kmxz / overlayfs-tools Goto Github PK

When run command: overlay -v -l /media/root-ro -u /media/root-rw/overlay -f diff

I have got an error: "Action aborted due to fatal error." that points "File %s can not be read for content." (for example /etc/ssh/sshd_config file)

System Description:
debian buster
selinux enabled & permissive mode
relabelling service active

Hi @kmxz. Would it be possible to add a license file into this repo? I plan to create an APK package for your software. Thanks.

[22:24:56] root@devpi:/tmp/zr/overlayfs-tools# make
gcc -Wall -std=c99 -c main.c
In file included from main.c:16:
/usr/include/linux/stat.h:56:8: error: redefinition of ‘struct statx_timestamp’
struct statx_timestamp {
^~~~~~~~~~~~~~~
In file included from /usr/include/arm-linux-gnueabihf/sys/stat.h:446,
from main.c:14:
/usr/include/arm-linux-gnueabihf/bits/statx.h:25:8: note: originally defined here
struct statx_timestamp
^~~~~~~~~~~~~~~
In file included from main.c:16:
/usr/include/linux/stat.h:99:8: error: redefinition of ‘struct statx’
struct statx {
^~~~~
In file included from /usr/include/arm-linux-gnueabihf/sys/stat.h:446,
from main.c:14:
/usr/include/arm-linux-gnueabihf/bits/statx.h:36:8: note: originally defined here
struct statx
^~~~~
make: *** [makefile:11: main.o] Fehler 1

According to the standard,

The nftw() function need not be reentrant.

Also, using nftw, too many global variables need to be maintained.

Moreover, it seemed not efficient enough for the use here, as links are never followed.

When a given directory does not exist, the tool currently says it was not specified

strace overlay diff --lowerdir=/sysroot
...
readlink("/sysroot", 0x7ffdfc3f36c0, 1023) = -1 ENOENT (No such file or directory)
write(2, "Lower directory not specified.\n", 31Lower directory not specified.
) = 31

Would be nice to print that the directory does not exist instead.

Also, adding a --version flag and tagging releases would be a good idea. This tool is packaged for fedora, but it is impossible to say at what code state.

Maybe this is by design...
Say you have a lower filesystem, "/lower" containing a directory "/lower/d" and a file "lower/f".
Then you mount an overlay, "/overlay" using an empty upper filesystem, "/upper".
Then rm -rf /overlay/d /overlay/f.
Using overlay merge -l /lower -u /upper command, in the generated shell script you get

rm -rf '/lower/d'
mv -T '/upper/d' '/lower/d'
rm -rf '/lower/f'
mv -T '/upper/f' '/lower/f'

The whiteout file and opaque directory from /upper are moved in after deleting the existing file.
I guess its a simple find 1-liner to find these files and delete them from "/lower" if you don't want them but I wonder if overlayfs-tools should either not copy these files in the first place or provide an option not to copy them.

Hi,

I'm looking for a rebuild function that rebuild a combined dir ready to use with a high dir (with updated files and dirs) with low dir and a script.
typically i want to backup a low and high dir and i want to restore a ready to use combined dir with special char device file regenerated.

kmxz using your merge tool with a single lower in https://github.com/StuartIanNaylor/zram-config.
Firstly many thanks as even though OverlayFS is now a mainline module there seems to be a total lack of any tools apart from yours.

I am terribly new to OverlayFS but when it comes to renaming folders and redirect_dir do you plan to add support?

Hi,
So, the script generated on a "merge" command ... basically performs a delete of "upperdir" which does not match what the behaviour stated in help file should be. There it states that the "upperdir" is left empty. When experimenting with merge when mounted ... this is problematic since the "upperdir" mountpoint goes missing and overlayfs looses track of everything at that point. Was wondering if this can be fixed to perform the behaviour indicated that it should be doing.
Heres a snippet from script generated:

rm -rf '/opt/zram/log.bind/daemon.log'
mv -T '/opt/zram/zram2/upper/daemon.log' '/opt/zram/log.bind/daemon.log'
rm -rf '/opt/zram/log.bind/messages'
mv -T '/opt/zram/zram2/upper/messages' '/opt/zram/log.bind/messages'
rm -rf '/opt/zram/log.bind/auth.log'
mv -T '/opt/zram/zram2/upper/auth.log' '/opt/zram/log.bind/auth.log'
rm -rf '/opt/zram/log.bind/syslog'
mv -T '/opt/zram/zram2/upper/syslog' '/opt/zram/log.bind/syslog'
rmdir '/opt/zram/zram2/upper'

gcc -Wall -std=c99 -c main.c
main.c: In function ‘directory_create’:
main.c:99:35: error: ‘errno’ undeclared (first use in this function)
   99 |     if (mkdir(path, 0755) == 0 || errno == EEXIST) { return true; }
      |                                   ^~~~~
main.c:21:1: note: ‘errno’ is defined in header ‘<errno.h>’; did you forget to ‘#include <errno.h>’?
   20 | #include "sh.h"
  +++ |+#include <errno.h>
   21 | 
main.c:99:35: note: each undeclared identifier is reported only once for each function it appears in
   99 |     if (mkdir(path, 0755) == 0 || errno == EEXIST) { return true; }
      |                                   ^~~~~
main.c:99:44: error: ‘EEXIST’ undeclared (first use in this function)
   99 |     if (mkdir(path, 0755) == 0 || errno == EEXIST) { return true; }
      |                                            ^~~~~~
make: *** [makefile:11: main.o] Error 1

Trivial PR to follow.