checkpatch emites warning:

    WARNING: braces {} are not necessary for single statement blocks

Do not use braces for single statement block.
Signed-off-by: Tobin C. Harding <me@tobin.cc>

checkpatch warns because of function definitions using empty parameter
list.  We should define these functions with 'void' as the parameter.

Use 'void' instead of empty parameter list for function definitions.
Signed-off-by: Tobin C. Harding <me@tobin.cc>

checkpatch emits error:

    ERROR: Macros with complex values should be enclosed in parentheses

Safeguard macro by use of parenthesis.
Signed-off-by: Tobin C. Harding <me@tobin.cc>

log: add logging tools for commands; lxc-usernsexec: cleanup and bugfixes

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

Add a thread-safe and uniform way to retrieve errno values in programs that are
shipped as part of LXC but are not expected to have access to the logging
system.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Add a thread-safe and uniform way to retrieve errno values in programs that are
shipped as part of LXC but are not expected to have access to the logging
system.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

Checkpatch

usernsexec: Make err out vebose for unshare error

checkpatch.pl emits error

    ERROR: do not use assignment in if condition

Move assignment out of if statement.
Signed-off-by: Tobin C. Harding <me@tobin.cc>

checkpatch.pl emits a bunch of warnings about various whitespace
issues.  Fix all these as a single patch since they are all whitespace
only changes.

Fix whitespace issues found by checkpatch.pl
Signed-off-by: Tobin C. Harding <me@tobin.cc>

checkpatch.pl emits error

    ERROR: do not initialise statics to 0

Do not initialise statics to 0.
Signed-off-by: Tobin C. Harding <me@tobin.cc>

checkpatch.pl emits error

    ERROR: do not use assignment in if condition

Correctly indent switch statement.
Signed-off-by: Tobin C. Harding <me@tobin.cc>

Currently if lxc-usernsexec is run on a kernel without user namespaces
enabled the error message is

	unshare: Invalid argument
	read pipe: Success

This error message 'Invalid argument' does not point at the root cause
of the error.  We can help the user out by giving a more detailed error
message and also not using perror() if errno==0.

Improve error message by
 - Printing unshare flags
 - Printing suggested cause of failure (user namespace not enabled)
 - Print error message with fprintf() if errno==0 (EOF)
Signed-off-by: Tobin C. Harding <me@tobin.cc>

doc: Fix minor grammatical errors

Current we have a few minor grammatical errors in the documentation for
lxc container configuration.

Fix minor grammatical errors.
Signed-off-by: Tobin C. Harding <me@tobin.cc>

state: s/sleep()/nanosleep()/

sleep() is not thread-safe but nanosleep() is. Since no resources are allocated
in lxc_wait() it is safe to call nanosleep() without cancellation handlers.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

lxccontainer: minor fixes

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

lxccontainer: improve file locking

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

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

lxccontainer: fix F_OFD_GETLK checks

When we check whether an open file description lock has been taken on a file we
need to set the l_pid field to 0 otherwise the kernel will send back EINVAL.
Additionally, the kernel will not do pid translation and simply set the l_pid
value to -1.

Fixes https://discuss.linuxcontainers.org/t/container-deleted-or-stopped-when-lxc-ls-executed-concurrently/2439Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

coverity: #1438392

Dereference before null check
Signed-off-by: 2xsec <dh48.jeong@samsung.com>

fix thread-safe issue (localtime => localtime_r)

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

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

netlink: add __netlink_{send,recv,transaction}

These allow to pass a struct nlmsghdr directly and are used in the higher level
netlink_{send,rcv,transaction}.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

netns: improve netnsid allocation

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

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

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

fix assignment of signed to bigger unsigned issue

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

tests: containertests: fix dereference pointer c

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