The current guid struct size is 56 bytes. Once reduced using compact
trees, it goes down to 32 (almost half). We're not on a critical path
and size matters here, so better switch to this.
It's worth noting that the name part could also be stored in the
guid_node at the end to save 8 extra byte (no pointer needed anymore),
however the purpose of this struct is to be embedded into other ones,
which is not compatible with having a dynamic size.
Affected struct sizes in bytes:
Before After Diff
server 4032 4032 0*
proxy 3184 3160 -24
listener 752 728 -24
*: struct server is full of holes and padding (176 bytes) and is
64-byte aligned. Moving the guid_node elsewhere such as after sess_conn
reduces it to 3968, or one less cache line. There's no point in moving
anything now because forthcoming patches will arrange other parts.
A valid build warning was reported in the CI with latest commit b40ce97ecc
("BUG/MEDIUM: server: fix crash after duplicate GUID insertion"). Indeed,
if the first test in the function fails, we branch to the err label
with guid==NULL and will crash there. Let's just test guid before
dereferencing it for freeing.
This needs to be backported to 3.0 as well since the commit above was
meant to go there.
On "add server", if a GUID is defined, guid_insert() is used to add the
entry into the global GUID tree. If a similar entry already exists, GUID
insertion fails and the server creation is eventually aborted.
A crash could occur in this case because of an invalid memory access via
guid_remove(). The latter is caused via free_server() as the server
insertion is rejected. The invalid occurs on GUID key.
The issue occurs because of guid_insert(). The function properly
deallocates the GUID key on duplicate insertion, but it failed to reset
<guid.node.key> to NULL. This caused the invalid memory access on
guid_remove(). To fix this, ensure that key member is properly resetted
on guid_insert() error path.
This must be backported up to 3.0.
Since 3.0, it is possible to assign a GUID to proxies, listeners and
servers. These objects are stored in a global tree guid_tree.
Proxies and listeners are static. However, servers may be added or
deleted at runtime, which imply that guid_tree must be protected. Fix
this by declaring a read-write lock to protect tree access.
For now, only guid_insert() and guid_remove() are protected using a
write lock. Outside of these, GUID tree is not accessed at runtime. If
server CLI commands are extended to support GUID as server identifier,
lookup operation should be extended with a read lock protection.
Note that during stat-file preloading, GUID tree is accessed for lookup.
However, as it is performed on startup which is single threaded, there
is no need for lock here. A BUG_ON() has been added to ensure this
precondition remains true.
This bug could caused a segfault when using dynamic servers with GUID.
However, it was never reproduced for now.
This must be backported up to 3.0. To avoid a conflict issue, the
previous cleanup patch can be merged before it.
Extract GUID format validation in a dedicated function named
guid_is_valid_fmt(). For the moment, it is only used on guid_insert().
This will be reused when parsing stats-file, to ensure GUID has a valid
format before tree lookup.
Using an invalid GUID for guid_insert() causes a crash. This is easily
reproducible using for example an invalid character with "guid" keyword.
Here is the provided backtrace :
Thread 1 "haproxy" received signal SIGSEGV, Segmentation fault.
0x00005555561fda95 in guid_insert (objt=0x520000002080, uid=0x519000002dac "@foo2", errmsg=0x7ffff4c0a7a0)
at src/guid.c:83
83 ha_free(&guid->node.key);
This error is present in guid_insert() cleanup parts. GUID node is not
allocated in case of an early error so it's impossible to dereference it
to free guid.node.key. Fix this simply by using an intermediary pointer
key.
This does not need to be backported.
This commit is similar with the two previous ones. Its purpose is to add
GUID support on listeners. Due to bind_conf and listeners configuration,
some specifities were required.
Its possible to define several listeners on a single bind line, for
example by specifying multiple addresses. As such, it's impossible to
support a "guid" keyword on a bind line. The problem is exacerbated by
the cloning of listeners when sharding is used.
To resolve this, a new keyword "guid-prefix" is defined for bind lines.
It allows to specify a string which will be used as a prefix for
automatically generated GUID for each listeners attached to a bind_conf.
Automatic GUID listeners generation is implemented via a new function
bind_generate_guid(). It is called on post-parsing, after
bind_complete_thread_setup(). For each listeners on a bind_conf, a new
GUID is generated with bind_conf prefix and the index of the listener
relative to other listeners in the bind_conf. This last value is stored
in a new bind_conf field named <guid_idx>. If a GUID cannot be inserted,
for example due to a non-unique value, an error is returned, startup is
interrupted with configuration rejected.
This commit is similar to previous one, except that it implements GUID
support for server instances. A guid_node field is inserted into server
structure. A new "guid" server keyword is defined.
Implement proxy identiciation through GUID. As such, a guid_node member
is inserted into proxy structure. A proxy keyword "guid" is defined to
allow user to fix its value.
GUID format is unspecified to allow users to choose the naming scheme.
Some restrictions however are added by this patch, mainly to ensure
coherence and memory usage.
The first restriction is on the length of GUID. No more than 127
characters can be used to prevent memory over consumption.
The second restriction is on the character set allowed in GUID. Utility
function invalid_char() is used for this : it allows alphanumeric
values and '-', '_', '.' and ':'.
Define a new module guid. Its purpose is to be able to attach a global
identifier for various objects such as proxies, servers and listeners.
A new type guid_node is defined. It will be stored in the objects which
can be referenced by such GUID. Several functions are implemented to
properly initialized, insert, remove and lookup GUID in a global tree.
Modification operations should only be conducted under thread isolation.
