5b8b38775 Fix overly eager BIP30 bypass (Alex Morcos)
Pull request description:
In #6931 we introduced a possible consensus breaking change by misunderstanding how completely BIP 34 obviated the need for BIP 30. Unfixed, this could break consensus after block height about 1.9M. Explained in code comment.
h/t @sdaftuar
Tree-SHA512: 8f798c3f203432fd4ae1c1c08bd6967b4a5ec2064ed5f6a7dcf3bff34ea830952838dd4ff70d70b5080cf4644f601e5526b60456c08f43789e4aae05621d9d6b
b156ff7c3 [tests] bind functional test nodes to 127.0.0.1 (Sjors Provoost)
Pull request description:
Replaces #12200 which broke `rpc_bind.py`.
Prevents OSX firewall allow-this-application-to-accept-inbound-connections permission popups and is generally safer.
To prevent binding to `127.0.0.1`, set `self.bind_to_localhost_only = False`.
cc @jnewbery
Tree-SHA512: 5e700124c91bd0cbdee83ca44910071d71d61d8842334755b685d14fbff6454d75de1ea7de67340370386f58b41361e80e90bb4dca5c4d5992f9d2b27985f999
08e0855b9 Give hint about gitian not able to download (kallewoof)
Pull request description:
Gitian fails to perform downloads right now on my set up. This can be circumvented by first checking out the tag being built and then doing the depends download step before running `gbuild`.
This should of course be fixed in gitian, but having this note until it's fixed is definitely useful.
Tree-SHA512: ae9d0eb44ecfdae44d35aecc6e5fd6db7d9e95b8e0badc76a1d9aaf8fe70bc00a2914dfcb4f516d030560835af411515ca13736ebf8b49b7040b340457882779
A risk exists where a malicious DNS seeder eclipses a node by returning an enormous number of IP addresses. In this commit we mitigate this risk by limiting the number of IP addresses addrman learns to 256 per DNS seeder.
92f1f8b31 Split off key_io_tests from base58_tests (Pieter Wuille)
119b0f85e Split key_io (address/key encodings) off from base58 (Pieter Wuille)
ebfe217b1 Stop using CBase58Data for ext keys (Pieter Wuille)
32e69fa0d Replace CBitcoinSecret with {Encode,Decode}Secret (Pieter Wuille)
Pull request description:
This PR contains some of the changes left as TODO in #11167 (and built on top of that PR). They are not intended for backporting.
This removes the `CBase58`, `CBitcoinSecret`, `CBitcoinExtKey`, and `CBitcoinExtPubKey` classes, in favor of simple `Encode`/`Decode` functions. Furthermore, all Bitcoin-specific logic (addresses, WIF, BIP32) is moved to `key_io.{h,cpp}`, leaving `base58.{h,cpp}` as a pure utility that implements the base58 encoding/decoding logic.
Tree-SHA512: a5962c0ed27ad53cbe00f22af432cf11aa530e3efc9798e25c004bc9ed1b5673db5df3956e398ee2c085e3a136ac8da69fe7a7d97a05fb2eb3be0b60d0479655
5f8cc0df1 Add a test for large tx output scripts with segwit input. (Richard Kiss)
Pull request description:
This test failed in pycoin but passed in bitcoin, so I thought I'd share it.
Tree-SHA512: 95dff4e03afea4d93ff5e99aa06004446c3df022c2e8a191cac8981107135a5ac2bd3ba1c3a9c4eda9f8f63f584cc1700b7ef57ee6ec2c66a72c699b51bdb61a
8dbf740f8 [scripts] lint-whitespace: check last N commits or unstaged changes (Sjors Provoost)
Pull request description:
E.g. before you push three commits to Github and upset Travis, check if you didn't make any whitespace mistakes:
```sh
contrib/devtools/lint-whitespace.sh 3
```
This is slightly more convenient than doing:
```sh
TRAVIS_COMMIT_RANGE=HEAD~3...HEAD contrib/devtools/lint-whitespace.sh
```
Tree-SHA512: 5d9c1ae978ccbe59477e8cf53391e9bd697d2da87f417a2519264af560d4768138e0b2d320dd497a1f1e704e18ab279d724f523b57c17a80ccd753133a5445bf
Gitian fails to perform downloads right now on my set up. This can be circumvented by first checking out the tag being built and then doing the depends download step before running `gbuild`.
