inappropriate ioctl for device

Question

I have a Perl script running in an AIX box    The script tries to open a file from a certain directory and it fails to read the file because file has no read permission  but I get a different error saying inappropriate ioctl for device    Shouldn t it say something like no read permissions for file or something similar   What does this inappropriate ioctl for device message mean   How can I fix it   EDIT  This is what I found when I did strace    open   local logs xxx xxxxServer log   O WRONLY O CREAT O APPEND O LARGEFILE       0666    4  llseek 4  0   77146   SEEK END    0 ioctl 4  SNDCTL TMR TIMEBASE or TCGETS  0xbffc14f8    -1 ENOTTY       Inappropriate ioctl for  device

User · Answer

Odd errors like  inappropriate ioctl for device  are usually a result of checking    at some point other than just after a system call failed   If you d show your code  I bet someone would rapidly point out your error

User · Answer

Most likely it means that the open didn t fail   When Perl opens a file  it checks whether or not the file is a TTY  so that it can answer the -T  fh filetest operator  by issuing the TCGETS ioctl against it  If the file is a regular file and not a tty  the ioctl fails and sets errno to ENOTTY  string value   Inappropriate ioctl for device    As ysth says  the most common reason for seeing an unexpected value in    is checking it when it s not valid -- that is  anywhere other than immediately after a syscall failed  so testing the result codes of your operations is critically important   If open actually did return false for you  and you found ENOTTY in    then I would consider this a small bug  giving a useless value of     but I would also be very curious as to how it happened  Code and or truss output would be nifty

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Ran into this error today while trying to use code to delete a folder files that are living on a Windoze 7 box that s mounted as a share on a Centos server    Got the inappropriate icotl for device error and tried everything that came to mind   Read just about every post on the net related to this   Obviously the problem was isolated to the mounted Windoze share on the Linux server   Looked at the file permissions on the Windoze box and noted the files had their permissions set to read only   Changed those  went back to the Linux server and all worked as expected    This may not be the solution for most but hopefully it saves someone some time

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I got the error Can t open file for reading  Inappropriate ioctl for device recently when I migrated an old UB2K forum with a DBM file-based database to a new host  Apparently there are multiple  incompatible implementations of DBM  I had a backup of the database  so I was able to load that  but it seems there are other options e g  moving a perl script dbm to a new server  and shifting out of dbm

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Since this is a fatal error and also quite difficult to debug  maybe the fix could be put somewhere  in the provided command line     export GPG TTY   tty    From  https   github com keybase keybase-issues issues 2798

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I just fixed this perl bug  See https   rt perl org Ticket Display html id 124232  When we push the buffer layer to PerlIO and do a failing isatty   check which obviously fails on all normal files  ignore the wrong errno ENOTTY

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I tried the following code that seemed to work   if open my  FILE    lt File txt          while  lt  FILE gt        print          else       print  File could not be opened or did not exists n

User · Answer

inappropriate ioctl for device  is the error string for the ENOTTY error  It used to be triggerred primarily by attempts to configure terminal properties  e g  echo mode  on a file descriptor that was no terminal  but  say  a regular file   hence ENOTTY  More generally  it is triggered when doing an ioctl on a device that does not support that ioctl  hence the error string   To find out what ioctl is being made that fails  and on what file descriptor  run the script under strace truss  You ll recognize ENOTTY  followed by the actual printing of the error message  Then find out what file number was used  and what open   call returned that file number

User · Answer

Eureka moment   I have had this error before    Did you invoke the perl debugger with something like  -  perl -d yourprog pl  gt  log txt   If so whats going on is perl debug tries to query and perhaps reset the terminal width  When stdout is not a terminal this fails with the IOCTL message   The alternative would be for your debug session to hang forever because you did not see the prompt for instructions

User · Answer

files  in  nix type systems are very much an abstract concept   They can be areas on disk organized by a file system  but they could equally well be a network connection  a bit of shared memory  the buffer output from another process  a screen or a keyboard   In order for perl to be really useful it mirrors this model very closely  and does not treat files by emulating a magnetic tape as many 4gls do   So it tried an  IOCTL  operation  open for write  on a file handle which does not allow write operations which is an inappropriate IOCTL operation for that device file   The easiest thing to do is stick an   or die  Cannot open  myfile   statement at the end of you open and you can choose your own meaningful message

[perl] "inappropriate ioctl for device"

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