Enhance scrobbling and storage management features

- Implemented a mechanism to check for the presence of an external scrobbler process and prevent duplicate logging in the .scrobbler.log file.
- Updated the deferred_up function to utilize the new scrobble_open_ours function for better management of scrobbling based on the presence of other scrobbler processes.
- Added functions to check the presence and mount status of microSD cards, ensuring that the player does not attempt to scan for music when the card is present but not mounted.
- Improved storage reporting to include both internal storage and microSD card status, providing clearer feedback to users about their storage situation.
- Enhanced database reading functions to handle legacy text and number formats gracefully, preventing library loading failures due to invalid UTF-8 or improperly formatted track numbers.
- Added logging for storage state changes and library loading processes to aid in troubleshooting and user feedback.
- Introduced a new API function to handle cases where a database scan is declined due to the SD card being unmounted, ensuring the UI reflects the correct state.

Author: superwilso

CHANGELOG.md

@@ -16,6 +16,93 @@ level the commit history supports; from `v0.1.6` onward, entries are written as
 
 ## [Unreleased]
 
+### Fixed
+
+- **One unusual tag could empty the whole library.** *Reproduced and fixed on the host
+  (`tracks_read_legacy_text_and_numbers_stored_as_text` failed with `Utf8Error` on the artist column
+  before the change and passes after it); device-unverified on the reporter's library.* Reported
+  2026-09-13 on r/walkman: a 1 TB card whose music shows on stock and not in Cinder. Their log settled
+  where the fault was not — the card was mounted and its files read fine — and where it was:
+
+  ```
+  housekeeping: the library database changed -> reloading library and playlists
+  [cinder-db] genres: 1196 entries
+  cinder-ffi: library loaded — 0 tracks, 0 albums, 0 artists
+  ```
+
+  SQLite types values, not columns, and Sony's scanner stores what the tags said. A legacy-encoded tag
+  (Latin-1 "Björk") arrives as text that is not valid UTF-8, and a track number written `03/12` stays
+  text inside an integer column. The track query read both with strict types, so one such value made
+  the *whole* query an error — and the library build turned that error into an empty list without a
+  word. Every column the scanner fills from a tag is now read leniently (invalid UTF-8 replaced,
+  `03/12` read as 3), a row that still will not read is skipped and logged instead of taking the
+  library with it, and a failed query now logs `track query FAILED — <reason>` rather than showing
+  "no music".
+
+- **The player never powered itself off on a flat battery.** *Cause device-verified 2026-09-13;
+  the fix is harness-verified, and the shutdown itself is device-unverified (it needs a real
+  discharge).* Reported by the owner: "I don't think it actually powers off." Sony's critical-battery
+  shutdown lives in the stock Qt app (`ForceShutdown.cpp`), which Cinder replaces, so Cinder's own
+  low-battery guard is the only thing that can do it — and that guard decided "on battery" from
+  `status == "Discharging"`. This board's battery driver never reports that. Pulling the cable with a
+  2 s sysfs logger running:
+
+  ```
+  status=Full         cap=100 usb=1 dc=0    on the cable
+  status=Not charging cap=94  usb=0 dc=0    cable out: this is what "on battery" looks like
+  status=Not charging cap=91  usb=1 dc=0    cable back in, before charging resumes
+  status=Charging     cap=99  usb=1 dc=0
+  ```
+
+  So every discharge read as charging, the guard returned on its first line, and the player ran to
+  the hardware cutoff with no "charge soon" warning and no clean shutdown, `/contents` still mounted
+  read-write. The same string also appears with the cable in, so no reading of it separates the two
+  states. The guard now asks the charger-detect nodes (`usb/online`, `dc/online`, `ac/online`), and
+  falls back to the status string only on a board without them. Manual power-off was already working
+  (the same helper, device-verified again today). Four new harness scenarios pin both directions:
+  `lowbatt-off`, `lowbatt-discharging`, `lowbatt-charger`, `lowbatt-warn`.
+
+- **An exFAT microSD card stayed unmounted after USB file transfer.** *The mount command is
+  device-verified against an exFAT image; the round trip with a real exFAT card is
+  device-unverified.* Any card over 32 GB is exFAT, and the player formats a big card that way
+  itself. Sony mounts one through FUSE (`mount.exfat` → `exfatfuse`), but `cinder-msc` only knew
+  vfat: leaving mass-storage mode it tried a vfat mount twelve times, failed every time, and the card
+  was gone for the rest of the boot. It now tells the two apart by the boot sector and remounts exFAT
+  with Sony's own script and option string (`batch_sync,waitonfat,noatime,iocharset=UTF-8`,
+  recovered from `libStorageMgrServiceFw.so`; the vfat string next to it is refused by `exfatfuse`,
+  which is how the two were told apart). On the way *into* mass storage it also waits for the
+  `exfatfuse` daemon to exit before handing the card to the PC, so the daemon's buffered writes can
+  never overlap the PC's.
+
+- **A library scan could erase the SD card's albums.** *Harness-verified that nothing changes for a
+  card-less build; the card path is device-unverified.* The scanner rebuilds the store from what it
+  can see, so a scan run while a card is in the slot but unmounted records every album on it as
+  deleted. The automatic scan after a USB session now waits for the card, and Settings ▸ Database
+  says "SD card not mounted — restart, then scan" instead of scanning.
+
+- **Duplicate scrobbles with unknown321's scrobbler installed.** *Device-verified 2026-09-13 on the
+  reference device, which had been running both: the boot logs `scrobble — unknown321/scrobbler is
+  running (pid 308) … standing down`, and cinder-home holds no `.scrobbler.log` descriptor. Harness
+  scenarios `scrobble-opens` and `scrobble-yields`.* Both scrobblers append to the same
+  `.scrobbler.log`, so every play reached Last.fm twice. `/contents/cinder_no_scrobble` could silence
+  Cinder's, but only for someone who had noticed the duplicates and found the flag — the reference
+  device itself ran both for a week. Cinder now looks for the other scrobbler's process and stands
+  its own down while it runs, including when `/contents` is reclaimed mid-boot.
+
+### Added
+
+- **Settings ▸ Storage shows the SD card.** *The label is built on device; the row itself has not
+  yet been looked at on the panel.* A card in the slot reads `SD 612 / 954 GB`, or
+  `SD not mounted` — before, the row showed internal storage only, so a card that had not mounted
+  looked the same as one that had. It refreshes when the card's state changes, including a big exFAT
+  card whose filesystem check finishes well after boot.
+- **The log says where the library is.** *Device-verified 2026-09-13: `library by storage — internal
+  2281, SD 1130, unresolved 0` and `storage: SD card mounted at /contents_ext (vfat)`.* One line per
+  library open and one per change in the card's mount state, with the filesystem type. "My SD music
+  is missing" can now be answered from `cinderhome.log`.
+- **README: Walkman One is listed as untested.** Walkman One makes the player identify as a different
+  model, and Cinder's package is packed for the stock NW-A50 model.
+
 ## [0.3.3] — 2026-09-12
 