40b17f5f9 [scripts] lint-whitespace: use perl instead of grep -P (Sjors Provoost)
Pull request description:
MacOS does not support `grep -P` out of the box. This change makes
it easier for developers to check for whitespace problems locally.
Based on [this](https://stackoverflow.com/a/16658690) and [this](https://serverfault.com/a/504387) Stack Exchange answer.
Tested with:
```sh
export TRAVIS_COMMIT_RANGE='fe78c9a...62e0453'
contrib/devtools/lint-whitespace.sh
This diff appears to have added new lines with tab characters instead of spaces.
The following changes were suspected:
diff --git a/src/test/bignum_tests.cpp b/src/test/bignum_tests.cpp
@@ -0,0 +1,110 @@
+ num.setint64(n);
```
Tree-SHA512: 37c342a0ca2580289cf326a278a051a7c21ba918d6b2143fd9987f159fab85f1de3d770fcf532a642cd5d1957afc8595678128196e102dc473924758f133db7f
Prevents OSX firewall allow-this-application-to-accept-inbound-connections
permission popups and is generally safer.
To prevent binding to 127.0.0.1, set self.bind_to_localhost_only = False.
f506c0a7f [qt] send: Clear All also resets coin control options (Sjors Provoost)
Pull request description:
This change makes it so that a custom change address and manual input selection are removed if the user clicks Clear All in the send screen.
Tree-SHA512: 78746043a74c9c26ef476eb0df7ce95411683749d9f6b2747222eaac751e241ea7d4d7ce9e4e69ed0b19fa76754d8584e5bef5bba1ad6598f8e39c784b4264d2
b4db76c55 net: Correct addrman logging (Wladimir J. van der Laan)
Pull request description:
These were introduced in #9037.
Found by @theuni (https://github.com/bitcoin/bitcoin/pull/9037#pullrequestreview-101704656).
Tree-SHA512: 9b5153da8a8e5d4ddf9513a5c453f9609cffd4df2924fd48c7b36c1b1055748c7077d4fc0e70be62ca36af87df7f621a744bb374a234baba271ce4982a240825
1dfb4e7d7 [Tests] Check output of parent/child tx list from getrawmempool, getmempooldescendants, getmempoolancestors, and REST interface (Conor Scott)
fc44cb108 [RPC] Add list of child transactions to verbose output of getrawmempool (Conor Scott)
Pull request description:
`bitcoin-cli getrawmempool true` only lists a transaction's parents in the `depends` field. This change adds a `spentby` field to the json response, which lists the transaction's children in the mempool.
Currently the only way to find child transactions is to use `getrawmempool` or make another call to `getmempooldescendants` and search the response for transactions that list the parent_txid in the `depends` list, which is inefficient.
This change allows direct lookup of children.
Example Output
```
"9a9b5733c0d89f207908cfa3fe17809bee71f629aa095c9f8754524e29e98ba4": {
...other geterawmempool data...
"wtxid": "9a9b5733c0d89f207908cfa3fe17809bee71f629aa095c9f8754524e29e98ba4",
"depends": [
"bdd92851d5766a42aeb62af667bb422a116cab4e032bba5e3dd6efe5b4b40aa0"
],
"spentby": [
"dc5d3ec388a9121421208738a041ac30a22163bc2e17758f2275b6c51a15ba7b"
]
},
```
Tree-SHA512: 83da7d421c9799a40ef65af3b7fdb586d6d87385f3f2ede3afd2c311725444b858f9d91cc110422a0fa31905779934fee07211ca6fe6b746792b83692c94b3ce
22b4aae02 [arith_uint256] Avoid unnecessary this-copy using prefix operator (Karl-Johan Alm)
Pull request description:
I noticed while profiling a related project that `operator-()` actually calls the `base_uint` constructor, which is because the postfix operator version of `operator++` (used in `operator-()`) creates a copy of `this` and returns it.
Tree-SHA512: d9a2665caa3d93f064cdeaf1c6fada101b9943bb53d93ccac6d9a0edac20279d2e921349e30239039c71e0a9629e45c29ec9f10d8d7499e936cdba6cb7c3c3eb
b7cd08b71 Add documentation to PeerLogicValidation interface and related functions (James O'Beirne)
Pull request description:
Adds docs for PeerLogicValidation's public interface and two related functions.
