Support URI scheme for root-path in netbooting

[bapt]

Summary

It supports the following scheme:
compat with before all the changes:
NFS for:
root-path = /path
root-path = <ip>:/path

New schemes:
tftpfs for
tftp:/path
tftp://ip/path

nfs for
nfs:/path
nfs://ip/path

[rgrimes]

Other than the comment expansion request I like this, very clean, very easy to understand, and even easier to expand in the future.

[bapt]

In D10947#226677, @rgrimes wrote:

Other than the comment expansion request I like this, very clean, very easy to understand, and even easier to expand in the future.

You mean you want more comments in that code? if yes I can do that yes :)

[tsoome]

sys/boot/common/dev_net.c

431 ↗

(On Diff #28884)

for pointer arithmetics it is good to use ((uintptr_t)val - (uintptr_t)ptr) - just to be at safe side, because we do have 64 and 32 bit builds there.

442 ↗

(On Diff #28884)

There is still the confusion about return types; we do get n_long as address from inet_addr, yet this function is stated to return uint32_t. And this may be problem with 64-bit binary.

[bapt]

Better pointer arithmetics

[bapt]

sys/boot/common/dev_net.c

442 ↗

(On Diff #28884)

I agree and this should be addressed in a second commit imho

[bapt]

Use size_t instead of unsigned long

[tsoome]

LGTM.

[rgrimes]

In D10947#226718, @bapt wrote:

In D10947#226677, @rgrimes wrote:

Other than the comment expansion request I like this, very clean, very easy to understand, and even easier to expand in the future.

You mean you want more comments in that code? if yes I can do that yes :)

Yes please, basically this function was re-written and enhanced without any change to the describing block comment that should exists before each function in the FreeBSD source tree. (see style(9)).

head/sys/boot/common/dev_net.c

391

The above is the block comment for the net_parse_rootpath() function, it is rather out of date now that this function has been greatly enhanced, so yes I would like to see a new block comment that more accurately describes what this function now does.