I extracted a
firmware.bin
using fmk mod kit and gave me 3 files: header.img , rootfs.img and footer.img
now whenever I cat and repack all the files together in firmware2.bin again, it works and it upgrades the router.
but when I unsquash the rootfs.img using this command unsquashfs rootfs.img into squashfs-root/
then I squash it again using mksquashfs rootfs-root/ squash_new.img -comp lzma -b 131072 "which it by the way the same compression method and block size as the original rootfs.img"
but it gives me a less size comparing to the rootfs.img and the router gives me upgrade failed
here are the sizes of the 2 files
squash_new.img (9,945,088 bytes)
rootfs.img (9,945,232 bytes)
is there a problem with unsquashfs or mksquashfs?
because when I used a hex editor software, I noticed some entries are different although I have not changed anything.
Related
I have the following command:
sudo tcpdump -ni enp0s3 -W 1 -C 1 -w file.cap
with this command I say: "listen on the network interface enp0s3 and capture all packets in a file whose maximum size must be 1 mb". It works, however the problem is that when the file reaches the size of 1mb, it is reset and the capture starts all over again from 0 kb, deleting all the packets.
I want that when the file is 1MB, only the older packages are deleted and the new ones are added replacing them. I don't want all packets to be deleted and acquisition restarts at 0kb. In other words, I want the file to always be around 1mb, adding the new incoming packets in place of the oldest ones.
You can use -U -W 2 with the -C size limit. It will then alternate between two files and you can concatenate them (or work on the older one).
Alternatives would be to write to a stream or pipe and not to files, at all.
I'm trying to create a swap partition/file on my board where a core-image-minimal has been installed.
The fdisk -l command doesn't show any partition thus I'm not able to figure out which block device I need to use to create a new partition.
Secondly, launchig a swapon command on a swapfile correctly initialized using mkswap will raise an invalid argument error saying that the file contains holes even though I created it using dd.
At this point I'm not sure if I can do something like this since the free output looks like:
total used free shared buff/cache available
Mem: 503304 32108 101108 216 370088 465180
Swap: 0 0 0
To add any partition to your image, you need to modify the wks file that is used for your build.
To get the current wks file run :
bitbake -e | grep ^WKS_FILE=
Then, look for that file in your layers sources.
In that file you can add (example 1GB swap):
part swap --ondisk mmcblk0 --size 44 --label swap --fstype=swap --size=1024M --overhead-factor 1
For a real example, you can see the raspberry-pi machine swap support commit here.
You can use a custom wks file and set it to your custom machine conf file:
WKS_FILE ?= "custom-image.wks"
For detailed info, check the Yocto reference about wks.
I have virtual image of a FreeBSD system and when I mount it I don't see the /etc/ directory and other files, instead is a big loader.gz on the filesystem, that I believe that is extracted during the boot process. I decompressed the loader.gz with gzip and I got it:
$ file loader
loader: ELF 64-bit LSB executable, x86-64, version 1 (FreeBSD), dynamically linked (uses shared libs), not stripped
Using grep I'm able to confirm that the files that I need to edit are inside, however I don't know how to edit it. I tried to mount it without success. How can I modify the contents of loader.gz and use it again?
Can you please give me an example?
I have a Linux system and a Mac to install tools and this FreeBSD image.
Please, help me.
The loader program is generally the last stage of the kernel bootstrapping process.
A recent image should have another signature. e.g. for a memory stick image;
> file tmp/FreeBSD-10.0-RELEASE-amd64-memstick.img
tmp/FreeBSD-10.0-RELEASE-amd64-memstick.img: Unix Fast File system
[v1] (little-endian), last mounted on ,
last written at Fri Jan 17 00:24:02 2014,
clean flag 1, number of blocks 681040, number of data blocks 679047,
number of cylinder groups 13, block size 8192, fragment size 1024,
minimum percentage of free blocks 8, rotational delay 0ms,
disk rotational speed 60rps, TIME optimization
Mounting an image on FreeBSD:
# mdconfig -a -t vnode -f tmp/FreeBSD-10.0-RELEASE-amd64-memstick.img -u 1
# mount /dev/md1a /mnt/root/
(Linux has the same capability, I just don't remember what its called.)
This image contains loader in the boot/ directory:
# ls /mnt/root/
.cshrc ERRATA.TXT README.TXT boot/ lib/ proc/ sys#
.profile HARDWARE.HTM RELNOTES.HTM dev/ libexec/ rescue/ tmp/
COPYRIGHT HARDWARE.TXT RELNOTES.TXT docbook.css media/ root/ usr/
ERRATA.HTM README.HTM bin/ etc/ mnt/ sbin/ var/
# ls /mnt/root/boot/
beastie.4th check-password.4th gptzfsboot menu.4th support.4th
boot color.4th kernel/ menu.rc userboot.so
boot0 defaults/ loader* menusets.4th version.4th
boot0sio delay.4th loader.4th modules/ zfs/
boot1 device.hints loader.help pmbr zfsboot
boot2 firmware/ loader.rc pxeboot zfsloader*
brand.4th frames.4th mbr screen.4th
cdboot gptboot menu-commands.4th shortcuts.4th
On my FreeBSD 10 system, loader has another signature;
/boot/loader: FreeBSD/i386 demand paged executable
I have an application that uses hugepage and the application suddenly crashed due to some bug.
