_mark_path(const char *who, struct file_remap *remap,
			   FhEntry *f_handle, unsigned long i_ino,
			   unsigned int s_dev, char *buf, size_t size,
			   int *target)
{
	char *path = NULL;
	int mntfd = -1;
	fh_t handle;

	if (!remap) {
		memzero(&handle, sizeof(handle));

		handle.type	= f_handle->type;
		handle.bytes	= f_handle->bytes;

		memcpy(handle.__handle, f_handle->handle,
		       min(pb_repeated_size(f_handle, handle),
			   sizeof(handle.__handle)));

		mntfd = open_mount(s_dev);
		if (mntfd < 0) {
			pr_err("Mount root for 0x%08x not found\n", s_dev);
			goto err;
		}

		*target = sys_open_by_handle_at(mntfd, (void *)&handle, 0);
		if (*target < 0) {
			pr_perror("Can't open file handle for 0x%08x:0x%016lx",
				  s_dev, i_ino);
			goto err;
		}
		snprintf(buf, size, "/proc/self/fd/%d", *target);
		path = buf;
	} else {
		*target = -1;
		path = remap->path;
	}

	pr_debug("\t\tRestore %s watch for 0x%08x:0x%016lx (via %s)\n",
		 who, s_dev, i_ino, path);

err:
	close_safe(&mntfd);
	return path;
}

static int restore_one_inotify(int inotify_fd, struct fsnotify_mark_info *info)
{
	InotifyWdEntry *iwe = info->iwe;
	int ret = -1, wd, target = -1;
	char buf[32], *path;

	path = get_mark_path("inotify", info->remap, iwe->f_handle,
			     iwe->i_ino, iwe->s_dev, buf, sizeof(buf),
			     &target);
	if (!path)
		goto err;

	/*
	 * FIXME The kernel allocates wd-s sequentially,
	 * this is suboptimal, but the kernel doesn't
	 * provide and API for this yet :(
	 */
	wd = 1;
	while (wd >= 0) {
		wd = inotify_add_watch(inotify_fd, path, iwe->mask);
		if (wd < 0) {
			pr_err("Can't add watch for %d with %d\n", inotify_fd, iwe->wd);
			break;
		} else if (wd == iwe->wd) {
			ret = 0;
			break;
		} else if (wd > iwe->wd) {
			pr_err("Unsorted watch found for %d with %d\n", inotify_fd, iwe->wd);
			break;
		}

		pr_debug("\t\tWatch got %d but %d expected\n", wd, iwe->wd);
		inotify_rm_watch(inotify_fd, wd);
	}

err:
	if (info->remap)
		remap_put(info->remap);

	close_safe(&target);
	return ret;
}

static int restore_one_fanotify(int fd, struct fsnotify_mark_info *mark)
{
	FanotifyMarkEntry *fme = mark->fme;
	unsigned int flags = FAN_MARK_ADD;
	int ret = -1, target = -1;
	char buf[32], *path = NULL;

	if (fme->type == MARK_TYPE__MOUNT) {
		struct mount_info *m;

		m = lookup_mnt_sdev(fme->s_dev);
		if (!m) {
			pr_err("Can't find mount s_dev %x\n", fme->s_dev);
			return -1;
		}

		flags |= FAN_MARK_MOUNT;
		path = m->mountpoint;
	} else if (fme->type == MARK_TYPE__INODE) {
		path = get_mark_path("fanotify", mark->remap,
				     fme->ie->f_handle, fme->ie->i_ino,
				     fme->s_dev, buf, sizeof(buf), &target);
		if (!path)
			goto err;
	} else
		BUG();

	flags |= fme->mflags;

	if (mark->fme->mask) {
		ret = sys_fanotify_mark(fd, flags, fme->mask, AT_FDCWD, path);
		if (ret) {
			pr_err("Adding fanotify mask %x on %x/%s failed (%d)\n",
			       fme->mask, fme->id, path, ret);
			goto err;
		}
	}

	if (fme->ignored_mask) {
		ret = sys_fanotify_mark(fd, flags | FAN_MARK_IGNORED_MASK,
					fme->ignored_mask, AT_FDCWD, path);
		if (ret) {
			pr_err("Adding fanotify ignored-mask %x on %x/%s failed (%d)\n",
			       fme->ignored_mask, fme->id, path, ret);
			goto err;
		}
	}

	if (mark->remap)
		remap_put(mark->remap);

err:
	close_safe(&target);
	return ret;
}

static int open_inotify_fd(struct file_desc *d)
{
	struct fsnotify_file_info *info;
	struct fsnotify_mark_info *wd_info;
	int tmp;

	info = container_of(d, struct fsnotify_file_info, d);

	tmp = inotify_init1(info->ife->flags);
	if (tmp < 0) {
		pr_perror("Can't create inotify for 0x%08x", info->ife->id);
		return -1;
	}

	list_for_each_entry(wd_info, &info->marks, list) {
		pr_info("\tRestore inotify for 0x%08x\n", wd_info->iwe->id);
		if (restore_one_inotify(tmp, wd_info)) {
			close_safe(&tmp);
			break;
		}
	}

