+2000-07-28 Philip Blundell <philb@gnu.org>
+
+ * math/test-fpucw.c: Ignore reserved bits in control word.
+
+2000-07-28 Philip Blundell <philb@gnu.org>
+
+ * sysdeps/unix/sysv/linux/arm/sysdep.h (PSEUDO_RET): New macro.
+ (ret): Redefine to PSEUDO_RET.
+ (PSEUDO): Remove jump to syscall_error.
+
+2000-07-29 Mark Kettenis <kettenis@gnu.org>
+
+ * resolv/README: Add some information about using the resolver in
+ multi-threaded code and with C++. Spelling fixes.
+
+2000-07-29 Mark Kettenis <kettenis@gnu.org>
+
+ * resolv/resolv.h (struct __sockaddr_in): Remove.
+ (struct __res_state) [!_LIBC]: Remove reference to __sockaddr_in.
+
2000-07-29 Greg McGary <greg@mcgary.org>
* Rules (test-bp-inputs, make-test-out): New variables.
pointers as __unbounded. Wrap bounds around variable `current'.
* sysdeps/i386/backtrace.c (struct layout): Make pointers __unbounded.
(ADVANCE_STACK_FRAME): Wrap bounds around return value.
- * sysdeps/powerpc/backtrace.c (struct layout): Make pointers __unbounded.
+ * sysdeps/powerpc/backtrace.c (struct layout): Make pointers
+ __unbounded.
(__backtrace): Qualify frame-pointer chain and return address
pointers as __unbounded. Wrap bounds around variable `current'.
+The resolver in the GNU C Library
+*********************************
+
Starting with version 2.2, the resolver in the GNU C Library comes
from BIND 8. Only a subset of the src/lib/resolv part of libbind is
included here; basically the parts that are needed to provide the
* The `res_close' function in glibc only tries to close open files
referenced through `_res' if the RES_INIT bit is set in
`_res.options'. This fixes a potential security bug with programs
- that bogusly call `res_close' without initializing the resolver
+ that bogusly call `res_close' without initialising the resolver
state first. Note that the thread-safe `res_nclose' still doesn't
check the RES_INIT bit. By the way, you're not really supposed to
call `res_close/res_nclose' directly.
+* The resolver in glibc can connect to a nameserver over IPv6. Just
+ specify the IPv6 address in /etc/resolv.conf. You cannot change the
+ address of an IPv6 nameserver dynamically in your program though.
+
+
+Using the resolver in multi-threaded code
+=========================================
+
+The traditional resolver interfaces `res_query', `res_search',
+`res_mkquery', `res_send' and `res_init', used a static (global)
+resolver state stored in the `_res' structure. Therefore, these
+interfaces are not thread-safe. Therefore, BIND 8.2 introduced a set
+of "new" interfaces `res_nquery', `res_nsearch', `res_nmkquery',
+`res_nsend' and `res_ninit' that take a `res_state' as their first
+argument, so you can use a per-thread resolver state. In glibc, when
+you link with -lpthread, such a per-thread resolver state is already
+present. It can be accessed using `_res', which has been redefined as
+a macro, in a similar way to what has been done for the `errno' and
+`h_errno' variables. This per-thread resolver state is also used for
+the `gethostby*' family of functions, which means that for example
+`gethostbyname_r' is now fully thread-safe and re-entrant. The
+traditional resolver interfaces however, continue to use a single
+resolver state and are therefore still thread-unsafe. The resolver
+state is the same resolver state that is used for the initial ("main")
+thread.
+
+This has the following consequences for existing binaries and source
+code:
+
+* Single-threaded programs will continue to work. There should be no
+ user-visible changes when you recompile them.
+
+* Multi-threaded programs that use the traditional resolver interfaces
+ in the "main" thread should continue to work, except that they no
+ longer see any changes in the global resolver state caused by calls
+ to, for example, `gethostbyname' in other threads. Again there
+ should be no user-visible changes when you recompile these programs.
+
+* Multi-threaded programs that use the traditional resolver interfaces
+ in more than one thread should be just as buggy as before (there are
+ no problems if you use proper locking of course). If you recompile
+ these programs, manipulating the _res structure in threads other
+ than the "main" thread will seem to have no effect though.
+
+* In Multi-threaded that manipulate the _res structure, calls to
+ functions like `gethostbyname' in threads other than the "main"
+ thread won't be influenced by the those changes anymore. So if you
+ set RES_USE_INET6, a call to `gethostbyname' won't return any IPv6
+ hosts anymore. If you recompile such programs, manipulating the
+ _res structure will affect the thread in which you do so instead of
+ the "main" thread.
+
+We recommend to use the new thread-safe interfaces in new code, since
+the traditional interfaces have been deprecated by the BIND folks.
+For compatibility with other (older) systems you might want to
+continue to use those interfaces though.
+
+
+Using the resolver in C++ code
+==============================
+
+There resolver contains some hooks which will allow the user to
+install some callback functions that make it possible to filter DNS
+requests and responses. Although we do not encourage you to make use
+of this facility at all, C++ developers should realise that it isn't
+safe to throw exceptions from such callback functions.
+
Source code
===========
src/lib/isc/
base64.c
-Some of these files have been optimized a bit, and adaptations have
+Some of these files have been optimised a bit, and adaptations have
been made to make them fit in with the rest of glibc. The more
non-obvious changes are wrapped in something like `#ifdef _LIBC'.
projects / external / glibc.git / commitdiff