Add and correct basic support files for the vmm-sys-util crate including:
- files generated by Cargo
- license files
- gitignore

Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>

The errno module wraps an interface to the error codes.
The eventfd module is a wraper around the Linux eventfd. Use result::Result<EventFd, io::Error>
instead of result::Result<EventFd, errno::Errno> as return type.
The terminal module is for configuring pseudo-terminals in raw mode.
The signal module is for registering signal handlers and for signalling threads.
The ioctl module is factoring out common ioctl wrappers and macros.

This is derived from crosvm code base e4ece32798ba436fbfa88466c571f46dab99e2be
and firecracker code base 1fdde1997fc763601f8a88399bc426bd5d4097cd.

Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>

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Change Log

Add license.
Append prefix test_ for each test.
Add verbose commit messages.

To use different init flag(e.g. SA_RESTART, SA_SIGINFO) for sigaction, add
a parameter to register_signal_handler and a function to set this flag.

Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>

Wrapping the libc timerfd for the usage of setting timer, waiting expiring,
disarm timer.

This is derived from crosvm code base e4ece32798ba436fbfa88466c571f46dab99e2be.

Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>

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Change Log:

Add license.
Split the summary and description for method.
Add link for structures and functions.
Append prefix test_ for tests.

The poll module addis the Poller object for waiting on mutliple file
descriptors at once. Add macro handle_eintr_errno! to check the epoll_wait return value.

The syslog module is for logging, temporarily defining the SYS_getpid syscall value.

This is derived from crosvm code base e4ece32798ba436fbfa88466c571f46dab99e2be.

Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>

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Change Log
Append prefix test_ for tests.

Copied verbatim from crosvm 107edb3e.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

This will be needed for the write_zeroes and seek_hole implementations.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

A dependency free alternative to the tempfile crate.
Copied verbatim from crosvm 107edb3e.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

This is needed for disk image format support like e.g. QCOW2.
Copied verbatim from crosvm 107edb3e.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

This is needed for disk image format support like e.g. QCOW2.
Copied verbatim from crosvm 107edb3e.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

Several places are improved to suppress the clippy warnings.

The changes of type casting in timerfd module are based on crosvm latest code base
b1de6323ab8c96c52a60e0ff735e4bbb8a8464c9.

The write_zeroes and seek_hole clippy warnings are only on test code, we
can safely allow them.

Signed-off-by: Jing Liu <jing2.liu@linux.intel.com>

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

musl does not define the SEEK_HOLE and SEEK_DATA constants.
We use the libc one when using glibc and we define them when building
for musl.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

Using the File wrappers leads to poisoned pointers when running under a
tmpfs based /dev mount.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

The vmm-sys-util test make heavy use of temporary dirs and files.
Running that under a container overlay leads to erratic behaviours and
this is fixed by using a real tmpfs mount into the container's /tmp.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>