In ISO C++, the signedness of 'char' is undefined. On some platforms (e.g.
ARM), 'char' is an unsigned type, but some of the code relies on 'char' being
signed (as it is on x86). This is indicated by compiler warnings like this:
bignum.h: In constructor 'CBigNum::CBigNum(char)':
bignum.h:81:59: warning: comparison is always true due to limited range of data type [-Wtype-limits]
util.cpp: In function 'bool IsHex(const string&)':
util.cpp:427:28: warning: comparison is always false due to limited range of data type [-Wtype-limits]
In particular, IsHex erroneously returned true regardless of the input
characters, as long as the length of the string was a positive multiple of 2.
Note: For testing, it's possible using GCC to force char to be unsigned by
adding the -funsigned-char parameter to xCXXFLAGS.
This commit removes the dependency of serialize.h on PROTOCOL_VERSION,
and makes this parameter required instead of implicit. This is much saner,
as it makes the places where changing a version number can have an
influence obvious.
Where possible, use boost::filesystem::path instead of std::string or
char* for filenames. This avoids a lot of manual string tinkering, in
favor of path::operator/.
GetDataDir is also reworked significantly, it now only keeps two cached
directory names (the network-specific data dir, and the root data dir),
which are decided through a parameter instead of pre-initialized global
variables.
Finally, remove the "upgrade from 0.1.5" case where a debug.log in the
current directory has to be removed.
All client version information is moved to version.cpp, which optionally
(-DHAVE_BUILD_INFO) includes build.h. build.h is automatically generated
on supporting platforms via contrib/genbuild.sh, using git describe.
The git export-subst attribute is used to put the commit id statically
in version.cpp inside generated archives, and this value is used if no
build.h is present.
The gitian descriptors are modified to use git archive instead of a
copy, to create the src/ directory in the output. This way,
src/src/version.cpp will contain the static commit id. To prevent
gitian builds from getting the "-dirty" marker in their git-describe
generated identifiers, no touching of files or running sed on the
makefile is performed anymore. This does not seem to influence
determinism.
This commit simplifies the locking system: CCriticalSection becomes a
simple typedef for boost::interprocess::interprocess_recursive_mutex,
and CCriticalBlock and CTryCriticalBlock are replaced by a templated
CMutexLock, which wraps boost::interprocess::scoped_lock.
By making the lock type a template parameter, some critical sections
can now be changed to non-recursive locks, which support waiting via
condition variables. These are implemented in CWaitableCriticalSection
and WAITABLE_CRITICAL_BLOCK.
CWaitableCriticalSection is a wrapper for a different Boost mutex,
which supports waiting/notification via condition variables. This
should enable us to remove much of the used polling code. Important
is that this mutex is not recursive, so functions that perform the
locking must not call eachother.
Because boost::interprocess::scoped_lock does not support assigning
and copying, I had to revert to the older CRITICAL_BLOCK macros that
use a nested for loop instead of a simple if.
- rename wxMessageBox, remove redundant arguments to noui/qtui calls
- also, add flag to force blocking, modal dialog box for disk space warning etc
- clarify function naming
- no more special MessageBox needed from AppInit2, as window object is created before calling AppInit2
This introduces CNetAddr and CService, respectively wrapping an
(IPv6) IP address and an IP+port combination. This functionality used
to be part of CAddress, which also contains network flags and
connection attempt information. These extra fields are however not
always necessary.
These classes, along with logic for creating connections and doing
name lookups, are moved to netbase.{h,cpp}, which does not depend on
headers.h.
Furthermore, CNetAddr is mostly IPv6-ready, though IPv6
functionality is not yet enabled for the application itself.
Remembering all time samples makes nTimeOffset slow to respond to
system clock corrections. For instance, I start my node with a system
clock that's 30 minutes slow and run it for a few days. During that
time, I accumulate 10,000 offset samples with a median of 1800
seconds. Now I correct my system clock. Without this change, my node
must collect another 10,000 samples before nTimeOffset is correct
again. With this change, I must only accumulate 100 samples to
correct the offset.
Storing unlimited time samples also allows an attacker with many IP
addresses (ex, a large botnet) to perform a memory exhaustion attack
against Bitcoin nodes. The attacker sends a version message from each
IP to his target, consuming more of the target's memory each time.
Time samples are small, so this attack might be impractical under the
old code, but it's impossible with the new code.
The full list of time samples is rarely useful outside of debugging.
The node's time offset, however is useful for discovering local clock
drift, so it's displayed in all logging modes.
Pieter Wuille