feat: create the logger, wired to nothing, and watch it say so

CMakeLists.txt

@@ -130,6 +130,7 @@ add_executable(baseline
     ${APP_DIR}/net/EthernetIf.c
     ${APP_DIR}/storage/diskio.c
     ${APP_DIR}/storage/SemihostingDisk.c
+    ${APP_DIR}/syslog/Syslog.c
     ${APP_DIR}/syslog/SyslogErrorHandler.c
     $<TARGET_OBJECTS:baseline_upstream>
 )

README.md

@@ -10,15 +10,15 @@ It builds on a baseline that simulates the sort of device you might be adding th
 measures itself: see [docs/baseline.md](docs/baseline.md) for what the baseline is, how the
 figures are made, and how to run it.
 
-## This stage — Error handler
+## This stage — Logger created
 
-The device installs its own handler on SolidSyslog's error slot, before creating anything. A
-`_Create` that cannot succeed returns a Null object rather than failing, so without this a
-mis-wired logger and a quiet one look identical.
+The logger exists, with nothing wired into it. Both collaborators that decide where a record goes
+are absent, so the handler from the previous stage reports them and the run report carries the
+faults — which is the point of creating it empty first.
 
 <!-- STAGE-COST:START (generated by scripts/gen-cost-table.py — do not edit by hand) -->
 
-**Cost above baseline: Flash +404 B, RAM +8 B.**
+**Cost above baseline: Flash +1,036 B, RAM +180 B.**
 
 <!-- STAGE-COST:END -->
 
@@ -34,6 +34,7 @@ committed as [`run-report.md`](run-report.md), and rewritten by every stage.
 | Baseline | a device that already networks, stores, and holds an mTLS session — before any syslog | — | — |
 | Linked | the core library and lwIP raw-mode networking, linked but not yet called | +0 | +0 |
 | Error handler | a fault inside the logger reaches the console instead of being silent | +404 | +8 |
+| Logger created | the logger object, reporting exactly what is still missing from it | +1,036 | +180 |
 
 *Deltas are bytes above the baseline, which is itself Flash 350,308 B, RAM 111,192 B.*
 

app/main.c

@@ -9,6 +9,7 @@
 #include "SemihostingExit.h"
 #include "ServiceTask.h"
 #include "SimulatedExistingApp.h"
+#include "Syslog.h"
 #include "SyslogErrorHandler.h"
 
 #include "lwip/tcpip.h"
@@ -97,6 +98,8 @@ int main(void)
     /* Before the first _Create — see SyslogErrorHandler.h for why that matters. */
     SyslogErrorHandler_Install();
 
+    Syslog_Start();
+
     /* lwIP tcpip thread + core-lock mutex + mbox. Pre-scheduler safe. */
     tcpip_init(NULL, NULL);
 

app/syslog/Syslog.c

@@ -0,0 +1,30 @@
+/* See Syslog.h. Created with nothing wired into it, on purpose: a missing
+ * collaborator is substituted with its Null object and reported, and the run
+ * report is where that shows. */
+
+#include "Syslog.h"
+
+#include "SolidSyslogConfig.h"
+
+#include <stddef.h>
+
+static struct SolidSyslog* s_logger = NULL;
+
+void Syslog_Start(void)
+{
+    /* Buffer and Sender decide where a record goes. NULL is "not supplied" and
+     * is reported; a collaborator deliberately done without is passed as its
+     * Null object instead, which is how the library tells the two apart. */
+    struct SolidSyslogConfig config = {
+        .Buffer = NULL,
+        .Sender = NULL,
+    };
+
+    /* No null check — Create returns a shared null instance rather than NULL. */
+    s_logger = SolidSyslog_Create(&config);
+}
+
+struct SolidSyslog* Syslog_Handle(void)
+{
+    return s_logger;
+}

app/syslog/Syslog.h

@@ -0,0 +1,15 @@
+/* The device's SolidSyslog wiring — the one place that knows how the logger is
+ * assembled. Everything else in the application just logs. */
+#ifndef SYSLOG_H
+#define SYSLOG_H
+
+struct SolidSyslog;
+
+/** Build the config and create the logger. Call once at startup, after
+ *  SyslogErrorHandler_Install so any fault in here is reported. */
+void Syslog_Start(void);
+
+/** The logger, for the tasks that log from it and drain it. */
+struct SolidSyslog* Syslog_Handle(void);
+
+#endif /* SYSLOG_H */

