test: probe existing SYS clock access and AT time queries from APP

docs/app_nitz_test.md

@@ -2,6 +2,17 @@
 
 当前 `test/time-fix` 在 PDP 首次激活后自动启动 NITZ 测试，替换上一版自动 NTP 测试。只改 APP；本次没有修改、编译或烧录内核，不依赖之前添加的内核诊断接口。NTP 测试源文件保留但不参与当前 APP 构建。此模块不访问时间服务器域名或 UDP 123，使用设备已有的运营商 NITZ 查询接口。
 
+## 新增 SYS 读取探测
+
+当前版本在 NITZ 测试之前运行 `[APP-SYS-PROBE]`，只使用当前源码声明过的函数签名和 APP 已有 AT 接口，不读取旧 AXF，不修改内核，不调用 `talkingq_time_diag_snapshot_v1`。原有 TIME-DIAG 日志是否可用，不影响本探测。
+
+- 动态查找 `PMIC_RTC_GetTime_Count` 和 `GetTimeZone`。如果原内核本来就导出这两个名字，调用 `SYS_OFFSET=0`，减去网络时区分钟数，间隔 3 秒读取两次，检查合理范围和推进量。找不到就输出 `direct_sys=unavailable`，不添加内核导出、不尝试固定地址。
+- 输出 `time(NULL)`、`ql_rtc_get_time_ex()` 作为对照，不把 `get_time_ex` 的名称当成读 SYS 的证据。
+- 通过 `ql_atcmd_send_sync` 连续两轮读取 `AT+QLTS=0`、`AT+QLTS=1`、`AT+QLTS=2`、`AT+CCLK?`。两轮间隔 3 秒，每个 AT 请求超时参数为 2 秒。记录返回码、运行计数和原始响应；本型号不支持时允许返回 ERROR。两个 QLTS 候选模式是否提供有效当前时间，需根据原始日志对照确认。
+- 本探测没有 RTC 设置调用。`direct_sys=candidate` 仅表示现有 SYS 函数可读、时间范围和推进正常，仍需与实际 UTC 核对；AT 返回成功也不等于已确认来源。
+
+刷入后提供从 `[APP-SYS-PROBE] begin` 到 `finished` 的完整输出。若 QLTS 返回正确且推进的当前时间，可进一步实现 APP 校时；若所有接口缺失/返回错误或只返回 APP 旧时间，该路线仍未得到可用依据。后续 NITZ 测试保持原有写入条件，快照冻结时不写 RTC。
+
 ## 编译和测试
 
 在现有 Windows 环境执行 `build.bat app`，按现有流程更新 APP 镜像。保持原内核、原 RTC/NVM 状态。核对 APP 构建成功及镜像容量后启动设备，保留从开机到测试结束、再到一次实际 WSS 连接尝试的完整串口日志。
@@ -10,7 +21,11 @@
 
 ```text
 [TIME-DIAG] nitz_enabled=1 app_nitz_test=once_after_pdp ntp_test=off
-[APP-NITZ-TEST] begin version=1 source=operator_nitz ntp=off
+[APP-SYS-PROBE] begin version=1 read_only=1 kernel_diag_used=0
+[APP-SYS-PROBE] exports sys_count=... network_zone=...
+...
+[APP-SYS-PROBE] finished rtc_not_written=1
+[APP-NITZ-TEST] begin version=2 source=operator_nitz ntp=off
 ```
 