 ### Fixed

README.md

@@ -135,6 +135,10 @@ artefact that does not exist.
   from Linux for months; it has not yet been sent from Windows. If it fails it fails safely — the
   files are staged and verified first, and the installer tells you which step did not happen.
 - **The Windows installer is unsigned**, and now asks for administrator — see [Install](#install).
+- **Untested on top of Walkman One.** Walkman One makes the player identify as a different model,
+  and Cinder's install package is packed for the stock NW-A50 model. Nobody has tried the
+  combination yet; the likeliest failure is the player's updater refusing the package. Make a wbrt
+  backup first either way, and please open an issue saying what happened.
 
 ## Install
 

cinder-home/cinder-msc

@@ -62,6 +62,10 @@ static void healthy_device(void) {
     cinder_harness_fs_write("/sys/class/power_supply/battery/status", "Discharging\n");
     cinder_harness_fs_write("/sys/class/power_supply/usb/online", "0\n");
     cinder_harness_fs_write("/sys/class/power_supply/usb/present", "0\n");
+    // The other charger-detect nodes, faked so a scenario never reads the build machine's: `dc` is
+    // this board's wall-charger supply (type Mains), `ac` the name other boards use for it.
+    cinder_harness_fs_write("/sys/class/power_supply/dc/online", "0\n");
+    cinder_harness_fs_write("/sys/class/power_supply/ac/online", "0\n");
     cinder_harness_fs_write("/sys/class/android_usb/android0/state", "DISCONNECTED\n");
     cinder_harness_fs_write("/sys/class/switch/cxd3778gf_h2w/state", "1\n");   // headphones in
     cinder_harness_fs_mkdir("/data/cinder");   // so the bad-boot counter can be cleared
@@ -482,6 +486,69 @@ static void s_auto_off_charging(void) {
              "never powers off a device sitting on a charger");
 }
 
