path: root/misc-utils/lsblk-mnt.c

#include "c.h"
#include "pathnames.h"
#include "xalloc.h"
#include "nls.h"

#include <libmount.h>

#include "lsblk.h"

static struct libmnt_table *mtab, *swaps;
static struct libmnt_cache *mntcache;

static int table_parser_errcb(struct libmnt_table *tb __attribute__((__unused__)),
			const char *filename, int line)
{
	if (filename)
		warnx(_("%s: parse error at line %d -- ignored"), filename, line);
	return 1;
}

static int is_active_swap(const char *filename)
{
	if (!swaps) {
		swaps = mnt_new_table();
		if (!swaps)
			return 0;
		if (!mntcache)
			mntcache = mnt_new_cache();

		mnt_table_set_parser_errcb(swaps, table_parser_errcb);
		mnt_table_set_cache(swaps, mntcache);

		if (!lsblk->sysroot)
			mnt_table_parse_swaps(swaps, NULL);
		else {
			char buf[PATH_MAX];
			snprintf(buf, sizeof(buf), "%s" _PATH_PROC_SWAPS, lsblk->sysroot);
			mnt_table_parse_swaps(swaps, buf);
		}
	}

	return mnt_table_find_srcpath(swaps, filename, MNT_ITER_BACKWARD) != NULL;
}

char *lsblk_device_get_mountpoint(struct blkdev_cxt *cxt)
{
	struct libmnt_fs *fs;
	const char *fsroot;

	assert(cxt);
	assert(cxt->filename);

	if (cxt->is_mounted)
		return cxt->mountpoint;

	if (!mtab) {
		mtab = mnt_new_table();
		if (!mtab)
			return NULL;
		if (!mntcache)
			mntcache = mnt_new_cache();

		mnt_table_set_parser_errcb(mtab, table_parser_errcb);
		mnt_table_set_cache(mtab, mntcache);

		if (!lsblk->sysroot)
			mnt_table_parse_mtab(mtab, NULL);
		else {
			char buf[PATH_MAX];
			snprintf(buf, sizeof(buf), "%s" _PATH_PROC_MOUNTINFO, lsblk->sysroot);
			mnt_table_parse_mtab(mtab, buf);
		}
	}

	/* Note that maj:min in /proc/self/mountinfo does not have to match with
	 * devno as returned by stat(), so we have to try devname too
	 */
	fs = mnt_table_find_devno(mtab, makedev(cxt->maj, cxt->min), MNT_ITER_BACKWARD);
	if (!fs)
		fs = mnt_table_find_srcpath(mtab, cxt->filename, MNT_ITER_BACKWARD);
	if (!fs) {
		cxt->mountpoint = is_active_swap(cxt->filename) ? xstrdup("[SWAP]") : NULL;
		cxt->is_mounted = 1;
		return cxt->mountpoint;
	}

	/* found */
	fsroot = mnt_fs_get_root(fs);
	if (fsroot && strcmp(fsroot, "/") != 0) {
		/* hmm.. we found bind mount or btrfs subvolume, let's try to
		 * get real FS root mountpoint */
		struct libmnt_fs *rfs;
		struct libmnt_iter *itr = mnt_new_iter(MNT_ITER_BACKWARD);

		mnt_table_set_iter(mtab, itr, fs);
		while (mnt_table_next_fs(mtab, itr, &rfs) == 0) {
			fsroot = mnt_fs_get_root(rfs);
			if ((!fsroot || strcmp(fsroot, "/") == 0)
			    && mnt_fs_match_source(rfs, cxt->filename, mntcache)) {
				fs = rfs;
				break;
			}
		}
		mnt_free_iter(itr);
	}

	DBG(DEV, ul_debugobj(cxt, "mountpoint: %s", mnt_fs_get_target(fs)));
	cxt->mountpoint = xstrdup(mnt_fs_get_target(fs));
	cxt->is_mounted = 1;
	return cxt->mountpoint;
}

void lsblk_mnt_init(void)
{
	mnt_init_debug(0);
}

void lsblk_mnt_deinit(void)
{
	mnt_unref_table(mtab);
	mnt_unref_table(swaps);
	mnt_unref_cache(mntcache);
}