In SPOP, when COUNT is greater than or equal to set's size,
we will remove the set. In dbDelete, we will do DEL or UNLINK
according to the lazy flag. This is also required for propagate.
In RESTORE, we won't store expired keys into the db, see #7472.
When used together with REPLACE, it should emit a DEL or UNLINK
according to the lazy flag.
This PR also adds tests to cover the propagation. The RESTORE
test will also cover #7472.
This commit excludes aux fields from the output of the `cluster nodes` and `cluster replicas` command.
We may decide to re-introduce them in some form or another in the future, but not in v7.2.
Technically declaring a prototype with an empty declaration has been deprecated since the early days of C, but we never got a warning for it. C2x will apparently be introducing a breaking change if you are using this type of declarator, so Clang 15 has started issuing a warning with -pedantic. Although not apparently a problem for any of the compiler we build on, if feels like the right thing is to properly adhere to the C standard and use (void).
We have cases where we print information (might be important but by
no means an error indicator) with the LL_WARNING level.
Demoting these to LL_NOTICE:
- oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
- User requested shutdown...
This is also true for cases that we encounter a rare but normal situation.
Demoting to LL_NOTICE. Examples:
- AOF was enabled but there is already another background operation. An AOF background was scheduled to start when possible.
- Connection with master lost.
base on yoav-steinberg's https://github.com/redis/redis/pull/10650#issuecomment-1112280554
and yossigo's https://github.com/redis/redis/pull/10650#pullrequestreview-967677676
In this PR, we use function pointer *isPresent replace the variable "present" in auxFieldHandler, so that in the future, when we have more aux fields, we could decide if the aux field is displayed or not.
Currently while a sharded pubsub message publish tries to propagate the message across the cluster, a NULL check is missing for clusterLink. clusterLink could be NULL if the link is causing memory beyond the set threshold cluster-link-sendbuf-limit and server terminates the link.
This change introduces two things:
Avoids the engine crashes on the publishing node if a message is tried to be sent to a node and the link is NULL.
Adds a debugging tool CLUSTERLINK KILL to terminate the clusterLink between two nodes.
This change improves the performance of cluster slots by removing the deferring lengths that are used. Deferring lengths are used in two contexts, the first is for determining the number of replicas that serve a slot (Added in 6.2 as part of a different performance improvement) and the second is for determining the extra networking options for each node (Added in 7.0). For continuous slots, (e.g. 0-8196) this improvement is very negligible, however it becomes more significant when slots are not continuous (e.g. 0 2 4 6 etc) which can happen in production for various users.
The `cluster slots` command is deprecated in favor of `cluster shards`, but since most clients don't support the new command yet I think it's important to not degrade performance here.
Benchmarking shows about 2x improvement, however I wasn't able to get a coherent TPS number since the benchmark process was being saturated long before Redis was, so had to run with multiple benchmarks and merge results. If needed I can add this to our memtier framework. Instead the next section shows the number of usec per call from the benchmark results, which shows significant improvement as well as having a more coherent response in the CoB.
| | New Code | Old Code | % Improvements
|----|----|----- |-----
| Uniform slots| usec_per_call=10.46 | usec_per_call=11.03 | 5.7%
| Worst case (Only even slots)| usec_per_call=963.80 | usec_per_call=2950.99 | 307%
This change also removes some extra white space that I added a when making a code change for adding hostnames.
This change increase the frequency of the failover log from 5 minutes to 10 seconds. This log is only emitted when a replica has an outstanding election is progress, and waiting 5 minutes for the next log makes debugging and alarming on the log messages too slow. It also now prints out the number of votes the replica has currently received as well as the number of votes it needs to achieve quorum so that we can track the progress if it's running slowly.
Co-authored-by: Madelyn Olson <34459052+madolson@users.noreply.github.com>
This change deletes the dictGetNext and dictGetNextRef functions, so the
dict API doesn't expose the next field at all.
The bucket function in dictScan is deleted. A separate dictScanDefrag function
is added which takes a defrag alloc function to defrag-reallocate the dict entries.
