Re: tramp (2.3.3.26.1); Faild savid file under su which located in other partision

[Michael Albinus]

address@hidden writes:

Hi,

> Reproduce steps
>   1) Open file in boot sector with su using tramp (in my case it was 
> /boot/EFI/refind/refind.conf)
>      a) C-x C-f /su::localhost
>      b) Enter password
>      c) /boot/EFI/refind/refind.conf
>   2) Edit opened file
>   3) Save file (by C-x C-s)
>
> Expected result
>   1) File saved
>
> Actual result
>   1) File didn't save
>   2) Error message :"tramp-file-name-handler: Copying directly failed, see 
> buffer ‘*tramp/su address@hidden for details."
>   3) Buffer *tramp/su address@hidden is empty
>
> Details:
>   1) All works fine while editing files under tramp su which located on
>   root sector (for example /etc/hosts)
>   2) All works fine while editing file /boot/EFI/refind/refind.conf by
>   emacs, which started under root.

Perhaps ACLs are in the way. Following are the relevant commands Tramp
has performed:

> 18:22:51.479677 tramp-send-command (6) # ( (test -e 
> /boot/EFI/refind/refind.conf || test -h /boot/EFI/refind/refind.conf) && (env 
> QUOTING_STYLE=locale \stat -c '((/////%N/////) %h /////%U///// /////%G///// 
> %Xe0 %Ye0 %Ze0 %se0 /////%A///// t %ie0 -1)' /boot/EFI/refind/refind.conf | 
> sed -e 's/"/\\"/g' -e 's/\/\/\/\/\//"/g') || echo nil) 2>/dev/null; echo 
> tramp_exit_status $?
> 18:22:51.483711 tramp-wait-for-regexp (6) # 
> (("‘/boot/EFI/refind/refind.conf’") 1 "root" "root" 1537565058e0 1537565058e0 
> 1537623302e0 28003e0 "-rwxr-xr-x" t 48e0 -1)

This is a check about the existing file "refind.conf". Most important: it
has uid and gid 0 (root).

> 18:22:51.546768 tramp-send-command (6) # getfacl -ac 
> /boot/EFI/refind/refind.conf 2>/dev/null; echo tramp_exit_status $?
> 18:22:51.547833 tramp-wait-for-regexp (6) # 
> user::rwx
> group::r-x
> other::r-x

ACLs are checked.

> 18:22:51.548268 tramp-send-command (6) # selinuxenabled 2>/dev/null; echo 
> tramp_exit_status $?
> 18:22:51.548976 tramp-wait-for-regexp (6) # 
> tramp_exit_status 127

SELinux is not enabled.

> 18:22:51.550123 tramp-send-command (6) # ( (test -e /boot/EFI/refind/ || test 
> -h /boot/EFI/refind/) && (env QUOTING_STYLE=locale \stat -c '((/////%N/////) 
> %h /////%U///// /////%G///// %Xe0 %Ye0 %Ze0 %se0 /////%A///// t %ie0 -1)' 
> /boot/EFI/refind/ | sed -e 's/"/\\"/g' -e 's/\/\/\/\/\//"/g') || echo nil) 
> 2>/dev/null; echo tramp_exit_status $?
> 18:22:51.553736 tramp-wait-for-regexp (6) # 
> (("‘/boot/EFI/refind/’") 5 "root" "root" 1537623302e0 1537623302e0 
> 1537623302e0 4096e0 "drwxr-xr-x" t 23e0 -1)

The directory "refind" is checked. It is writable for user root.

> 18:22:51.558454 tramp-send-command (6) # test -w /boot/EFI/refind/ 
> 2>/dev/null; echo tramp_exit_status $?
> 18:22:51.558800 tramp-wait-for-regexp (6) # 
> tramp_exit_status 0

The same.

> 18:22:51.566790 tramp-send-command (6) # mv -f /boot/EFI/refind/refind.conf 
> /boot/EFI/refind/refind.conf\~ 2>/dev/null; echo tramp_exit_status $?
> 18:22:51.568523 tramp-wait-for-regexp (6) # 
> tramp_exit_status 0

The file "refind.conf" is renamed to "refind.conf~", no problem.

> 18:22:51.582302 tramp-send-command (6) # env TZ=UTC \touch -t 201809212124.18 
> /boot/EFI/refind/refind.conf\~ 2>/dev/null; echo tramp_exit_status $?
> 18:22:51.583698 tramp-wait-for-regexp (6) # 
> tramp_exit_status 0
> ///1a55e6f4fdda667545d90c960c19b7c4#$
> 18:22:51.584143 tramp-send-command (6) # chmod 755 
> /boot/EFI/refind/refind.conf\~ 2>/dev/null; echo tramp_exit_status $?
> 18:22:51.585234 tramp-wait-for-regexp (6) # 
> tramp_exit_status 0

It gets the timestamp and permissions of the original file.

> 18:22:51.623200 tramp-send-command (6) # ( (test -e /tmp/tramp.a7nx5C.conf || 
> test -h /tmp/tramp.a7nx5C.conf) && (env QUOTING_STYLE=locale \stat -c 
> '((/////%N/////) %h /////%U///// /////%G///// %Xe0 %Ye0 %Ze0 %se0 
> /////%A///// t %ie0 -1)' /tmp/tramp.a7nx5C.conf | sed -e 's/"/\\"/g' -e 
> 's/\/\/\/\/\//"/g') || echo nil) 2>/dev/null; echo tramp_exit_status $?
> 18:22:51.628222 tramp-wait-for-regexp (6) # 
> (("‘/tmp/tramp.a7nx5C.conf’") 1 "robbie" "adm" 1537629771e0 1537629771e0 
> 1537629771e0 27993e0 "-rw-r--r--" t 464952e0 -1)

The temporary file /tmp/tramp.a7nx5C.conf, which is used for editing, is
checked. It belongs to user/group robbie/adm.

> 18:22:51.639260 tramp-send-command (6) # cp -f -p /tmp/tramp.a7nx5C.conf 
> /boot/EFI/refind/refind.conf 2>/dev/null; echo tramp_exit_status $?
> 18:22:51.640592 tramp-wait-for-regexp (6) # 
> tramp_exit_status 1
> ///1a55e6f4fdda667545d90c960c19b7c4#$
> 18:22:51.640898 tramp-do-copy-or-rename-file-directly (1) # File error: 
> Copying directly failed, see buffer ‘*tramp/su address@hidden for details.

Tramp tries to apply "cp -f -p /tmp/tramp.a7nx5C.conf
/boot/EFI/refind/refind.conf", which fails with error code 1. Unfortunately,
due to "2>/dev/null", we don't see why.

> 18:22:54.233581 tramp-send-command (6) # mv -f /boot/EFI/refind/refind.conf\~ 
> /boot/EFI/refind/refind.conf 2>/dev/null; echo tramp_exit_status $?
> 18:22:54.235271 tramp-wait-for-regexp (6) # 
> tramp_exit_status 0

Tramp tries to limit the damage, and moves the backup file back.

That's it. Could you pls prepare a similar temp file with such
permissions, and try to copy this way? Hopefully, we see the error
message then.

Best regards, Michael.