* [PATCH] kexec: determine size of block device
@ 2015-10-09 13:27 Andreas Fenkart
2015-10-16 1:30 ` Simon Horman
0 siblings, 1 reply; 4+ messages in thread
From: Andreas Fenkart @ 2015-10-09 13:27 UTC (permalink / raw)
To: kexec; +Cc: Andreas Fenkart
starting 'kexec -l /dev/mmcblk0p1' fails since the size of
a block device can not be determined with stat
Signed-off-by: Andreas Fenkart <andreas.fenkart@dev.digitalstrom.org>
---
kexec/kexec.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/kexec/kexec.c b/kexec/kexec.c
index ff024f3..8b8846e 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -26,7 +26,9 @@
#include <stdlib.h>
#include <errno.h>
#include <limits.h>
+#include <sys/ioctl.h>
#include <sys/mman.h>
+#include <sys/mount.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/reboot.h>
@@ -554,6 +556,14 @@ char *slurp_file(const char *filename, off_t *r_size)
die("Can not seek to the begin of file %s: %s\n",
filename, strerror(errno));
buf = slurp_fd(fd, filename, size, &nread);
+ } else if (S_ISBLK(stats.st_mode)) {
+ /* taken from blockdev */
+ unsigned long long llu = -1;
+ err = ioctl(fd, BLKGETSIZE64, &llu);
+ if (err < 0)
+ die("Can't retrieve size of block device %s: %s\n",
+ filename, strerror(errno));
+ size = llu;
} else {
size = nread = stats.st_size;
buf = mmap(NULL, size,
--
2.5.1
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] kexec: determine size of block device
2015-10-09 13:27 [PATCH] kexec: determine size of block device Andreas Fenkart
@ 2015-10-16 1:30 ` Simon Horman
2015-10-19 9:32 ` Andreas Fenkart
0 siblings, 1 reply; 4+ messages in thread
From: Simon Horman @ 2015-10-16 1:30 UTC (permalink / raw)
To: Andreas Fenkart; +Cc: Andreas Fenkart, kexec
Hi Andreas,
On Fri, Oct 09, 2015 at 03:27:18PM +0200, Andreas Fenkart wrote:
> starting 'kexec -l /dev/mmcblk0p1' fails since the size of
> a block device can not be determined with stat
Could you provide some motivation for kexec reading a kernel image
from a block device as per the example above?
> Signed-off-by: Andreas Fenkart <andreas.fenkart@dev.digitalstrom.org>
> ---
> kexec/kexec.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/kexec/kexec.c b/kexec/kexec.c
> index ff024f3..8b8846e 100644
> --- a/kexec/kexec.c
> +++ b/kexec/kexec.c
> @@ -26,7 +26,9 @@
> #include <stdlib.h>
> #include <errno.h>
> #include <limits.h>
> +#include <sys/ioctl.h>
> #include <sys/mman.h>
> +#include <sys/mount.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <sys/reboot.h>
> @@ -554,6 +556,14 @@ char *slurp_file(const char *filename, off_t *r_size)
> die("Can not seek to the begin of file %s: %s\n",
> filename, strerror(errno));
> buf = slurp_fd(fd, filename, size, &nread);
> + } else if (S_ISBLK(stats.st_mode)) {
> + /* taken from blockdev */
Is "blockdev" Linux kernel code?
> + unsigned long long llu = -1;
> + err = ioctl(fd, BLKGETSIZE64, &llu);
> + if (err < 0)
> + die("Can't retrieve size of block device %s: %s\n",
> + filename, strerror(errno));
> + size = llu;
> } else {
> size = nread = stats.st_size;
> buf = mmap(NULL, size,
> --
> 2.5.1
>
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
>
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] kexec: determine size of block device
2015-10-16 1:30 ` Simon Horman
@ 2015-10-19 9:32 ` Andreas Fenkart
2015-10-20 1:27 ` Simon Horman
0 siblings, 1 reply; 4+ messages in thread
From: Andreas Fenkart @ 2015-10-19 9:32 UTC (permalink / raw)
To: Simon Horman; +Cc: Andreas Fenkart, kexec
Hi Simon,
2015-10-16 3:30 GMT+02:00 Simon Horman <horms@verge.net.au>:
> On Fri, Oct 09, 2015 at 03:27:18PM +0200, Andreas Fenkart wrote:
>> starting 'kexec -l /dev/mmcblk0p1' fails since the size of
>> a block device can not be determined with stat
>
> Could you provide some motivation for kexec reading a kernel image
> from a block device as per the example above?
We plan to use it for our embedded system
We have an interim initramfs, that selects the kernel we want to boot
our real system. Something like a n+1 stage boot loader,
where n is the last stage of u-boot. The motivation is to do a safe
kernel upgrade on the production rootfs through package management.