"Dirty" code accessing the dict internals in active defrag is removed.
An 'afterReplaceEntry' is added to dictType, which allows the dict user
to keep the dictEntry metadata up to date after reallocation/defrag/move.
Additionally, for updating the cluster slot-to-key mapping, after a dictEntry
has been reallocated, we need to know which db a dict belongs to, so we store
a pointer to the db in a new metadata section in the dict struct, which is
a new mechanism similar to dictEntry metadata. This adds some complexity but
provides better isolation.
*TL;DR*
---------------------------------------
Following the discussion over the issue [#7551](https://github.com/redis/redis/issues/7551)
We decided to refactor the client blocking code to eliminate some of the code duplications
and to rebuild the infrastructure better for future key blocking cases.
*In this PR*
---------------------------------------
1. reprocess the command once a client becomes unblocked on key (instead of running
custom code for the unblocked path that's different than the one that would have run if
blocking wasn't needed)
2. eliminate some (now) irrelevant code for handling unblocking lists/zsets/streams etc...
3. modify some tests to intercept the error in cases of error on reprocess after unblock (see
details in the notes section below)
4. replace '$' on the client argv with current stream id. Since once we reprocess the stream
XREAD we need to read from the last msg and not wait for new msg in order to prevent
endless block loop.
5. Added statistics to the info "Clients" section to report the:
* `total_blocking_keys` - number of blocking keys
* `total_blocking_keys_on_nokey` - number of blocking keys which have at least 1 client
which would like
to be unblocked on when the key is deleted.
6. Avoid expiring unblocked key during unblock. Previously we used to lookup the unblocked key
which might have been expired during the lookup. Now we lookup the key using NOTOUCH and
NOEXPIRE to avoid deleting it at this point, so propagating commands in blocked.c is no longer needed.
7. deprecated command flags. We decided to remove the CMD_CALL_STATS and CMD_CALL_SLOWLOG
and make an explicit verification in the call() function in order to decide if stats update should take place.
This should simplify the logic and also mitigate existing issues: for example module calls which are
triggered as part of AOF loading might still report stats even though they are called during AOF loading.
*Behavior changes*
---------------------------------------------------
1. As this implementation prevents writing dedicated code handling unblocked streams/lists/zsets,
since we now re-process the command once the client is unblocked some errors will be reported differently.
The old implementation used to issue
``UNBLOCKED the stream key no longer exists``
in the following cases:
- The stream key has been deleted (ie. calling DEL)
- The stream and group existed but the key type was changed by overriding it (ie. with set command)
- The key not longer exists after we swapdb with a db which does not contains this key
- After swapdb when the new db has this key but with different type.
In the new implementation the reported errors will be the same as if the command was processed after effect:
**NOGROUP** - in case key no longer exists, or **WRONGTYPE** in case the key was overridden with a different type.
2. Reprocessing the command means that some checks will be reevaluated once the
client is unblocked.
For example, ACL rules might change since the command originally was executed and
will fail once the client is unblocked.
Another example is OOM condition checks which might enable the command to run and
block but fail the command reprocess once the client is unblocked.
3. One of the changes in this PR is that no command stats are being updated once the
command is blocked (all stats will be updated once the client is unblocked). This implies
that when we have many clients blocked, users will no longer be able to get that information
from the command stats. However the information can still be gathered from the client list.
**Client blocking**
---------------------------------------------------
the blocking on key will still be triggered the same way as it is done today.
in order to block the current client on list of keys, the call to
blockForKeys will still need to be made which will perform the same as it is today:
* add the client to the list of blocked clients on each key
* keep the key with a matching list node (position in the global blocking clients list for that key)
in the client private blocking key dict.
* flag the client with CLIENT_BLOCKED
* update blocking statistics
* register the client on the timeout table
**Key Unblock**
---------------------------------------------------
Unblocking a specific key will be triggered (same as today) by calling signalKeyAsReady.
the implementation in that part will stay the same as today - adding the key to the global readyList.
The reason to maintain the readyList (as apposed to iterating over all clients blocked on the specific key)
is in order to keep the signal operation as short as possible, since it is called during the command processing.