+// ── low battery: warn, then power off before the cell browns out ─────────────────────────────
+// Sony's critical-battery shutdown lives in the stock Qt app (model/force_shutdown/ForceShutdown.cpp)
+// — the app Cinder replaces — so battery_guard is the ONLY thing on this device that turns it off on
+// a flat battery. It shipped deciding "on battery" from status == "Discharging", and this board's
+// battery driver reports "Not charging" with no charger attached: the guard returned on its first
+// line for every discharge, and the player ran to the hardware cutoff with no warning and no clean
+// shutdown. The rule is now the charger-detect nodes, and these pin both directions of it.
+static const char* kPowerOff = "system:/system/vendor/unknown321/bin/cinder-power off";
+
+static void low_battery(const char* pct, const char* status, const char* usb_online) {
+    healthy_device();
+    cinder_harness_fs_write("/sys/class/power_supply/battery/capacity", pct);
+    cinder_harness_fs_write("/sys/class/power_supply/battery/status", status);
+    cinder_harness_fs_write("/sys/class/power_supply/usb/online", usb_online);
+    cinder_harness_set_budget_ms(60000);
+    cinder_harness_run();
+}
+
+static void s_low_battery_not_charging(void) {
+    low_battery("3\n", "Not charging\n", "0\n");   // what the device reports on battery alone
+    long long at = cinder_harness_first_ms(kPowerOff);
+    std::printf("  .... first power-off attempt at %lldms\n", at);
+    check_range(at, 0, 25000, "a critical battery with no charger attached powers off");
+    check_eq(cinder_harness_count(kPowerOff), 1, "once — the retry back-off holds for a minute's run");
+}
+
+static void s_low_battery_discharging(void) {
+    low_battery("3\n", "Discharging\n", "0\n");    // the kernel's other name for the same state
+    check_range(cinder_harness_first_ms(kPowerOff), 0, 25000,
+                "\"Discharging\" with no charger attached powers off too");
+}
+
+static void s_low_battery_on_charger(void) {
+    low_battery("3\n", "Not charging\n", "1\n");   // cable in, charge held: plugged in, not dying
+    check_eq(cinder_harness_count(kPowerOff), 0,
+             "never powers off at 3% while a charger is attached, whatever the status string says");
+}
+
+// ── one scrobbler per play ───────────────────────────────────────────────────────────────────
+// unknown321/scrobbler appends to the same .scrobbler.log, so with both alive every play reached
+// Last.fm twice. Cinder stands its own down when that process is running — and only then.
+static void s_scrobble_opens(void) {
+    healthy_device();
+    cinder_harness_set_budget_ms(20000);
+    cinder_harness_run();
+    check_eq(cinder_harness_count("cinder_scrobble_open"), 1, "scrobbles when it is the only scrobbler");
+}
+
+static void s_scrobble_yields(void) {
+    healthy_device();
+    cinder_harness_fs_write("/proc/321/cmdline", "/system/vendor/unknown321/bin/scrobbler");
+    cinder_harness_set_budget_ms(20000);
+    cinder_harness_run();
+    check_eq(cinder_harness_count("cinder_scrobble_open"), 0,
+             "stands down while unknown321/scrobbler is running");
+}
+
+static void s_low_battery_warns(void) {
+    low_battery("8\n", "Not charging\n", "0\n");
+    check(cinder_harness_count("cinder_toast") >= 1, "warns below 10% on battery");
+    check_eq(cinder_harness_count(kPowerOff), 0, "…and does not power off above the critical level");
+}
+
 // ── the DSP reconcile must not depend on having found a settings file ────────────────────────
 // The DSP is not ours and does not boot empty: it holds whatever the stock player last left in it.
 // This used to run only `if (g_settings_loaded)`, so on a boot with no readable
@@ -968,6 +1035,12 @@ static const Scenario kScenarios[] = {
     {"autooff-idle",      s_auto_off_idle,           "idle and silent: power off, and back off if it fails"},
     {"autooff-playing",   s_auto_off_playing,        "never power off while audio is playing"},
     {"autooff-charging",  s_auto_off_charging,       "never power off a device on a charger"},
+    {"lowbatt-off",       s_low_battery_not_charging, "critical battery, no charger (\"Not charging\"): power off"},
+    {"lowbatt-discharging", s_low_battery_discharging, "critical battery reported as \"Discharging\": power off"},
+    {"lowbatt-charger",   s_low_battery_on_charger,  "critical battery on a charger: stay up"},
+    {"lowbatt-warn",      s_low_battery_warns,       "low battery on battery: warn, do not power off"},
+    {"scrobble-opens",    s_scrobble_opens,          "the built-in scrobbler opens when it is alone"},
+    {"scrobble-yields",   s_scrobble_yields,         "…and stands down while unknown321/scrobbler runs"},
     {"dsp-reconcile",     s_dsp_reconcile_no_settings, "the DSP is reconciled even with no settings file"},
     {"wake-on-touch",     s_wake_on_touch,           "a dark panel wakes on touch, without pressing anything"},
     {"touch-gestures",    s_touch_gestures,          "a tap is a tap and a drag is a drag"},