xref: /openbmc/qemu/hw/usb/dev-mtp.c (revision c16de0d9)
1 /*
2  * Media Transfer Protocol implementation, backed by host filesystem.
3  *
4  * Copyright Red Hat, Inc 2014
5  *
6  * Author:
7  *   Gerd Hoffmann <kraxel@redhat.com>
8  *
9  * This code is licensed under the GPL v2 or later.
10  */
11 
12 #include "qemu/osdep.h"
13 #include "qapi/error.h"
14 #include "qemu/error-report.h"
15 #include <wchar.h>
16 #include <dirent.h>
17 #include <glib/gstdio.h>
18 #include <sys/statvfs.h>
19 
20 
21 #include "qemu/iov.h"
22 #include "qemu/module.h"
23 #include "qemu/filemonitor.h"
24 #include "trace.h"
25 #include "hw/qdev-properties.h"
26 #include "hw/usb.h"
27 #include "migration/vmstate.h"
28 #include "desc.h"
29 #include "qemu/units.h"
30 #include "qom/object.h"
31 
32 /* ----------------------------------------------------------------------- */
33 
34 enum mtp_container_type {
35     TYPE_COMMAND  = 1,
36     TYPE_DATA     = 2,
37     TYPE_RESPONSE = 3,
38     TYPE_EVENT    = 4,
39 };
40 
41 /* MTP write stage, for internal use only */
42 enum mtp_write_status {
43     WRITE_START    = 1,
44     WRITE_CONTINUE = 2,
45     WRITE_END      = 3,
46 };
47 
48 enum mtp_code {
49     /* command codes */
50     CMD_GET_DEVICE_INFO            = 0x1001,
51     CMD_OPEN_SESSION               = 0x1002,
52     CMD_CLOSE_SESSION              = 0x1003,
53     CMD_GET_STORAGE_IDS            = 0x1004,
54     CMD_GET_STORAGE_INFO           = 0x1005,
55     CMD_GET_NUM_OBJECTS            = 0x1006,
56     CMD_GET_OBJECT_HANDLES         = 0x1007,
57     CMD_GET_OBJECT_INFO            = 0x1008,
58     CMD_GET_OBJECT                 = 0x1009,
59     CMD_DELETE_OBJECT              = 0x100b,
60     CMD_SEND_OBJECT_INFO           = 0x100c,
61     CMD_SEND_OBJECT                = 0x100d,
62     CMD_GET_PARTIAL_OBJECT         = 0x101b,
63     CMD_GET_OBJECT_PROPS_SUPPORTED = 0x9801,
64     CMD_GET_OBJECT_PROP_DESC       = 0x9802,
65     CMD_GET_OBJECT_PROP_VALUE      = 0x9803,
66 
67     /* response codes */
68     RES_OK                         = 0x2001,
69     RES_GENERAL_ERROR              = 0x2002,
70     RES_SESSION_NOT_OPEN           = 0x2003,
71     RES_INVALID_TRANSACTION_ID     = 0x2004,
72     RES_OPERATION_NOT_SUPPORTED    = 0x2005,
73     RES_PARAMETER_NOT_SUPPORTED    = 0x2006,
74     RES_INCOMPLETE_TRANSFER        = 0x2007,
75     RES_INVALID_STORAGE_ID         = 0x2008,
76     RES_INVALID_OBJECT_HANDLE      = 0x2009,
77     RES_INVALID_OBJECT_FORMAT_CODE = 0x200b,
78     RES_STORE_FULL                 = 0x200c,
79     RES_STORE_READ_ONLY            = 0x200e,
80     RES_PARTIAL_DELETE             = 0x2012,
81     RES_STORE_NOT_AVAILABLE        = 0x2013,
82     RES_SPEC_BY_FORMAT_UNSUPPORTED = 0x2014,
83     RES_INVALID_OBJECTINFO         = 0x2015,
84     RES_DESTINATION_UNSUPPORTED    = 0x2020,
85     RES_INVALID_PARENT_OBJECT      = 0x201a,
86     RES_INVALID_PARAMETER          = 0x201d,
87     RES_SESSION_ALREADY_OPEN       = 0x201e,
88     RES_INVALID_OBJECT_PROP_CODE   = 0xA801,
89 
90     /* format codes */
91     FMT_UNDEFINED_OBJECT           = 0x3000,
92     FMT_ASSOCIATION                = 0x3001,
93 
94     /* event codes */
95     EVT_CANCEL_TRANSACTION         = 0x4001,
96     EVT_OBJ_ADDED                  = 0x4002,
97     EVT_OBJ_REMOVED                = 0x4003,
98     EVT_OBJ_INFO_CHANGED           = 0x4007,
99 
100     /* object properties */
101     PROP_STORAGE_ID                = 0xDC01,
102     PROP_OBJECT_FORMAT             = 0xDC02,
103     PROP_OBJECT_COMPRESSED_SIZE    = 0xDC04,
104     PROP_PARENT_OBJECT             = 0xDC0B,
105     PROP_PERSISTENT_UNIQUE_OBJECT_IDENTIFIER = 0xDC41,
106     PROP_NAME                      = 0xDC44,
107 };
108 
109 enum mtp_data_type {
110     DATA_TYPE_UINT16  = 0x0004,
111     DATA_TYPE_UINT32  = 0x0006,
112     DATA_TYPE_UINT64  = 0x0008,
113     DATA_TYPE_UINT128 = 0x000a,
114     DATA_TYPE_STRING  = 0xffff,
115 };
116 
117 typedef struct {
118     uint32_t length;
119     uint16_t type;
120     uint16_t code;
121     uint32_t trans;
122 } QEMU_PACKED mtp_container;
123 
124 /* ----------------------------------------------------------------------- */
125 
126 typedef struct MTPState MTPState;
127 typedef struct MTPControl MTPControl;
128 typedef struct MTPData MTPData;
129 typedef struct MTPObject MTPObject;
130 
131 enum {
132     EP_DATA_IN = 1,
133     EP_DATA_OUT,
134     EP_EVENT,
135 };
136 
137 typedef struct MTPMonEntry MTPMonEntry;
138 
139 struct MTPMonEntry {
140     uint32_t event;
141     uint32_t handle;
142 
143     QTAILQ_ENTRY(MTPMonEntry) next;
144 };
145 
146 struct MTPControl {
147     uint16_t     code;
148     uint32_t     trans;
149     int          argc;
150     uint32_t     argv[5];
151 };
152 
153 struct MTPData {
154     uint16_t     code;
155     uint32_t     trans;
156     uint64_t     offset;
157     uint64_t     length;
158     uint64_t     alloc;
159     uint8_t      *data;
160     bool         first;
161     /* Used for >4G file sizes */
162     bool         pending;
163     int          fd;
164     uint8_t      write_status;
165     /* Internal pointer per every MTP_WRITE_BUF_SZ */
166     uint64_t     data_offset;
167 };
168 
169 struct MTPObject {
170     uint32_t     handle;
171     uint16_t     format;
172     char         *name;
173     char         *path;
174     struct stat  stat;
175     /* file monitor watch id */
176     int64_t      watchid;
177     MTPObject    *parent;
178     uint32_t     nchildren;
179     QLIST_HEAD(, MTPObject) children;
180     QLIST_ENTRY(MTPObject) list;
181     bool         have_children;
182     QTAILQ_ENTRY(MTPObject) next;
183 };
184 
185 struct MTPState {
186     USBDevice    dev;
187     char         *root;
188     char         *desc;
189     uint32_t     flags;
190 
191     MTPData      *data_in;
192     MTPData      *data_out;
193     MTPControl   *result;
194     uint32_t     session;
195     uint32_t     next_handle;
196     bool         readonly;
197 
198     QTAILQ_HEAD(, MTPObject) objects;
199     QFileMonitor *file_monitor;
200     QTAILQ_HEAD(, MTPMonEntry) events;
201     /* Responder is expecting a write operation */
202     bool write_pending;
203     struct {
204         uint32_t parent_handle;
205         uint16_t format;
206         uint32_t size;
207         char *filename;
208     } dataset;
209 };
210 
211 /*
212  * ObjectInfo dataset received from initiator
213  * Fields we don't care about are ignored
214  */
215 typedef struct {
216     uint32_t storage_id; /*unused*/
217     uint16_t format;
218     uint16_t protection_status; /*unused*/
219     uint32_t size;
220     uint16_t thumb_format; /*unused*/
221     uint32_t thumb_comp_sz; /*unused*/
222     uint32_t thumb_pix_width; /*unused*/
223     uint32_t thumb_pix_height; /*unused*/
224     uint32_t image_pix_width; /*unused*/
225     uint32_t image_pix_height; /*unused*/
226     uint32_t image_bit_depth; /*unused*/
227     uint32_t parent; /*unused*/
228     uint16_t assoc_type;
229     uint32_t assoc_desc;
230     uint32_t seq_no; /*unused*/
231     uint8_t length; /*part of filename field*/
232     uint8_t filename[0]; /* UTF-16 encoded */
233     char date_created[0]; /*unused*/
234     char date_modified[0]; /*unused*/
235     char keywords[0]; /*unused*/
236     /* string and other data follows */
237 } QEMU_PACKED ObjectInfo;
238 
239 #define TYPE_USB_MTP "usb-mtp"
240 OBJECT_DECLARE_SIMPLE_TYPE(MTPState, USB_MTP)
241 
242 #define QEMU_STORAGE_ID 0x00010001
243 
244 #define MTP_FLAG_WRITABLE 0
245 
246 #define FLAG_SET(_mtp, _flag)  ((_mtp)->flags & (1 << (_flag)))
247 
248 /* ----------------------------------------------------------------------- */
249 
250 #define MTP_MANUFACTURER  "QEMU"
251 #define MTP_PRODUCT       "QEMU filesharing"
252 #define MTP_WRITE_BUF_SZ  (512 * KiB)
253 
254 enum {
255     STR_MANUFACTURER = 1,
256     STR_PRODUCT,
257     STR_SERIALNUMBER,
258     STR_MTP,
259     STR_CONFIG_FULL,
260     STR_CONFIG_HIGH,
261     STR_CONFIG_SUPER,
262 };
263 
264 static const USBDescStrings desc_strings = {
265     [STR_MANUFACTURER] = MTP_MANUFACTURER,
266     [STR_PRODUCT]      = MTP_PRODUCT,
267     [STR_SERIALNUMBER] = "34617",
268     [STR_MTP]          = "MTP",
269     [STR_CONFIG_FULL]  = "Full speed config (usb 1.1)",
270     [STR_CONFIG_HIGH]  = "High speed config (usb 2.0)",
271     [STR_CONFIG_SUPER] = "Super speed config (usb 3.0)",
272 };
273 
274 static const USBDescIface desc_iface_full = {
275     .bInterfaceNumber              = 0,
276     .bNumEndpoints                 = 3,
277     .bInterfaceClass               = USB_CLASS_STILL_IMAGE,
278     .bInterfaceSubClass            = 0x01,
279     .bInterfaceProtocol            = 0x01,
280     .iInterface                    = STR_MTP,
281     .eps = (USBDescEndpoint[]) {
282         {
283             .bEndpointAddress      = USB_DIR_IN | EP_DATA_IN,
