[lxc-devel] [lxc/lxc] b789a3: attach: simplify lxc_attach_getpwshell()

Mon Dec 10 18:11:08 UTC 2018

  Branch: refs/heads/stable-2.0
  Home:   https://github.com/lxc/lxc
  Commit: b789a324dd26c8e42e6aa43be76f666711efcaf0
      https://github.com/lxc/lxc/commit/b789a324dd26c8e42e6aa43be76f666711efcaf0
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/attach.c

  Log Message:
  -----------
  attach: simplify lxc_attach_getpwshell()

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: dd4ad068bc4ab09f7797d75ae6b9f75ee63e5fab
      https://github.com/lxc/lxc/commit/dd4ad068bc4ab09f7797d75ae6b9f75ee63e5fab
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/attach.c

  Log Message:
  -----------
  coverity: #1437936

Unchecked return value

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: f0127c98a2d2daacb713ec8d1238790724caeb34
      https://github.com/lxc/lxc/commit/f0127c98a2d2daacb713ec8d1238790724caeb34
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/tools/lxc_usernsexec.c

  Log Message:
  -----------
  coverity: #1437935

Unchecked return value

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 2e264c8572f4b71eaef1c999c8b7c292f9e7ace3
      https://github.com/lxc/lxc/commit/2e264c8572f4b71eaef1c999c8b7c292f9e7ace3
  Author: 2xsec <dh48.jeong at samsung.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/lxclock.c

  Log Message:
  -----------
  lxclock: change error log using strerror to SYSERROR

Signed-off-by: 2xsec <dh48.jeong at samsung.com>

  Commit: cacde1a9bc8e0175b16688d4e2a30edd211d735a
      https://github.com/lxc/lxc/commit/cacde1a9bc8e0175b16688d4e2a30edd211d735a
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/conf.c

  Log Message:
  -----------
  conf: the atime flags are locked in userns

This means they need to be added for remount and for fresh mounts.

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: a16d90b5e22aba2b6dc5cd00f08d6ff3f386ed5b
      https://github.com/lxc/lxc/commit/a16d90b5e22aba2b6dc5cd00f08d6ff3f386ed5b
  Author: 2xsec <dh48.jeong at samsung.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/attach.c

  Log Message:
  -----------
  coverity: #1438067

Explicit null dereferenced

Signed-off-by: 2xsec <dh48.jeong at samsung.com>

  Commit: a1b60d342a9c134151f9a40c32de807b40dd1176
      https://github.com/lxc/lxc/commit/a1b60d342a9c134151f9a40c32de807b40dd1176
  Author: 2xsec <dh48.jeong at samsung.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/caps.c
    M src/lxc/start.c

  Log Message:
  -----------
  change log macro of error case from lxc_ambient_caps_up/down

Signed-off-by: 2xsec <dh48.jeong at samsung.com>

  Commit: cba71d5205111e945ed16b3d25766b7833d64371
      https://github.com/lxc/lxc/commit/cba71d5205111e945ed16b3d25766b7833d64371
  Author: Rafał Miłecki <rafal at milecki.pl>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/nl.c

  Log Message:
  -----------
  nl: avoid NULL pointer dereference

It's a valid case to call nla_put() with NULL data and 0 len. It's done e.g. in
the nla_put_attr().

There has to be a check for data in nla_put() as passing NULL to the memcpy()
is not allowed. Even if length is 0, both pointers have to be valid.

For a reference see C99 standard (7.21.1/2), it says: "pointer arguments on
such a call shall still have valid values".

Reported-by: Daniel Gimpelevich <daniel at gimpelevich.san-francisco.ca.us>
Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
[christian.brauner at ubuntu.com: adapted commit message]
Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 3c887fcb70c8f0293037e2ee2820dce42af3a863
      https://github.com/lxc/lxc/commit/3c887fcb70c8f0293037e2ee2820dce42af3a863
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/conf.c

  Log Message:
  -----------
  conf: s/pipe()/pipe2()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 7a12b86c8ed5b97244563b49078cd3d850466a56
      https://github.com/lxc/lxc/commit/7a12b86c8ed5b97244563b49078cd3d850466a56
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/conf.c

  Log Message:
  -----------
  conf: always close pipe in run_userns_fn()

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 705f5735284bb16de76d91946ebce5bff846ace7
      https://github.com/lxc/lxc/commit/705f5735284bb16de76d91946ebce5bff846ace7
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/criu.c