 本机只进行了主机模拟测试和 ARM 目标语法检查，尚未完成 Windows 完整固件构建或实机测试。
@@ -18,7 +33,7 @@
 ## 实际流程
 
 1. 检查原内核是否导出公开 SDK 接口 `ql_nw_get_nitz_time_info`、`ql_localtime_r`、`ql_rtc_set_time`、`ql_rtc_get_time`。
-2. 查询运营商 NITZ，输出完整原始字符串、返回值、`abs_time`、`leap_sec` 和查询耗时。支持 SDK 文档格式 `YY/MM/DD HH:MM:SS +32 00` 和紧凑格式 `YY/MM/DD,HH:MM:SS+32`。严格检查日期、闰年、时区及 UTC 范围（2024 年起，至 signed 32 位秒数上限）。不把语义未明确的 `abs_time` 当 Unix 时间戳使用。
+2. 查询运营商 NITZ，输出完整原始字符串、返回值、`abs_time`、`leap_sec` 和查询耗时。支持 SDK 文档格式 `YY/MM/DD HH:MM:SS +32 00` 、紧凑格式 `YY/MM/DD,HH:MM:SS+32`，以及实机已返回的无正号、一位夏令时格式 `YY/MM/DD HH:MM:SS 32 0`。严格检查日期、闰年、时区及 UTC 范围（2024 年起，至 signed 32 位秒数上限）。不把语义未明确的 `abs_time` 当 Unix 时间戳使用。
 3. 间隔 3 秒再次查询。两次 UTC 必须向前推进，并与系统运行计数的增量相差不超过 1 秒，时区相同；单次查询超过 2 秒不采用。冻结的 NITZ 快照不写入 APP。最多尝试 3 组，组间等待 5 秒。
 4. 使用 NITZ 的 UT 日期字段生成 UTC 秒数。时区字段以 15 分钟为单位，只记录，不再次从 UT 扣除。这个解释依据仓库旧 SDK 镜像的 NITZ 转换逻辑：UT 日期转换后加时区生成 SYS 本地日历。原始值和解释会保留在日志中，供实机核对。
 5. 通过 SDK `ql_localtime_r` 按现有 PMIC 时区把 UTC 转成 APP RTC 日历，再调用 `ql_rtc_set_time`。不改时区、不操作 `app_ever` 或内部跟随标记、不直接写 NVM 文件。
@@ -53,3 +68,5 @@ SDK 可能只提供 NITZ 最近一次通知的快照；如出现冻结拒绝，
 ## 主机回归
 
 `python3 tools/test_app_nitz_test.py` 编译实际 C 模块，模拟 API 缺失、查询失败、空串、无终止符、无效日期、冻结时间、UTC 跨天、时区转换、运行计数回绕、signed 32 位边界、首次查询失败恢复、写入失败、读回偏差及任务创建失败。启用 ASan/UBSan；不发送设备或公网数据。
+
+`python3 tools/test_app_sys_time_probe.py` 对实际 SYS/AT 探测模块验证 10 种场景：接口缺失、动态读取、无效/冻结时间、AT 错误、无终止符响应、tick 回绕等。测试不链接 RTC setter 或新增诊断接口；主机测试不证明本型号支持 QLTS。

ql-application/threadx/interface/custom_app/Makefile

@@ -84,6 +84,7 @@ SRC_FILES+= \
   mqtt_connect_diag.c \
   time_diag.c \
   app_nitz_test.c \
+  app_sys_time_probe.c \
   vad_det.c \
   sleep_wake.c \
   battery.c \

ql-application/threadx/interface/custom_app/app_nitz_test.c

@@ -7,6 +7,7 @@
 #include "ql_nw.h"
 #include "ql_rtc.h"
 #include "app_nitz_test.h"
+#include "app_sys_time_probe.h"
 
 /* SDK wrapper uses the same PMIC timezone as time(); no libc TZ assumptions. */
 extern struct tm *ql_localtime_r(const time_t *, struct tm *);
@@ -52,13 +53,14 @@ static int two_digits(const char *s)
     return (s[0] - '0') * 10 + s[1] - '0';
 }
 