284             .bmAttributes          = USB_ENDPOINT_XFER_BULK,
285             .wMaxPacketSize        = 64,
286         },{
287             .bEndpointAddress      = USB_DIR_OUT | EP_DATA_OUT,
288             .bmAttributes          = USB_ENDPOINT_XFER_BULK,
289             .wMaxPacketSize        = 64,
290         },{
291             .bEndpointAddress      = USB_DIR_IN | EP_EVENT,
292             .bmAttributes          = USB_ENDPOINT_XFER_INT,
293             .wMaxPacketSize        = 64,
294             .bInterval             = 0x0a,
295         },
296     }
297 };
298 
299 static const USBDescDevice desc_device_full = {
300     .bcdUSB                        = 0x0200,
301     .bMaxPacketSize0               = 8,
302     .bNumConfigurations            = 1,
303     .confs = (USBDescConfig[]) {
304         {
305             .bNumInterfaces        = 1,
306             .bConfigurationValue   = 1,
307             .iConfiguration        = STR_CONFIG_FULL,
308             .bmAttributes          = USB_CFG_ATT_ONE | USB_CFG_ATT_WAKEUP,
309             .bMaxPower             = 2,
310             .nif = 1,
311             .ifs = &desc_iface_full,
312         },
313     },
314 };
315 
316 static const USBDescIface desc_iface_high = {
317     .bInterfaceNumber              = 0,
318     .bNumEndpoints                 = 3,
319     .bInterfaceClass               = USB_CLASS_STILL_IMAGE,
320     .bInterfaceSubClass            = 0x01,
321     .bInterfaceProtocol            = 0x01,
322     .iInterface                    = STR_MTP,
323     .eps = (USBDescEndpoint[]) {
324         {
325             .bEndpointAddress      = USB_DIR_IN | EP_DATA_IN,
326             .bmAttributes          = USB_ENDPOINT_XFER_BULK,
327             .wMaxPacketSize        = 512,
328         },{
329             .bEndpointAddress      = USB_DIR_OUT | EP_DATA_OUT,
330             .bmAttributes          = USB_ENDPOINT_XFER_BULK,
331             .wMaxPacketSize        = 512,
332         },{
333             .bEndpointAddress      = USB_DIR_IN | EP_EVENT,
334             .bmAttributes          = USB_ENDPOINT_XFER_INT,
335             .wMaxPacketSize        = 64,
336             .bInterval             = 0x0a,
337         },
338     }
339 };
340 
341 static const USBDescDevice desc_device_high = {
342     .bcdUSB                        = 0x0200,
343     .bMaxPacketSize0               = 64,
344     .bNumConfigurations            = 1,
345     .confs = (USBDescConfig[]) {
346         {
347             .bNumInterfaces        = 1,
348             .bConfigurationValue   = 1,
349             .iConfiguration        = STR_CONFIG_HIGH,
350             .bmAttributes          = USB_CFG_ATT_ONE | USB_CFG_ATT_WAKEUP,
351             .bMaxPower             = 2,
352             .nif = 1,
353             .ifs = &desc_iface_high,
354         },
355     },
356 };
357 
358 static const USBDescMSOS desc_msos = {
359     .CompatibleID = "MTP",
360     .SelectiveSuspendEnabled = true,
361 };
362 
363 static const USBDesc desc = {
364     .id = {
365         .idVendor          = 0x46f4, /* CRC16() of "QEMU" */
366         .idProduct         = 0x0004,
367         .bcdDevice         = 0,
368         .iManufacturer     = STR_MANUFACTURER,
369         .iProduct          = STR_PRODUCT,
370         .iSerialNumber     = STR_SERIALNUMBER,
371     },
372     .full  = &desc_device_full,
373     .high  = &desc_device_high,
374     .str   = desc_strings,
375     .msos  = &desc_msos,
376 };
377 
378 /* ----------------------------------------------------------------------- */
379 
380 static MTPObject *usb_mtp_object_alloc(MTPState *s, uint32_t handle,
381                                        MTPObject *parent, const char *name)
382 {
383     MTPObject *o = g_new0(MTPObject, 1);
384 
385     if (name[0] == '.') {
386         goto ignore;
387     }
388 
389     o->watchid = -1;
390     o->handle = handle;
391     o->parent = parent;
392     o->name = g_strdup(name);
393     if (parent == NULL) {
394         o->path = g_strdup(name);
395     } else {
396         o->path = g_strdup_printf("%s/%s", parent->path, name);
397     }
398 
399     if (lstat(o->path, &o->stat) != 0) {
400         goto ignore;
401     }
402     if (S_ISREG(o->stat.st_mode)) {
403         o->format = FMT_UNDEFINED_OBJECT;
404     } else if (S_ISDIR(o->stat.st_mode)) {
405         o->format = FMT_ASSOCIATION;
406     } else {
407         goto ignore;
408     }
409 
410     if (access(o->path, R_OK) != 0) {
411         goto ignore;
412     }
413 
414     trace_usb_mtp_object_alloc(s->dev.addr, o->handle, o->path);
415 
416     QTAILQ_INSERT_TAIL(&s->objects, o, next);
417     return o;
418 
419 ignore:
420     g_free(o->name);
421     g_free(o->path);
422     g_free(o);
423     return NULL;
424 }
425 
426 static void usb_mtp_object_free(MTPState *s, MTPObject *o)
427 {
428     MTPObject *iter;
429 
430     if (!o) {
431         return;
432     }
433 
434     trace_usb_mtp_object_free(s->dev.addr, o->handle, o->path);
435 
436     if (o->watchid != -1 && s->file_monitor) {
437         qemu_file_monitor_remove_watch(s->file_monitor, o->path, o->watchid);
438     }
439 
440     QTAILQ_REMOVE(&s->objects, o, next);
441     if (o->parent) {
442         QLIST_REMOVE(o, list);
443         o->parent->nchildren--;
444     }
445 
446     while (!QLIST_EMPTY(&o->children)) {
447         iter = QLIST_FIRST(&o->children);
448         usb_mtp_object_free(s, iter);
449     }
450     g_free(o->name);
451     g_free(o->path);
452     g_free(o);
453 }
454 
455 static MTPObject *usb_mtp_object_lookup(MTPState *s, uint32_t handle)
456 {
457     MTPObject *o;
458 
459     QTAILQ_FOREACH(o, &s->objects, next) {
460         if (o->handle == handle) {
461             return o;
462         }
463     }
464     return NULL;
465 }
466 
467 static MTPObject *usb_mtp_add_child(MTPState *s, MTPObject *o,
468                                     const char *name)
469 {
470     MTPObject *child =
471         usb_mtp_object_alloc(s, s->next_handle++, o, name);
472 
473     if (child) {
474         trace_usb_mtp_add_child(s->dev.addr, child->handle, child->path);
475         QLIST_INSERT_HEAD(&o->children, child, list);
476         o->nchildren++;
477 
478         if (child->format == FMT_ASSOCIATION) {
479             QLIST_INIT(&child->children);
480         }
481     }
482 
483     return child;
484 }
485 
486 static MTPObject *usb_mtp_object_lookup_name(MTPObject *parent,
487                                              const char *name, int len)
488 {
489     MTPObject *iter;
490 
491     if (len == -1) {
492         len = strlen(name);
493     }
494 
495     QLIST_FOREACH(iter, &parent->children, list) {
496         if (strncmp(iter->name, name, len) == 0) {
497             return iter;
498         }
499     }
500 
501     return NULL;
502 }
503 
504 static MTPObject *usb_mtp_object_lookup_id(MTPState *s, int64_t id)
505 {
506     MTPObject *iter;
507 
508     QTAILQ_FOREACH(iter, &s->objects, next) {
509         if (iter->watchid == id) {
510             return iter;
511         }
512     }
513 
514     return NULL;
515 }
516 
517 static void file_monitor_event(int64_t id,
518                                QFileMonitorEvent ev,
519                                const char *name,
520                                void *opaque)
521 {
522     MTPState *s = opaque;
523     MTPObject *parent = usb_mtp_object_lookup_id(s, id);
524     MTPMonEntry *entry = NULL;
525     MTPObject *o;
526 
527     if (!parent) {
528         return;
529     }
530 
531     switch (ev) {
532     case QFILE_MONITOR_EVENT_CREATED:
533         if (usb_mtp_object_lookup_name(parent, name, -1)) {
534             /* Duplicate create event */
535             return;
536         }
537         entry = g_new0(MTPMonEntry, 1);
538         entry->handle = s->next_handle;
539         entry->event = EVT_OBJ_ADDED;
540         o = usb_mtp_add_child(s, parent, name);
541         if (!o) {
542             g_free(entry);
543             return;
544         }
545         trace_usb_mtp_file_monitor_event(s->dev.addr, name, "Obj Added");
546         break;
547 
548     case QFILE_MONITOR_EVENT_DELETED:
549         /*
550          * The kernel issues a IN_IGNORED event
551          * when a dir containing a watchpoint is
552          * deleted, so we don't have to delete the
553          * watchpoint
554          */
555         o = usb_mtp_object_lookup_name(parent, name, -1);
556         if (!o) {
557             return;
558         }
559         entry = g_new0(MTPMonEntry, 1);
560         entry->handle = o->handle;
561         entry->event = EVT_OBJ_REMOVED;
562         trace_usb_mtp_file_monitor_event(s->dev.addr, o->path, "Obj Deleted");
563         usb_mtp_object_free(s, o);
564         break;
565 
566     case QFILE_MONITOR_EVENT_MODIFIED:
567         o = usb_mtp_object_lookup_name(parent, name, -1);
568         if (!o) {
569             return;
570         }
571         entry = g_new0(MTPMonEntry, 1);
572         entry->handle = o->handle;
573         entry->event = EVT_OBJ_INFO_CHANGED;
574         trace_usb_mtp_file_monitor_event(s->dev.addr, o->path, "Obj Modified");
575         break;
576 
577     case QFILE_MONITOR_EVENT_IGNORED:
578         trace_usb_mtp_file_monitor_event(s->dev.addr, parent->path,
579                                     "Obj parent dir ignored");
580         break;
581 
582     case QFILE_MONITOR_EVENT_ATTRIBUTES:
583         break;
584 
585     default:
586         g_assert_not_reached();
587     }
588 
589     if (entry) {
590         QTAILQ_INSERT_HEAD(&s->events, entry, next);
591     }
592 }
593 
594 static void usb_mtp_file_monitor_cleanup(MTPState *s)
595 {
596     MTPMonEntry *e, *p;
597 
598     QTAILQ_FOREACH_SAFE(e, &s->events, next, p) {
599         QTAILQ_REMOVE(&s->events, e, next);
600         g_free(e);
601     }
602 
603     qemu_file_monitor_free(s->file_monitor);
604     s->file_monitor = NULL;
605 }
606 
607 
608 static void usb_mtp_object_readdir(MTPState *s, MTPObject *o)
609 {
610     struct dirent *entry;
611     DIR *dir;
612     int fd;
613     Error *err = NULL;
614 
615     if (o->have_children) {
616         return;
617     }
618     o->have_children = true;
619 
620     fd = open(o->path, O_DIRECTORY | O_CLOEXEC | O_NOFOLLOW);
621     if (fd < 0) {
622         return;
623     }
624     dir = fdopendir(fd);
625     if (!dir) {
626         close(fd);
627         return;
628     }
629 
630     if (s->file_monitor) {
631         int64_t id = qemu_file_monitor_add_watch(s->file_monitor, o->path, NULL,
632                                                  file_monitor_event, s, &err);
633         if (id == -1) {
634             error_reportf_err(err,
635                               "usb-mtp: failed to add watch for %s: ",
636                               o->path);
637         } else {
638             trace_usb_mtp_file_monitor_event(s->dev.addr, o->path,
639                                              "Watch Added");
640             o->watchid = id;
641         }
642     }
643 
644     while ((entry = readdir(dir)) != NULL) {
645         usb_mtp_add_child(s, o, entry->d_name);
646     }
647     closedir(dir);
648 }
649 
650 /* ----------------------------------------------------------------------- */
651 
652 static MTPData *usb_mtp_data_alloc(MTPControl *c)
653 {
654     MTPData *data = g_new0(MTPData, 1);
655 
656     data->code  = c->code;
657     data->trans = c->trans;
658     data->fd    = -1;
659     data->first = true;
660     return data;
661 }
662 
663 static void usb_mtp_data_free(MTPData *data)
664 {
665     if (data == NULL) {
666         return;
667     }
668     if (data->fd != -1) {
669         close(data->fd);
670     }
671     g_free(data->data);
672     g_free(data);
673 }
674 
675 static void usb_mtp_realloc(MTPData *data, uint32_t bytes)
676 {
677     if (data->length + bytes <= data->alloc) {
678         return;
679     }
680     data->alloc = (data->length + bytes + 0xff) & ~0xff;
681     data->data  = g_realloc(data->data, data->alloc);
682 }
683 
684 static void usb_mtp_add_u8(MTPData *data, uint8_t val)
685 {
686     usb_mtp_realloc(data, 1);
687     data->data[data->length++] = val;
688 }
689 
690 static void usb_mtp_add_u16(MTPData *data, uint16_t val)
691 {
692     usb_mtp_realloc(data, 2);
693     data->data[data->length++] = (val >> 0) & 0xff;
694     data->data[data->length++] = (val >> 8) & 0xff;
695 }
696 
697 static void usb_mtp_add_u32(MTPData *data, uint32_t val)
698 {
699     usb_mtp_realloc(data, 4);
700     data->data[data->length++] = (val >>  0) & 0xff;
701     data->data[data->length++] = (val >>  8) & 0xff;
702     data->data[data->length++] = (val >> 16) & 0xff;
703     data->data[data->length++] = (val >> 24) & 0xff;
704 }
705 
706 static void usb_mtp_add_u64(MTPData *data, uint64_t val)
707 {
708     usb_mtp_realloc(data, 8);
709     data->data[data->length++] = (val >>  0) & 0xff;
710     data->data[data->length++] = (val >>  8) & 0xff;
711     data->data[data->length++] = (val >> 16) & 0xff;
712     data->data[data->length++] = (val >> 24) & 0xff;
713     data->data[data->length++] = (val >> 32) & 0xff;
714     data->data[data->length++] = (val >> 40) & 0xff;
715     data->data[data->length++] = (val >> 48) & 0xff;
716     data->data[data->length++] = (val >> 56) & 0xff;
717 }
718 
719 static void usb_mtp_add_u16_array(MTPData *data, uint32_t len,
720                                   const uint16_t *vals)
721 {
722     int i;
723 
724     usb_mtp_add_u32(data, len);
725     for (i = 0; i < len; i++) {
726         usb_mtp_add_u16(data, vals[i]);
727     }
728 }
729 
730 static void usb_mtp_add_u32_array(MTPData *data, uint32_t len,
731                                   const uint32_t *vals)
732 {
733     int i;
734 
735     usb_mtp_add_u32(data, len);
736     for (i = 0; i < len; i++) {
737         usb_mtp_add_u32(data, vals[i]);
738     }
739 }
740 
741 static void usb_mtp_add_wstr(MTPData *data, const wchar_t *str)
742 {
743     uint32_t len = wcslen(str);
744     int i;
745 
746     if (len > 0) {
747         len++; /* include terminating L'\0' */
748     }
749 
750     usb_mtp_add_u8(data, len);
751     for (i = 0; i < len; i++) {
752         usb_mtp_add_u16(data, str[i]);
753     }
754 }
755 
756 static void usb_mtp_add_str(MTPData *data, const char *str)
757 {
758     uint32_t len = strlen(str)+1;
759     wchar_t *wstr = g_new(wchar_t, len);
760     size_t ret;
761 
762     ret = mbstowcs(wstr, str, len);
763     if (ret == -1) {
764         usb_mtp_add_wstr(data, L"Oops");
765     } else {
766         usb_mtp_add_wstr(data, wstr);
767     }
768 
769     g_free(wstr);
770 }
771 
772 static void usb_mtp_add_time(MTPData *data, time_t time)
773 {
774     g_autoptr(GDateTime) then = g_date_time_new_from_unix_utc(time);
775     g_autofree char *thenstr = g_date_time_format(then, "%Y%m%dT%H%M%S");
776     usb_mtp_add_str(data, thenstr);
777 }
778 
779 /* ----------------------------------------------------------------------- */
780 
781 static void usb_mtp_queue_result(MTPState *s, uint16_t code, uint32_t trans,
782                                  int argc, uint32_t arg0, uint32_t arg1,
783                                  uint32_t arg2)
784 {
785     MTPControl *c = g_new0(MTPControl, 1);
786 
787     c->code  = code;
788     c->trans = trans;
789     c->argc  = argc;
790     if (argc > 0) {
791         c->argv[0] = arg0;
792     }
793     if (argc > 1) {
794         c->argv[1] = arg1;
795     }
796     if (argc > 2) {
797         c->argv[2] = arg2;
798     }
799 
800     assert(s->result == NULL);
801     s->result = c;
802 }
803 
804 /* ----------------------------------------------------------------------- */
805 
806 static MTPData *usb_mtp_get_device_info(MTPState *s, MTPControl *c)
807 {
808     static const uint16_t ops[] = {
809         CMD_GET_DEVICE_INFO,
810         CMD_OPEN_SESSION,
811         CMD_CLOSE_SESSION,
812         CMD_GET_STORAGE_IDS,
813         CMD_GET_STORAGE_INFO,
814         CMD_GET_NUM_OBJECTS,
815         CMD_GET_OBJECT_HANDLES,
816         CMD_GET_OBJECT_INFO,
817         CMD_DELETE_OBJECT,
818         CMD_SEND_OBJECT_INFO,
819         CMD_SEND_OBJECT,
820         CMD_GET_OBJECT,
821         CMD_GET_PARTIAL_OBJECT,
822         CMD_GET_OBJECT_PROPS_SUPPORTED,
823         CMD_GET_OBJECT_PROP_DESC,
824         CMD_GET_OBJECT_PROP_VALUE,
825     };
826     static const uint16_t fmt[] = {
827         FMT_UNDEFINED_OBJECT,
828         FMT_ASSOCIATION,
829     };
830     MTPData *d = usb_mtp_data_alloc(c);
831 
832     trace_usb_mtp_op_get_device_info(s->dev.addr);
833 
834     usb_mtp_add_u16(d, 100);
835     usb_mtp_add_u32(d, 0x00000006);
836     usb_mtp_add_u16(d, 0x0064);
837     usb_mtp_add_wstr(d, L"");
838     usb_mtp_add_u16(d, 0x0000);
839 
840     usb_mtp_add_u16_array(d, ARRAY_SIZE(ops), ops);
841     usb_mtp_add_u16_array(d, 0, NULL);
842     usb_mtp_add_u16_array(d, 0, NULL);
843     usb_mtp_add_u16_array(d, 0, NULL);
844     usb_mtp_add_u16_array(d, ARRAY_SIZE(fmt), fmt);
845 
846     usb_mtp_add_wstr(d, L"" MTP_MANUFACTURER);
847     usb_mtp_add_wstr(d, L"" MTP_PRODUCT);
848     usb_mtp_add_wstr(d, L"0.1");
849     usb_mtp_add_wstr(d, L"0123456789abcdef0123456789abcdef");
850 
851     return d;
852 }
853 
854 static MTPData *usb_mtp_get_storage_ids(MTPState *s, MTPControl *c)
855 {
856     static const uint32_t ids[] = {
857         QEMU_STORAGE_ID,
858     };
859     MTPData *d = usb_mtp_data_alloc(c);
860 
861     trace_usb_mtp_op_get_storage_ids(s->dev.addr);
862 
863     usb_mtp_add_u32_array(d, ARRAY_SIZE(ids), ids);
864 
865     return d;
866 }
867 
868 static MTPData *usb_mtp_get_storage_info(MTPState *s, MTPControl *c)
869 {
870     MTPData *d = usb_mtp_data_alloc(c);
871     struct statvfs buf;
872     int rc;
873 
874     trace_usb_mtp_op_get_storage_info(s->dev.addr);
875 
876     if (FLAG_SET(s, MTP_FLAG_WRITABLE)) {
877         usb_mtp_add_u16(d, 0x0003);
878         usb_mtp_add_u16(d, 0x0002);
879         usb_mtp_add_u16(d, 0x0000);
880     } else {
881         usb_mtp_add_u16(d, 0x0001);
882         usb_mtp_add_u16(d, 0x0002);
883         usb_mtp_add_u16(d, 0x0001);
884     }
885 
886     rc = statvfs(s->root, &buf);
887     if (rc == 0) {
888         usb_mtp_add_u64(d, (uint64_t)buf.f_frsize * buf.f_blocks);
889         usb_mtp_add_u64(d, (uint64_t)buf.f_bavail * buf.f_blocks);
890         usb_mtp_add_u32(d, buf.f_ffree);
891     } else {
892         usb_mtp_add_u64(d, 0xffffffff);
893         usb_mtp_add_u64(d, 0xffffffff);
894         usb_mtp_add_u32(d, 0xffffffff);
895     }
896 
897     usb_mtp_add_str(d, s->desc);
898     usb_mtp_add_wstr(d, L"123456789abcdef");
899     return d;
900 }
901 
902 static MTPData *usb_mtp_get_object_handles(MTPState *s, MTPControl *c,
903                                            MTPObject *o)
904 {
905     MTPData *d = usb_mtp_data_alloc(c);
906     uint32_t i = 0;
907     g_autofree uint32_t *handles = g_new(uint32_t, o->nchildren);
908     MTPObject *iter;
909 
910     trace_usb_mtp_op_get_object_handles(s->dev.addr, o->handle, o->path);
911 
912     QLIST_FOREACH(iter, &o->children, list) {
913         handles[i++] = iter->handle;
914     }
915     assert(i == o->nchildren);
916     usb_mtp_add_u32_array(d, o->nchildren, handles);
917 
918     return d;
919 }
920 
921 static MTPData *usb_mtp_get_object_info(MTPState *s, MTPControl *c,
922                                         MTPObject *o)
923 {
924     MTPData *d = usb_mtp_data_alloc(c);
925 
926     trace_usb_mtp_op_get_object_info(s->dev.addr, o->handle, o->path);
927 
928     usb_mtp_add_u32(d, QEMU_STORAGE_ID);
929     usb_mtp_add_u16(d, o->format);
930     usb_mtp_add_u16(d, 0);
931 
932     if (o->stat.st_size > 0xFFFFFFFF) {
933         usb_mtp_add_u32(d, 0xFFFFFFFF);
934     } else {
935         usb_mtp_add_u32(d, o->stat.st_size);
936     }
937 
938     usb_mtp_add_u16(d, 0);
939     usb_mtp_add_u32(d, 0);
940     usb_mtp_add_u32(d, 0);
941     usb_mtp_add_u32(d, 0);
942     usb_mtp_add_u32(d, 0);
943     usb_mtp_add_u32(d, 0);
944     usb_mtp_add_u32(d, 0);
945 
946     if (o->parent) {
947         usb_mtp_add_u32(d, o->parent->handle);
948     } else {
949         usb_mtp_add_u32(d, 0);
950     }
951     if (o->format == FMT_ASSOCIATION) {
952         usb_mtp_add_u16(d, 0x0001);
953         usb_mtp_add_u32(d, 0x00000001);
954         usb_mtp_add_u32(d, 0);
955     } else {
956         usb_mtp_add_u16(d, 0);
957         usb_mtp_add_u32(d, 0);
958         usb_mtp_add_u32(d, 0);
959     }
960 
961     usb_mtp_add_str(d, o->name);
962     usb_mtp_add_time(d, o->stat.st_ctime);
963     usb_mtp_add_time(d, o->stat.st_mtime);
964     usb_mtp_add_wstr(d, L"");
965 
966     return d;
967 }
968 
969 static MTPData *usb_mtp_get_object(MTPState *s, MTPControl *c,
970                                    MTPObject *o)
971 {
972     MTPData *d = usb_mtp_data_alloc(c);
973 
974     trace_usb_mtp_op_get_object(s->dev.addr, o->handle, o->path);
975 
976     d->fd = open(o->path, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
977     if (d->fd == -1) {
978         usb_mtp_data_free(d);
979         return NULL;
980     }
981     d->length = o->stat.st_size;
982     d->alloc  = 512;
983     d->data   = g_malloc(d->alloc);
984     return d;
985 }
986 
987 static MTPData *usb_mtp_get_partial_object(MTPState *s, MTPControl *c,
988                                            MTPObject *o)
989 {
990     MTPData *d;
991     off_t offset;
992 
993     if (c->argc <= 2) {
994         return NULL;
995     }
996     trace_usb_mtp_op_get_partial_object(s->dev.addr, o->handle, o->path,
997                                         c->argv[1], c->argv[2]);
998 
999     d = usb_mtp_data_alloc(c);
1000     d->fd = open(o->path, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
1001     if (d->fd == -1) {
1002         usb_mtp_data_free(d);
1003         return NULL;
1004     }
1005 
1006     offset = c->argv[1];
1007     if (offset > o->stat.st_size) {
1008         offset = o->stat.st_size;
1009     }
1010     if (lseek(d->fd, offset, SEEK_SET) < 0) {
1011         usb_mtp_data_free(d);
1012         return NULL;
1013     }
1014 
1015     d->length = c->argv[2];
1016     if (d->length > o->stat.st_size - offset) {
1017         d->length = o->stat.st_size - offset;
1018     }
1019 
1020     return d;
1021 }
1022 
1023 static MTPData *usb_mtp_get_object_props_supported(MTPState *s, MTPControl *c)
1024 {
1025     static const uint16_t props[] = {
1026         PROP_STORAGE_ID,
1027         PROP_OBJECT_FORMAT,
1028         PROP_OBJECT_COMPRESSED_SIZE,
1029         PROP_PARENT_OBJECT,
1030         PROP_PERSISTENT_UNIQUE_OBJECT_IDENTIFIER,
1031         PROP_NAME,
1032     };
1033     MTPData *d = usb_mtp_data_alloc(c);
1034     usb_mtp_add_u16_array(d, ARRAY_SIZE(props), props);
1035 
1036     return d;
1037 }
1038 
1039 static MTPData *usb_mtp_get_object_prop_desc(MTPState *s, MTPControl *c)
1040 {
1041     MTPData *d = usb_mtp_data_alloc(c);
1042     switch (c->argv[0]) {
1043     case PROP_STORAGE_ID:
1044         usb_mtp_add_u16(d, PROP_STORAGE_ID);
1045         usb_mtp_add_u16(d, DATA_TYPE_UINT32);
1046         usb_mtp_add_u8(d, 0x00);
1047         usb_mtp_add_u32(d, 0x00000000);
1048         usb_mtp_add_u32(d, 0x00000000);
1049         usb_mtp_add_u8(d, 0x00);
1050         break;
1051     case PROP_OBJECT_FORMAT:
1052         usb_mtp_add_u16(d, PROP_OBJECT_FORMAT);
1053         usb_mtp_add_u16(d, DATA_TYPE_UINT16);
1054         usb_mtp_add_u8(d, 0x00);
1055         usb_mtp_add_u16(d, 0x0000);
1056         usb_mtp_add_u32(d, 0x00000000);
1057         usb_mtp_add_u8(d, 0x00);
1058         break;
1059     case PROP_OBJECT_COMPRESSED_SIZE:
1060         usb_mtp_add_u16(d, PROP_OBJECT_COMPRESSED_SIZE);
1061         usb_mtp_add_u16(d, DATA_TYPE_UINT64);
1062         usb_mtp_add_u8(d, 0x00);
1063         usb_mtp_add_u64(d, 0x0000000000000000);
1064         usb_mtp_add_u32(d, 0x00000000);
1065         usb_mtp_add_u8(d, 0x00);
1066         break;
1067     case PROP_PARENT_OBJECT:
1068         usb_mtp_add_u16(d, PROP_PARENT_OBJECT);
1069         usb_mtp_add_u16(d, DATA_TYPE_UINT32);
1070         usb_mtp_add_u8(d, 0x00);
1071         usb_mtp_add_u32(d, 0x00000000);
1072         usb_mtp_add_u32(d, 0x00000000);
1073         usb_mtp_add_u8(d, 0x00);
1074         break;
1075     case PROP_PERSISTENT_UNIQUE_OBJECT_IDENTIFIER:
1076         usb_mtp_add_u16(d, PROP_PERSISTENT_UNIQUE_OBJECT_IDENTIFIER);
1077         usb_mtp_add_u16(d, DATA_TYPE_UINT128);
1078         usb_mtp_add_u8(d, 0x00);
1079         usb_mtp_add_u64(d, 0x0000000000000000);
1080         usb_mtp_add_u64(d, 0x0000000000000000);
1081         usb_mtp_add_u32(d, 0x00000000);
1082         usb_mtp_add_u8(d, 0x00);
1083         break;
1084     case PROP_NAME:
1085         usb_mtp_add_u16(d, PROP_NAME);
1086         usb_mtp_add_u16(d, DATA_TYPE_STRING);
1087         usb_mtp_add_u8(d, 0x00);
1088         usb_mtp_add_u8(d, 0x00);
1089         usb_mtp_add_u32(d, 0x00000000);
1090         usb_mtp_add_u8(d, 0x00);
1091         break;
1092     default:
1093         usb_mtp_data_free(d);
1094         return NULL;
1095     }
1096 
1097     return d;
1098 }
1099 
1100 static MTPData *usb_mtp_get_object_prop_value(MTPState *s, MTPControl *c,
1101                                               MTPObject *o)
1102 {
1103     MTPData *d = usb_mtp_data_alloc(c);
1104     switch (c->argv[1]) {
1105     case PROP_STORAGE_ID:
1106         usb_mtp_add_u32(d, QEMU_STORAGE_ID);
1107         break;
1108     case PROP_OBJECT_FORMAT:
1109         usb_mtp_add_u16(d, o->format);
1110         break;
1111     case PROP_OBJECT_COMPRESSED_SIZE:
1112         usb_mtp_add_u64(d, o->stat.st_size);
1113         break;
1114     case PROP_PARENT_OBJECT:
1115         if (o->parent == NULL) {
1116             usb_mtp_add_u32(d, 0x00000000);
1117         } else {
1118             usb_mtp_add_u32(d, o->parent->handle);
1119         }
1120         break;
1121     case PROP_PERSISTENT_UNIQUE_OBJECT_IDENTIFIER:
1122         /* Should be persistent between sessions,
1123          * but using our objedt ID is "good enough"
1124          * for now */
1125         usb_mtp_add_u64(d, 0x0000000000000000);
1126         usb_mtp_add_u64(d, o->handle);
1127         break;
1128     case PROP_NAME:
1129         usb_mtp_add_str(d, o->name);
1130         break;
1131     default:
1132         usb_mtp_data_free(d);
1133         return NULL;
1134     }
1135 
1136     return d;
1137 }
1138 
1139 /*
1140  * Return values when object @o is deleted.