  Log Message:
  -----------
  criu: s/pipe()/pipe2()/

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 988c11f7309a3df5b742d3e94a9ccf41d1925338
      https://github.com/lxc/lxc/commit/988c11f7309a3df5b742d3e94a9ccf41d1925338
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/lxccontainer.c

  Log Message:
  -----------
  lxccontainer: cleanup do_lxcapi_get_interfaces()

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 0e8afcc0d72c02a40630fdf6938699474462fa43
      https://github.com/lxc/lxc/commit/0e8afcc0d72c02a40630fdf6938699474462fa43
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/lxccontainer.c

  Log Message:
  -----------
  lxccontainer: s/pipe()/pipe2()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: c14d9ffe338c4174e5aa1c463038df34069df579
      https://github.com/lxc/lxc/commit/c14d9ffe338c4174e5aa1c463038df34069df579
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/tools/lxc_usernsexec.c

  Log Message:
  -----------
  cmd: s/pipe()/pipe2()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 41b1a847f19fd9f0dff06f1440705ffce68abf7c
      https://github.com/lxc/lxc/commit/41b1a847f19fd9f0dff06f1440705ffce68abf7c
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/lxc_monitord.c
    M src/lxc/tools/lxc_usernsexec.c

  Log Message:
  -----------
  cmd: s/write()/lxc_write_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: d2bd14f02146ebe1081f2b6b711285fe69ee80fe
      https://github.com/lxc/lxc/commit/d2bd14f02146ebe1081f2b6b711285fe69ee80fe
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/lxc_monitord.c
    M src/lxc/tools/lxc_usernsexec.c

  Log Message:
  -----------
  cmd: s/read()/lxc_read_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 95bc087fbe0159f27a74155b5b2f38f7fdf255fb
      https://github.com/lxc/lxc/commit/95bc087fbe0159f27a74155b5b2f38f7fdf255fb
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/criu.c

  Log Message:
  -----------
  criu: s/read()/lxc_read_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 41d8fd0f28e70d6b53f3503cdbd6233b23e4fe79
      https://github.com/lxc/lxc/commit/41d8fd0f28e70d6b53f3503cdbd6233b23e4fe79
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/criu.c

  Log Message:
  -----------
  criu: s/write()/lxc_write_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: ba0ac146073f376222f87e709b3090c96783cde5
      https://github.com/lxc/lxc/commit/ba0ac146073f376222f87e709b3090c96783cde5
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/lxccontainer.c

  Log Message:
  -----------
  lxccontainer: s/write()/lxc_write_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: a11cad8211bb7d5216c83999515ec50e76db261a
      https://github.com/lxc/lxc/commit/a11cad8211bb7d5216c83999515ec50e76db261a
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/lxccontainer.c

  Log Message:
  -----------
  lxccontainer: s/read()/lxc_read_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 089ad11c63ccbcc78835fb31cab1c18bdac663b5
      https://github.com/lxc/lxc/commit/089ad11c63ccbcc78835fb31cab1c18bdac663b5
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/network.c

  Log Message:
  -----------
  network: s/read()/lxc_read_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: e3a9bfbfc9823b2e180e9197a166bd918be43b23
      https://github.com/lxc/lxc/commit/e3a9bfbfc9823b2e180e9197a166bd918be43b23
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/network.c

  Log Message:
  -----------
  network: s/write()/lxc_write_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: d98d27e2df4c81894a0388abd335fdd9af8bae05
      https://github.com/lxc/lxc/commit/d98d27e2df4c81894a0388abd335fdd9af8bae05
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/sync.c

  Log Message:
  -----------
  sync: s/read()/lxc_read_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 9345a89879736b7bf5dcba938226f95ad001bc20
      https://github.com/lxc/lxc/commit/9345a89879736b7bf5dcba938226f95ad001bc20
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/sync.c

  Log Message:
  -----------
  sync: s/write()/lxc_write_nointr()/g

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: c66853b8bd78bff33417e2b5b96033c3a9757f8e
      https://github.com/lxc/lxc/commit/c66853b8bd78bff33417e2b5b96033c3a9757f8e
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/log.c

  Log Message:
  -----------
  log: handle EINTR in read()

We don't want to link log.{c,h} against utils.{c,h} for the sake of our static
builds init.lxc.static. This means lxc_write_nointr() will not be available. So
handle it EINTR.

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: b608a3d963003925e3e9406185a0497bf1be6fd5
      https://github.com/lxc/lxc/commit/b608a3d963003925e3e9406185a0497bf1be6fd5
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/caps.c

  Log Message:
  -----------
  caps: handle EINTR in read()

We don't want to link caps.{c,h} against utils.{c,h} for the sake of our static
builds init.lxc.static. This means lxc_write_nointr() will not be available. So
handle it EINTR.