The new kernel is dropped into a folder where the interim system will
selects the kernel with the highest priority. No reconfiguration of
u-boot/rescue system needed. In case no kernel has yet been installed,
we fall back to the factory default, which is installed in a raw flash
partition on eMMC without filesystem.
https://git.digitalstrom.org/bsp/dss-rescue-tools/blob/master/src/kernel-fallback-dss11-1gb-t1.config
>> Signed-off-by: Andreas Fenkart <andreas.fenkart@dev.digitalstrom.org>
>> ---
>> kexec/kexec.c | 10 ++++++++++
>> 1 file changed, 10 insertions(+)
>>
>> diff --git a/kexec/kexec.c b/kexec/kexec.c
>> index ff024f3..8b8846e 100644
>> --- a/kexec/kexec.c
>> +++ b/kexec/kexec.c
>> @@ -26,7 +26,9 @@
>> #include <stdlib.h>
>> #include <errno.h>
>> #include <limits.h>
>> +#include <sys/ioctl.h>
>> #include <sys/mman.h>
>> +#include <sys/mount.h>
>> #include <sys/types.h>
>> #include <sys/stat.h>
>> #include <sys/reboot.h>
>> @@ -554,6 +556,14 @@ char *slurp_file(const char *filename, off_t *r_size)
>> die("Can not seek to the begin of file %s: %s\n",
>> filename, strerror(errno));
>> buf = slurp_fd(fd, filename, size, &nread);
>> + } else if (S_ISBLK(stats.st_mode)) {
>> + /* taken from blockdev */
>
> Is "blockdev" Linux kernel code?
It is a util-linux tool, which is GPL of course. I added the comment
as a reference, since I couldn't find a man page for BLKGETSIZE64.
Since it's a straight forward ioctl call, there is probably no
copyright violation at all, and I could well remove it.
>
>> + unsigned long long llu = -1;
>> + err = ioctl(fd, BLKGETSIZE64, &llu);
>> + if (err < 0)
>> + die("Can't retrieve size of block device %s: %s\n",
>> + filename, strerror(errno));
>> + size = llu;
>> } else {
>> size = nread = stats.st_size;
>> buf = mmap(NULL, size,
>> --
>> 2.5.1
>>
>>
>> _______________________________________________
>> kexec mailing list
>> kexec@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec
>>
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] kexec: determine size of block device
2015-10-19 9:32 ` Andreas Fenkart
@ 2015-10-20 1:27 ` Simon Horman
0 siblings, 0 replies; 4+ messages in thread
From: Simon Horman @ 2015-10-20 1:27 UTC (permalink / raw)
To: Andreas Fenkart; +Cc: Andreas Fenkart, kexec
On Mon, Oct 19, 2015 at 11:32:58AM +0200, Andreas Fenkart wrote:
> Hi Simon,
>
> 2015-10-16 3:30 GMT+02:00 Simon Horman <horms@verge.net.au>:
> > On Fri, Oct 09, 2015 at 03:27:18PM +0200, Andreas Fenkart wrote:
> >> starting 'kexec -l /dev/mmcblk0p1' fails since the size of
> >> a block device can not be determined with stat
> >
> > Could you provide some motivation for kexec reading a kernel image
> > from a block device as per the example above?
>
> We plan to use it for our embedded system
>
> We have an interim initramfs, that selects the kernel we want to boot
> our real system. Something like a n+1 stage boot loader,
> where n is the last stage of u-boot. The motivation is to do a safe
> kernel upgrade on the production rootfs through package management.
> The new kernel is dropped into a folder where the interim system will
> selects the kernel with the highest priority. No reconfiguration of
> u-boot/rescue system needed. In case no kernel has yet been installed,
> we fall back to the factory default, which is installed in a raw flash
> partition on eMMC without filesystem.
>
> https://git.digitalstrom.org/bsp/dss-rescue-tools/blob/master/src/kernel-fallback-dss11-1gb-t1.config
Nice :)
> >> Signed-off-by: Andreas Fenkart <andreas.fenkart@dev.digitalstrom.org>
> >> ---
> >> kexec/kexec.c | 10 ++++++++++
> >> 1 file changed, 10 insertions(+)
> >>
> >> diff --git a/kexec/kexec.c b/kexec/kexec.c
> >> index ff024f3..8b8846e 100644
> >> --- a/kexec/kexec.c
> >> +++ b/kexec/kexec.c
> >> @@ -26,7 +26,9 @@
> >> #include <stdlib.h>
> >> #include <errno.h>
> >> #include <limits.h>
> >> +#include <sys/ioctl.h>
> >> #include <sys/mman.h>
> >> +#include <sys/mount.h>
> >> #include <sys/types.h>
> >> #include <sys/stat.h>
> >> #include <sys/reboot.h>
> >> @@ -554,6 +556,14 @@ char *slurp_file(const char *filename, off_t *r_size)
> >> die("Can not seek to the begin of file %s: %s\n",
> >> filename, strerror(errno));
> >> buf = slurp_fd(fd, filename, size, &nread);
> >> + } else if (S_ISBLK(stats.st_mode)) {
> >> + /* taken from blockdev */
> >
> > Is "blockdev" Linux kernel code?
>
> It is a util-linux tool, which is GPL of course. I added the comment
> as a reference, since I couldn't find a man page for BLKGETSIZE64.
> Since it's a straight forward ioctl call, there is probably no
> copyright violation at all, and I could well remove it.
Understood. Could you repost with the blockdev comment removed?
> >> + unsigned long long llu = -1;
> >> + err = ioctl(fd, BLKGETSIZE64, &llu);
> >> + if (err < 0)
> >> + die("Can't retrieve size of block device %s: %s\n",
> >> + filename, strerror(errno));
> >> + size = llu;
> >> } else {
> >> size = nread = stats.st_size;
> >> buf = mmap(NULL, size,
> >> --
> >> 2.5.1
> >>
> >>
> >> _______________________________________________
> >> kexec mailing list
> >> kexec@lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/kexec
> >>
>
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-10-20 1:27 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-10-09 13:27 [PATCH] kexec: determine size of block device Andreas Fenkart
2015-10-16 1:30 ` Simon Horman
2015-10-19 9:32 ` Andreas Fenkart
2015-10-20 1:27 ` Simon Horman
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox