Partition mode: use a mounted DOS device (DH1:) as the test target

Makefile

@@ -14,7 +14,7 @@ SRCDIR   := src
 OBJDIR   := obj
 SOURCES  := main.c args.c output.c timer.c content.c ring.c ops.c buf.c \
             engine.c stripe.c stats.c worker.c audit.c invariant.c quirks.c \
-            scsicmd.c removable.c soft64.c
+            scsicmd.c removable.c soft64.c dosdev.c
 OBJECTS  := $(SOURCES:%.c=$(OBJDIR)/%.o)
 TARGET   := devsoak
 

README.md

@@ -44,10 +44,13 @@ dependency. If you change the toolchain flags, re-check with
 
 ```
 devsoak DEVICE UNIT -d -r START,LEN [options]
+devsoak NAME: -d [options]           (partition mode; see below)
 
   -d            destructive (required)
   -r START,LEN  test range in sectors (required); K/M/G suffixes multiply
-                by 1024 (sector counts, not bytes); 0x hex accepted
+                by 1024 (sector counts, not bytes); 0x hex accepted.
+                Partition mode: optional, a sub-range relative to the
+                partition's own start instead of the whole test range.
   -t DURATION   e.g. 30s, 20m, 8h (default 60s)
   -w N          worker tasks (default 4, max 8)
   -q N          outstanding requests per worker (default 4, max 8)
@@ -80,6 +83,37 @@ devsoak refuses to run without both `-d` and `-r`, prints the device
 geometry and the range, and asks for confirmation unless `-y` is given.
 It never writes outside the range (the §8 bounds probes included).
 
+### Partition mode
+
+`devsoak DH1: -d [options]` — a single positional argument ending in `:`
+is taken as a mounted DOS device name instead of `DEVICE UNIT`. devsoak
+looks it up in the DosList, resolves it to the underlying exec
+device/unit and OpenDevice flags, and turns the partition's own extent
+(from its `DosEnvec`: cylinders, surfaces, blocks/track) into the test
+range — printed as `DH1: = scsi.device unit 0, partition sectors
+1004832..1209455`, same as the ordinary `-r` banner. `-r START,LEN` is
+still accepted in this mode, but is reinterpreted as a sub-range
+*relative to the partition's start* (for low-RAM machines that can't
+soak the whole thing); devsoak still never writes outside that range, so
+device-end probes stay read-only and can never spill past the partition
+either.
+
+Before any test traffic, devsoak sends `ACTION_INHIBIT` to the
+partition's handler so the filesystem stops touching the device for the
+run (uninhibited again on every exit path, including errors — a crash
+is the one case that can't clean this up; `--resume` says so). If the
+handler was never started there is nothing to inhibit and devsoak says
+so and continues.
+
+The destructive-run confirmation escalates by what's actually on the
+partition: an empty or unrecognised partition gets the normal `y/N`
+prompt; a recognised filesystem signature with no live volume mounted
+adds a warning line ahead of the same prompt; a **live mounted volume**
+requires typing the volume's name back (case-insensitive) instead of
+`y` — and `-y` does *not* bypass that last tier, so a live volume
+forces an interactive run: a misconfigured CI job must not be able to
+destroy a filesystem someone still has open.
+
 ### Exit codes
 
 | code | meaning |

src/args.c

@@ -200,7 +200,9 @@ LONG
 args_parse(int argc, char **argv)
 {
     int i;
+    int optstart;
     ULONG u;
+    size_t l;
 
     memset(&cfg, 0, sizeof(cfg));
     cfg.duration_s = 60;
@@ -212,19 +214,31 @@ args_parse(int argc, char **argv)
     cfg.watchdog_s = 5;
     cfg.outmode = OUT_CON;
 
-    if (argc < 3) {
-        seterr("usage: devsoak DEVICE UNIT -d -r START,LEN [options]", NULL);
-        return 1;
-    }
-
-    cfg.device = argv[1];
-    if (parse_ulong(argv[2], &u) != 0) {
-        seterr("bad UNIT: ", argv[2]);
-        return 1;
+    /* second form: `devsoak DH1: -d [options]` -- a single positional
+     * argument ending in ':' is a DOS device name; device/unit/range are
+     * resolved from the mount later (dosdev.c, main.c -- args_parse must
+     * never print, so no resolution happens here). */
+    l = (argc >= 2) ? strlen(argv[1]) : 0;
+    if (l > 1 && argv[1][l - 1] == ':') {
+        cfg.partition = 1;
+        cfg.dosdev = argv[1];
+        optstart = 2;
+    } else {
+        if (argc < 3) {
+            seterr("usage: devsoak DEVICE UNIT -d -r START,LEN [options], "
+                   "or: devsoak NAME: -d [options]", NULL);
+            return 1;
+        }
+        cfg.device = argv[1];
+        if (parse_ulong(argv[2], &u) != 0) {
+            seterr("bad UNIT: ", argv[2]);
+            return 1;
+        }
+        cfg.unit = (LONG)u;
+        optstart = 3;
     }
-    cfg.unit = (LONG)u;
 
-    for (i = 3; i < argc; i++) {
+    for (i = optstart; i < argc; i++) {
         char *arg = argv[i];
 
         if (strcmp(arg, "-d") == 0) {
@@ -349,7 +363,10 @@ args_parse(int argc, char **argv)
             seterr("-d is required (devsoak is destructive by design)", NULL);
             return 1;
         }
-        if (!cfg.have_range) {
+        /* partition mode: -r is optional (a relative sub-range of the
+         * partition, resolved once the mount is looked up); otherwise
+         * it is the whole test range and is required as before. */
+        if (!cfg.partition && !cfg.have_range) {
             seterr("-r START,LEN is required", NULL);
             return 1;
         }
@@ -362,9 +379,11 @@ void
 args_usage(void)
 {
     out_printf("devsoak DEVICE UNIT -d -r START,LEN [options]");
+    out_printf("devsoak NAME: -d [options]   (partition mode; see README)");
     out_printf("");
     out_printf("  -d            destructive (required)");
     out_printf("  -r START,LEN  test range in sectors (required); LEN may use K/M/G suffix");
+    out_printf("                partition mode: optional, relative to the partition start");
     out_printf("  -t DURATION   e.g. 30s, 20m, 8h (default 60s)");
     out_printf("  -w N          worker tasks (default 4)");
     out_printf("  -q N          outstanding requests per worker (default 4)");

src/devsoak.h

@@ -90,7 +90,10 @@ struct NSDQueryResult {
 struct Config {
     char   *device;             /* device name, e.g. "uaehf.device" */
     LONG    unit;
-    U64     range_start;        /* -r, in sectors */
+    UBYTE   partition;          /* positional arg was NAME: (partition mode) */
+    char   *dosdev;             /* the raw NAME: argument, incl. ':' */
+    U64     range_start;        /* -r, in sectors (partition mode: relative
+                                    to the partition start until resolved) */
     U64     range_len;          /* -r, in sectors */
     ULONG   duration_s;         /* -t, seconds (default 60) */
     ULONG   workers;            /* -w (default 4) */
@@ -149,6 +152,41 @@ struct DevUnderTest {
 extern struct Config       cfg;
 extern struct DevUnderTest dev;
 
+/* ---- dosdev.c: partition mode (`devsoak DH1: -d [options]`) ----
+ * Resolves a DOS device name (a single positional argument ending in ':')
+ * to the exec device/unit and partition extent it is mounted on, by
+ * walking the DosList: LockDosList()/FindDosEntry() on V36+, a manual
+ * Forbid()-protected walk of DOSBase->dl_Root->rn_Info->di_DevInfo on
+ * Kickstart 1.3 (same struct DosList layout either way -- BCPL BPTR/BSTR
+ * fields throughout, hence BADDR() everywhere below). Every field is
+ * validated before use (§ args_parse must never print, so all of this
+ * runs from main() after out_init(), and prints its own one-line reason
+ * on failure). Callers treat a nonzero return as RC_FATAL. */
+
+struct PartInfo {
+    char             devname[64];   /* exec device name, e.g. "scsi.device" */
+    LONG             unit;          /* fssm_Unit */
+    ULONG            opendevice_flags; /* fssm_Flags, passed to OpenDevice() */
+    ULONG            sizeblock;     /* de_SizeBlock, in LONGWORDS */
+    ULONG            surfaces;      /* de_Surfaces */
+    ULONG            blockspertrack;/* de_BlocksPerTrack */
+    ULONG            lowcyl;        /* de_LowCyl */
+    ULONG            highcyl;       /* de_HighCyl */
+    struct MsgPort  *handler;       /* dol_Task; NULL = handler never started */
+    UBYTE            have_volume;   /* a DLT_VOLUME entry names this handler */
+    char             volname[64];   /* if have_volume: its BSTR name, as C */
+};
+
+LONG dosdev_resolve(const char *name, struct PartInfo *out);
+/* ACTION_INHIBIT the handler (dp_Arg1 = DOSTRUE); DoPkt() on V36+, a
+ * hand-rolled struct StandardPacket on Kickstart 1.3. Prints its own
+ * failure reason and returns nonzero (RC_FATAL) on refusal. *inhibited is
+ * set on success, left 0 if handler is NULL (nothing to inhibit) or the
+ * packet failed; pass the same variable to dosdev_uninhibit() unchanged
+ * on every exit path -- it is a no-op unless *inhibited is set. */
+LONG dosdev_inhibit(struct MsgPort *handler, UBYTE *inhibited);
+void dosdev_uninhibit(struct MsgPort *handler, UBYTE *inhibited);
+
 /* ---- PRNG: xorshift32, one state per task (§13) ---- */
 
 static __inline ULONG xs32(ULONG *s)