lib/loopdev: fix is_loopdev() to be usable with partitions

The current implementation of the function does not care if the device
is whole-disk device or partition, all is loopdev. This is regression
as the original is_loopdev() version was based on whole-disk devices
major numbers only.

Fixes: https://github.com/karelzak/util-linux/issues/1202
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/lib/Makemodule.am b/lib/Makemodule.am
index 0f18c9489bba789f268f07e3abdb814ac392f551..d112736dada47c148b3ddd6943663fa1cd512c37 100644 (file)
--- a/lib/Makemodule.am
+++ b/lib/Makemodule.am
@@ -101,7 +101,8 @@ endif
 check_PROGRAMS += \
        test_sysfs \
        test_pager \
-       test_caputils
+       test_caputils \
+       test_loopdev
 endif
 
 if HAVE_OPENAT
@@ -164,6 +165,7 @@ test_pty_LDADD = $(LDADD) libcommon.la $(MATH_LIBS) $(REALTIME_LIBS) -lutil
 endif
 
 if LINUX
+
 test_cpuset_SOURCES = lib/cpuset.c
 test_cpuset_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM_CPUSET
 
@@ -199,3 +201,8 @@ test_remove_env_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM
 
 test_buffer_SOURCES = lib/buffer.c
 test_buffer_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM_BUFFER
+
+test_loopdev_SOURCES = lib/loopdev.c \
+                      $(test_sysfs_SOURCES) \
+                      $(test_canonicalize_SOURCES)
+test_loopdev_CFLAGS = $(AM_CFLAGS) -DTEST_PROGRAM_LOOPDEV

diff --git a/lib/loopdev.c b/lib/loopdev.c
index b946acf3190d83e724ddd28a0b676dfad185aa4d..1eef15d8966286e6ae0eea07915fe1d440622d08 100644 (file)
--- a/lib/loopdev.c
+++ b/lib/loopdev.c
@@ -641,7 +641,7 @@ int is_loopdev(const char *device)
                rc = 0;
        else if (major(st.st_rdev) == LOOPDEV_MAJOR)
                rc = 1;
-       else {
+       else if (sysfs_devno_is_wholedisk(st.st_rdev)) {
                /* It's possible that kernel creates a device with a different
                 * major number ... check by /sys it's really loop device.
                 */
@@ -1881,3 +1881,22 @@ int loopdev_count_by_backing_file(const char *filename, char **loopdev)
        return count;
 }
 
+#ifdef TEST_PROGRAM_LOOPDEV
+int main(int argc, char *argv[])
+{
+       if (argc < 2)
+               goto usage;
+
+       if (strcmp(argv[1], "--is-loopdev") == 0 && argc == 3)
+               printf("%s: %s\n", argv[2], is_loopdev(argv[2]) ? "OK" : "FAIL");
+       else
+               goto usage;
+
+       return EXIT_SUCCESS;
+usage:
+       fprintf(stderr, "usage: %1$s --is-loopdev <dev>\n",
+                       program_invocation_short_name);
+       return EXIT_FAILURE;
+}
+#endif
+