1141  * If at least one of the deletions succeeded,
1142  * DELETE_SUCCESS is set and if at least one
1143  * of the deletions failed, DELETE_FAILURE is
1144  * set. Both bits being set (DELETE_PARTIAL)
1145  * signifies a  RES_PARTIAL_DELETE being sent
1146  * back to the initiator.
1147  */
1148 enum {
1149     DELETE_SUCCESS = (1 << 0),
1150     DELETE_FAILURE = (1 << 1),
1151     DELETE_PARTIAL = (DELETE_FAILURE | DELETE_SUCCESS),
1152 };
1153 
1154 static int usb_mtp_deletefn(MTPState *s, MTPObject *o, uint32_t trans)
1155 {
1156     MTPObject *iter, *iter2;
1157     int ret = 0;
1158 
1159     /*
1160      * TODO: Add support for Protection Status
1161      */
1162 
1163     QLIST_FOREACH(iter, &o->children, list) {
1164         if (iter->format == FMT_ASSOCIATION) {
1165             QLIST_FOREACH(iter2, &iter->children, list) {
1166                 ret |= usb_mtp_deletefn(s, iter2, trans);
1167             }
1168         }
1169     }
1170 
1171     if (o->format == FMT_UNDEFINED_OBJECT) {
1172         if (remove(o->path)) {
1173             ret |= DELETE_FAILURE;
1174         } else {
1175             usb_mtp_object_free(s, o);
1176             ret |= DELETE_SUCCESS;
1177         }
1178     } else if (o->format == FMT_ASSOCIATION) {
1179         if (rmdir(o->path)) {
1180             ret |= DELETE_FAILURE;
1181         } else {
1182             usb_mtp_object_free(s, o);
1183             ret |= DELETE_SUCCESS;
1184         }
1185     }
1186 
1187     return ret;
1188 }
1189 
1190 static void usb_mtp_object_delete(MTPState *s, uint32_t handle,
1191                                   uint32_t format_code, uint32_t trans)
1192 {
1193     MTPObject *o;
1194     int ret;
1195 
1196     /* Return error if store is read-only */
1197     if (!FLAG_SET(s, MTP_FLAG_WRITABLE)) {
1198         usb_mtp_queue_result(s, RES_STORE_READ_ONLY,
1199                              trans, 0, 0, 0, 0);
1200         return;
1201     }
1202 
1203     if (format_code != 0) {
1204         usb_mtp_queue_result(s, RES_SPEC_BY_FORMAT_UNSUPPORTED,
1205                              trans, 0, 0, 0, 0);
1206         return;
1207     }
1208 
1209     if (handle == 0xFFFFFFF) {
1210         o = QTAILQ_FIRST(&s->objects);
1211     } else {
1212         o = usb_mtp_object_lookup(s, handle);
1213     }
1214     if (o == NULL) {
1215         usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE,
1216                              trans, 0, 0, 0, 0);
1217         return;
1218     }
1219 
1220     ret = usb_mtp_deletefn(s, o, trans);
1221     switch (ret) {
1222     case DELETE_SUCCESS:
1223         usb_mtp_queue_result(s, RES_OK, trans,
1224                              0, 0, 0, 0);
1225         break;
1226     case DELETE_FAILURE:
1227         usb_mtp_queue_result(s, RES_PARTIAL_DELETE,
1228                              trans, 0, 0, 0, 0);
1229         break;
1230     case DELETE_PARTIAL:
1231         usb_mtp_queue_result(s, RES_PARTIAL_DELETE,
1232                              trans, 0, 0, 0, 0);
1233         break;
1234     default:
1235         g_assert_not_reached();
1236     }
1237 
1238     return;
1239 }
1240 
1241 static void usb_mtp_command(MTPState *s, MTPControl *c)
1242 {
1243     MTPData *data_in = NULL;
1244     MTPObject *o = NULL;
1245     uint32_t nres = 0, res0 = 0;
1246     Error *err = NULL;
1247 
1248     /* sanity checks */
1249     if (c->code >= CMD_CLOSE_SESSION && s->session == 0) {
1250         usb_mtp_queue_result(s, RES_SESSION_NOT_OPEN,
1251                              c->trans, 0, 0, 0, 0);
1252         return;
1253     }
1254 
1255     /* process commands */
1256     switch (c->code) {
1257     case CMD_GET_DEVICE_INFO:
1258         data_in = usb_mtp_get_device_info(s, c);
1259         break;
1260     case CMD_OPEN_SESSION:
1261         if (s->session) {
1262             usb_mtp_queue_result(s, RES_SESSION_ALREADY_OPEN,
1263                                  c->trans, 1, s->session, 0, 0);
1264             return;
1265         }
1266         if (c->argv[0] == 0) {
1267             usb_mtp_queue_result(s, RES_INVALID_PARAMETER,
1268                                  c->trans, 0, 0, 0, 0);
1269             return;
1270         }
1271         trace_usb_mtp_op_open_session(s->dev.addr);
1272         s->session = c->argv[0];
1273         usb_mtp_object_alloc(s, s->next_handle++, NULL, s->root);
1274 
1275         s->file_monitor = qemu_file_monitor_new(&err);
1276         if (err) {
1277             error_reportf_err(err,
1278                               "usb-mtp: file monitoring init failed: ");
1279         } else {
1280             QTAILQ_INIT(&s->events);
1281         }
1282         break;
1283     case CMD_CLOSE_SESSION:
1284         trace_usb_mtp_op_close_session(s->dev.addr);
1285         s->session = 0;
1286         s->next_handle = 0;
1287         usb_mtp_file_monitor_cleanup(s);
1288         usb_mtp_object_free(s, QTAILQ_FIRST(&s->objects));
1289         assert(QTAILQ_EMPTY(&s->objects));
1290         break;
1291     case CMD_GET_STORAGE_IDS:
1292         data_in = usb_mtp_get_storage_ids(s, c);
1293         break;
1294     case CMD_GET_STORAGE_INFO:
1295         if (c->argv[0] != QEMU_STORAGE_ID &&
1296             c->argv[0] != 0xffffffff) {
1297             usb_mtp_queue_result(s, RES_INVALID_STORAGE_ID,
1298                                  c->trans, 0, 0, 0, 0);
1299             return;
1300         }
1301         data_in = usb_mtp_get_storage_info(s, c);
1302         break;
1303     case CMD_GET_NUM_OBJECTS:
1304     case CMD_GET_OBJECT_HANDLES:
1305         if (c->argv[0] != QEMU_STORAGE_ID &&
1306             c->argv[0] != 0xffffffff) {
1307             usb_mtp_queue_result(s, RES_INVALID_STORAGE_ID,
1308                                  c->trans, 0, 0, 0, 0);
1309             return;
1310         }
1311         if (c->argv[1] != 0x00000000) {
1312             usb_mtp_queue_result(s, RES_SPEC_BY_FORMAT_UNSUPPORTED,
1313                                  c->trans, 0, 0, 0, 0);
1314             return;
1315         }
1316         if (c->argv[2] == 0x00000000 ||
1317             c->argv[2] == 0xffffffff) {
1318             o = QTAILQ_FIRST(&s->objects);
1319         } else {
1320             o = usb_mtp_object_lookup(s, c->argv[2]);
1321         }
1322         if (o == NULL) {
1323             usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE,
1324                                  c->trans, 0, 0, 0, 0);
1325             return;
1326         }
1327         if (o->format != FMT_ASSOCIATION) {
1328             usb_mtp_queue_result(s, RES_INVALID_PARENT_OBJECT,
1329                                  c->trans, 0, 0, 0, 0);
1330             return;
1331         }
1332         usb_mtp_object_readdir(s, o);
1333         if (c->code == CMD_GET_NUM_OBJECTS) {
1334             trace_usb_mtp_op_get_num_objects(s->dev.addr, o->handle, o->path);
1335             nres = 1;
1336             res0 = o->nchildren;
1337         } else {
1338             data_in = usb_mtp_get_object_handles(s, c, o);
1339         }
1340         break;
1341     case CMD_GET_OBJECT_INFO:
1342         o = usb_mtp_object_lookup(s, c->argv[0]);
1343         if (o == NULL) {
1344             usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE,
1345                                  c->trans, 0, 0, 0, 0);
1346             return;
1347         }
1348         data_in = usb_mtp_get_object_info(s, c, o);
1349         break;
1350     case CMD_GET_OBJECT:
1351         o = usb_mtp_object_lookup(s, c->argv[0]);
1352         if (o == NULL) {
1353             usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE,
1354                                  c->trans, 0, 0, 0, 0);
1355             return;
1356         }
1357         if (o->format == FMT_ASSOCIATION) {
1358             usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE,
1359                                  c->trans, 0, 0, 0, 0);
1360             return;
1361         }
1362         data_in = usb_mtp_get_object(s, c, o);
1363         if (data_in == NULL) {
1364             usb_mtp_queue_result(s, RES_GENERAL_ERROR,
1365                                  c->trans, 0, 0, 0, 0);
1366             return;
1367         }
1368         break;
1369     case CMD_DELETE_OBJECT:
1370         usb_mtp_object_delete(s, c->argv[0], c->argv[1], c->trans);
1371         return;
1372     case CMD_GET_PARTIAL_OBJECT:
1373         o = usb_mtp_object_lookup(s, c->argv[0]);
1374         if (o == NULL) {
1375             usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE,
1376                                  c->trans, 0, 0, 0, 0);
1377             return;
1378         }
1379         if (o->format == FMT_ASSOCIATION) {
1380             usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE,
1381                                  c->trans, 0, 0, 0, 0);
1382             return;
1383         }
1384         data_in = usb_mtp_get_partial_object(s, c, o);
1385         if (data_in == NULL) {
1386             usb_mtp_queue_result(s, RES_GENERAL_ERROR,
1387                                  c->trans, 0, 0, 0, 0);
1388             return;
1389         }
1390         nres = 1;
1391         res0 = data_in->length;