The main change is that instead of going through a dedicated code path that operates the blocked command
we will just call processPendingCommandsAndResetClient.
**ClientUnblock (keys)**
---------------------------------------------------
1. Unblocking clients on keys will be triggered after command is
processed and during the beforeSleep
8. the general schema is:
9. For each key *k* in the readyList:
```
For each client *c* which is blocked on *k*:
in case either:
1. *k* exists AND the *k* type matches the current client blocking type
OR
2. *k* exists and *c* is blocked on module command
OR
3. *k* does not exists and *c* was blocked with the flag
unblock_on_deleted_key
do:
1. remove the client from the list of clients blocked on this key
2. remove the blocking list node from the client blocking key dict
3. remove the client from the timeout list
10. queue the client on the unblocked_clients list
11. *NEW*: call processCommandAndResetClient(c);
```
*NOTE:* for module blocked clients we will still call the moduleUnblockClientByHandle
which will queue the client for processing in moduleUnblockedClients list.
**Process Unblocked clients**
---------------------------------------------------
The process of all unblocked clients is done in the beforeSleep and no change is planned
in that part.
The general schema will be:
For each client *c* in server.unblocked_clients:
* remove client from the server.unblocked_clients
* set back the client readHandler
* continue processing the pending command and input buffer.
*Some notes regarding the new implementation*
---------------------------------------------------
1. Although it was proposed, it is currently difficult to remove the
read handler from the client while it is blocked.
The reason is that a blocked client should be unblocked when it is
disconnected, or we might consume data into void.
2. While this PR mainly keep the current blocking logic as-is, there
might be some future additions to the infrastructure that we would
like to have:
- allow non-preemptive blocking of client - sometimes we can think
that a new kind of blocking can be expected to not be preempt. for
example lets imagine we hold some keys on disk and when a command
needs to process them it will block until the keys are uploaded.
in this case we will want the client to not disconnect or be
unblocked until the process is completed (remove the client read
handler, prevent client timeout, disable unblock via debug command etc...).
- allow generic blocking based on command declared keys - we might
want to add a hook before command processing to check if any of the
declared keys require the command to block. this way it would be
easier to add new kinds of key-based blocking mechanisms.
Co-authored-by: Oran Agra <oran@redislabs.com>
Signed-off-by: Ran Shidlansik <ranshid@amazon.com>
1. Get rid of server.core_propagates - we can just rely on module/call nesting levels
2. Rename in_nested_call to execution_nesting and update the comment
3. Remove module_ctx_nesting (redundant, we can use execution_nesting)
4. Modify postExecutionUnitOperations according to the comment (The main purpose of this PR)
5. trackingHandlePendingKeyInvalidations: Check the nesting level inside this function
The cluster-announce-port/cluster-announce-bus-port/cluster-announce-tls-port should take effect at runtime
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
### Summary of API additions
* `RedisModule_AddPostNotificationJob` - new API to call inside a key space
notification (and on more locations in the future) and allow to add a post job as describe above.
* New module option, `REDISMODULE_OPTIONS_ALLOW_NESTED_KEYSPACE_NOTIFICATIONS`,
allows to disable Redis protection of nested key-space notifications.
* `RedisModule_GetModuleOptionsAll` - gets the mask of all supported module options so a module
will be able to check if a given option is supported by the current running Redis instance.
### Background
The following PR is a proposal of handling write operations inside module key space notifications.
After a lot of discussions we came to a conclusion that module should not perform any write
operations on key space notification.
Some examples of issues that such write operation can cause are describe on the following links:
* Bad replication oreder - https://github.com/redis/redis/pull/10969
* Used after free - https://github.com/redis/redis/pull/10969#issuecomment-1223771006
* Used after free - https://github.com/redis/redis/pull/9406#issuecomment-1221684054
There are probably more issues that are yet to be discovered. The underline problem with writing
inside key space notification is that the notification runs synchronously, this means that the notification
code will be executed in the middle on Redis logic (commands logic, eviction, expire).