-/* Accept SDK documented "YY/MM/DD HH:MM:SS +32 00" and compact
+/* Accept actual "YY/MM/DD HH:MM:SS 32 0", documented signed format, and compact
  * "YY/MM/DD,HH:MM:SS+32". NITZ UT is UTC; zone is metadata, not subtracted.
  * abs_time/leap_sec have insufficient documented semantics to use as epoch. */
 static int parse_nitz(const char *s, time_t *epoch, int *zone)
 {
     size_t n = strlen(s), pos = 17;
-    int yy, mo, dd, hh, mm, ss, q, dst;
+    int yy, mo, dd, hh, mm, ss, q, dst, negative = 0;
+    size_t start;
     long long value;
     if (n < 20 || s[2] != '/' || s[5] != '/' ||
         (s[8] != ' ' && s[8] != ',') || s[11] != ':' || s[14] != ':') return -1;
@@ -66,16 +68,23 @@ static int parse_nitz(const char *s, time_t *epoch, int *zone)
     hh = two_digits(s + 9); mm = two_digits(s + 12); ss = two_digits(s + 15);
     if (yy < 0 || calendar_epoch(2000 + yy, mo, dd, hh, mm, ss, &value) != 0 ||
         value < MIN_EPOCH || value > MAX_EPOCH) return -2;
+    /* Actual SDK output is also "26/10/26 08:00:10 32 0". */
     if (s[pos] == ' ') ++pos;
-    if (n < pos + 3 || (s[pos] != '+' && s[pos] != '-')) return -3;
+    else if (s[pos] != '+' && s[pos] != '-') return -3;
-    q = two_digits(s + pos + 1);
+    if (s[pos] == '+' || s[pos] == '-') negative = s[pos++] == '-';
-    if (q < 0 || q > 56 || (s[pos] == '-' && q > 48)) return -3;
+    start = pos;
-    *zone = s[pos] == '-' ? -q : q;
+    q = 0;
-    pos += 3;
+    while (pos < n && s[pos] >= '0' && s[pos] <= '9' && pos - start < 2)
+        q = q * 10 + s[pos++] - '0';
+    if (pos == start || q > 56 || (negative && q > 48)) return -3;
+    *zone = negative ? -q : q;
     if (pos < n) {
-        if (n != pos + 3 || s[pos] != ' ') return -4;
+        if (s[pos++] != ' ') return -4;
-        dst = two_digits(s + pos + 1);
+        start = pos;
-        if (dst < 0 || dst > 2) return -4;
+        dst = 0;
+        while (pos < n && s[pos] >= '0' && s[pos] <= '9' && pos - start < 2)
+            dst = dst * 10 + s[pos++] - '0';
+        if (pos == start || pos != n || dst > 2) return -4;
     }
     *epoch = (time_t)value;
     return 0;
@@ -177,7 +186,8 @@ static void nitz_test_worker(void *arg)
     long long advance, elapsed, drift;
     unsigned int span;
     (void)arg;
-    printf("[APP-NITZ-TEST] begin version=1 source=operator_nitz ntp=off\r\n");
+    app_sys_time_probe_run();
+    printf("[APP-NITZ-TEST] begin version=2 source=operator_nitz ntp=off\r\n");
     if (!m_get_api_ptr || !m_get_api_ptr("ql_nw_get_nitz_time_info") ||
         !m_get_api_ptr("ql_localtime_r") || !m_get_api_ptr("ql_rtc_set_time") ||
         !m_get_api_ptr("ql_rtc_get_time")) {