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: c92a2062f441977f6166e6891a5bbc1905724ce4
      https://github.com/lxc/lxc/commit/c92a2062f441977f6166e6891a5bbc1905724ce4
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/tools/lxc_destroy.c

  Log Message:
  -----------
  coverity: #438136

String not null terminated

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: d82ddb32a56dbb263ff09a92a5c7256f892d64c9
      https://github.com/lxc/lxc/commit/d82ddb32a56dbb263ff09a92a5c7256f892d64c9
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M README.md

  Log Message:
  -----------
  READEM: update Serge's mail address

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
Cc: Serge Hallyn <serge at hallyn.com>

  Commit: eedea69140c44c37a35f002a3081171a8c1cf93b
      https://github.com/lxc/lxc/commit/eedea69140c44c37a35f002a3081171a8c1cf93b
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M MAINTAINERS

  Log Message:
  -----------
  MAINTAINERS: add Wolfgang Bumiller

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 85a7cf828e7eec7812360d190d182bb25d5be905
      https://github.com/lxc/lxc/commit/85a7cf828e7eec7812360d190d182bb25d5be905
  Author: Tobin C. Harding <me at tobin.cc>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M CONTRIBUTING

  Log Message:
  -----------
  CONTRIBUTING: Update reference to kernel coding style

Kernel coding style guide filename is stale, this file has been renamed
in the kernel tree.  While this file still exists we should use the new
filename.

Update reference to kernel coding style guide to use the new file name.

Signed-off-by: Tobin C. Harding <me at tobin.cc>

  Commit: 33d6b9d63859a1cc0d1ca868677ffab7dc4645d6
      https://github.com/lxc/lxc/commit/33d6b9d63859a1cc0d1ca868677ffab7dc4645d6
  Author: Tobin C. Harding <me at tobin.cc>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M CONTRIBUTING

  Log Message:
  -----------
  CONTRIBUTING: Link to latest online kernel docs

Currently we link to a URL for v4.10 of the kernel docs.  Since we
already mention the kernel tree we should link to the _latest_ kernel
docs online instead of a fixed past version.

Link to latest online kernel docs tracking the mainline instead of past
fixed version.

Signed-off-by: Tobin C. Harding <me at tobin.cc>

  Commit: 2dccaea3e6eb2c977b39d9f8f5e86e068c10b6fa
      https://github.com/lxc/lxc/commit/2dccaea3e6eb2c977b39d9f8f5e86e068c10b6fa
  Author: Tobin C. Harding <me at tobin.cc>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M CONTRIBUTING

  Log Message:
  -----------
  CONTRIBUTING: Direct readers to CODING_STYLE.md

Currently the 'Coding Style' section mentions only the kernel coding
style.  We have additions on top on this outlined in CODING_STYLE.md.
We should direct readers to this document as well as the kernel docs.

Direct readers to CODING_STLYE.md in the 'Coding Style' section.

Signed-off-by: Tobin C. Harding <me at tobin.cc>

  Commit: 942496001ec183baff6240d2e0a3925f2987a4e5
      https://github.com/lxc/lxc/commit/942496001ec183baff6240d2e0a3925f2987a4e5
  Author: Tobin C. Harding <me at tobin.cc>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M CODING_STYLE.md

  Log Message:
  -----------
  CODING_STYLE: Mention kernel style in introduction

Currently the coding style guide does not mention that we use kernel
coding style as a base style for LXC.  We have just linked to
CODING_STLYE.md from CONTRIBUTING (which mentions use of kernel coding
style).  We can increase documentation congruence and completeness by
mentioning kernel coding style guide in the introduction to our style
guide.

Add heading and introduction to coding style guide informing readers
that we follow kernel coding style as a base before explaining our style
additions.

Signed-off-by: Tobin C. Harding <me at tobin.cc>

  Commit: 5d48ee40030e6c6170be59fad48a1056ace6e1c6
      https://github.com/lxc/lxc/commit/5d48ee40030e6c6170be59fad48a1056ace6e1c6
  Author: Tobin C. Harding <me at tobin.cc>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M CONTRIBUTING

  Log Message:
  -----------
  CONTRIBUTING: Add 'be' to fix grammar

Fix minor grammatical issue.