measurements/logger.csv

@@ -0,0 +1,13 @@
+# logger figures (bytes) — captured by scripts/run.sh (CAPTURE=1).
+# The device reads measurements/Baseline.csv as its frozen baseline and reports current-minus-Baseline.
+flash_text,350960
+flash_data,384
+static_bss,110988
+heap_used,4440
+mbedtls_peak,21192
+mbedtls_free,11576
+lwip_mem_free,7576
+lwip_pbufs_free,13
+stack_log,120
+stack_service,52
+stack_harness,2840

measurements/stages.tsv

@@ -12,3 +12,4 @@
 Baseline	Baseline	a device that already networks, stores, and holds an mTLS session — before any syslog
 linked	Linked	the core library and lwIP raw-mode networking, linked but not yet called
 error-handler	Error handler	a fault inside the logger reaches the console instead of being silent
+logger	Logger created	the logger object, reporting exactly what is still missing from it

run-report.md

@@ -1,20 +1,23 @@
-# solid-syslog-example — run (error-handler)
+# solid-syslog-example — run (logger)
 
 ## Device (self-measured)
 
 ```text
 [device] solid-syslog-example (FreeRTOS + lwIP + mbedTLS + FatFs)
+[syslog] CRITICAL SolidSyslog bad-config (detail 1)
+[syslog] CRITICAL SolidSyslog bad-config (detail 2)
+[syslog] CRITICAL SolidSyslog bad-config (detail 3)
 [device] starting simulated existing application...
 [sim] broker session to 10.0.2.2:8883: TLSv1.3, TLS1-3-CHACHA20-POLY1305-SHA256
 [device]   sim app (lwIP up, FatFs mounted, broker session held over mTLS): ready
 [report] --- SolidSyslog cost above baseline (simulated existing application) ---
 [report] key,current,baseline,used_above_baseline
-[report] flash_text,350392,349992,400
-[report] flash_data,320,316,4
-[report] static_bss,110880,110876,4
+[report] flash_text,350960,349992,968
+[report] flash_data,384,316,68
+[report] static_bss,110988,110876,112
 [report] heap_used,4440,4440,0
-[report] mbedtls_peak,21208,21332,-124
-[report] mbedtls_free,11560,11436,124
+[report] mbedtls_peak,21228,21332,-104
+[report] mbedtls_free,11540,11436,104
 [report] lwip_mem_free,7576,7576,0
 [report] lwip_pbufs_free,13,14,-1
 [report] stack_log,120,120,0
@@ -28,7 +31,7 @@
 
 ```text
    text	   data	    bss	    dec	    hex	filename
- 350384	    328	 110880	 461592	  70b18	/w/build/baseline-cross/baseline.elf
+ 350952	    392	 110988	 462332	  70dfc	/w/build/baseline-cross/baseline.elf
 ```
 
 ## Listeners (proved before the device ran)
@@ -49,17 +52,17 @@
 (nothing — this device sends no records yet)
 ```
 
-## Self-check (vs measurements/error-handler.csv)
+## Self-check (vs measurements/logger.csv)
 
 ```text
-  OK    flash_text: 350392 (expected 350392, Δ0)
-  OK    flash_data: 320 (expected 320, Δ0)
-  OK    static_bss: 110880 (expected 110880, Δ0)
+  OK    flash_text: 350960 (expected 350960, Δ0)
+  OK    flash_data: 384 (expected 384, Δ0)
+  OK    static_bss: 110988 (expected 110988, Δ0)
   OK    heap_used: 4440 (expected 4440, Δ0)
-  OK    mbedtls_peak: 21208 (expected 21336, Δ128)
-  OK    mbedtls_free: 11560 (expected 11432, Δ128)
+  OK    mbedtls_peak: 21228 (expected 21192, Δ36)
+  OK    mbedtls_free: 11540 (expected 11576, Δ36)
   OK    lwip_mem_free: 7576 (expected 7576, Δ0)
-  OK    lwip_pbufs_free: 13 (expected 14, Δ1)
+  OK    lwip_pbufs_free: 13 (expected 13, Δ0)
   OK    stack_log: 120 (expected 120, Δ0)
   OK    stack_service: 52 (expected 52, Δ0)
   OK    stack_harness: 2840 (expected 2840, Δ0)