If array has N elements, we can't read +1 if we are already at N.

Also, we need to move elements by their storage size in the array,
not just by individual bytes.

[maybe] Fixes valgrind errors:
32 bytes in 4 blocks are definitely lost in loss record 107 of 228
   at 0x80EA447: je_malloc (jemalloc.c:944)
   by 0x806E59C: zrealloc (zmalloc.c:125)
   by 0x80A9AFC: clusterSetMaster (cluster.c:801)
   by 0x80AEDC9: clusterCommand (cluster.c:3994)
   by 0x80682A5: call (redis.c:2049)
   by 0x8068A20: processCommand (redis.c:2309)
   by 0x8076497: processInputBuffer (networking.c:1143)
   by 0x8073BAF: readQueryFromClient (networking.c:1208)
   by 0x8060E98: aeProcessEvents (ae.c:412)
   by 0x806123B: aeMain (ae.c:455)
   by 0x806C3DB: main (redis.c:3832)

64 bytes in 8 blocks are definitely lost in loss record 143 of 228
   at 0x80EA447: je_malloc (jemalloc.c:944)
   by 0x806E59C: zrealloc (zmalloc.c:125)
   by 0x80AAB40: clusterProcessPacket (cluster.c:801)
   by 0x80A847F: clusterReadHandler (cluster.c:1975)
   by 0x30000FF: ???

80 bytes in 10 blocks are definitely lost in loss record 148 of 228
   at 0x80EA447: je_malloc (jemalloc.c:944)
   by 0x806E59C: zrealloc (zmalloc.c:125)
   by 0x80AAB40: clusterProcessPacket (cluster.c:801)
   by 0x80A847F: clusterReadHandler (cluster.c:1975)
   by 0x2FFFFFF: ???

Fixes valgrind error:
Syscall param write(buf) points to uninitialised byte(s)
   at 0x514C35D: ??? (syscall-template.S:81)
   by 0x456B81: clusterWriteHandler (cluster.c:1907)
   by 0x41D596: aeProcessEvents (ae.c:416)
   by 0x41D8EA: aeMain (ae.c:455)
   by 0x41A84B: main (redis.c:3832)
 Address 0x5f268e2 is 2,274 bytes inside a block of size 8,192 alloc'd
   at 0x4932D1: je_realloc (jemalloc.c:1297)
   by 0x428185: zrealloc (zmalloc.c:162)
   by 0x4269E0: sdsMakeRoomFor.part.0 (sds.c:142)
   by 0x426CD7: sdscatlen (sds.c:251)
   by 0x4579E7: clusterSendMessage (cluster.c:1995)
   by 0x45805A: clusterSendPing (cluster.c:2140)
   by 0x45BB03: clusterCron (cluster.c:2944)
   by 0x423344: serverCron (redis.c:1239)
   by 0x41D6CD: aeProcessEvents (ae.c:311)
   by 0x41D8EA: aeMain (ae.c:455)
   by 0x41A84B: main (redis.c:3832)
 Uninitialised value was created by a stack allocation
   at 0x457810: nodeUpdateAddressIfNeeded (cluster.c:1236)

Otherwise kill_instance + restart_instance in short succession will
still find the port busy and will fail.

Related to issue #2289.

Rationale is that when re-entering, it is likely due to Lua debugging
hooks. Returning an error will be ignored in most cases, going totally
unnoticed. With the log at least we leave a trace.

Related to issue #2302.

Instead of calling redisPanic() to abort the server.

Related to issue #2302.

Related to issue #2302.

In order to avoid that misconfigured cluster nodes at some time may
force an IP update on other nodes, it is required that nodes update
their own address only on MEET messages. However it does not make sense
to do this the first time a node is contacted and yet does not have an
IP, we just risk that myself->ip remains not assigned if there are
messages lost or cluster creation procedures that don't make sure
everybody is targeted by at least one incoming MEET message.

Also fix the logging of the IP switch avoiding the :-1 tail.

Also explicitly set version to 0, add a protocol version define, improve
comments in the gossip structure.

Note that the structure layout is the same after the change, we are just
making the padding explicit with an additional not used 16 bits field.
So this commit is still able to talk with the previous versions of
cluster nodes.

Valgrind checks that the buffers we transfer via syscalls are all
composed of bytes actually initialized. This is useful, it makes we able
to avoid leaking informations in non initialized parts fo messages
transferred to other hosts. This commit fixes one of such issues.

This reverts commit 2c925b0c.

Nevermind.

Three fixes: explicit supervise, pidfile create, remove memory leaks.

Can't be initialized by resetManualFailover() since it's actual state
the function uses, so we need to initialize it at startup time. Not
really a bug in practical terms, but showed up into valgrind and is not
technically correct anyway.

Adds configuration option 'supervised [no | upstart | systemd | auto]'

Also removed 'bzero' from the previous implementation because it's 2015.
(We could actually statically initialize those structs, but clang
throws an invalid warning when we try, so it looks bad even though it
isn't bad.)

Fixes #2264

We want pidfile to be NULL on startup so we can detect if the user
set an explicit value versus only using the default value.

Closes #1967
Fixes #2076

Previously, Redis only wrote the pid file if
it was daemonizing, but many times it's useful to have
the pid written out even if you're in the foreground.

Some background for this is:
I usually run redis via daemontools. That entails running
redis-server on the foreground. Given that, I'd also want
redis-server to create a pidfile so other processes (e.g. nagios)
can run checks for that.

Closes #463

This fix is from @NanXiao, however I was not able to retain authorship
because the Pull Request original repository was removed.

Before this commit scripts were able to access / create keys outside the
set of hash slots served by the local node.

Fix redis-trib creation failure

Under certain conditions the node list wasn't being fully populated
and 'create' would fail trying to call methods on nil objects.

Explain make distclean which seems not well known

Thx to @badboy.