Tree-SHA512: b4c2f47e9baa9396d2b6faf3792e46b371c50cd91b9ac890f263f4d14eb24a71e7b40ceb4cbb41e254f5008eff357f417b842618e7ebece9039802ab2a5dd728
e68172ed9 Add test-before-evict discipline to addrman (Ethan Heilman)
Pull request description:
This change implement countermeasures 3 (test-before-evict) suggested in our paper: ["Eclipse Attacks on Bitcoin’s Peer-to-Peer Network"](http://cs-people.bu.edu/heilman/eclipse/).
# Design:
A collision occurs when an address, addr1, is being moved to the tried table from the new table, but maps to a position in the tried table which already contains an address (addr2). The current behavior is that addr1 would evict addr2 from the tried table.
This change ensures that during a collision, addr1 is not inserted into tried but instead inserted into a buffer (setTriedCollisions). The to-be-evicted address, addr2, is then tested by [a feeler connection](https://github.com/bitcoin/bitcoin/pull/8282). If addr2 is found to be online, we remove addr1 from the buffer and addr2 is not evicted, on the other hand if addr2 is found be offline it is replaced by addr1.
An additional small advantage of this change is that, as no more than ten addresses can be in the test buffer at once, and addresses are only cleared one at a time from the test buffer (at 2 minute intervals), thus an attacker is forced to wait at least two minutes to insert a new address into tried after filling up the test buffer. This rate limits an attacker attempting to launch an eclipse attack.
# Risk mitigation:
- To prevent this functionality from being used as a DoS vector, we limit the number of addresses which are to be tested to ten. If we have more than ten addresses to test, we drop new addresses being added to tried if they would evict an address. Since the feeler thread only creates one new connection every 2 minutes the additional network overhead is limited.
- An address in tried gains immunity from tests for 4 hours after it has been tested or successfully connected to.
# Tests:
This change includes additional addrman unittests which test this behavior.
I ran an instance of this change with a much smaller tried table (2 buckets of 64 addresses) so that collisions were much more likely and observed evictions.
```
2016-10-27 07:20:26 Swapping 208.12.64.252:8333 for 68.62.95.247:8333 in tried table
2016-10-27 07:20:26 Moving 208.12.64.252:8333 to tried
```
I documented tests we ran against similar earlier versions of this change in #6355.
# Security Benefit
This is was originally posted in PR #8282 see [this comment for full details](https://github.com/bitcoin/bitcoin/pull/8282#issuecomment-237255215).
To determine the security benefit of these larger numbers of IPs in the tried table I modeled the attack presented in [Eclipse Attacks on Bitcoin’s Peer-to-Peer Network](https://eprint.iacr.org/2015/263).
**Default node:** 595 attacker IPs for ~50% attack success.
**Default node + test-before-evict:** 620 attacker IPs for ~50% attack success.
**Feeler node:** 5540 attacker IPs for ~50% attack success.
**Feeler node + test-before-evict:** 8600 attacker IPs for ~50% attack success.
The node running feeler connections has 10 times as many online IP addresses in its tried table making an attack 10 times harder (i.e. requiring the an attacker require 10 times as many IP addresses in different /16s). Adding test-before-evict increases resistance of the node by an additional 3000 attacker IP addresses.
Below I graph the attack over even greater attacker resources (i.e. more attacker controled IP addresses). Note that test-before-evict maintains some security far longer even against an attacker with 50,000 IPs. If this node had a larger tried table test-before-evict could greatly boost a nodes resistance to eclipse attacks.
Tree-SHA512: fdad4d26aadeaad9bcdc71929b3eb4e1f855b3ee3541fbfbe25dca8d7d0a1667815402db0cb4319db6bd3fcd32d67b5bbc0e12045c4252d62d6239b7d77c4395
6fbc0986f gui: Show messages as text not html (Wladimir J. van der Laan)
Pull request description:
Currently, error messages (such as InitError) are displayed as-is, which means Qt does auto detection on the format.
This means that it's possible to inject HTML from the command line though e.g. specifying a wallet name with HTML in it. This isn't a direct security risk because fetching content from internet is
disabled (and as far as I know we never report strings received from the network this way). However, it can be confusing.
So explicitly force the format as text.