ql-application/threadx/interface/custom_app/app_sys_time_probe.c

@@ -0,0 +1,121 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <time.h>
+#include "ql_func.h"
+#include "ql_rtos.h"
+#include "ql_rtc.h"
+#include "ql_atcmd.h"
+#include "app_sys_time_probe.h"
+
+/* Exact signatures from the existing kernel pmic_rtc.h/duster.h.
+ * Lookup only: never add exports, use fixed addresses, or use our diagnostic API.
+ * SYS_OFFSET is 0 in pmic_rtc.h. Missing exports are an expected result. */
+typedef unsigned int (*sys_count_fn)(int);
+typedef int (*zone_minutes_fn)(void);
+
+static void probe_sys_exports(void)
+{
+    sys_count_fn get_count;
+    zone_minutes_fn get_zone;
+    unsigned int raw[2], ticks[2];
+    int zone[2], i;
+    long long utc[2], advance, elapsed, drift;
+
+    get_count = (sys_count_fn)(intptr_t)m_get_api_ptr("PMIC_RTC_GetTime_Count");
+    get_zone = (zone_minutes_fn)(intptr_t)m_get_api_ptr("GetTimeZone");
+    printf("[APP-SYS-PROBE] exports sys_count=%d network_zone=%d\r\n",
+           get_count != NULL, get_zone != NULL);
+    if (!get_count || !get_zone) {
+        printf("[APP-SYS-PROBE] direct_sys=unavailable no_kernel_change=1\r\n");
+        return;
+    }
+    for (i = 0; i < 2; ++i) {
+        raw[i] = get_count(0);
+        zone[i] = get_zone();
+        ticks[i] = ql_rtos_get_systicks();
+        utc[i] = (long long)raw[i] - (long long)zone[i] * 60;
+        printf("[APP-SYS-PROBE] direct index=%d raw=%lu zone_minutes=%d "
+               "utc=%lld ticks=%lu\r\n", i + 1, (unsigned long)raw[i],
+               zone[i], utc[i], (unsigned long)ticks[i]);
+        if (i == 0) ql_rtos_task_sleep_ms(3000);
+    }
+    elapsed = (ticks[1] - ticks[0]) / 200U;
+    advance = utc[1] - utc[0];
+    drift = advance - elapsed;
+    if (utc[0] >= 1704067200LL && utc[1] <= 2147483647LL &&
+        zone[0] >= -720 && zone[0] <= 840 && zone[0] == zone[1] &&
+        elapsed >= 2 && elapsed <= 10 && advance > 0 && drift >= -1 && drift <= 1) {
+        printf("[APP-SYS-PROBE] direct_sys=candidate advancing=1 "
+               "advance_s=%lld elapsed_s=%lld external_utc_check_required=1\r\n",
+               advance, elapsed);
+    } else {
+        printf("[APP-SYS-PROBE] direct_sys=rejected advance_s=%lld "
+               "elapsed_s=%lld drift_s=%lld\r\n", advance, elapsed, drift);
+    }
+}
+
+static void probe_app_rtc(int round)
+{
+    ql_rtc_time_t calendar;
+    int rc;
+    printf("[APP-SYS-PROBE] app round=%d utc=%ld ticks=%lu\r\n",
+           round, (long)time(NULL), (unsigned long)ql_rtos_get_systicks());
+    if (!m_get_api_ptr("ql_rtc_get_time_ex")) {
+        printf("[APP-SYS-PROBE] rtc_ex=unavailable\r\n");
+        return;
+    }
+    memset(&calendar, 0, sizeof(calendar));
+    rc = ql_rtc_get_time_ex(&calendar);
+    printf("[APP-SYS-PROBE] rtc_ex round=%d rc=%d calendar="
+           "%04d-%02d-%02dT%02d:%02d:%02d source_not_assumed=1\r\n",
+           round, rc, calendar.tm_year, calendar.tm_mon, calendar.tm_mday,
+           calendar.tm_hour, calendar.tm_min, calendar.tm_sec);
+}
+
+static void probe_at(int round, char *command, const char *label)
+{
+    char response[256];
+    unsigned int began = ql_rtos_get_systicks(), ended;
+    int rc, terminated;
+    size_t i;
+    memset(response, 0, sizeof(response));
+    rc = ql_atcmd_send_sync(command, response, sizeof(response), NULL, 2);
+    ended = ql_rtos_get_systicks();
+    terminated = memchr(response, '\0', sizeof(response)) != NULL;
+    response[sizeof(response) - 1] = '\0';
+    for (i = 0; response[i]; ++i)
+        if ((unsigned char)response[i] < 32 || response[i] == '"') response[i] = ' ';
+    printf("[APP-SYS-PROBE] at round=%d query=%s rc=%d duration_ms=%lu "
+           "ticks=%lu terminated=%d raw=\"%s\"\r\n", round, label, rc,
+           (unsigned long)(ended - began) * 5UL, (unsigned long)ended,
+           terminated, response);
+}
+
+void app_sys_time_probe_run(void)
+{
+    int round;
+    printf("[APP-SYS-PROBE] begin version=1 read_only=1 kernel_diag_used=0\r\n");
+    if (!m_get_api_ptr) {
+        printf("[APP-SYS-PROBE] FAIL stage=api_lookup_unavailable\r\n");
+        goto done;
+    }
+    probe_sys_exports();
+    if (!m_get_api_ptr("ql_atcmd_send_sync")) {
+        printf("[APP-SYS-PROBE] at=unavailable\r\n");
+        goto done;
+    }
+    for (round = 1; round <= 2; ++round) {
+        probe_app_rtc(round);
+        /* QLTS support/semantics on this model must be established on-device.
+         * Mode 0 may be a snapshot; mode 1/2 on supported models advances.
+         * CCLK is comparison only; it may expose the same broken APP RTC. */
+        probe_at(round, "AT+QLTS=0\r\n", "QLTS_0");
+        probe_at(round, "AT+QLTS=1\r\n", "QLTS_1");
+        probe_at(round, "AT+QLTS=2\r\n", "QLTS_2");
+        probe_at(round, "AT+CCLK?\r\n", "CCLK");
+        if (round == 1) ql_rtos_task_sleep_ms(3000);
+    }
+done:
+    printf("[APP-SYS-PROBE] finished rtc_not_written=1\r\n");
+}

