Dear Wolfgang,
2013/7/25 Wolfgang Denk wd@denx.de:
Dear Guilherme Maciel Ferreira,
In message CAF=5bWftE3UwPrOH+q+JPm-ag0igmAr_G4s=kLzhSObNhN=YyA@mail.gmail.com you wrote:
I made a patch to allow mkimage to extract files from images, which just works for multi-file image. But, the fact that nobody has ever done this means that this feature is not desired in the tool?
Speaking just for myself: I needed such features only in very rare occasions, where it was way faster to use a one-liner on the command line than to write any actual code.
YMMV...
But I fear that mkimage explodes from creaping featurism, so if you go and implement something like this, please do not add it to kmimage, but rather create a separate, new tool, say "dumpimage" or so.
How does 'unimage' sound to you? =) Following the example of unsquashfs and unubi?
I mean, if people really consider this tool of some use.
IMHO, it is very convenient to have a C code to do that, specially for embedded systems where scripting is noticeably slower than binary code. Besides it requires 'dd' to extract and another tool to parse file's offsets inside the image.
Well, when I was doing such things, I never did this on the embedded targets, nor did I ever have to care about performance because I always needed it just once or twice.
Could you please be so kind and feed my curiousity a bit: what exactly are you doing that you need such a feature on the target? I can't think of useful applications at the moment...
Well, I'm not allowed to say much, but broadly speaking it's intended for a less intrusive firmware upgrade.
Today, in order to upgrade the firmware, the device receives a Multifile image composed by a new kernel and a new root file system and overwrite both of them. Which requires the device to hang for a moment.
However, now we want a selective upgrade, where we can pick a few directories from within the new root file system without the need to write the whole new file system and kernel.
Best regards,