Tree-SHA512: 96c9196f20552544b862071bca61817ef03653019cc3548023d435f3a9c48b6cd501fab3246783cb0be68c8c7bb1b865913d92070a7c4e84e82c6577709f0934
cfaac2a60 Add build support for 'gprof' profiling. (murrayn)
Pull request description:
Support for profiling build: `./configure --enable-profiling`
Tree-SHA512: ea983cfce385f1893bb4ab7f94ac141b7d620951dc430da3bbc92ae1357fb05521eac689216e66dc87040171a8a57e76dd7ad98036e12a2896cfe5ab544347f0
13a399a46 depends: patch pthread_set_name_np out of zeromq (Cory Fields)
8f7922636 depends: zeromq 4.2.3 (fanquake)
Pull request description:
This is a followup to #9254 and #11981. Zeromq 4.2.3 was released just after #9254 was merged, and contains a years worth of improvements/bug fixes. See the release notes [here](https://github.com/zeromq/libzmq/releases/tag/v4.2.3).
Todo:
- [ ] Add zeromq-4.2.3.tar.gz to /depends-sources on bitcoincore.org
- [ ] Verify gitian builds are still OK
- [ ] Check: https://github.com/zeromq/libzmq/pull/2787
Tree-SHA512: 85e06f47be3e1fdedcee50ce90e3391d69df2ea1c167472ffc3126d8970d418eb75141b970e422eb2fda9a8cad00e6ba5b36afa53565171a9ebaa152a9dc9b60
937bf4335 Use std:🧵:hardware_concurrency, instead of Boost, to determine available cores (fanquake)
Pull request description:
Following discussion on IRC about replacing Boost usage for detecting available system cores, I've opened this to collect some benchmarks + further discussion.
The current method for detecting available cores was introduced in #6361.
Recap of the IRC chat:
```
21:14:08 fanquake: Since we seem to be giving Boost removal a good shot for 0.15, does anyone have suggestions for replacing GetNumCores?
21:14:26 fanquake: There is std:🧵:hardware_concurrency(), but that seems to count virtual cores, which I don't think we want.
21:14:51 BlueMatt: fanquake: I doubt we'll do boost removal for 0.15
21:14:58 BlueMatt: shit like BOOST_FOREACH, sure
21:15:07 BlueMatt: but all of boost? doubtful, there are still things we need
21:16:36 fanquake: Yea sorry, not the whole lot, but we can remove a decent chunk. Just looking into what else needs to be done to replace some of the less involved Boost usage.
21:16:43 BlueMatt: fair
21:17:14 wumpus: yes, it makes sense to plan ahead a bit, without immediately doing it
21:18:12 wumpus: right, don't count virtual cores, that used to be the case but it makes no sense for our usage
21:19:15 wumpus: it'd create a swarm of threads overwhelming any machine with hyperthreading (+accompanying thread stack overhead), for script validation, and there was no gain at all for that
21:20:03 sipa: BlueMatt: don't worry, there is no hurry
21:59:10 morcos: wumpus: i don't think that is correct
21:59:24 morcos: suppose you have 4 cores (8 virtual cores)
21:59:24 wumpus: fanquake: indeed seems that std has no equivalent to physical_concurrency, on any standard. That's annoying as it is non-trivial to implement
21:59:35 morcos: i think running par=8 (if it let you) would be notably faster
21:59:59 morcos: jeremyrubin and i discussed this at length a while back... i think i commented about it on irc at the time
22:00:21 wumpus: morcos: I think the conclusion at the time was that it made no difference, but sure would make sense to benchmark
22:00:39 morcos: perhaps historical testing on the virtual vs actual cores was polluted by concurrency issues that have now improved
22:00:47 wumpus: I think there are not more ALUs, so there is not really a point in having more threads
22:01:40 wumpus: hyperthreads are basically just a stored register state right?
22:02:23 sipa: wumpus: yes but it helps the scheduler
22:02:27 wumpus: in which case the only speedup using "number of cores" threads would give you is, possibly, excluding other software from running on the cores on the same time
22:02:37 morcos: well this is where i get out of my depth
22:02:50 sipa: if one of the threads is waiting on a read from ram, the other can use the arithmetic unit for example
22:02:54 morcos: wumpus: i'm pretty sure though that the speed up is considerably more than what you might expect from that
22:02:59 wumpus: sipa: ok, I back down, I didn't want to argue this at all
22:03:35 morcos: the reason i haven't tested it myself, is the machine i usually use has 16 cores... so not easy due to remaining concurrency issues to get much more speedup
22:03:36 wumpus: I'm fine with restoring it to number of virtual threads if that's faster
22:03:54 morcos: we should have somene with 4 cores (and  actually test it though, i agree
22:03:58 sipa: i would expect (but we should benchmark...) that if 8 scriot validation threads instead of 4 on a quadcore hyperthreading is not faster, it's due to lock contention
22:04:20 morcos: sipa: yeah thats my point, i think lock contention isn't that bad with 8 now
22:04:22 wumpus: on 64-bit systems the additional thread overhead wouldn't be important at least
22:04:23 gmaxwell: I previously benchmarked, a long time ago, it was faster.