Redis **do not assume** that the data might change while running the logic and such changes
can crash Redis or cause unexpected behaviour.
The solution is to state that modules **should not** perform any write command inside key space
notification (we can chose whether or not we want to force it). To still cover the use-case where
module wants to perform a write operation as a reaction to key space notifications, we introduce
a new API , `RedisModule_AddPostNotificationJob`, that allows to register a callback that will be
called by Redis when the following conditions hold:
* It is safe to perform any write operation.
* The job will be called atomically along side the operation that triggers it (in our case, key
space notification).
Module can use this new API to safely perform any write operation and still achieve atomicity
between the notification and the write.
Although currently the API is supported on key space notifications, the API is written in a generic
way so that in the future we will be able to use it on other places (server events for example).
### Technical Details
Whenever a module uses `RedisModule_AddPostNotificationJob` the callback is added to a list
of callbacks (called `modulePostExecUnitJobs`) that need to be invoke after the current execution
unit ends (whether its a command, eviction, or active expire). In order to trigger those callback
atomically with the notification effect, we call those callbacks on `postExecutionUnitOperations`
(which was `propagatePendingCommands` before this PR). The new function fires the post jobs
and then calls `propagatePendingCommands`.
If the callback perform more operations that triggers more key space notifications. Those keys
space notifications might register more callbacks. Those callbacks will be added to the end
of `modulePostExecUnitJobs` list and will be invoke atomically after the current callback ends.
This raises a concerns of entering an infinite loops, we consider infinite loops as a logical bug
that need to be fixed in the module, an attempt to protect against infinite loops by halting the
execution could result in violation of the feature correctness and so **Redis will make no attempt
to protect the module from infinite loops**
In addition, currently key space notifications are not nested. Some modules might want to allow
nesting key-space notifications. To allow that and keep backward compatibility, we introduce a
new module option called `REDISMODULE_OPTIONS_ALLOW_NESTED_KEYSPACE_NOTIFICATIONS`.
Setting this option will disable the Redis key-space notifications nesting protection and will
pass this responsibility to the module.
### Redis infrastructure
This PR promotes the existing `propagatePendingCommands` to an "Execution Unit" concept,
which is called after each atomic unit of execution,
Co-authored-by: Oran Agra <oran@redislabs.com>
Co-authored-by: Yossi Gottlieb <yossigo@gmail.com>
Co-authored-by: Madelyn Olson <34459052+madolson@users.noreply.github.com>
Introduce Shard IDs to logically group nodes in cluster mode.
1. Added a new "shard_id" field to "cluster nodes" output and nodes.conf after "hostname"
2. Added a new PING extension to propagate "shard_id"
3. Handled upgrade from pre-7.2 releases automatically
4. Refactored PING extension assembling/parsing logic
Behavior of Shard IDs:
Replicas will always follow the shards of their reported primaries. If a primary updates its shard ID, the replica will follow. (This need not follow for cluster v2) This is not an expected use case.
* Print IP and port on cluster bus message sanity check
Add a print statement to indicate which IP/port is sending
the error messages. That way we can at least check to see
if it is a node in the cluster or some other nefarious nodes.
It is proposed in #11339.
Unrelated changes: the return check for connAddrPeerName should
be -1 instead of C_ERR, although the value of C_ERR is also -1.
Co-authored-by: Madelyn Olson <34459052+madolson@users.noreply.github.com>
Renamed from "Pause Clients" to "Pause Actions" since the mechanism can pause
several actions in redis, not just clients (e.g. eviction, expiration).
Previously each pause purpose (which has a timeout that's tracked separately from others purposes),
also implicitly dictated what it pauses (reads, writes, eviction, etc). Now it is explicit, and
the actions that are paused (bit flags) are defined separately from the purpose.
- Previously, when using feature pause-client it also implicitly means to make the server static:
- Pause replica traffic
- Pauses eviction processing
- Pauses expire processing
Making the server static is used also for failover and shutdown. This PR internally rebrand
pause-client API to become pause-action API. It also Simplifies pauseClients structure
by replacing pointers array with static array.
