MFC r297790:
r297790 (by pfg):

libc: replace 0 with NULL for pointers.

While here also cleanup some surrounding code; particularly
drop some malloc() casts.

Found with devel/coccinelle.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

libc: Make various internal file descriptors from fopen() close-on-exec.

Use the stored length value instead of calculating it by strlen().

Add capability to use a db version of services. It is enabled by
specifying `db' as source of service in /etc/nsswitch.conf.

MFC after: 2 weeks

Reduce duplicate code.

MFC after: 2 weeks

Treat '+' as special only when in compat mode, and simplify
the logic bit.

MFC after: 2 weeks

Stop adding trailing '\n'. The servent_unpack() doesn't expect
lines terminated with '\n'.

MFC after: 2 weeks

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

- Extend the nsswitch to support Services, Protocols and Rpc
databases.
- Make nsswitch support caching.

Submitted by: Michael Bushkov <bushman__at__rsu.ru>
Sponsored by: Google Summer of Code 2005

- make reentrant version of netdb functions glibc style API, and
expose them to outside of libc.
- make netdb functions NSS friendly.

Reviewed by: arch@ and current@ (no objection)

Include <sys/types.h> and <limits.h> ourselves, don't assume they are included
through <pthread.h>.

gen/sem.c: Prerequisite for <_semaphore.h>
net/getprotoent.c: USHRT_MAX
net/getservent.c: USHRT_MAX
stdio/ungetwc.c: MB_LEN_MAX
stdio/vfwscanf.c: MB_LEN_MAX

make getnetby*() thread-safe.

rename the NIS related fields to have yp_ prefix.

Suggested by: delphij

Do not check whether a pointer is NULL, since free(3) already takes care of
this case.

Reviewed by: ume

Fix build for !YP case.

BTW. Shall we change these fields to have yp_ prefix? That will make the
code easier to read.

libc-internal interfaces should have two underscores in front
of their names.

Pointed out by: das

- add getserv{byname,byport,ent}_r for internal use within libc.
- make getserv{byname,byport,ent} thread-safe.

Reviewed by: gnn

Don't ignore the last line of config file (/etc/hosts, /etc/services, etc)
which doesn't end in \n, since it may be very confusing. Also this should
increase consistency, since most other config files work just fine regardless
of the presence of traling \n in the last line.

MFC After: 2 weeks

Eliminate 19 warnings in libc (at level WARNS=2) of the
`implicit declaration of function' variety.

Remove __P() usage.

Remove 'register' keyword.

Remove trailing characters from #endif.
Actually this #endif is not needed, so remove leading characters also.

o Move NTOHL() and associated macros into <sys/param.h>. These are
deprecated in favor of the POSIX-defined lowercase variants.
o Change all occurrences of NTOHL() and associated marcros in the
source tree to use the lowercase function variants.
o Add missing license bits to sparc64's <machine/endian.h>.
Approved by: jake
o Clean up <machine/endian.h> files.
o Remove unused __uint16_swap_uint32() from i386's <machine/endian.h>.
o Remove prototypes for non-existent bswapXX() functions.
o Include <machine/endian.h> in <arpa/inet.h> to define the
POSIX-required ntohl() family of functions.
o Do similar things to expose the ntohl() family in libstand, <netinet/in.h>,
and <sys/param.h>.
o Prepend underscores to the ntohl() family to help deal with
complexities associated with having MD (asm and inline) versions, and
having to prevent exposure of these functions in other headers that
happen to make use of endian-specific defines.
o Create weak aliases to the canonical function name to help deal with
third-party software forgetting to include an appropriate header.
o Remove some now unneeded pollution from <sys/types.h>.
o Add missing <arpa/inet.h> includes in userland.

Tested on: alpha, i386
Reviewed by: bde, jake, tmm

Small yet significant tweaks/cleanups:

- getservent:
o put _yp_check() proto under #ifdef YP where it belongs
o local YP buffers should be YPMAXRECORD + 2 bytes long and should
be NUL terminated after copying

- gethostbynis:
o local YP buffer should be YPMAXRECORD + 2 bytes long

- getnetbynis:
o local YP buffer should be YPMAXRECORD + 2 bytes long and should
be NUL terminated after copying

- ether_addr:
o local YP buffers should be YPMAXRECORD + 2 bytes long and should
be NUL terminated after copying (in this case it's BUFSIZ + 2 bytes,
but it happens that BUFSIZ == YPMAXRECORD.

- gethostbydns:
o nuke stray 'return(NULL)' in __dns_getanswer() (harmless but looks silly)

These are 2.2 candidates. I will wait a few days to make sure these don't
break anything and then, if there are no objections, move them to the 2.2
branch.

Eliminate 3 more examples of gratutiously passing arrays by address.

Everyone please call ParaSoft today and say "I will buy 57 copies of
Insure++ tomorrow, but first I want a FreeBSD version." :-)

General -Wall warning cleanup, part I.
Submitted-By: Kent Vander Velden <graphix@iastate.edu>

Improve NIS performace of getservbyname() and getservbyport(). Both these
functions are implimented as wrappers around getservent(), which means it's
up to getservent() to do all the work. The NIS support in getservent()
only allows it to scan through the services.byname map one entry at a
time until it finds the requested service name/port. This can be painfully
slow due to the overhead involved (lots and lots of successive RPCs).

To fix this, we allow getservbyname() and getservbyport() to signal
getservent() that if NIS is turned on (there's a '+' in /etc/services),
the usual yp_first()/yp_next() linear search should be abandoned and
yp_match() used instead. This causes getservent() to immediately
locate the requested entry instead of wasting time groping through the
whole map.

The downside is that this trick is accomplished by exporting a couple of
pointers from getservent.c which getservbyname.c and getservbyport.c can
preset in order to tell getservent() what to do. If all three functions
were in the same source module, then the extra cruft could be delcared
static to avoid poluting the global symbol space. Maybe they should be
combined anyway. For now I've settled on prepending lots of underscores.

Getpwent() and getservent() can wind up calling free() with
an invalid pointer if a call to yp_first() fails. Closes PR # 964,
and possibly # 952.

Add NIS support to getservent(3) functions (getservbyport() and getservbyname()
both call getservent() to do most of the work, so we only need to modify
this file to take care of everybody).

Note that there is only one NIS services map (services.byname) even
though there are getservbyname() and getservbyport() library functions.

This commit was generated by cvs2svn to compensate for changes in r1573,
which included commits to RCS files with non-trunk default branches.

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