22:04:33 gmaxwell: (to use the HT core count)
22:04:44 wumpus: why was this changed at all then?
22:04:47 wumpus: I'm confused
22:05:04 sipa: good question!
22:05:06 gmaxwell: I had no idea we changed it.
22:05:25 wumpus: sigh 
22:05:54 gmaxwell: What PR changed it?
22:06:51 gmaxwell: In any case, on 32-bit it's probably a good tradeoff... the extra ram overhead is worth avoiding.
22:07:22 wumpus: https://github.com/bitcoin/bitcoin/pull/6361
22:07:28 gmaxwell: PR 6461 btw.
22:07:37 gmaxwell: er lol at least you got it right.
22:07:45 wumpus: the complaint was that systems became unsuably slow when using that many thread
22:07:51 wumpus: so at least I got one thing right, woohoo
22:07:55 sipa: seems i even acked it!
22:07:57 BlueMatt: wumpus: there are more alus
22:08:38 BlueMatt: but we need to improve lock contention first
22:08:40 morcos: anywya, i think in the past the lock contention made 8 threads regardless of cores a bit dicey.. now that is much better (although more still to be done)
22:09:01 BlueMatt: or we can just merge #10192, thats fee
22:09:04 gribble: https://github.com/bitcoin/bitcoin/issues/10192 | Cache full script execution results in addition to signatures by TheBlueMatt · Pull Request #10192 · bitcoin/bitcoin · GitHub
22:09:11 BlueMatt: s/fee/free/
22:09:21 morcos: no, we do not need to improve lock contention first. but we should probably do that before we increase the max beyond 16
22:09:26 BlueMatt: then we can toss concurrency issues out the window and get more speedup anyway
22:09:35 gmaxwell: wumpus: yea, well in QT I thought we also diminished the count by 1 or something? but yes, if the motivation was to reduce how heavily the machine was used, thats fair.
22:09:56 sipa: the benefit of using HT cores is certainly not a factor 2
22:09:58 wumpus: gmaxwell: for the default I think this makes a lot of sense, yes
22:10:10 gmaxwell: morcos: right now on my 24/28 physical core hosts going beyond 16 still reduces performance.
22:10:11 wumpus: gmaxwell: do we also restrict the maximum par using this? that'd make less sense
22:10:51 wumpus: if someone *wants* to use the virtual cores they should be able to by setting -par=
22:10:51 sipa: *flies to US*
22:10:52 BlueMatt: sipa: sure, but the shared cache helps us get more out of it than some others, as morcos points out
22:11:30 BlueMatt: (because it means our thread contention issues are less)
22:12:05 morcos: gmaxwell: yeah i've been bogged down in fee estimation as well (and the rest of life) for a while now.. otherwise i would have put more effort into jeremy's checkqueue
22:12:36 BlueMatt: morcos: heh, well now you can do other stuff while the rest of us get bogged down in understanding fee estimation enough to review it 
22:12:37 wumpus: [to answer my own question: no, the limit for par is MAX_SCRIPTCHECK_THREADS, or 16]
22:12:54 morcos: but to me optimizing for more than 16 cores is pretty valuable as miners could use beefy machines and be less concerned by block validation time
22:14:38 BlueMatt: morcos: i think you may be surprised by the number of mining pools that are on VPSes that do not have 16 cores 
22:15:34 gmaxwell: I assume right now most of the time block validation is bogged in the parts that are not as concurrent. simple because caching makes the concurrent parts so fast. (and soon to hopefully increase with bluematt's patch)
22:17:55 gmaxwell: improving sha2 speed, or transaction malloc overhead are probably bigger wins now for connection at the tip than parallelism beyond 16 (though I'd like that too).
22:18:21 BlueMatt: sha2 speed is big
22:18:27 morcos: yeah lots of things to do actually...
22:18:57 gmaxwell: BlueMatt: might be a tiny bit less big if we didn't hash the block header 8 times for every block. 
