Fix various thread assertion errors caused during shutdown.
Cherry-picked from the following upstream PRs:
- bitcoin/bitcoin#6719
- bitcoin/bitcoin#6990
- bitcoin/bitcoin#8421
- Second commit only in this PR
- bitcoin/bitcoin#11006
I've cherry-picked the relevant commits, along with a note in each commit referring to the original Bitcoin commit ID (and the Zcash issue numbers where applicable). I've tested each issue with/without these patches applied.
Closes#2214, #2334, and #2554.
Move libsnark in-repo as a git subtree
This PR pulls in the libsnark subtree at the exact commit that we currently fetch via the depends system. To verify:
```
$ ./contrib/devtools/git-subtree-check.sh src/snark
src/snark in HEAD was last updated to upstream commit 9ada3f84ab484c57b2247c2f41091fd6a0916573 (tree c10a38c759)
src/snark in HEAD currently refers to tree 34e916d3f6
:100644 100644 427f4f4ce913e54da68b M Makefile
:040000 040000 42f29e42d1dd73536163 M src
FAIL: subtree directory tree doesn't match subtree commit tree
```
This shows that there are changes relative to what we currently use, due to the later commits in the PR. If we exclude them, we see that the code is identical:
```
$ git checkout 26a8f68ea8
$ ./contrib/devtools/git-subtree-check.sh src/snark
src/snark in HEAD was last updated to upstream commit 9ada3f84ab484c57b2247c2f41091fd6a0916573 (tree c10a38c759)
src/snark in HEAD currently refers to tree c10a38c759
GOOD
```
Closes#820.
Importprivkey shows address
Scratching an itch: make `importprivkey` output the corresponding address.
Without this PR, `importprivkey` shows no output. Because we're moving towards an "address-based" RPC interface, rather than "account-based", there's a gap when using `importprivkey` because there's no way to assign it to a specific account, but also no easy way to determine the address. This change fixes that wart.
Fixes for gcc 7
This fixes a few issues when using a newer compiler (in my case gcc 7.1.1) available in for example Arch Linux.
Solves for example this issue: https://github.com/zcash/zcash/issues/2304
The first thing is an error when checking for boost_system and is solved by disabling that warning (wich is treated as an error and, hence, stops the build):
```
configure:22242: checking for exit in -lboost_system-mt
configure:22267: g++ -m64 -o conftest -std=c++11 -pipe -fPIC -O1 -fwrapv -fno-strict-aliasing -Werror -g -Wformat -Wformat-security -Wstack-protector -fstack-protector-all -fPIE ..<snip>... /x86_64-unknown-linux-gnu/share/../lib conftest.cpp -lboost_system-mt -lanl >&5
conftest.cpp:70:6: error: declaration of 'char exit()' conflicts with built-in declaration 'void exit(int)' [-Werror=builtin-declaration-mismatch]
char exit ();
^~~~
cc1plus: all warnings being treated as errors
```
The second thing was to clean some code that is deprecated in C++11 which also lead to a warning treated as error. It could also be fixed with `-Wno-deprecated` but better to fix the issue in my opinion.
Previously various user-facing strings have used inconsistent currency units "BTC",
"btc" and "bitcoins". This adds a single constant and uses it for each reference to
the currency unit.
Also adds a description of the unit for --maxtxfee, and adds the missing "amount"
field description to the (deprecated) move RPC command.
When using std::thread in place of boost::thread, letting the threads destruct
results in a std::terminate. According to the docs, the same thing should be
be happening in later boost versions:
http://www.boost.org/doc/libs/1_55_0/doc/html/thread/thread_management.html#thread.thread_management.thread.destructor
I'm unsure why this hasn't blown up already, but explicitly detaching can't
hurt.
Zcash: cherry-picked from commit d3773ca9aeb0d2f12dc0c5a0726778050c8cb455
This fixes#2554 (zcash-cli stop during getblocktemplate long poll
causes 'Assertion `!pthread_mutex_unlock(&m)' failed.')
This continues/fixes #6719.
`event_base_loopbreak` was not doing what I expected it to, at least in
libevent 2.0.21.
What I expected was that it sets a timeout, given that no other pending
events it would exit in N seconds. However, what it does was delay the
event loop exit with 10 seconds, even if nothing is pending.
Solve it in a different way: give the event loop thread time to exit
out of itself, and if it doesn't, send loopbreak.
This speeds up the RPC tests a lot, each exit incurred a 10 second
overhead, with this change there should be no shutdown overhead in the
common case and up to two seconds if the event loop is blocking.
As a bonus this breaks dependency on boost::thread_group, as the HTTP
server minds its own offspring.
Zcash: cherry-picked from commit a264c32e3321ae909ca59cb8ce8bf5d812dbc4e1
This makes sure that the event loop eventually terminates, even if an
event (like an open timeout, or a hanging connection) happens to be
holding it up.
Zcash: cherry-picked from commit ec908d5f7aa9ad7e3487018e06a24cb6449cc58b
Add a WaitExit() call to http's WorkQueue to make it delete the work
queue only when all worker threads stopped.
This fixes a problem that was reproducable by pressing Ctrl-C during
AppInit2:
```
/usr/include/boost/thread/pthread/condition_variable_fwd.hpp:81: boost::condition_variable::~condition_variable(): Assertion `!ret' failed.
/usr/include/boost/thread/pthread/mutex.hpp:108: boost::mutex::~mutex(): Assertion `!posix::pthread_mutex_destroy(&m)' failed.
```
I was assuming that `threadGroup->join_all();` would always have been
called when entering the Shutdown(). However this is not the case in
bitcoind's AppInit2-non-zero-exit case "was left out intentionally
here".
Zcash: cherry-picked from commit de9de2de361ab1355b976f17371d73e36fe3bf56
Fixes#2334 and #2214.
Shutting down the HTTP server currently breaks off all current requests.
This can create a race condition with RPC `stop` command, where the calling
process never receives confirmation.
This change removes the listening sockets on shutdown so that no new
requests can come in, but no longer breaks off requests in progress.
Meant to fix bitcoin/#6717.
Zcash: cherry-picked from commit 5e0c22135600fe36811da3b78216efc61ba765fb
