[Bug 1692420] Re: Ubuntu 17.04: "command substitution: ignored null byte in input" warning message is displayed while running few RAS commands.

[Tiago Stürmer Daitx]

** Description changed:

+ [Impact]
+ 
+ The current version of powerpc-utils in Ubuntu Zesty and Artful carries
+ a bug exposed by bash 4.4+ which causes a warning to be logged to stderr
+ in 4 different commands: ls-veth, ls-vscsi, lsdevinfo, and ofpathname.
+ Bash is unable to store the NUL bytes in the result of a command
+ substitution, prior to 4.4 it silently dropped the NUL bytes, but since
+ 4.4 it drops the NUL bytes with a warning: "command substitution:
+ ignored null byte in input".
+ 
+ Additionally to that the ofpathname command also had a bug that caused a
+ "cd: too many arguments" warning.
+ 
+ Upstream has fixed both [1] and they now need to be backport to Zesty.
+ 
+ [Test Case 1]
+ 
+ Call any of the affected commands without arguments.
+ 
+ The same warning can easily be reproduced in bash 4.4+ by executing:
+ $ x=$(cat < /proc/$$/cmdline)
+ bash: warning: command substitution: ignored null byte in input
+ 
+ And to fix it:
+ $ x=$(tr -d '\0' < /proc/$$/cmdline)
+ <no output, as expected>
+ 
+ [Test Case 2]
+ Call ofpathname with no arguments:
+ $ ofpathname
+ cd: too many arguments
+ 
+ 
+ [Regression Potential] 
+ 
+ The replacement of 'cat' with 'tr -d "\0"' causes no regression. Also,
+ both commands are part of coreutils.
+ 
+ The 'cd' fix replaces it with a drop_dir call. In case the requested
+ path is not found then the previous behavior would be kept (ie. no
+ directory change).
+ 
+ [Other Info]
+ 
+ Upstream fix link: 
+ [1] https://github.com/ibm-power-utilities/powerpc-utils/commit/4fcc611a09caea70e6bca6a1275211c72ac4bb45
+ 
+ 
+ [Old description]
  Please cherry pick...
  
  https://github.com/ibm-power-utilities/powerpc-
  utils/commit/4fcc611a09caea70e6bca6a1275211c72ac4bb45

** Summary changed:

- Ubuntu 17.04: "command substitution: ignored null byte in input" warning message is displayed while running few RAS commands.
+ [SRU] powerpc-utils commans exhibits "command substitution: ignored null byte in input" warning message

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https://bugs.launchpad.net/bugs/1692420

Title:
  [SRU] powerpc-utils commans exhibits "command substitution: ignored
  null byte in input" warning message

Status in The Ubuntu-power-systems project:
  New
Status in powerpc-utils package in Ubuntu:
  Triaged

Bug description:
  [Impact]

  The current version of powerpc-utils in Ubuntu Zesty and Artful
  carries a bug exposed by bash 4.4+ which causes a warning to be logged
  to stderr in 4 different commands: ls-veth, ls-vscsi, lsdevinfo, and
  ofpathname. Bash is unable to store the NUL bytes in the result of a
  command substitution, prior to 4.4 it silently dropped the NUL bytes,
  but since 4.4 it drops the NUL bytes with a warning: "command
  substitution: ignored null byte in input".

  Additionally to that the ofpathname command also had a bug that caused
  a "cd: too many arguments" warning.

  Upstream has fixed both [1] and they now need to be backport to Zesty.

  [Test Case 1]

  Call any of the affected commands without arguments.

  The same warning can easily be reproduced in bash 4.4+ by executing:
  $ x=$(cat < /proc/$$/cmdline)
  bash: warning: command substitution: ignored null byte in input

  And to fix it:
  $ x=$(tr -d '\0' < /proc/$$/cmdline)
  <no output, as expected>

  [Test Case 2]
  Call ofpathname with no arguments:
  $ ofpathname
  cd: too many arguments

  
  [Regression Potential] 

  The replacement of 'cat' with 'tr -d "\0"' causes no regression. Also,
  both commands are part of coreutils.

  The 'cd' fix replaces it with a drop_dir call. In case the requested
  path is not found then the previous behavior would be kept (ie. no
  directory change).

  [Other Info]

  Upstream fix link: 
  [1] https://github.com/ibm-power-utilities/powerpc-utils/commit/4fcc611a09caea70e6bca6a1275211c72ac4bb45

  
  [Old description]
  Please cherry pick...

  https://github.com/ibm-power-utilities/powerpc-
  utils/commit/4fcc611a09caea70e6bca6a1275211c72ac4bb45

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