22:21:27 BlueMatt: ehh, probably, but I'm less rushed there
22:21:43 BlueMatt: my new cache thing is about to add a bunch of hashing
22:21:50 BlueMatt: 1 sha round per tx
22:22:25 BlueMatt: and sigcache is obviously a ton
```
Tree-SHA512: a594430e2a77d8cc741ea8c664a2867b1e1693e5050a4bbc8511e8d66a2bffe241a9965f6dff1e7fbb99f21dd1fdeb95b826365da8bd8f9fab2d0ffd80d5059c
6058766de Remove deprecated PyZMQ call from Python ZMQ example (Michał Zabielski)
Pull request description:
PyZMQ 17.0.0 has deprecated and removed zmq.asyncio.install() call
with advice to use asyncio native run-loop instead of zmq specific.
This caused exception when running the contrib/zmq/zmq_sub*.py examples.
This commit simply follows the advice and fixes mentioned examples.
Tree-SHA512: af357aafa5eb9506cfa3f513f06979bbc49f6132fddc1e96fbcea175da4f8e2ea298be7c7055e7d3377f0814364e13bb88b5c195f6a07898cd28c341d23a93c5
e2b2e48b6 doc: SIGNER can contains space inside now. (Ken Lee)
Pull request description:
SIGNER can contains space inside now. mentioned in https://github.com/bitcoin/bitcoin/pull/12527#issuecomment-370506416
Tree-SHA512: 8da1e8146751457c351058c0142fa3d474a338fe7304a31ebed4726202202724aaca94441806458512259238a703601b87961196abc3fdd57b5eb0f062ff0c12
Changes addrman to use the test-before-evict discipline in which an
address is to be evicted from the tried table is first tested and if
it is still online it is not evicted.
Adds tests to provide test coverage for this change.
This change was suggested as Countermeasure 3 in
Eclipse Attacks on Bitcoin’s Peer-to-Peer Network, Ethan Heilman,
Alison Kendler, Aviv Zohar, Sharon Goldberg. ePrint Archive Report
2015/263. March 2015.
Currently, error messages (such as InitError) are displayed as-is, which
means Qt does auto detection on the format.
This means that it's possible to inject HTML from the command line
though e.g. specifying a wallet name with HTML in it. This isn't
a direct security risk because fetching content from internet is
disabled (and as far as I know we never report strings received
from the network this way). However, it can be confusing.
So explicitly force the format as text.
741f0177c Add DynamicMemoryUsage() to LevelDB (Evan Klitzke)
Pull request description:
This adds a new method `CDBWrapper::DynamicMemoryUsage()` similar to Bitcoin's existing methods of the same name. It's implemented by asking LevelDB for the information, and then parsing the string response. I've also added logging to `CDBWrapper::WriteBatch()` to track this information:
```
$ tail -f ~/.bitcoin/testnet3/debug.log | grep WriteBatch
2018-03-05 19:34:55 WriteBatch memory usage: db=chainstate, before=0.0MiB, after=0.0MiB
2018-03-05 19:35:17 WriteBatch memory usage: db=index, before=0.0MiB, after=0.0MiB
2018-03-05 19:35:17 WriteBatch memory usage: db=chainstate, before=0.0MiB, after=8.0MiB
2018-03-05 19:35:22 WriteBatch memory usage: db=index, before=0.0MiB, after=0.0MiB
2018-03-05 19:35:22 WriteBatch memory usage: db=chainstate, before=8.0MiB, after=17.0MiB
2018-03-05 19:35:26 WriteBatch memory usage: db=index, before=0.0MiB, after=0.0MiB
2018-03-05 19:35:27 WriteBatch memory usage: db=chainstate, before=9.0MiB, after=18.0MiB
2018-03-05 19:35:40 WriteBatch memory usage: db=index, before=0.0MiB, after=0.0MiB
2018-03-05 19:35:41 WriteBatch memory usage: db=chainstate, before=9.0MiB, after=7.0MiB
2018-03-05 19:35:52 WriteBatch memory usage: db=index, before=0.0MiB, after=0.0MiB
2018-03-05 19:35:52 WriteBatch memory usage: db=chainstate, before=7.0MiB, after=9.0MiB
^C
```
As LevelDB doesn't seem to provide a way to get the database name, I've also added a new `m_name` field to the `CDBWrapper`. This is necessary because we have multiple LevelDB databases (two now, and possibly more later, e.g. #11857).
I am using this information in other branches where I'm experimenting with changing LevelDB buffer sizes.
Tree-SHA512: 7ea8ff5484bb07ef806af17d000c74ccca27d2e0f6c3229e12d93818f00874553335d87428482bd8acbcae81ea35aef2a243326f9fccbfac25989323d24391b4