1392         break;
1393     case CMD_SEND_OBJECT_INFO:
1394         /* Return error if store is read-only */
1395         if (!FLAG_SET(s, MTP_FLAG_WRITABLE)) {
1396             usb_mtp_queue_result(s, RES_STORE_READ_ONLY,
1397                                  c->trans, 0, 0, 0, 0);
1398         } else if (c->argv[0] && (c->argv[0] != QEMU_STORAGE_ID)) {
1399             /* First parameter points to storage id or is 0 */
1400             usb_mtp_queue_result(s, RES_STORE_NOT_AVAILABLE, c->trans,
1401                                  0, 0, 0, 0);
1402         } else if (c->argv[1] && !c->argv[0]) {
1403             /* If second parameter is specified, first must also be specified */
1404             usb_mtp_queue_result(s, RES_DESTINATION_UNSUPPORTED, c->trans,
1405                                  0, 0, 0, 0);
1406         } else {
1407             uint32_t handle = c->argv[1];
1408             if (handle == 0xFFFFFFFF || handle == 0) {
1409                 /* root object */
1410                 o = QTAILQ_FIRST(&s->objects);
1411             } else {
1412                 o = usb_mtp_object_lookup(s, handle);
1413             }
1414             if (o == NULL) {
1415                 usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE, c->trans,
1416                                      0, 0, 0, 0);
1417             } else if (o->format != FMT_ASSOCIATION) {
1418                 usb_mtp_queue_result(s, RES_INVALID_PARENT_OBJECT, c->trans,
1419                                      0, 0, 0, 0);
1420             }
1421         }
1422         if (o) {
1423             s->dataset.parent_handle = o->handle;
1424         }
1425         s->data_out = usb_mtp_data_alloc(c);
1426         return;
1427     case CMD_SEND_OBJECT:
1428         if (!FLAG_SET(s, MTP_FLAG_WRITABLE)) {
1429             usb_mtp_queue_result(s, RES_STORE_READ_ONLY,
1430                                  c->trans, 0, 0, 0, 0);
1431             return;
1432         }
1433         if (!s->write_pending) {
1434             usb_mtp_queue_result(s, RES_INVALID_OBJECTINFO,
1435                                  c->trans, 0, 0, 0, 0);
1436             return;
1437         }
1438         s->data_out = usb_mtp_data_alloc(c);
1439         return;
1440     case CMD_GET_OBJECT_PROPS_SUPPORTED:
1441         if (c->argv[0] != FMT_UNDEFINED_OBJECT &&
1442             c->argv[0] != FMT_ASSOCIATION) {
1443             usb_mtp_queue_result(s, RES_INVALID_OBJECT_FORMAT_CODE,
1444                                  c->trans, 0, 0, 0, 0);
1445             return;
1446         }
1447         data_in = usb_mtp_get_object_props_supported(s, c);
1448         break;
1449     case CMD_GET_OBJECT_PROP_DESC:
1450         if (c->argv[1] != FMT_UNDEFINED_OBJECT &&
1451             c->argv[1] != FMT_ASSOCIATION) {
1452             usb_mtp_queue_result(s, RES_INVALID_OBJECT_FORMAT_CODE,
1453                                  c->trans, 0, 0, 0, 0);
1454             return;
1455         }
1456         data_in = usb_mtp_get_object_prop_desc(s, c);
1457         if (data_in == NULL) {
1458             usb_mtp_queue_result(s, RES_INVALID_OBJECT_PROP_CODE,
1459                                  c->trans, 0, 0, 0, 0);
1460             return;
1461         }
1462         break;
1463     case CMD_GET_OBJECT_PROP_VALUE:
1464         o = usb_mtp_object_lookup(s, c->argv[0]);
1465         if (o == NULL) {
1466             usb_mtp_queue_result(s, RES_INVALID_OBJECT_HANDLE,
1467                                  c->trans, 0, 0, 0, 0);
1468             return;
1469         }
1470         data_in = usb_mtp_get_object_prop_value(s, c, o);
1471         if (data_in == NULL) {
1472             usb_mtp_queue_result(s, RES_INVALID_OBJECT_PROP_CODE,
1473                                  c->trans, 0, 0, 0, 0);
1474             return;
1475         }
1476         break;
1477     default:
1478         trace_usb_mtp_op_unknown(s->dev.addr, c->code);
1479         usb_mtp_queue_result(s, RES_OPERATION_NOT_SUPPORTED,
1480                              c->trans, 0, 0, 0, 0);
1481         return;
1482     }
1483 
1484     /* return results on success */
1485     if (data_in) {
1486         assert(s->data_in == NULL);
1487         s->data_in = data_in;
1488     }
1489     usb_mtp_queue_result(s, RES_OK, c->trans, nres, res0, 0, 0);
1490 }
1491 
1492 /* ----------------------------------------------------------------------- */
1493 
1494 static void usb_mtp_handle_reset(USBDevice *dev)
1495 {
1496     MTPState *s = USB_MTP(dev);
1497 
1498     trace_usb_mtp_reset(s->dev.addr);
1499 
1500     usb_mtp_file_monitor_cleanup(s);
1501     usb_mtp_object_free(s, QTAILQ_FIRST(&s->objects));
1502     s->session = 0;
1503     usb_mtp_data_free(s->data_in);
1504     s->data_in = NULL;
1505     usb_mtp_data_free(s->data_out);
1506     s->data_out = NULL;
1507     g_free(s->result);
1508     s->result = NULL;
1509 }
1510 
1511 static void usb_mtp_handle_control(USBDevice *dev, USBPacket *p,
1512                                    int request, int value, int index,
1513                                    int length, uint8_t *data)
1514 {
1515     int ret;
1516     MTPState *s = USB_MTP(dev);
1517     uint16_t *event = (uint16_t *)data;
1518 
1519     switch (request) {
1520     case ClassInterfaceOutRequest | 0x64:
1521         if (*event == EVT_CANCEL_TRANSACTION) {
1522             g_free(s->result);
1523             s->result = NULL;
1524             usb_mtp_data_free(s->data_in);
1525             s->data_in = NULL;
1526             if (s->write_pending) {
1527                 g_free(s->dataset.filename);
1528                 s->write_pending = false;
1529                 s->dataset.size = 0;
1530             }
1531             usb_mtp_data_free(s->data_out);
1532             s->data_out = NULL;
1533         } else {
1534             p->status = USB_RET_STALL;
1535         }
1536         break;
1537     default:
1538         ret = usb_desc_handle_control(dev, p, request,
1539                                       value, index, length, data);
1540         if (ret >= 0) {
1541             return;
1542         }
1543     }
1544 
1545     trace_usb_mtp_stall(dev->addr, "unknown control request");
1546 }
1547 
1548 static void usb_mtp_cancel_packet(USBDevice *dev, USBPacket *p)
1549 {
1550     /* we don't use async packets, so this should never be called */
1551     fprintf(stderr, "%s\n", __func__);
1552 }
1553 
1554 static char *utf16_to_str(uint8_t len, uint8_t *str16)
1555 {
1556     wchar_t *wstr = g_new0(wchar_t, len + 1);
1557     int count, dlen;
1558     char *dest;
1559 
1560     for (count = 0; count < len; count++) {
1561         /* FIXME: not working for surrogate pairs */
1562         wstr[count] = lduw_le_p(str16 + (count * 2));
1563     }
1564     wstr[count] = 0;
1565 
1566     dlen = wcstombs(NULL, wstr, 0) + 1;
1567     dest = g_malloc(dlen);
1568     wcstombs(dest, wstr, dlen);
1569     g_free(wstr);
1570     return dest;
1571 }
1572 
1573 /* Wrapper around write, returns 0 on failure */
1574 static uint64_t write_retry(int fd, void *buf, uint64_t size, off_t offset)
1575 {
1576         uint64_t ret = 0;
1577 
1578         if (lseek(fd, offset, SEEK_SET) < 0) {
1579             goto done;
1580         }
1581 
1582         ret = qemu_write_full(fd, buf, size);
1583 
1584 done:
1585         return ret;
1586 }
1587 
1588 static int usb_mtp_update_object(MTPObject *parent, char *name)
1589 {
1590     int ret = 0;
1591 
1592     MTPObject *o =
1593         usb_mtp_object_lookup_name(parent, name, strlen(name));
1594 
1595     if (o) {
1596         ret = lstat(o->path, &o->stat);
1597     }
1598 
1599     return ret;
1600 }
1601 
1602 static void usb_mtp_write_data(MTPState *s, uint32_t handle)
1603 {
1604     MTPData *d = s->data_out;
1605     MTPObject *parent =
1606         usb_mtp_object_lookup(s, s->dataset.parent_handle);
1607     char *path = NULL;
1608     uint64_t rc;
1609     mode_t mask = 0755;
1610     int ret = 0;
1611 
1612     assert(d != NULL);
1613 
1614     switch (d->write_status) {
1615     case WRITE_START:
1616         if (!parent || !s->write_pending) {
1617             usb_mtp_queue_result(s, RES_INVALID_OBJECTINFO, d->trans,
1618                 0, 0, 0, 0);
1619             return;
1620         }
1621 
1622         if (s->dataset.filename) {
1623             path = g_strdup_printf("%s/%s", parent->path, s->dataset.filename);
1624             if (s->dataset.format == FMT_ASSOCIATION) {
1625                 ret = g_mkdir(path, mask);
1626                 if (!ret) {
1627                     usb_mtp_queue_result(s, RES_OK, d->trans, 3,
1628                                          QEMU_STORAGE_ID,
1629                                          s->dataset.parent_handle,
1630                                          handle);
1631                     goto close;
1632                 }
1633                 goto done;
1634             }
1635 
1636             d->fd = open(path, O_CREAT | O_WRONLY |
1637                          O_CLOEXEC | O_NOFOLLOW, mask & 0666);
1638             if (d->fd == -1) {
1639                 ret = 1;
1640                 goto done;
1641             }