	if (restore_fown(tmp, info->ife->fown))
		close_safe(&tmp);

	return tmp;
}

static int open_fanotify_fd(struct file_desc *d)
{
	struct fsnotify_file_info *info;
	struct fsnotify_mark_info *mark;
	unsigned int flags = 0;
	int ret;

	info = container_of(d, struct fsnotify_file_info, d);

	flags = info->ffe->faflags;
	if (info->ffe->flags & O_CLOEXEC)
		flags |= FAN_CLOEXEC;
	if (info->ffe->flags & O_NONBLOCK)
		flags |= FAN_NONBLOCK;

	ret = sys_fanotify_init(flags, info->ffe->evflags);
	if (ret < 0) {
		errno = -ret;
		pr_perror("Can't init fanotify mark (%d)", ret);
		return -1;
	}

	list_for_each_entry(mark, &info->marks, list) {
		pr_info("\tRestore fanotify for 0x%08x\n", mark->fme->id);
		if (restore_one_fanotify(ret, mark)) {
			close_safe(&ret);
			break;
		}
	}

	if (restore_fown(ret, info->ffe->fown))
		close_safe(&ret);

	return ret;
}

static struct file_desc_ops inotify_desc_ops = {
	.type = FD_TYPES__INOTIFY,
	.open = open_inotify_fd,
};

static struct file_desc_ops fanotify_desc_ops = {
	.type = FD_TYPES__FANOTIFY,
	.open = open_fanotify_fd,
};

static int collect_inotify_mark(struct fsnotify_mark_info *mark)
{
	struct fsnotify_file_info *p;

	list_for_each_entry(p, &inotify_info_head, list) {
		if (p->ife->id == mark->iwe->id) {
			list_add(&mark->list, &p->marks);
			mark->remap = lookup_ghost_remap(mark->iwe->s_dev, mark->iwe->i_ino);
			return 0;
		}
	}

	pr_err("Can't find inotify with id 0x%08x\n", mark->iwe->id);
	return -1;
}

static int collect_fanotify_mark(struct fsnotify_mark_info *mark)
{
	struct fsnotify_file_info *p;

	list_for_each_entry(p, &fanotify_info_head, list) {
		if (p->ffe->id == mark->fme->id) {
			list_add(&mark->list, &p->marks);
			if (mark->fme->type == MARK_TYPE__INODE)
				mark->remap = lookup_ghost_remap(mark->fme->s_dev,
								 mark->fme->ie->i_ino);
			return 0;
		}
	}

	pr_err("Can't find fanotify with id 0x%08x\n", mark->fme->id);
	return -1;
}

static int collect_one_inotify(void *o, ProtobufCMessage *msg)
{
	struct fsnotify_file_info *info = o;

	info->ife = pb_msg(msg, InotifyFileEntry);
	INIT_LIST_HEAD(&info->marks);
	list_add(&info->list, &inotify_info_head);
	pr_info("Collected id 0x%08x flags 0x%08x\n", info->ife->id, info->ife->flags);
	return file_desc_add(&info->d, info->ife->id, &inotify_desc_ops);
}

static int collect_one_fanotify(void *o, ProtobufCMessage *msg)
{
	struct fsnotify_file_info *info = o;

	info->ffe = pb_msg(msg, FanotifyFileEntry);
	INIT_LIST_HEAD(&info->marks);
	list_add(&info->list, &fanotify_info_head);
	pr_info("Collected id 0x%08x flags 0x%08x\n", info->ffe->id, info->ffe->flags);
	return file_desc_add(&info->d, info->ffe->id, &fanotify_desc_ops);
}

static int collect_one_inotify_mark(void *o, ProtobufCMessage *msg)
{
	struct fsnotify_mark_info *mark = o;

	mark->iwe = pb_msg(msg, InotifyWdEntry);
	INIT_LIST_HEAD(&mark->list);
	mark->remap = NULL;

	return collect_inotify_mark(mark);
}

static int collect_one_fanotify_mark(void *o, ProtobufCMessage *msg)
{
	struct fsnotify_mark_info *mark = o;

	mark->fme = pb_msg(msg, FanotifyMarkEntry);
	INIT_LIST_HEAD(&mark->list);
	mark->remap = NULL;

	return collect_fanotify_mark(mark);
}

int collect_inotify(void)
{
	int ret;

	ret = collect_image(CR_FD_INOTIFY, PB_INOTIFY,
			sizeof(struct fsnotify_file_info), collect_one_inotify);
	if (ret && errno == ENOENT)
		return 0;
	if (!ret)
		ret = collect_image(CR_FD_INOTIFY_WD, PB_INOTIFY_WD,
				sizeof(struct fsnotify_mark_info),
				collect_one_inotify_mark);
	if (!ret)
		ret = collect_image(CR_FD_FANOTIFY, PB_FANOTIFY,
				    sizeof(struct fsnotify_file_info),
				    collect_one_fanotify);
	if (ret && errno == ENOENT)
		return 0;
	if (!ret)
		ret = collect_image(CR_FD_FANOTIFY_MARK, PB_FANOTIFY_MARK,
				    sizeof(struct fsnotify_mark_info),
				    collect_one_fanotify_mark);
	return ret;
}