Signed-off-by: Tobin C. Harding <me at tobin.cc>

  Commit: 8b9be4bd240666501ce8cabaf17b881533658e35
      https://github.com/lxc/lxc/commit/8b9be4bd240666501ce8cabaf17b881533658e35
  Author: Tobin C. Harding <me at tobin.cc>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M CODING_STYLE.md

  Log Message:
  -----------
  CODING_STLYE: Simplify explanation for use of 'extern'

Current explanation of rules around usage of 'extern' are overly
verbose.  It is not necessary to state that functions should be declared
in header files, the compiler already enforces this.  These rules are
simple, they are better described with simple statements.  An example is
not necessary for such simple rules and serves only to make the document
longer.

Use two simple statements describing the rules that govern function
declaration and the usage of the 'extern' keyword.

Signed-off-by: Tobin C. Harding <me at tobin.cc>

  Commit: f6fab4d950522b9c38ad7e1a5db25718d2601585
      https://github.com/lxc/lxc/commit/f6fab4d950522b9c38ad7e1a5db25718d2601585
  Author: Tobin C. Harding <me at tobin.cc>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M CODING_STYLE.md

  Log Message:
  -----------
  CODING_STLYE: Remove sections implied by 'kernel style'

We explicitly state that LXC uses coding style based on Linux kernel
style.  It is redundant to then document obvious, and well known, kernel
style rules.  Identifier names certainly fall into this category as does
usage of braces.

Remove sections implied by 'kernel style'.  Naming conventions and brace
placement conventions.

Signed-off-by: Tobin C. Harding <me at tobin.cc>

  Commit: f2872db03a598b05b4f213ba4461e52ac11def69
      https://github.com/lxc/lxc/commit/f2872db03a598b05b4f213ba4461e52ac11def69
  Author: Tobin C. Harding <me at tobin.cc>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M CODING_STYLE.md

  Log Message:
  -----------
  CODING_STYLE: Fix non-uniform heading level

Heading uses only 3 level header (###) but the rest of the file uses
four (####).  We should be uniform.

Use uniform heading level in line with the rest of the file.

Signed-off-by: Tobin C. Harding <me at tobin.cc>

  Commit: 34484cdaf528083f6d777097b93c74960ab1f48e
      https://github.com/lxc/lxc/commit/34484cdaf528083f6d777097b93c74960ab1f48e
  Author: Tobin C. Harding <me at tobin.cc>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M CODING_STYLE.md

  Log Message:
  -----------
  CODING_STYLE: Update section header format

Currently for section headings we use fourth level markdown heading
level (####).  We do not have levels two or three.

We can use standard incremental levels for heading adornments i.e

1) =========
2) ##
3) ###
ect.

Since this document is likely referenced by maintainers when guiding new
contributors it can save maintainer time to be able to quickly reference
a section in the coding stlye guide.  If we add numbers to each heading
(like the kernel stlye guide) then maintainers can say:

   Nice patch, please see section 3 of the coding style guide and ...

So, this patch makes two changes

- Use incremental level heading adornments
- Add a number to each section heading

Signed-off-by: Tobin C. Harding <me at tobin.cc>

  Commit: 0c0f00595f630770447364c7ee7802b534a8def6
      https://github.com/lxc/lxc/commit/0c0f00595f630770447364c7ee7802b534a8def6
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M configure.ac

  Log Message:
  -----------
  autotools: add --{disable,enable}-thread-safety

Fail the build if --enable-thread-safety is passed and the environment cannot
guarantee thread-safety.

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

  Commit: 4523e218410946cead3fbad1de225fc14caf1e09
      https://github.com/lxc/lxc/commit/4523e218410946cead3fbad1de225fc14caf1e09
  Author: Stephen Barber <smbarber at chromium.org>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/attach.c

  Log Message:
  -----------
  attach: don't shutdown ipc socket in child

shutdown() affects sockets even across forked processes. The
attached child process doesn't have any interest in using the
IPC socket, so just close it in the child process and let the
intermediate process handle shutting it down.

This fixes a bug seen with lxc exec in crbug.com/884244

Signed-off-by: Stephen Barber <smbarber at chromium.org>

  Commit: 4941288ca598366a03ac1787c0b3b2a59984e7c8
      https://github.com/lxc/lxc/commit/4941288ca598366a03ac1787c0b3b2a59984e7c8
  Author: Christian Brauner <christian.brauner at ubuntu.com>
  Date:   2018-12-10 (Mon, 10 Dec 2018)

  Changed paths:
    M src/lxc/attach.c

  Log Message:
  -----------
  attach: report standard shell exit codes

custom backport

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>

Compare: https://github.com/lxc/lxc/compare/c619ba29a4f5...4941288ca598
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