ql-application/threadx/interface/custom_app/inc/app_sys_time_probe.h

@@ -0,0 +1,7 @@
+#ifndef APP_SYS_TIME_PROBE_H
+#define APP_SYS_TIME_PROBE_H
+
+/* Run in the existing time-test worker; read only, no new kernel dependency. */
+void app_sys_time_probe_run(void);
+
+#endif

tools/test_app_nitz_test.py

@@ -32,7 +32,8 @@ int ql_rtc_get_time(ql_rtc_time_t *);
 #include <assert.h>
 #include <stdlib.h>
 #include "APP_SOURCE"
-static int mode, creates, queries, sets;
+static int mode, creates, queries, sets, probes;
+void app_sys_time_probe_run(void) {++probes;}
 static unsigned int ticks=100;
 static time_t app_epoch=100;
 static int zone_minutes=480;
@@ -53,7 +54,10 @@ int ql_nw_get_nitz_time_info(QL_NW_NITZ_TIME_INFO_T *info) {
     if (mode==3) return 0;
     if (mode==4) {memset(info->nitz_time,'X',32); return 0;}
     if (mode==5) {strcpy(info->nitz_time,"26/02/30 13:00:00 +32 00"); return 0;}
-    if (mode==6) {strcpy(info->nitz_time,"26/10/26 13:00:00 +32 00"); return 0;}
+    if (mode==6 || mode==22) {
+        strcpy(info->nitz_time,mode==22 ? "26/10/26 08:00:10 32 0" : "26/10/26 13:00:00 +32 00");
+        return 0;
+    }
     if (mode==16 && queries==1) return 1;
     if (mode==17) ticks+=600; /* slow query must be rejected */
     if (mode==14) value=1793059198; /* near midnight UTC */
@@ -63,7 +67,7 @@ int ql_nw_get_nitz_time_info(QL_NW_NITZ_TIME_INFO_T *info) {
     /* Compute relative elapsed correctly in wrap scenario. */
     if (mode==13) value=1793019600+(unsigned int)(ticks-(UINT32_MAX-199U))/200U;
     utc=gmtime(&value); assert(utc);
-    snprintf(info->nitz_time,32,"%02d/%02d/%02d %02d:%02d:%02d +32 00",
+    snprintf(info->nitz_time,32,mode==21 ? "%02d/%02d/%02d %02d:%02d:%02d 32 0" : "%02d/%02d/%02d %02d:%02d:%02d +32 00",
              utc->tm_year%100,utc->tm_mon+1,utc->tm_mday,utc->tm_hour,utc->tm_min,utc->tm_sec);
     return 0;
 }
@@ -100,6 +104,11 @@ static void check_parser(void) {
     assert(parse_nitz("26/10/26,13:00:00-22",&epoch,&zone)==0 &&
            epoch==1793019600 && zone==-22);
     assert(parse_nitz("26/10/26 13:00:00 +56 02",&epoch,&zone)==0);
+    assert(parse_nitz("26/10/26 08:00:10 32 0",&epoch,&zone)==0 && epoch==1793001610 && zone==32);
+    assert(parse_nitz("26/10/26 13:00:00 -22 0",&epoch,&zone)==0 && zone==-22);
+    assert(parse_nitz("26/10/26 13:00:00 0 0",&epoch,&zone)==0 && zone==0);
+    assert(parse_nitz("26/10/26 13:00:00  0",&epoch,&zone)!=0);
