From 5a89aa99a7f13722102fa8730f4647da9138134d Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Tue, 19 Jun 2018 12:02:52 +0200
Subject: [PATCH] lsblk: use prefix for DM name

Signed-off-by: Karel Zak <kzak@redhat.com>
---
 include/canonicalize.h |  1 +
 lib/canonicalize.c     | 14 +++++++++++---
 misc-utils/lsblk.c     | 18 ++++++++++++++----
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/include/canonicalize.h b/include/canonicalize.h
index 0a292fc32c..ff6ef0dd6e 100644
--- a/include/canonicalize.h
+++ b/include/canonicalize.h
@@ -18,6 +18,7 @@
 extern char *canonicalize_path(const char *path);
 extern char *canonicalize_path_restricted(const char *path);
 extern char *canonicalize_dm_name(const char *ptname);
+extern char *__canonicalize_dm_name(const char *prefix, const char *ptname);
 
 extern char *absolute_path(const char *path);
 
diff --git a/lib/canonicalize.c b/lib/canonicalize.c
index ef3342b12b..f3a2a3af29 100644
--- a/lib/canonicalize.c
+++ b/lib/canonicalize.c
@@ -24,7 +24,7 @@
  * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs
  * provides the real DM device names in /sys/block/<ptname>/dm/name
  */
-char *canonicalize_dm_name(const char *ptname)
+char *__canonicalize_dm_name(const char *prefix, const char *ptname)
 {
 	FILE	*f;
 	size_t	sz;
@@ -33,7 +33,10 @@ char *canonicalize_dm_name(const char *ptname)
 	if (!ptname || !*ptname)
 		return NULL;
 
-	snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname);
+	if (!prefix)
+		prefix = "";
+
+	snprintf(path, sizeof(path), "%s/sys/block/%s/dm/name", prefix, ptname);
 	if (!(f = fopen(path, "r" UL_CLOEXECSTR)))
 		return NULL;
 
@@ -42,13 +45,18 @@ char *canonicalize_dm_name(const char *ptname)
 		name[sz - 1] = '\0';
 		snprintf(path, sizeof(path), _PATH_DEV_MAPPER "/%s", name);
 
-		if (access(path, F_OK) == 0)
+		if (prefix || access(path, F_OK) == 0)
 			res = strdup(path);
 	}
 	fclose(f);
 	return res;
 }
 
+char *canonicalize_dm_name(const char *ptname)
+{
+	return __canonicalize_dm_name(NULL, ptname);
+}
+
 static int is_dm_devname(char *canonical, char **name)
 {
 	struct stat sb;
diff --git a/misc-utils/lsblk.c b/misc-utils/lsblk.c
index 2d0c981274..26b58ab4e7 100644
--- a/misc-utils/lsblk.c
+++ b/misc-utils/lsblk.c
@@ -446,7 +446,7 @@ static char *get_device_path(struct blkdev_cxt *cxt)
 	assert(cxt->name);
 
 	if (is_dm(cxt->name))
-		return canonicalize_dm_name(cxt->name);
+		return __canonicalize_dm_name(lsblk->sysroot, cxt->name);
 
 	snprintf(path, sizeof(path), "/dev/%s", cxt->name);
 	sysfs_devname_sys_to_dev(path);
@@ -1473,9 +1473,17 @@ static int iterate_block_devices(void)
 	DIR *dir;
 	struct dirent *d;
 	struct blkdev_cxt cxt = { NULL };
+	struct path_cxt *pc = ul_new_path(_PATH_SYS_BLOCK);
 
-	if (!(dir = opendir(_PATH_SYS_BLOCK)))
-		return -errno;
+	if (!pc)
+		err(EXIT_FAILURE, _("failed to allocate /sys handler"));
+
+	ul_path_set_prefix(pc, lsblk->sysroot);
+
+	/* TODO: reuse @pc in set_cxt(), etc. */
+	dir = ul_path_opendir(pc, NULL);
+	if (!dir)
+		goto done;
 
 	DBG(DEV, ul_debug("iterate on " _PATH_SYS_BLOCK));
 
@@ -1499,7 +1507,8 @@ static int iterate_block_devices(void)
 	}
 
 	closedir(dir);
-
+done:
+	ul_unref_path(pc);
 	DBG(DEV, ul_debug("iterate on " _PATH_SYS_BLOCK " -- done"));
 	return 0;
 }
@@ -1929,6 +1938,7 @@ int main(int argc, char *argv[])
 
 	mnt_init_debug(0);
 	scols_init_debug(0);
+	ul_path_init_debug();
 
 	/*
 	 * initialize output columns
-- 
2.39.2