After crashing, since the application does not release the hugepage properly, the free hugepage number is not increased in sys filesystem.
$ sudo cat /sys/kernel/mm/hugepages/hugepages-2048kB/free_hugepages
0
$ sudo cat /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
1024
Is there a way to release the hugepages by force?
Sometimes need to check all directory that hugetlbfs has been mounted.
So,
find mounted directory by command mount | grep huge.
check every directory except especially /dev/hugepages.
delete all 2M-sized files. (2M is the size of hugepage)
Use ipcs -m to list the shared memory segments.
Use ipcrm to remove the left over shared memory segments.
Edit on 06/24/2019:
Ok, so, the above answer, while correct as far as it goes, was a bit brief. In particular, if you have a host with multiple DB instances, and only one is crashed how can you determine which (if any) memory segments should be cleaned up?
Well, this too, can be done. For each running instance, connect w/ / as sysdba, then do oradebug setmypid (any pid will do, as all Oracle PIDs connect to the SGA). Then do oradebug ipc. That will (hopefully) return IPC information written to the trace file. So, go to the udump (or diag_dest) directory, and look for your trace file. It will contain all the IPC information for the instance. This will include ShmId. Look through the file for the ShmId(s) that this instance is using. Now look at the output of ipcs -m.
When you have done that for all the running instances, any memory segment output by ipcs -m that shows non-zero memory allocation, and that you cannot account for in the oradebug ipc information from any running instance, must be the left over memory segments from the crashed instance. Use ipcrm to remove it/them.
When doing this on a host with multiple running instances, this can be a bit fraught. Please proceed with caution. You don't want to remove the SGA of a running instance!
Hope that helps....
HugeTLB can either be used for shared memory (and Mark J. Bobak's answer would deal with that) or the app mmaps files created in a hugetlb filesystem. If the app crashes without removing those files they survive and keep corresponding memory 'allocated'.
Check hugeTLB filesystem and see if there are any leftover files from the app. Removing them would release the memory.
If you follow the instruction below, you can get rid of the allocated hugepages:
1) Let's check the hugepages which were free at restart
dpdk#dpdkvm:~$ ls /mnt/huge/
empty
dpdk#dpdkvm:~/dpdk-1.8.0/examples/kni$ cat /proc/meminfo
...
HugePages_Total: 256
HugePages_Free: 256
...
2) Starting a dpdk application with wrong parameters, producing an error
dpdk#dpdkvm:~/dpdk-1.8.0/examples/kni$ sudo ./build/kni -c 0x03 -n 2 -- -P -p 0x03 --config="(0,0,1),(1,0,1)"
...
EAL: Error - exiting with code: 1
Cause: No supported Ethernet device found
3) When I check hugepages, there is not any free
dpdk#dpdkvm:~/dpdk-1.8.0/examples/kni$ cat /proc/meminfo
...
HugePages_Total: 256
HugePages_Free: 0
...
4) Now, when I check the mounted hugepage directory, I can see the files which are not given back to OS by dpdk application.
dpdk#dpdkvm:~/dpdk-1.8.0/examples/kni$ ls /mnt/huge/
...
rtemap_0 rtemap_137 rtemap_176 rtemap_214 rtemap_253 rtemap_62
...
5) Finally, if you remove the files starting with rtemap, you can give the hugepages back
dpdk#dpdkvm:~/dpdk-1.8.0/examples/kni$ sudo rm /mnt/huge/*
[sudo] password for dpdk:
dpdk#dpdkvm:~/dpdk-1.8.0/examples/kni$ cat /proc/meminfo
...
HugePages_Total: 256
HugePages_Free: 256
...
your hugetlb may be used by shared memory or mmap files.
try to remove the shared memories or umount the hugetlb fs
We have a few linux based (Centos) virtual machines which are to be used as distributable virtual appliances. We want to be able to compress them as much as possible for distribution ( via tar.gz, zip, etc).
We've removed all unnecessary files (.log's, /tmp/*, /var/log/, etc) and have written /dev/zero to the free space on the disk.
Is it possible to write zeros via /dev/zero to the swap partitions and files? I know I would need to swapoff -a first. I'm worried about corrupting any internal structures.
Our vm uses both partition swap and file swap.
Also, are there any other strategies for reducing the size of a VM for distribution?
We need to support all of the hypervisor technologies (Xen, VMW, etc), so although the vendors tools maybe useful, I'm looking for strategies that are cross platform.
--- Thanks
You may want to write zeroes and then use mkswap to create an empty swap partition.
$ dd -if=/dev/zero of=/path/to/file bs=512 count=1
adjust the size that you want your files to be.
sudo swapoff -v /dev/sda2 <== The swap partition
sudo dd if=/dev/zero of=/dev/sda2 bs=512 status=progress
sudo mkswap /dev/sda2 UUID=46c1a133-bfdd-4695-a484-08fcf8286896 <== The original UUID of the swap partition