+    assert(parse_nitz("26/10/26 13:00:00 320 0",&epoch,&zone)!=0);
     assert(parse_nitz("24/02/29 23:59:59 +00 00",&epoch,&zone)==0);
     assert(parse_nitz("26/02/29 00:00:00 +00 00",&epoch,&zone)!=0);
     assert(parse_nitz("38/01/19 03:14:07 +00 00",&epoch,&zone)==0 && epoch==2147483647);
@@ -110,7 +119,7 @@ static void check_parser(void) {
         "26/10/26 24:00:00 +00 00", "26/10/26 13:60:00 +00 00",
         "26/10/26 13:00:60 +00 00", "26/10/26 13:00:00 +57 00",
         "26/10/26 13:00:00 -49 00", "26/10/26 13:00:00 +32 03",
-        "26/10/26 13:00:00 +32 0", "26/10/26 13:00:00 +32 junk",
+        "26/10/26 13:00:00 +32 junk",
         "26/10/26 13:00:00 +32 00junk", "x6/10/26 13:00:00 +32 00"};
     for (unsigned int i=0;i<sizeof(bad)/sizeof(bad[0]);++i)
         assert(parse_nitz(bad[i],&epoch,&zone)!=0);
@@ -124,10 +133,11 @@ int main(int argc,char **argv) {
     if (mode==13) ticks=UINT32_MAX-199U;
     app_nitz_test_start(); app_nitz_test_start();
     assert(creates==(mode==19 ? 2 : 1));
-    if ((mode>=1 && mode<=6) || mode==15 || mode==17 || mode==18 || mode==19 || mode==7)
+    if ((mode>=1 && mode<=6) || mode==15 || mode==17 || mode==18 || mode==19 || mode==7 || mode==22)
         assert(sets==0);
     else assert(sets==1);
     assert(queries<=6);
+    assert(probes==(mode==19 ? 0 : 1));
     return 0;
 }
 '''.replace('APP_SOURCE', str(APP / 'app_nitz_test.c'))
@@ -147,10 +157,10 @@ int main(int argc,char **argv) {
              12: 'PASS source=nitz', 13: 'PASS source=nitz', 14: 'PASS source=nitz',
              15: 'FAIL stage=no_fresh_nitz', 16: 'PASS source=nitz',
              17: 'FAIL stage=no_fresh_nitz', 18: 'cached_or_inconsistent_nitz=1',
-             19: 'FAIL stage=create_task', 20: 'FAIL stage=app_clock_verification'}
+             19: 'FAIL stage=create_task', 20: 'FAIL stage=app_clock_verification', 21: 'PASS source=nitz', 22: 'FAIL stage=no_fresh_nitz'}
     for mode, expected in cases.items():
         log = subprocess.check_output([str(work / 'test'), str(mode)], text=True)
         assert expected in log, log
-        if mode not in (0, 12, 13, 14, 16):
+        if mode not in (0, 12, 13, 14, 16, 21):
             assert '[APP-NITZ-TEST] PASS ' not in log, log
-    print('PASS: Gregorian/parser validation and 21 API/freshness/RTC scenarios (ASan/UBSan)')
+    print('PASS: Gregorian/parser validation and 23 API/freshness/RTC scenarios (ASan/UBSan)')