1642 
1643             /* Return success if initiator sent 0 sized data */
1644             if (!s->dataset.size) {
1645                 goto done;
1646             }
1647             if (d->length != MTP_WRITE_BUF_SZ && !d->pending) {
1648                 d->write_status = WRITE_END;
1649             }
1650         }
1651         /* fall through */
1652     case WRITE_CONTINUE:
1653     case WRITE_END:
1654         rc = write_retry(d->fd, d->data, d->data_offset,
1655                          d->offset - d->data_offset);
1656         if (rc != d->data_offset) {
1657             ret = 1;
1658             goto done;
1659         }
1660         if (d->write_status != WRITE_END) {
1661             g_free(path);
1662             return;
1663         } else {
1664             /*
1665              * Return an incomplete transfer if file size doesn't match
1666              * for < 4G file or if lstat fails which will result in an incorrect
1667              * file size
1668              */
1669             if ((s->dataset.size != 0xFFFFFFFF &&
1670                  d->offset != s->dataset.size) ||
1671                 usb_mtp_update_object(parent, s->dataset.filename)) {
1672                 usb_mtp_queue_result(s, RES_INCOMPLETE_TRANSFER, d->trans,
1673                                      0, 0, 0, 0);
1674                 goto close;
1675             }
1676         }
1677     }
1678 
1679 done:
1680     if (ret) {
1681         usb_mtp_queue_result(s, RES_STORE_FULL, d->trans,
1682                              0, 0, 0, 0);
1683     } else {
1684         usb_mtp_queue_result(s, RES_OK, d->trans,
1685                              0, 0, 0, 0);
1686     }
1687 close:
1688     /*
1689      * The write dataset is kept around and freed only
1690      * on success or if another write request comes in
1691      */
1692     if (d->fd != -1) {
1693         close(d->fd);
1694         d->fd = -1;
1695     }
1696     g_free(s->dataset.filename);
1697     s->dataset.size = 0;
1698     g_free(path);
1699     s->write_pending = false;
1700 }
1701 
1702 static void usb_mtp_write_metadata(MTPState *s, uint64_t dlen)
1703 {
1704     MTPData *d = s->data_out;
1705     ObjectInfo *dataset = (ObjectInfo *)d->data;
1706     char *filename;
1707     MTPObject *o;
1708     MTPObject *p = usb_mtp_object_lookup(s, s->dataset.parent_handle);
1709     uint32_t next_handle = s->next_handle;
1710     size_t filename_chars = dlen - offsetof(ObjectInfo, filename);
1711 
1712     /*
1713      * filename is utf-16. We're intentionally doing
1714      * integer division to truncate if malicious guest
1715      * sent an odd number of bytes.
1716      */
1717     filename_chars /= 2;
1718 
1719     assert(!s->write_pending);
1720     assert(p != NULL);
1721 
1722     filename = utf16_to_str(MIN(dataset->length, filename_chars),
1723                             dataset->filename);
1724 
1725     if (strchr(filename, '/')) {
1726         usb_mtp_queue_result(s, RES_PARAMETER_NOT_SUPPORTED, d->trans,
1727                              0, 0, 0, 0);
1728         g_free(filename);
1729         return;
1730     }
1731 
1732     o = usb_mtp_object_lookup_name(p, filename, -1);
1733     if (o != NULL) {
1734         next_handle = o->handle;
1735     }
1736 
1737     s->dataset.filename = filename;
1738     s->dataset.format = dataset->format;
1739     s->dataset.size = dataset->size;
1740     s->write_pending = true;
1741 
1742     if (s->dataset.format == FMT_ASSOCIATION) {
1743         usb_mtp_write_data(s, next_handle);
1744     } else {
1745         usb_mtp_queue_result(s, RES_OK, d->trans, 3, QEMU_STORAGE_ID,
1746                              s->dataset.parent_handle, next_handle);
1747     }
1748 }
1749 
1750 static void usb_mtp_get_data(MTPState *s, mtp_container *container,
1751                              USBPacket *p)
1752 {
1753     MTPData *d = s->data_out;
1754     uint64_t dlen;
1755     uint32_t data_len = p->iov.size;
1756     uint64_t total_len;
1757 
1758     if (!d) {
1759             usb_mtp_queue_result(s, RES_INVALID_OBJECTINFO, 0,
1760                                  0, 0, 0, 0);
1761             return;
1762     }
1763     if (d->first) {
1764         /* Total length of incoming data */
1765         total_len = cpu_to_le32(container->length) - sizeof(mtp_container);
1766         /* Length of data in this packet */
1767         data_len -= sizeof(mtp_container);
1768         if (total_len < MTP_WRITE_BUF_SZ) {
1769                 usb_mtp_realloc(d, total_len);
1770                 d->length += total_len;
1771         } else {
1772                 usb_mtp_realloc(d, MTP_WRITE_BUF_SZ - sizeof(mtp_container));
1773                 d->length += MTP_WRITE_BUF_SZ - sizeof(mtp_container);
1774         }
1775         d->offset = 0;
1776         d->first = false;
1777         d->pending = false;
1778         d->data_offset = 0;
1779         d->write_status = WRITE_START;
1780     }
1781 
1782     if (d->pending) {
1783         memset(d->data, 0, d->length);
1784         if (d->length != MTP_WRITE_BUF_SZ) {
1785             usb_mtp_realloc(d, MTP_WRITE_BUF_SZ - d->length);
1786             d->length += (MTP_WRITE_BUF_SZ - d->length);
1787         }
1788         d->pending = false;
1789         d->write_status = WRITE_CONTINUE;
1790         d->data_offset = 0;
1791     }
1792 
1793     if (d->length - d->data_offset > data_len) {
1794         dlen = data_len;
1795     } else {
1796         dlen = d->length - d->data_offset;
1797     }
1798 
1799     switch (d->code) {
1800     case CMD_SEND_OBJECT_INFO:
1801         usb_packet_copy(p, d->data + d->data_offset, dlen);
1802         d->offset += dlen;
1803         d->data_offset += dlen;
1804         if (d->data_offset == d->length) {
1805             /* The operation might have already failed */
1806             if (!s->result) {
1807                 usb_mtp_write_metadata(s, dlen);
1808             }
1809             usb_mtp_data_free(s->data_out);
1810             s->data_out = NULL;
1811             return;
1812         }
1813         break;
1814     case CMD_SEND_OBJECT:
1815         usb_packet_copy(p, d->data + d->data_offset, dlen);
1816         d->offset += dlen;
1817         d->data_offset += dlen;
1818         if ((p->iov.size % 64) || !p->iov.size) {
1819             assert((s->dataset.size == 0xFFFFFFFF) ||
1820                    (s->dataset.size == d->offset));
1821 
1822             if (d->length == MTP_WRITE_BUF_SZ) {
1823                 d->write_status = WRITE_END;
1824             } else {
1825                 d->write_status = WRITE_START;
1826             }
1827             usb_mtp_write_data(s, 0);
1828             usb_mtp_data_free(s->data_out);
1829             s->data_out = NULL;
1830             return;
1831         }
1832         if (d->data_offset == d->length) {
1833             d->pending = true;
1834             usb_mtp_write_data(s, 0);
1835         }
1836         break;
1837     default:
1838         p->status = USB_RET_STALL;
1839         return;
1840     }
1841 }
1842 
1843 static void usb_mtp_handle_data(USBDevice *dev, USBPacket *p)
1844 {
1845     MTPState *s = USB_MTP(dev);
1846     MTPControl cmd;
1847     mtp_container container;
1848     uint32_t params[5];
1849     uint16_t container_type;
1850     int i, rc;
1851 
1852     switch (p->ep->nr) {
1853     case EP_DATA_IN:
1854         if (s->data_out != NULL) {
1855             /* guest bug */
1856             trace_usb_mtp_stall(s->dev.addr, "awaiting data-out");
1857             p->status = USB_RET_STALL;
1858             return;
1859         }
1860         if (p->iov.size < sizeof(container)) {
1861             trace_usb_mtp_stall(s->dev.addr, "packet too small");
1862             p->status = USB_RET_STALL;
1863             return;
1864         }
1865         if (s->data_in !=  NULL) {
1866             MTPData *d = s->data_in;
1867             uint64_t dlen = d->length - d->offset;
1868             if (d->first) {
1869                 trace_usb_mtp_data_in(s->dev.addr, d->trans, d->length);
1870                 if (d->length + sizeof(container) > 0xFFFFFFFF) {
1871                     container.length = cpu_to_le32(0xFFFFFFFF);
1872                 } else {
1873                     container.length =
1874                         cpu_to_le32(d->length + sizeof(container));
1875                 }
1876                 container.type   = cpu_to_le16(TYPE_DATA);
1877                 container.code   = cpu_to_le16(d->code);
1878                 container.trans  = cpu_to_le32(d->trans);
1879                 usb_packet_copy(p, &container, sizeof(container));
1880                 d->first = false;
1881                 if (dlen > p->iov.size - sizeof(container)) {
1882                     dlen = p->iov.size - sizeof(container);
1883                 }
1884             } else {
1885                 if (dlen > p->iov.size) {
1886                     dlen = p->iov.size;
1887                 }
1888             }
1889             if (d->fd == -1) {
1890                 usb_packet_copy(p, d->data + d->offset, dlen);
1891             } else {
1892                 if (d->alloc < p->iov.size) {
1893                     d->alloc = p->iov.size;
