Re: [libvirt] [PATCH v2] util: Set backing file name for LOOP_GET_STATUS64 queries.
On Mon, Sep 02, 2019 at 02:00:27PM -0300, jcfara...@gmail.com wrote:
> From: Julio Faracco
>
> This is an issue for LXC loop devices when you are trying to get loop
> devices info using `ioctl`. Modern apps uses `/sys/dev/block` to grab
> information about devices, but if you use the method mention you won't
> be able to retrive the associated file with that loop device. See
> example below from cryptsetup sources:
>
> static char *_ioctl_backing_file(const char *loop)
> {
> struct loop_info64 lo64 = {0};
> int loop_fd;
>
> loop_fd = open(loop, O_RDONLY);
> if (loop_fd < 0)
> return NULL;
>
> if (ioctl(loop_fd, LOOP_GET_STATUS64, ) < 0) {
> close(loop_fd);
> return NULL;
> }
>
> lo64.lo_file_name[LO_NAME_SIZE-2] = '*';
> lo64.lo_file_name[LO_NAME_SIZE-1] = 0;
>
> close(loop_fd);
> return strdup((char*)lo64.lo_file_name);
> }
>
> It will return an empty string because lo_file_name was not set.
> Function `virFileLoopDeviceOpenSearch()` is using `ioctl` to query data,
> but it is not checking `lo_file_name` field.
>
> v1: I accidentally committed two wrong lines.
This type of message should be put after the "---" lines...
>
> Signed-off-by: Julio Faracco
> ---
Here, so that it doesn't get into git history when the patch
is applied
> src/util/virfile.c | 8
> 1 file changed, 8 insertions(+)
Reviewed-by: Daniel P. Berrangé
and pushed to git
Regards,
Daniel
--
|: https://berrange.com -o-https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o-https://fstop138.berrange.com :|
|: https://entangle-photo.org-o-https://www.instagram.com/dberrange :|
--
libvir-list mailing list
libvir-list@redhat.com
https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH v2] util: Set backing file name for LOOP_GET_STATUS64 queries.
For further reference:
https://github.com/lxc/lxc/commit/a70c9e85a6d8ac1b75d6705d2373fd9c7b567240
Em seg, 2 de set de 2019 às 14:00, escreveu:
>
> From: Julio Faracco
>
> This is an issue for LXC loop devices when you are trying to get loop
> devices info using `ioctl`. Modern apps uses `/sys/dev/block` to grab
> information about devices, but if you use the method mention you won't
> be able to retrive the associated file with that loop device. See
> example below from cryptsetup sources:
>
> static char *_ioctl_backing_file(const char *loop)
> {
> struct loop_info64 lo64 = {0};
> int loop_fd;
>
> loop_fd = open(loop, O_RDONLY);
> if (loop_fd < 0)
> return NULL;
>
> if (ioctl(loop_fd, LOOP_GET_STATUS64, ) < 0) {
> close(loop_fd);
> return NULL;
> }
>
> lo64.lo_file_name[LO_NAME_SIZE-2] = '*';
> lo64.lo_file_name[LO_NAME_SIZE-1] = 0;
>
> close(loop_fd);
> return strdup((char*)lo64.lo_file_name);
> }
>
> It will return an empty string because lo_file_name was not set.
> Function `virFileLoopDeviceOpenSearch()` is using `ioctl` to query data,
> but it is not checking `lo_file_name` field.
>
> v1: I accidentally committed two wrong lines.
>
> Signed-off-by: Julio Faracco
> ---
> src/util/virfile.c | 8
> 1 file changed, 8 insertions(+)
>
> diff --git a/src/util/virfile.c b/src/util/virfile.c
> index 81a3c096eb..dbfe74e24f 100644
> --- a/src/util/virfile.c
> +++ b/src/util/virfile.c
> @@ -781,6 +781,14 @@ int virFileLoopDeviceAssociate(const char *file,
> memset(, 0, sizeof(lo));
> lo.lo_flags = LO_FLAGS_AUTOCLEAR;
>
> +/* Set backing file name for LOOP_GET_STATUS64 queries */
> +if (virStrncpy((char *) lo.lo_file_name, file,
> + strlen(file), LO_NAME_SIZE) < 0) {
> +virReportSystemError(errno,
> + _("Unable to set backing file %s"), file);
> +goto cleanup;
> +}
> +
> if ((fsfd = open(file, O_RDWR)) < 0) {
> virReportSystemError(errno,
> _("Unable to open %s"), file);
> --
> 2.20.1
>
--
libvir-list mailing list
libvir-list@redhat.com
https://www.redhat.com/mailman/listinfo/libvir-list
[libvirt] [PATCH v2] util: Set backing file name for LOOP_GET_STATUS64 queries.
From: Julio Faracco
This is an issue for LXC loop devices when you are trying to get loop
devices info using `ioctl`. Modern apps uses `/sys/dev/block` to grab
information about devices, but if you use the method mention you won't
be able to retrive the associated file with that loop device. See
example below from cryptsetup sources:
static char *_ioctl_backing_file(const char *loop)
{
struct loop_info64 lo64 = {0};
int loop_fd;
loop_fd = open(loop, O_RDONLY);
if (loop_fd < 0)
return NULL;
if (ioctl(loop_fd, LOOP_GET_STATUS64, ) < 0) {
close(loop_fd);
return NULL;
}
lo64.lo_file_name[LO_NAME_SIZE-2] = '*';
lo64.lo_file_name[LO_NAME_SIZE-1] = 0;
close(loop_fd);
return strdup((char*)lo64.lo_file_name);
}
It will return an empty string because lo_file_name was not set.
Function `virFileLoopDeviceOpenSearch()` is using `ioctl` to query data,
but it is not checking `lo_file_name` field.
v1: I accidentally committed two wrong lines.
Signed-off-by: Julio Faracco
---
src/util/virfile.c | 8
1 file changed, 8 insertions(+)
diff --git a/src/util/virfile.c b/src/util/virfile.c
index 81a3c096eb..dbfe74e24f 100644
--- a/src/util/virfile.c
+++ b/src/util/virfile.c
@@ -781,6 +781,14 @@ int virFileLoopDeviceAssociate(const char *file,
memset(, 0, sizeof(lo));
lo.lo_flags = LO_FLAGS_AUTOCLEAR;
+/* Set backing file name for LOOP_GET_STATUS64 queries */
+if (virStrncpy((char *) lo.lo_file_name, file,
+ strlen(file), LO_NAME_SIZE) < 0) {
+virReportSystemError(errno,
+ _("Unable to set backing file %s"), file);
+goto cleanup;
+}
+
if ((fsfd = open(file, O_RDWR)) < 0) {
virReportSystemError(errno,
_("Unable to open %s"), file);
--
2.20.1
--
libvir-list mailing list
libvir-list@redhat.com
https://www.redhat.com/mailman/listinfo/libvir-list
