lsblk: add udev support

[kzak@redhat.com: - enable udev support by default
                  - don't check for libudev.h
                  - minor udev code refactoring in lsblk.c]

Signed-off-by: Ilias Mamedov <arknir@yandex.ru>
Signed-off-by: Karel Zak <kzak@redhat.com>

3 files changed, 66 insertions, 5 deletions

diff --git a/configure.ac b/configure.ac
index fb0b0eb37..d12a4a037 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1111,11 +1111,28 @@ else
   UTIL_CHECK_LIB(audit, audit_log_user_message)
   case "$with_audit:$have_audit" in
   yes:no)
-   AC_MSG_ERROR([Audit selected but libaudit not found (or doesn't support audit_log_user_message())])
+   AC_MSG_ERROR([Audit selected but libaudit not found (or does not support audit_log_user_message())])
    ;;
   esac
 fi
 
+
+AC_ARG_WITH([udev], AS_HELP_STRING([--without-udev], [compile without udev support]),
+  [], with_udev=auto
+)
+
+if test "x$with_udev" = xno; then
+  AM_CONDITIONAL(HAVE_UDEV, false)
+else
+  UTIL_CHECK_LIB(udev, udev_new)
+  case "$with_udev:$have_udev" in
+  yes:no)
+   AC_MSG_ERROR([udev selected but libudev not found])
+   ;;
+  esac
+fi
+
+
 AC_ARG_ENABLE([schedutils],
   AS_HELP_STRING([--disable-schedutils], [do not build chrt, ionice, teskset]),
   [], enable_schedutils=yes
diff --git a/misc-utils/Makefile.am b/misc-utils/Makefile.am
index 300dab46e..9b941f518 100644
--- a/misc-utils/Makefile.am
+++ b/misc-utils/Makefile.am
@@ -66,6 +66,9 @@ lsblk_SOURCES = lsblk.c \
 		$(top_srcdir)/lib/at.c
 lsblk_LDADD = $(ul_libblkid_la)
 lsblk_CFLAGS = $(AM_CFLAGS) -I$(ul_libblkid_incdir)
+if HAVE_UDEV
+lsblk_LDADD += -ludev
+endif
 endif
 
 if HAVE_STATIC_BLKID
diff --git a/misc-utils/lsblk.c b/misc-utils/lsblk.c
index 3c4555d87..f9c06fe07 100644
--- a/misc-utils/lsblk.c
+++ b/misc-utils/lsblk.c
@@ -41,6 +41,10 @@
 
 #include <blkid.h>
 
+#ifdef HAVE_LIBUDEV
+#include <libudev.h>
+#endif
+
 #include <assert.h>
 
 #include "pathnames.h"
@@ -284,20 +288,58 @@ static char *get_device_mountpoint(struct blkdev_cxt *cxt)
 	return strlen(mnt) ? xstrdup(mnt) : NULL;
 }
 
-/* TODO: read info from udev db (if possible) for non-root users
- */
+#ifndef HAVE_LIBUDEV
+static int probe_device_by_udev(struct blkdev_cxt *cxt
+				__attribute__((__unused__)))
+{
+	return -1;
+}
+#else
+static int probe_device_by_udev(struct blkdev_cxt *cxt)
+{
+	struct udev *udev;
+	struct udev_device *dev;
+
+	udev = udev_new();
+	if (!udev)
+		return -1;
+
+	dev = udev_device_new_from_subsystem_sysname(udev, "block", cxt->name);
+	if (dev) {
+		const char *data;
+
+		if ((data = udev_device_get_property_value(dev, "ID_FS_LABEL")))
+			cxt->label = xstrdup(data);
+		if ((data = udev_device_get_property_value(dev, "ID_FS_TYPE")))
+			cxt->fstype = xstrdup(data);
+		if ((data = udev_device_get_property_value(dev, "ID_FS_UUID")))
+			cxt->uuid = xstrdup(data);
+
+		udev_device_unref(dev);
+	}
+
+	udev_unref(udev);
+        return 0;
+}
+#endif /* HAVE_LIBUDEV */
+
 static void probe_device(struct blkdev_cxt *cxt)
 {
-	char *path = NULL;
 	blkid_probe pr = NULL;
 
 	if (cxt->probed)
 		return;
+
 	cxt->probed = 1;
 
 	if (!cxt->size)
 		return;
 
+	/* try udev DB */
+	if (probe_device_by_udev(cxt) == 0)
+		return;				/* success */
+
+	/* try libblkid */
 	pr = blkid_new_probe_from_filename(cxt->filename);
 	if (!pr)
 		return;
@@ -320,7 +362,6 @@ static void probe_device(struct blkdev_cxt *cxt)
 			cxt->label = xstrdup(data);
 	}
 
-	free(path);
 	blkid_free_probe(pr);
 	return;
 }