The getaddrinfo(3), getipnodebyname(3) and resolver(3) can coincide now
with what should be totally reentrant, and h_errno values will now
be preserved correctly, but this does not affect interfaces such as
gethostbyname(3) which are still mostly non-reentrant.
In all of these relevant functions, the thread-safety has been pushed
down as far as it seems possible right now. This means that operations
that are selected via nsdispatch(3) (i.e. files, yp, dns) are protected
still under global locks that getaddrinfo(3) defines, but where possible
the locking is greatly reduced. The most noticeable improvement is
that multiple DNS lookups can now be run at the same time, and this
shows major improvement in performance of DNS-lookup threaded programs,
and solves the "Mozilla tab serialization" problem.
No single-threaded applications need to be recompiled. Multi-threaded
applications that reference "_res" to change resolver(3) options will
need to be recompiled, and ones which reference "h_errno" will also
if they desire the correct h_errno values. If the applications already
understood that _res and h_errno were not thread-safe and had their own
locking, they will see no performance improvement but will not
actually break in any way.
Please note that when NSS modules are used, or when nsdispatch(3)
defaults to adding any lookups of its own to the individual libc
_nsdispatch() calls, those MUST be reentrant as well.
configure FreeBSD so that various databases such as passwd and group can be
looked up using flat files, NIS, or Hesiod.
= Hesiod has been added to libc (see hesiod(3)).
= A library routine for parsing nsswitch.conf and invoking callback
functions as specified has been added to libc (see nsdispatch(3)).
= The following C library functions have been modified to use nsdispatch:
. getgrent, getgrnam, getgrgid
. getpwent, getpwnam, getpwuid
. getusershell
. getaddrinfo
. gethostbyname, gethostbyname2, gethostbyaddr
. getnetbyname, getnetbyaddr
. getipnodebyname, getipnodebyaddr, getnodebyname, getnodebyaddr
= host.conf has been removed from src/etc. rc.network has been modified
to warn that host.conf is no longer used at boot time. In addition, if
there is a host.conf but no nsswitch.conf, the latter is created at boot
time from the former.
Obtained from: NetBSD
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
- 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.
lookup results. Without this, doing multiple host/addr lookups in a
single process yeilds strange results (the buffer is static, and
garbage may be left behind from previous lookups).
I just noticed this in 2.2-BETA. Unless somebody threatens to chop my
hands off with an axe, I'm going to move this to the 2.2-RELENG branch
shortly.
- Fix problem described in PR #1079: _gethostbynisaddr() doesn't
work. Make it accept the same arguments as all the other
gethostby*addr() functions and properly convert the supplied IP
address into a text string so that yp_match() can find it in the
hosts.byaddr map.
- Also fix potential memory leak: copy the results of yp_match() to
a static buffer and free the result (yp_match() returns dynamically
allocated memory).
ether_addr.c:
- Since I was in the neighborhood, fix ether_ntohost() and
ether_hostton() so that they don't bogusly for a free(result)
when yp_match() fails.
