[Libguestfs] [p2v PATCH] disks.c: skip SCSI floppy drives with no disk inserted
A SCSI floppy drive with no disk inserted looks like a normal /dev/sd*
node, but causes the nbdkit file plugin to fail with ENOMEDIUM. Filter out
such devices altogether -- unlike CD-ROMs (for which we create a device
model in the target, albeit with no medium inserted), empty floppies
should not be converted in any way.
https://bugzilla.redhat.com/show_bug.cgi?id=2140997
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
---
Notes:
This patch still needs testing; the ISO image is at
<http://lacos.interhost.hu/exclude-floppies-rhbz-2140997/b19895a5acd1/live...;,
sha256 sum:
b0666a9140b03e12829982179bf7da2ac5477737fb53760d2e8c527d8a2bf55a.
disks.c | 58 ++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/disks.c b/disks.c
index 4eb006246d84..aafe467f9e9a 100644
--- a/disks.c
+++ b/disks.c
@@ -20,6 +20,7 @@
#include <dirent.h>
#include <errno.h>
#include <error.h>
+#include <fcntl.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
@@ -67,6 +68,57 @@ partition_parent (dev_t part_dev)
return makedev (parent_major, parent_minor);
}
+/**
+ * Return true if the named device (eg. C<dev == "sda">) is a Removable
Media
+ * SCSI Disk with no media inserted. This covers floppy drives, but not CD-ROM
+ * drives (intentionally).
+ */
+static int
+device_has_no_media (const char *dev)
+{
+ int ret;
+ gchar *sysfs_pathname;
+ gchar *sysfs_contents;
+ gsize sysfs_size;
+ gchar *dev_pathname;
+ int dev_fd;
+
+ ret = 0;
+
+ if (!STRPREFIX (dev, "sd"))
+ return ret;
+
+ sysfs_pathname = g_strdup_printf ("/sys/block/%s/removable", dev);
+
+ if (!g_file_get_contents (sysfs_pathname, &sysfs_contents, &sysfs_size, NULL))
+ goto free_sysfs_pathname;
+
+ if (sysfs_size < 2 || sysfs_contents[0] != '1' || sysfs_contents[1] !=
'\n')
+ goto free_sysfs_contents;
+
+ dev_pathname = g_strdup_printf ("/dev/%s", dev);
+
+ dev_fd = open (dev_pathname, O_RDONLY | O_CLOEXEC);
+ if (dev_fd == -1) {
+ if (errno == ENOMEDIUM)
+ ret = 1;
+
+ goto free_dev_pathname;
+ }
+ close (dev_fd);
+
+free_dev_pathname:
+ g_free (dev_pathname);
+
+free_sysfs_contents:
+ g_free (sysfs_contents);
+
+free_sysfs_pathname:
+ g_free (sysfs_pathname);
+
+ return ret;
+}
+
/**
* Return true if the named device (eg. C<dev == "sda">) contains the
* root filesystem. C<root_device> is the major:minor of the root
@@ -139,6 +191,12 @@ find_all_disks (char ***disks, char ***removable)
STRPREFIX (d->d_name, "ubd") ||
STRPREFIX (d->d_name, "vd")) {
char *p;
+ /* Skip SCSI disk drives with removable media that have no media inserted
+ * -- effectively, empty floppy drives. Note that SCSI CD-ROMs are named
+ * C<sr*> and thus handled on the other branch.
+ */
+ if (device_has_no_media (d->d_name))
+ continue;
/* Skip the device containing the root filesystem. */
if (device_contains (d->d_name, root_device))