The context of this PR is to add another trigger to pause-client which will activated in case
of OOM as throttling mechanism ([see here](https://github.com/redis/redis/issues/10907)).
In this case we want only to pause client, and eviction actions.
As discussed on #11084, `propagatePendingCommands` should happened after the del
notification is fired so that the notification effect and the `del` will be replicated inside MULTI EXEC.
Test was added to verify the fix.
PR #9320 introduces initialization order changes. Now cluster is initialized after modules.
This changes causes a crash if the module uses RM_Call inside the load function
on cluster mode (the code will try to access `server.cluster` which at this point is NULL).
To solve it, separate cluster initialization into 2 phases:
1. Structure initialization that happened before the modules initialization
2. Listener initialization that happened after.
Test was added to verify the fix.
Freeze time during execution of scripts and all other commands.
This means that a key is either expired or not, and doesn't change
state during a script execution. resolves#10182
This PR try to add a new `commandTimeSnapshot` function.
The function logic is extracted from `keyIsExpired`, but the related
calls to `fixed_time_expire` and `mstime()` are removed, see below.
In commands, we will avoid calling `mstime()` multiple times
and just use the one that sampled in call. The background is,
e.g. using `PEXPIRE 1` with valgrind sometimes result in the key
being deleted rather than expired. The reason is that both `PEXPIRE`
command and `checkAlreadyExpired` call `mstime()` separately.
There are other more important changes in this PR:
1. Eliminate `fixed_time_expire`, it is no longer needed.
When we want to sample time we should always use a time snapshot.
We will use `in_nested_call` instead to update the cached time in `call`.
2. Move the call for `updateCachedTime` from `serverCron` to `afterSleep`.
Now `commandTimeSnapshot` will always return the sample time, the
`lookupKeyReadWithFlags` call in `getNodeByQuery` will get a outdated
cached time (because `processCommand` is out of the `call` context).
We put the call to `updateCachedTime` in `aftersleep`.
3. Cache the time each time the module lock Redis.
Call `updateCachedTime` in `moduleGILAfterLock`, affecting `RM_ThreadSafeContextLock`
and `RM_ThreadSafeContextTryLock`
Currently the commandTimeSnapshot change affects the following TTL commands:
- SET EX / SET PX
- EXPIRE / PEXPIRE
- SETEX / PSETEX
- GETEX EX / GETEX PX
- TTL / PTTL
- EXPIRETIME / PEXPIRETIME
- RESTORE key TTL
And other commands just use the cached mstime (including TIME).
This is considered to be a breaking change since it can break a script
that uses a loop to wait for a key to expire.
This PR introduces a couple of changes to improve cluster test stability:
1. Increase the cluster node timeout to 3 seconds, which is similar to the
normal cluster tests, but introduce a new mechanism to increase the ping
period so that the tests are still fast. This new config is a debug config.
2. Set `cluster-replica-no-failover yes` on a wider array of tests which are
sensitive to failovers. This was occurring on the ARM CI.
- fix `the the` typo
- `LPOPRPUSH` does not exist, should be `RPOPLPUSH`
- `CLUSTER GETKEYINSLOT` 's time complexity should be O(N)
- `there bytes` should be `three bytes`, this closes#11266
- `slave` word to `replica` in log, modified the front and missed the back
- remove useless aofReadDiffFromParent in server.h
- `trackingHandlePendingKeyInvalidations` method adds a void parameter
* Fix CLUSTER SHARDS showing empty hostname
In #10290, we changed clusterNode hostname from `char*`
to `sds`, and the old `node->hostname` was changed to
`sdslen(node->hostname)!=0`.
But in `addNodeDetailsToShardReply` it is missing.
It results in the return of an empty string hostname
in CLUSTER SHARDS command if it unavailable.
Like this (note that we listed it as optional in the doc):
```
9) "hostname"
10) ""
```
EVAL scripts are by default not considered `write` commands, so they were allowed on a replica.
But when adding a shebang, they become `write` command (unless the `no-writes` flag is added).