1894                     d->data = g_realloc(d->data, d->alloc);
1895                 }
1896                 rc = read(d->fd, d->data, dlen);
1897                 if (rc != dlen) {
1898                     memset(d->data, 0, dlen);
1899                     s->result->code = RES_INCOMPLETE_TRANSFER;
1900                 }
1901                 usb_packet_copy(p, d->data, dlen);
1902             }
1903             d->offset += dlen;
1904             if (d->offset == d->length) {
1905                 usb_mtp_data_free(s->data_in);
1906                 s->data_in = NULL;
1907             }
1908         } else if (s->result != NULL) {
1909             MTPControl *r = s->result;
1910             int length = sizeof(container) + r->argc * sizeof(uint32_t);
1911             if (r->code == RES_OK) {
1912                 trace_usb_mtp_success(s->dev.addr, r->trans,
1913                                       (r->argc > 0) ? r->argv[0] : 0,
1914                                       (r->argc > 1) ? r->argv[1] : 0);
1915             } else {
1916                 trace_usb_mtp_error(s->dev.addr, r->code, r->trans,
1917                                     (r->argc > 0) ? r->argv[0] : 0,
1918                                     (r->argc > 1) ? r->argv[1] : 0);
1919             }
1920             container.length = cpu_to_le32(length);
1921             container.type   = cpu_to_le16(TYPE_RESPONSE);
1922             container.code   = cpu_to_le16(r->code);
1923             container.trans  = cpu_to_le32(r->trans);
1924             for (i = 0; i < r->argc; i++) {
1925                 params[i] = cpu_to_le32(r->argv[i]);
1926             }
1927             usb_packet_copy(p, &container, sizeof(container));
1928             usb_packet_copy(p, &params, length - sizeof(container));
1929             g_free(s->result);
1930             s->result = NULL;
1931         }
1932         break;
1933     case EP_DATA_OUT:
1934         if (p->iov.size < sizeof(container)) {
1935             trace_usb_mtp_stall(s->dev.addr, "packet too small");
1936             p->status = USB_RET_STALL;
1937             return;
1938         }
1939         if ((s->data_out != NULL) && !s->data_out->first) {
1940             container_type = TYPE_DATA;
1941         } else {
1942             usb_packet_copy(p, &container, sizeof(container));
1943             container_type = le16_to_cpu(container.type);
1944         }
1945         switch (container_type) {
1946         case TYPE_COMMAND:
1947             if (s->data_in || s->data_out || s->result) {
1948                 trace_usb_mtp_stall(s->dev.addr, "transaction inflight");
1949                 p->status = USB_RET_STALL;
1950                 return;
1951             }
1952             cmd.code = le16_to_cpu(container.code);
1953             cmd.argc = (le32_to_cpu(container.length) - sizeof(container))
1954                 / sizeof(uint32_t);
1955             cmd.trans = le32_to_cpu(container.trans);
1956             if (cmd.argc > ARRAY_SIZE(cmd.argv)) {
1957                 cmd.argc = ARRAY_SIZE(cmd.argv);
1958             }
1959             if (p->iov.size < sizeof(container) + cmd.argc * sizeof(uint32_t)) {
1960                 trace_usb_mtp_stall(s->dev.addr, "packet too small");
1961                 p->status = USB_RET_STALL;
1962                 return;
1963             }
1964             usb_packet_copy(p, &params, cmd.argc * sizeof(uint32_t));
1965             for (i = 0; i < cmd.argc; i++) {
1966                 cmd.argv[i] = le32_to_cpu(params[i]);
1967             }
1968             trace_usb_mtp_command(s->dev.addr, cmd.code, cmd.trans,
1969                                   (cmd.argc > 0) ? cmd.argv[0] : 0,
1970                                   (cmd.argc > 1) ? cmd.argv[1] : 0,
1971                                   (cmd.argc > 2) ? cmd.argv[2] : 0,
1972                                   (cmd.argc > 3) ? cmd.argv[3] : 0,
1973                                   (cmd.argc > 4) ? cmd.argv[4] : 0);
1974             usb_mtp_command(s, &cmd);
1975             break;
1976         case TYPE_DATA:
1977             /* One of the previous transfers has already errored but the
1978              * responder is still sending data associated with it
1979              */
1980             if (s->result != NULL) {
1981                 return;
1982             }
1983             usb_mtp_get_data(s, &container, p);
1984             break;
1985         default:
1986             /* not needed as long as the mtp device is read-only */
1987             p->status = USB_RET_STALL;
1988             return;
1989         }
1990         break;
1991     case EP_EVENT:
1992         if (!QTAILQ_EMPTY(&s->events)) {
1993             struct MTPMonEntry *e = QTAILQ_LAST(&s->events);
1994             uint32_t handle;
1995             int len = sizeof(container) + sizeof(uint32_t);
1996 
1997             if (p->iov.size < len) {
1998                 trace_usb_mtp_stall(s->dev.addr,
1999                                     "packet too small to send event");
2000                 p->status = USB_RET_STALL;
2001                 return;
2002             }
2003 
2004             QTAILQ_REMOVE(&s->events, e, next);
2005             container.length = cpu_to_le32(len);
2006             container.type = cpu_to_le32(TYPE_EVENT);
2007             container.code = cpu_to_le16(e->event);
2008             container.trans = 0; /* no trans specific events */
2009             handle = cpu_to_le32(e->handle);
2010             usb_packet_copy(p, &container, sizeof(container));
2011             usb_packet_copy(p, &handle, sizeof(uint32_t));
2012             g_free(e);
2013             return;
2014         }
2015         p->status = USB_RET_NAK;
2016         return;
2017     default:
2018         trace_usb_mtp_stall(s->dev.addr, "invalid endpoint");
2019         p->status = USB_RET_STALL;
2020         return;
2021     }
2022 
2023     if (p->actual_length == 0) {
2024         trace_usb_mtp_nak(s->dev.addr, p->ep->nr);
2025         p->status = USB_RET_NAK;
2026         return;
2027     } else {
2028         trace_usb_mtp_xfer(s->dev.addr, p->ep->nr, p->actual_length,
2029                            p->iov.size);
2030         return;
2031     }
2032 }
2033 
2034 static void usb_mtp_realize(USBDevice *dev, Error **errp)
2035 {
2036     MTPState *s = USB_MTP(dev);
2037 
2038     if ((s->root == NULL) || !g_path_is_absolute(s->root)) {
2039         error_setg(errp, "usb-mtp: rootdir must be configured and be an absolute path");
2040         return;
2041     }
2042 
2043     if (access(s->root, R_OK) != 0) {
2044         error_setg(errp, "usb-mtp: rootdir does not exist/not readable");
2045         return;
2046     } else if (!s->readonly && access(s->root, W_OK) != 0) {
2047         error_setg(errp, "usb-mtp: rootdir does not have write permissions");
2048         return;
2049     }
2050 
2051     /* Mark store as RW */
2052     if (!s->readonly) {
2053         s->flags |= (1 << MTP_FLAG_WRITABLE);
2054     }
2055 
2056     if (s->desc == NULL) {
2057         /*
2058          * This does not check if path exists
2059          * but we have the checks above
2060          */
2061         s->desc = g_path_get_basename(s->root);
2062     }
2063 
2064     usb_desc_create_serial(dev);
2065     usb_desc_init(dev);
2066     QTAILQ_INIT(&s->objects);
2067 
2068 }
2069 
2070 static const VMStateDescription vmstate_usb_mtp = {
2071     .name = "usb-mtp",
2072     .unmigratable = 1,
2073     .version_id = 1,
2074     .minimum_version_id = 1,
2075     .fields = (const VMStateField[]) {
2076         VMSTATE_USB_DEVICE(dev, MTPState),
2077         VMSTATE_END_OF_LIST()
2078     }
2079 };
2080 
2081 static Property mtp_properties[] = {
2082     DEFINE_PROP_STRING("rootdir", MTPState, root),
2083     DEFINE_PROP_STRING("desc", MTPState, desc),
2084     DEFINE_PROP_BOOL("readonly", MTPState, readonly, true),
2085     DEFINE_PROP_END_OF_LIST(),
2086 };
2087 
2088 static void usb_mtp_class_initfn(ObjectClass *klass, void *data)
2089 {
2090     DeviceClass *dc = DEVICE_CLASS(klass);
2091     USBDeviceClass *uc = USB_DEVICE_CLASS(klass);
2092 
2093     uc->realize        = usb_mtp_realize;
2094     uc->product_desc   = "QEMU USB MTP";
2095     uc->usb_desc       = &desc;
2096     uc->cancel_packet  = usb_mtp_cancel_packet;
2097     uc->handle_attach  = usb_desc_attach;
2098     uc->handle_reset   = usb_mtp_handle_reset;
2099     uc->handle_control = usb_mtp_handle_control;
2100     uc->handle_data    = usb_mtp_handle_data;
2101     set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
2102     dc->desc = "USB Media Transfer Protocol device";
2103     dc->fw_name = "mtp";
2104     dc->vmsd = &vmstate_usb_mtp;
2105     device_class_set_props(dc, mtp_properties);
2106 }
2107 
2108 static const TypeInfo mtp_info = {
2109     .name          = TYPE_USB_MTP,
2110     .parent        = TYPE_USB_DEVICE,
2111     .instance_size = sizeof(MTPState),
2112     .class_init    = usb_mtp_class_initfn,
2113 };
2114 
2115 static void usb_mtp_register_types(void)
2116 {
2117     type_register_static(&mtp_info);
2118 }
2119 
2120 type_init(usb_mtp_register_types)
2121