Posix¶
Platform/Posix/ wraps the standard POSIX APIs — BSD sockets, pthreads, POSIX
message queues, clock_gettime, stdio
(POSIX.1-2017 specification).
Linux is the reference target.
Fills the Resolver, Datagram, Stream, Buffer, File and Mutex roles, plus the clock / hostname / process-id / sleep callbacks.
What it ships¶
| Header | What it is |
|---|---|
SolidSyslogPosixAddress.h |
A POSIX destination-address handle wrapping struct sockaddr_in. |
SolidSyslogPosixAddressErrors.h |
Error codes and Source identity for the PosixAddress adapter. |
SolidSyslogPosixClock.h |
The POSIX SolidSyslogClockFunction, for SolidSyslogConfig.Clock. |
SolidSyslogPosixDatagram.h |
UDP transport over a POSIX socket, for a UdpSender. |
SolidSyslogPosixDatagramErrors.h |
Error codes and Source identity for the PosixDatagram adapter. |
SolidSyslogPosixFile.h |
POSIX file I/O (open / read / write / lseek / ftruncate) behind the SolidSyslogFile vtable, for a file-backed BlockDevice or Store. |
SolidSyslogPosixFileErrors.h |
Error codes and Source identity for the PosixFile adapter. |
SolidSyslogPosixHostname.h |
The POSIX SolidSyslogHeaderFieldFunction for RFC 5424 HOSTNAME, for SolidSyslogConfig.GetHostname. |
SolidSyslogPosixMessageQueueBuffer.h |
A Buffer backed by a POSIX message queue, decoupling SolidSyslog_Log (enqueue) from Service (drain) across tasks or processes. |
SolidSyslogPosixMessageQueueBufferErrors.h |
Error codes and Source identity for the PosixMessageQueueBuffer adapter. |
SolidSyslogPosixMutex.h |
A Mutex wrapping pthread_mutex_t, for thread-safe buffers and pools on a POSIX host. |
SolidSyslogPosixMutexErrors.h |
Error codes and Source identity for the PosixMutex adapter. |
SolidSyslogPosixProcessId.h |
The POSIX SolidSyslogHeaderFieldFunction for RFC 5424 PROCID, for SolidSyslogConfig.GetProcessId. |
SolidSyslogPosixResolver.h |
A blocking DNS resolver over POSIX getaddrinfo. |
SolidSyslogPosixResolverErrors.h |
Error codes and Source identity for the PosixResolver adapter. |
SolidSyslogPosixSleep.h |
The POSIX SolidSyslogSleepFunction. |
SolidSyslogPosixSysUpTime.h |
The POSIX SolidSyslogSysUpTimeFunction, for MetaSd. |
SolidSyslogPosixTcpStream.h |
A non-blocking TCP stream over a POSIX socket, for a StreamSender or as the byte transport under a TLS stream. |
SolidSyslogPosixTcpStreamErrors.h |
Error codes and Source identity for the PosixTcpStream adapter. |
Requirements¶
A POSIX-conformant OS; Linux is the tested target. The message-queue buffer needs POSIX message queues.
Security behaviour and obligations¶
The transport carries syslog in clear¶
Neither the datagram nor the TCP stream provides confidentiality, integrity or peer authentication. Anything on the path can read and alter the records. TLS is a separate role filled by a different platform — the platform × capability matrix shows which — layered over this stream rather than replacing it.
An over-large record is trimmed to the path, not lost¶
Once the socket is connected the datagram asks the kernel for the path MTU and reports what is left after the IPv4 and UDP headers. Before that, or where the kernel does not answer, it reports the IPv6-safe payload of 1232 bytes, which is the conservative answer the Datagram contract asks for.
A send that exceeds the path is reported as oversize rather than as a failure, so the sender trims the record to the payload just reported — on a UTF-8 codepoint boundary — and sends it again. A record longer than the path therefore arrives truncated rather than being dropped, and the truncation is visible to the collector as a short message rather than as a gap.
The store file is owner-only; its directory is yours¶
Files are created readable and writable by the owning user alone. That protects the file, not the path to it: the ownership and permissions of the directory you place the store in, and whether another process on the device runs as the same user, are yours to set and to verify.
Host identity is only as good as the operating system's¶
The host name is what gethostname reports and the process id is getpid. They
identify the record's origin exactly as far as the OS can be trusted to report
it, and the library performs no independent check.
A written record is the kernel's, not the disk's¶
The file layer writes and returns; nothing calls fsync. A record the store
believes is stored survives the process exiting and may not survive the machine
losing power, so durability is a property of the filesystem and volume you point
the store at.
A peer that dies silently is detected in 30 to 85 seconds¶
Keepalive probes after 45 seconds idle, then four times at ten-second intervals, and a write already in flight is bounded separately by a 30-second user timeout. Until one of those fires, sends into the dead connection are accepted by the kernel and reported as delivered, so the records inside that window are released by store-and-forward and lost with the connection.
The message-queue buffer is capped by the system, not by you¶
SolidSyslogPosixMessageQueueBuffer_Create passes its maxMessages and
maxMessageSize to mq_open, and an unprivileged process cannot exceed
fs/mqueue/msg_max and fs/mqueue/msgsize_max — 10 messages and 8192 bytes on a
default Linux, where asking for 11 already fails. A failed open reports ERROR
and returns the Null buffer, so nothing is delivered through it. Size the queue
within the limits, or raise them for the deployment.
The blocking surface is bounded but not zero¶
The TCP stream's socket is non-blocking once open, so a send returns immediately against a wedged peer. The initial connection is the bounded exception, and its budget is a tunable. The UDP socket is left blocking: a datagram send is not expected to wait, but nothing here bounds it if the kernel's send buffer fills. A deployment with a hard real-time deadline should drive delivery from a service thread rather than the calling one.