lvm2/lib/activate/fs.c

/*
 * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.  
 * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
 *
 * This file is part of LVM2.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License v.2.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "lib.h"
#include "fs.h"
#include "toolcontext.h"
#include "lvm-string.h"
#include "lvm-file.h"
#include "memlock.h"

#ifdef HAVE_SELINUX
#  include "selinux.h"
#endif

#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <limits.h>
#include <dirent.h>
#include <libdevmapper.h>

static int _mk_dir(const char *dev_dir, const char *vg_name)
{
	char vg_path[PATH_MAX];

	if (lvm_snprintf(vg_path, sizeof(vg_path), "%s%s",
			 dev_dir, vg_name) == -1) {
		log_error("Couldn't construct name of volume "
			  "group directory.");
		return 0;
	}

	if (dir_exists(vg_path))
		return 1;

	log_very_verbose("Creating directory %s", vg_path);
	if (mkdir(vg_path, 0777)) {
		log_sys_error("mkdir", vg_path);
		return 0;
	}

	return 1;
}

static int _rm_dir(const char *dev_dir, const char *vg_name)
{
	char vg_path[PATH_MAX];

	if (lvm_snprintf(vg_path, sizeof(vg_path), "%s%s",
			 dev_dir, vg_name) == -1) {
		log_error("Couldn't construct name of volume "
			  "group directory.");
		return 0;
	}

	log_very_verbose("Removing directory %s", vg_path);

	if (is_empty_dir(vg_path))
		rmdir(vg_path);

	return 1;
}

static void _rm_blks(const char *dir)
{
	const char *name;
	char path[PATH_MAX];
	struct dirent *dirent;
	struct stat buf;
	DIR *d;

	if (!(d = opendir(dir))) {
		log_sys_error("opendir", dir);
		return;
	}

	while ((dirent = readdir(d))) {
		name = dirent->d_name;

		if (!strcmp(name, ".") || !strcmp(name, ".."))
			continue;

		if (lvm_snprintf(path, sizeof(path), "%s/%s", dir, name) == -1) {
			log_error("Couldn't create path for %s", name);
			continue;
		}

		if (!lstat(path, &buf)) {
			if (!S_ISBLK(buf.st_mode))
				continue;
			log_very_verbose("Removing %s", path);
			if (unlink(path) < 0)
				log_sys_error("unlink", path);
		}
	}
}

static int _mk_link(const char *dev_dir, const char *vg_name,
		    const char *lv_name, const char *dev)
{
	char lv_path[PATH_MAX], link_path[PATH_MAX], lvm1_group_path[PATH_MAX];
	char vg_path[PATH_MAX];
	struct stat buf;

	if (lvm_snprintf(vg_path, sizeof(vg_path), "%s%s",
			 dev_dir, vg_name) == -1) {
		log_error("Couldn't create path for volume group dir %s",
			  vg_name);
		return 0;
	}

	if (lvm_snprintf(lv_path, sizeof(lv_path), "%s/%s", vg_path,
			 lv_name) == -1) {
		log_error("Couldn't create source pathname for "
			  "logical volume link %s", lv_name);
		return 0;
	}

	if (lvm_snprintf(link_path, sizeof(link_path), "%s/%s",
			 dm_dir(), dev) == -1) {
		log_error("Couldn't create destination pathname for "
			  "logical volume link for %s", lv_name);
		return 0;
	}

	if (lvm_snprintf(lvm1_group_path, sizeof(lvm1_group_path), "%s/group",
			 vg_path) == -1) {
		log_error("Couldn't create pathname for LVM1 group file for %s",
			  vg_name);
		return 0;
	}

	/* To reach this point, the VG must have been locked.
	 * As locking fails if the VG is active under LVM1, it's 
	 * now safe to remove any LVM1 devices we find here
	 * (as well as any existing LVM2 symlink). */
	if (!lstat(lvm1_group_path, &buf)) {
		if (!S_ISCHR(buf.st_mode)) {
			log_error("Non-LVM1 character device found at %s",
				  lvm1_group_path);
		} else {
			_rm_blks(vg_path);

			log_very_verbose("Removing %s", lvm1_group_path);
			if (unlink(lvm1_group_path) < 0)
				log_sys_error("unlink", lvm1_group_path);
		}
	}

	if (!lstat(lv_path, &buf)) {
		if (!S_ISLNK(buf.st_mode) && !S_ISBLK(buf.st_mode)) {
			log_error("Symbolic link %s not created: file exists",
				  link_path);
			return 0;
		}

		log_very_verbose("Removing %s", lv_path);
		if (unlink(lv_path) < 0) {
			log_sys_error("unlink", lv_path);
			return 0;
		}
	}

	log_very_verbose("Linking %s -> %s", lv_path, link_path);
	if (symlink(link_path, lv_path) < 0) {
		log_sys_error("symlink", lv_path);
		return 0;
	}

#ifdef HAVE_SELINUX
        if (!set_selinux_context(lv_path)) {
                stack;
                return 0;
        }
#endif

	return 1;
}

static int _rm_link(const char *dev_dir, const char *vg_name,
		    const char *lv_name)
{
	struct stat buf;
	char lv_path[PATH_MAX];

	if (lvm_snprintf(lv_path, sizeof(lv_path), "%s%s/%s",
			 dev_dir, vg_name, lv_name) == -1) {
		log_error("Couldn't determine link pathname.");
		return 0;
	}

	if (lstat(lv_path, &buf) || !S_ISLNK(buf.st_mode)) {
		if (errno != ENOENT)
			log_error("%s not symbolic link - not removing",
				  lv_path);
		return 0;
	}

	log_very_verbose("Removing link %s", lv_path);
	if (unlink(lv_path) < 0) {
		log_sys_error("unlink", lv_path);
		return 0;
	}

	return 1;
}

typedef enum {
	FS_ADD,
	FS_DEL,
	FS_RENAME
} fs_op_t;

static int _do_fs_op(fs_op_t type, const char *dev_dir, const char *vg_name,
		     const char *lv_name, const char *dev,
		     const char *old_lv_name)
{
	switch (type) {
	case FS_ADD:
		if (!_mk_dir(dev_dir, vg_name) ||
		    !_mk_link(dev_dir, vg_name, lv_name, dev)) {
			stack;
			return 0;
		}
		break;
	case FS_DEL:
		if (!_rm_link(dev_dir, vg_name, lv_name) ||
		    !_rm_dir(dev_dir, vg_name)) {
			stack;
			return 0;
		}
		break;
		/* FIXME Use rename() */
	case FS_RENAME:
		if (old_lv_name && !_rm_link(dev_dir, vg_name, old_lv_name))
			stack;

		if (!_mk_link(dev_dir, vg_name, lv_name, dev))
			stack;
	}

	return 1;
}

static LIST_INIT(_fs_ops);

struct fs_op_parms {
	struct list list;
	fs_op_t type;
	char *dev_dir;
	char *vg_name;
	char *lv_name;
	char *dev;
	char *old_lv_name;
	char names[0];
};

static void _store_str(char **pos, char **ptr, const char *str)
{
	strcpy(*pos, str);
	*ptr = *pos;
	*pos += strlen(*ptr) + 1;
}

static int _stack_fs_op(fs_op_t type, const char *dev_dir, const char *vg_name,
			const char *lv_name, const char *dev,
			const char *old_lv_name)
{
	struct fs_op_parms *fsp;
	size_t len = strlen(dev_dir) + strlen(vg_name) + strlen(lv_name) +
	    strlen(dev) + strlen(old_lv_name) + 5;
	char *pos;

	if (!(fsp = dbg_malloc(sizeof(*fsp) + len))) {
		log_error("No space to stack fs operation");
		return 0;
	}

	pos = fsp->names;
	fsp->type = type;

	_store_str(&pos, &fsp->dev_dir, dev_dir);
	_store_str(&pos, &fsp->vg_name, vg_name);
	_store_str(&pos, &fsp->lv_name, lv_name);
	_store_str(&pos, &fsp->dev, dev);
	_store_str(&pos, &fsp->old_lv_name, old_lv_name);

	list_add(&_fs_ops, &fsp->list);

	return 1;
}

static void _pop_fs_ops(void)
{
	struct list *fsph, *fspht;
	struct fs_op_parms *fsp;

	list_iterate_safe(fsph, fspht, &_fs_ops) {
		fsp = list_item(fsph, struct fs_op_parms);
		_do_fs_op(fsp->type, fsp->dev_dir, fsp->vg_name, fsp->lv_name,
			  fsp->dev, fsp->old_lv_name);
		list_del(&fsp->list);
		dbg_free(fsp);
	}
}

static int _fs_op(fs_op_t type, const char *dev_dir, const char *vg_name,
		  const char *lv_name, const char *dev, const char *old_lv_name)
{
	if (memlock()) {
		if (!_stack_fs_op(type, dev_dir, vg_name, lv_name, dev,
				  old_lv_name)) {
			stack;
			return 0;
		}
		return 1;
	}

	return _do_fs_op(type, dev_dir, vg_name, lv_name, dev, old_lv_name);
}

int fs_add_lv(const struct logical_volume *lv, const char *dev)
{
	return _fs_op(FS_ADD, lv->vg->cmd->dev_dir, lv->vg->name, lv->name,
		      dev, "");
}

int fs_del_lv(const struct logical_volume *lv)
{
	return _fs_op(FS_DEL, lv->vg->cmd->dev_dir, lv->vg->name, lv->name,
		      "", "");
}

int fs_rename_lv(struct logical_volume *lv,
		 const char *dev, const char *old_name)
{
	return _fs_op(FS_RENAME, lv->vg->cmd->dev_dir, lv->vg->name, lv->name,
		      dev, old_name);
}

void fs_unlock(void)
{
	if (!memlock()) {
		dm_lib_release();
		_pop_fs_ops();
	}
}