With this change we'll handle them as write commands, and reply with MOVED instead of
READONLY when executed on a redis cluster replica.
Co-authored-by: chendianqiang <chendianqiang@meituan.com>
Bugfix:
with the scenario if we force assigned a slot to other master,
old master will lose the slot ownership, then old master will
call the function delKeysInSlot() to delete all keys which in
the slot. These delete operations should replicate to replicas,
avoid the data divergence issue in master and replicas.
Additionally, in this case, we now call:
* signalModifiedKey (to invalidate WATCH)
* moduleNotifyKeyspaceEvent (key space notification for modules)
* dirty++ (to signal that the persistence file may be outdated)
Co-authored-by: weimeng <weimeng@didiglobal.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
Redis 7.0 has #9890 which added an assertion when the propagation queue
was not flushed and we got to beforeSleep.
But it turns out that when processCommands calls getNodeByQuery and
decides to reject the command, it can lead to a key that was lazy
expired and is deleted without later flushing the propagation queue.
This change prevents lazy expiry from deleting the key at this stage
(not as part of a command being processed in `call`)
Introduce listen method into connection type, this allows no hard code
of listen logic. Originally, we initialize server during startup like
this:
if (server.port)
listenToPort(server.port,&server.ipfd);
if (server.tls_port)
listenToPort(server.port,&server.tlsfd);
if (server.unixsocket)
anetUnixServer(...server.unixsocket...);
...
if (createSocketAcceptHandler(&server.ipfd, acceptTcpHandler) != C_OK)
if (createSocketAcceptHandler(&server.tlsfd, acceptTcpHandler) != C_OK)
if (createSocketAcceptHandler(&server.sofd, acceptTcpHandler) != C_OK)
...
If a new connection type gets supported, we have to add more hard code
to setup listener.
Introduce .listen and refactor listener, and Unix socket supports this.
this allows to setup listener arguments and create listener in a loop.
What's more, '.listen' is defined in connection.h, so we should include
server.h to import 'struct socketFds', but server.h has already include
'connection.h'. To avoid including loop(also to make code reasonable),
define 'struct connListener' in connection.h instead of 'struct socketFds'
in server.h. This leads this commit to get more changes.
There are more fields in 'struct connListener', hence it's possible to
simplify changeBindAddr & applyTLSPort() & updatePort() into a single
logic: update the listener config from the server.xxx, and re-create
the listener.
Because of the new field 'priv' in struct connListener, we expect to pass
this to the accept handler(even it's not used currently), this may be used
in the future.
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Suggested by Oran, use an array to store all the connection types
instead of a linked list, and use connection name of string. The index
of a connection is dynamically allocated.
Currently we support max 8 connection types, include:
- tcp
- unix socket
- tls
and RDMA is in the plan, then we have another 4 types to support, it
should be enough in a long time.
Introduce 3 functions to get connection type by a fast path:
- connectionTypeTcp()
- connectionTypeTls()
- connectionTypeUnix()
Note that connectionByType() is designed to use only in unlikely code path.
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Abstract common interface of connection type, so Redis can hide the
implementation and uplayer only calls connection API without macro.
uplayer
|
connection layer
/ \
socket TLS
Currently, for both socket and TLS, all the methods of connection type
are declared as static functions.
It's possible to build TLS(even socket) as a shared library, and Redis
loads it dynamically in the next step.
Also add helper function connTypeOfCluster() and
connTypeOfReplication() to simplify the code:
link->conn = server.tls_cluster ? connCreateTLS() : connCreateSocket();
-> link->conn = connCreate(connTypeOfCluster());
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
Originally, connPeerToString is designed to get the address info from
socket only(for both TCP & TLS), and the API 'connPeerToString' is
oriented to operate a FD like:
int connPeerToString(connection *conn, char *ip, size_t ip_len, int *port) {
return anetFdToString(conn ? conn->fd : -1, ip, ip_len, port, FD_TO_PEER_NAME);
}
Introduce connAddr and implement .addr method for socket and TLS,
thus the API 'connAddr' and 'connFormatAddr' become oriented to a
connection like:
static inline int connAddr(connection *conn, char *ip, size_t ip_len, int *port, int remote) {
if (conn && conn->type->addr) {
return conn->type->addr(conn, ip, ip_len, port, remote);
}
return -1;
}
Also remove 'FD_TO_PEER_NAME' & 'FD_TO_SOCK_NAME', use a boolean type
'remote' to get local/remote address of a connection.
