b6f0b4d wallet: Improve logging when BerkeleyDB environment fails to close (Tim Ruffing)
264c643 wallet: Reset BerkeleyDB handle after connection fails (Tim Ruffing)
Pull request description:
According to the BerkeleyDB docs, the DbEnv handle may not be accessed
after close() has been called. This change ensures that we create a new
handle after close() is called. This avoids a segfault when the first
connection attempt fails and then a second connection attempt tries to
call open() on the already closed DbEnv handle.
Without the patch, bitcoindd reliably crashes in the second call to `set_lg_dir()` after `close()` if
there is an issue with the database:
```
2018-05-03T13:27:21Z Bitcoin Core version v0.16.99.0-a024a1841-dirty (debug build)
[...]
2018-05-03T13:27:21Z Using wallet directory /home/tim/.bitcoin
2018-05-03T13:27:21Z init message: Verifying wallet(s)...
2018-05-03T13:27:21Z Using BerkeleyDB version Berkeley DB 4.8.30: (April 9, 2010)
2018-05-03T13:27:21Z Using wallet wallet.dat
2018-05-03T13:27:21Z BerkeleyEnvironment::Open: LogDir=/home/tim/.bitcoin/database
2018-05-03T13:27:21Z BerkeleyEnvironment::Open: Error -30974 opening database environment: DB_RUNRECOVERY: Fatal error, run database recovery
2018-05-03T13:27:21Z Moved old /home/tim/.bitcoin/database to /home/tim/.bitcoin/database.1525354041.bak. Retrying.
2018-05-03T13:27:21Z BerkeleyEnvironment::Open: LogDir=/home/tim/.bitcoin/database ErrorFile=/home/tim/.bitcoin/db.log
[1] 14533 segmentation fault (core dumped) ./src/bitcoind
```
After the fix:
```
2018-05-03T17:19:32Z Bitcoin Core version v0.16.99.0-cc09e3bd0-dirty (release build)
[...]
2018-05-03T17:19:32Z Using wallet directory /home/tim/.bitcoin
2018-05-03T17:19:32Z init message: Verifying wallet(s)...
2018-05-03T17:19:32Z Using BerkeleyDB version Berkeley DB 4.8.30: (April 9, 2010)
2018-05-03T17:19:32Z Using wallet wallet.dat
2018-05-03T17:19:32Z BerkeleyEnvironment::Open: LogDir=/home/tim/.bitcoin/database ErrorFile=/home/tim/.bitcoin/db.log
2018-05-03T17:19:32Z scheduler thread start
2018-05-03T17:19:32Z BerkeleyEnvironment::Open: Error -30974 opening database environment: DB_RUNRECOVERY: Fatal error, run database recovery
2018-05-03T17:19:32Z Moved old /home/tim/.bitcoin/database to /home/tim/.bitcoin/database.1525367972.bak. Retrying.
2018-05-03T17:19:32Z BerkeleyEnvironment::Open: LogDir=/home/tim/.bitcoin/database ErrorFile=/home/tim/.bitcoin/db.log
2018-05-03T17:19:32Z Cache configuration:
2018-05-03T17:19:32Z * Using 2.0MiB for block index database
2018-05-03T17:19:32Z * Using 8.0MiB for chain state database
2018-05-03T17:19:32Z * Using 440.0MiB for in-memory UTXO set (plus up to 286.1MiB of unused mempool space)
2018-05-03T17:19:32Z init message: Loading block index..
[...]
```
Tree-SHA512: b809b318e5014ec47d023dc3dc40826b9706bfb211fa08bc2d29f36971b96caa10ad48d9a3f96c03933be46fa4ff7e00e952ac77bfffb6563767fb08aa4f23d6