Improve doc in linux-object and migrate some simple syscalls

[yunwei37]

Add syscalls

• sysinfo
• flock

Maybe some of them are just interfaces...

• I'm trying to port symlink syscall from rcore, but the rcorefs-hostfs is not support it (and some other syscall is not support well), so maybe I can make some change to this?
• this pull-request maybe only for some simple things...

other

• add some simple syscall tests
• fix some syscall info log
• change some schedule syscall to unimplement

[coveralls]

Pull Request Test Coverage Report for Build 205410702

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 33 of 47 (70.21%) changed or added relevant lines in 8 files are covered.
• 1046 unchanged lines in 30 files lost coverage.
• Overall coverage increased (+2.2%) to 43.798%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
linux-syscall/src/misc.rs	18	19	94.74%
linux-syscall/src/task.rs	1	2	50.0%
linux-syscall/src/lib.rs	2	4	50.0%
linux-syscall/src/file/poll.rs	0	3	0.0%
linux-syscall/src/file/fd.rs	0	7	0.0%

Files with Coverage Reduction	New Missed Lines	%
zircon-syscall/src/lib.rs	1	0.0%
linux-syscall/src/misc.rs	2	43.33%
zircon-syscall/src/resource.rs	3	0.0%
zircon-syscall/src/debug.rs	4	0.0%
linux-object/src/fs/file.rs	5	58.82%
zircon-syscall/src/cprng.rs	5	0.0%
../../../../../usr/share/rust/.cargo/registry/src/github.com-1ecc6299db9ec823/bitflags-1.2.1/src/lib.rs	9	42.86%
zircon-syscall/src/port.rs	9	0.0%
zircon-syscall/src/system.rs	9	0.0%
zircon-syscall/src/fifo.rs	15	0.0%

Totals
Change from base Build 204048433:	2.2%
Covered Lines:	5985
Relevant Lines:	13665

---

💛 - Coveralls

[yunwei37]

about rustc

Currently we can run rustc with help informations output, but cannot compile files.

It seems poll syscall may have some bugs or unexpected behavior with pipe, maybe because the pipe has not imply the async_poll. I think it can be fix in the future.

[wangrunji0408]

Thanks!

[wangrunji0408]

You are welcomed to add symlink support for rcore-fs-hostfs :)