With these changes, it's possible to support the other connection
types which does not use socket(Ex, RDMA).
Thanks to Oran for suggestions!
Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
In clusterMsgPingExtForgottenNode, sizeof(name) is CLUSTER_NAMELEN,
and sizeof(clusterMsgPingExtForgottenNode) is > CLUSTER_NAMELEN.
Doing a (name + sizeof(clusterMsgPingExtForgottenNode)) sanitizer
generates an out-of-bounds error which is a false positive in here
Gossip the cluster node blacklist in ping and pong messages.
This means that CLUSTER FORGET doesn't need to be sent to all nodes in a cluster.
It can be sent to one or more nodes and then be propagated to the rest of them.
For each blacklisted node, its node id and its remaining blacklist TTL is gossiped in a
cluster bus ping extension (introduced in #9530).
As an outstanding part mentioned in #10737, we could just make the cluster config file and
ACL file saving done with a more safe and atomic pattern (write to temp file, fsync, rename, fsync dir).
The cluster config file uses an in-place overwrite and truncation (which was also used by the
main config file before #7824).
The ACL file is using the temp file and rename approach, but was missing an fsync.
Co-authored-by: 朱天 <zhutian03@meituan.com>
replace use of:
sprintf --> snprintf
strcpy/strncpy --> redis_strlcpy
strcat/strncat --> redis_strlcat
**why are we making this change?**
Much of the code uses some unsafe variants or deprecated buffer handling
functions.
While most cases are probably not presenting any issue on the known path
programming errors and unterminated strings might lead to potential
buffer overflows which are not covered by tests.
**As part of this PR we change**
1. added implementation for redis_strlcpy and redis_strlcat based on the strl implementation: https://linux.die.net/man/3/strl
2. change all occurrences of use of sprintf with use of snprintf
3. change occurrences of use of strcpy/strncpy with redis_strlcpy
4. change occurrences of use of strcat/strncat with redis_strlcat
5. change the behavior of ll2string/ull2string/ld2string so that it will always place null
termination ('\0') on the output buffer in the first index. this was done in order to make
the use of these functions more safe in cases were the user will not check the output
returned by them (for example in rdbRemoveTempFile)
6. we added a compiler directive to issue a deprecation error in case a use of
sprintf/strcpy/strcat is found during compilation which will result in error during compile time.
However keep in mind that since the deprecation attribute is not supported on all compilers,
this is expected to fail during push workflows.
**NOTE:** while this is only an initial milestone. We might also consider
using the *_s implementation provided by the C11 Extensions (however not
yet widly supported). I would also suggest to start
looking at static code analyzers to track unsafe use cases.
For example LLVM clang checker supports security.insecureAPI.DeprecatedOrUnsafeBufferHandling
which can help locate unsafe function usage.
https://clang.llvm.org/docs/analyzer/checkers.html#security-insecureapi-deprecatedorunsafebufferhandling-c
The main reason not to onboard it at this stage is that the alternative
excepted by clang is to use the C11 extensions which are not always
supported by stdlib.
Currently in cluster mode, Redis process locks the cluster config file when
starting up and holds the lock for the entire lifetime of the process.
When the server shuts down, it doesn't explicitly release the lock on the
cluster config file. We noticed a problem with restart testing that if you shut down
a very large redis-server process (i.e. with several hundred GB of data stored),
it takes the OS a while to free the resources and unlock the cluster config file.
So if we immediately try to restart the redis server process, it might fail to acquire
the lock on the cluster config file and fail to come up.
This fix explicitly releases the lock on the cluster config file upon a shutdown rather
than relying on the OS to release the lock, which is a cleaner and safer approach to
free up resources acquired.