tools/test_app_sys_time_probe.py

@@ -0,0 +1,90 @@
+"""Exercise the actual read-only SYS/AT probe without a modem or kernel image."""
+from pathlib import Path
+import shutil
+import subprocess
+import tempfile
+
+ROOT = Path(__file__).resolve().parents[1]
+APP = ROOT / 'ql-application/threadx/interface/custom_app'
+with tempfile.TemporaryDirectory(prefix='app-sys-probe-') as directory:
+    work = Path(directory)
+    headers = {
+        'ql_rtos.h': '''unsigned int ql_rtos_get_systicks(void);
+void ql_rtos_task_sleep_ms(unsigned int);
+''',
+        'ql_func.h': '#include <stdint.h>\nextern intptr_t (*m_get_api_ptr)(char *);\n',
+        'ql_rtc.h': '''typedef struct {int tm_sec,tm_min,tm_hour,tm_mday,tm_mon,tm_year,tm_wday;} ql_rtc_time_t;
+int ql_rtc_get_time_ex(ql_rtc_time_t *);
+''',
+        'ql_atcmd.h': 'int ql_atcmd_send_sync(char *,char *,int,char *,int);\n',
+    }
+    for name, content in headers.items():
+        (work / name).write_text(content)
+    harness = r'''
+#include <assert.h>
+#include <stdlib.h>
+#include "APP_SOURCE"
+static int mode, sends, reads, sys_reads;
+static unsigned int ticks=100, origin=100;
+unsigned int ql_rtos_get_systicks(void) {return ticks;}
+void ql_rtos_task_sleep_ms(unsigned int ms) {assert(ms==3000); ticks+=ms/5;}
+static unsigned int get_count(int offset) {
+    assert(offset==0); ++sys_reads;
+    if (mode==4) return 100;
+    return 1793030410U+(mode==5 ? 0 : (ticks-origin)/200U);
+}
+static int get_zone(void) {return 480;}
+static intptr_t lookup(char *name) {
+    assert(strstr(name,"diag")==NULL);
+    if (!strcmp(name,"PMIC_RTC_GetTime_Count")) return mode==1 ? 0 : (intptr_t)get_count;
+    if (!strcmp(name,"GetTimeZone")) return mode==1 || mode==2 ? 0 : (intptr_t)get_zone;
+    if (!strcmp(name,"ql_rtc_get_time_ex")) return mode==7 ? 0 : 1;
+    if (!strcmp(name,"ql_atcmd_send_sync")) return mode==8 ? 0 : 1;
+    assert(0); return 0;
+}
+intptr_t (*m_get_api_ptr)(char *)=lookup;
+time_t time(time_t *out) {(void)out; return 100;}
+int ql_rtc_get_time_ex(ql_rtc_time_t *out) {
+    ++reads; out->tm_year=1970; out->tm_mon=1; out->tm_mday=1; return 0;
+}
+int ql_atcmd_send_sync(char *cmd,char *resp,int len,char *filter,int timeout) {
+    static const char *commands[]={"AT+QLTS=0\r\n","AT+QLTS=1\r\n","AT+QLTS=2\r\n","AT+CCLK?\r\n"};
+    assert(!strcmp(cmd,commands[sends%4]));
+    assert(len==256 && filter==NULL && timeout==2);
+    ++sends; ticks+=20;
+    if (mode==1) {strcpy(resp,"\r\nERROR\r\n"); return 1;}
+    if (mode==6) {memset(resp,'X',len); return 0;}
+    strcpy(resp,"\r\n+QLTS: \"2026/10/26,08:00:10+32,0\"\r\nOK\r\n"); return 0;
+}
+int main(int argc,char **argv) {
+    assert(argc==2); mode=atoi(argv[1]);
+    if (mode==3) m_get_api_ptr=NULL;
+    if (mode==9) ticks=origin=UINT32_MAX-199U;
+    app_sys_time_probe_run();
+    assert(sends==(mode==3 || mode==8 ? 0 : 8));
+    assert(reads==(mode==3 || mode==7 || mode==8 ? 0 : 2));
+    assert(sys_reads==(mode==1 || mode==2 || mode==3 ? 0 : 2));
+    return 0;
+}
+'''.replace('APP_SOURCE', str(APP / 'app_sys_time_probe.c'))
+    (work / 'test.c').write_text(harness)
+    compiler = shutil.which('clang') or shutil.which('cc')
+    if not compiler:
+        raise SystemExit('A native C compiler is required')
+    subprocess.run([compiler, '-std=c99', '-Wall', '-Wextra', '-Werror',
+                    '-fsanitize=address,undefined', '-I', str(work), '-I', str(APP / 'inc'),
+                    str(work / 'test.c'), '-o', str(work / 'test')], check=True)
+    cases = {0: 'direct_sys=candidate', 1: 'direct_sys=unavailable',
+             2: 'direct_sys=unavailable', 3: 'FAIL stage=api_lookup_unavailable',
+             4: 'direct_sys=rejected', 5: 'direct_sys=rejected',
+             6: 'terminated=0', 7: 'rtc_ex=unavailable', 8: 'at=unavailable',
+             9: 'direct_sys=candidate'}
+    for mode, expected in cases.items():
+        log = subprocess.check_output([str(work / 'test'), str(mode)], text=True)
+        assert expected in log, log
+        assert '[APP-SYS-PROBE] finished rtc_not_written=1' in log, log
+        if mode == 1:
+            assert 'query=QLTS_1 rc=1' in log, log
+        if mode not in (0, 6, 7, 8, 9):
+            assert 'direct_sys=candidate' not in log, log
+    print('PASS: 10 SYS/AT probe scenarios (ASan/UBSan); no setter or diagnostic API linked')