aboutsummaryrefslogtreecommitdiff
path: root/scsi/pr-manager-helper.c
blob: 5acccfb4e30c1c817315f70f90b6dc17f1e56079 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
/*
 * Persistent reservation manager that talks to qemu-pr-helper
 *
 * Copyright (c) 2017 Red Hat, Inc.
 *
 * Author: Paolo Bonzini <pbonzini@redhat.com>
 *
 * This code is licensed under the LGPL v2.1 or later.
 *
 */

#include "qemu/osdep.h"
#include "qapi/error.h"
#include "scsi/constants.h"
#include "scsi/pr-manager.h"
#include "scsi/utils.h"
#include "io/channel.h"
#include "io/channel-socket.h"
#include "pr-helper.h"
#include "qapi/qapi-events-block.h"
#include "qemu/module.h"

#include <scsi/sg.h>

#define PR_MAX_RECONNECT_ATTEMPTS 5

#define TYPE_PR_MANAGER_HELPER "pr-manager-helper"

#define PR_MANAGER_HELPER(obj) \
     OBJECT_CHECK(PRManagerHelper, (obj), \
                  TYPE_PR_MANAGER_HELPER)

typedef struct PRManagerHelper {
    /* <private> */
    PRManager parent;

    char *path;

    QemuMutex lock;
    QIOChannel *ioc;
} PRManagerHelper;

static void pr_manager_send_status_changed_event(PRManagerHelper *pr_mgr)
{
    const char *id = object_get_canonical_path_component(OBJECT(pr_mgr));

    if (id) {
        qapi_event_send_pr_manager_status_changed(id, !!pr_mgr->ioc);
    }
}

/* Called with lock held.  */
static int pr_manager_helper_read(PRManagerHelper *pr_mgr,
                                  void *buf, int sz, Error **errp)
{
    ssize_t r = qio_channel_read_all(pr_mgr->ioc, buf, sz, errp);

    if (r < 0) {
        object_unref(OBJECT(pr_mgr->ioc));
        pr_mgr->ioc = NULL;
        pr_manager_send_status_changed_event(pr_mgr);
        return -EINVAL;
    }

    return 0;
}

/* Called with lock held.  */
static int pr_manager_helper_write(PRManagerHelper *pr_mgr,
                                   int fd,
                                   const void *buf, int sz, Error **errp)
{
    size_t nfds = (fd != -1);
    while (sz > 0) {
        struct iovec iov;
        ssize_t n_written;

        iov.iov_base = (void *)buf;
        iov.iov_len = sz;
        n_written = qio_channel_writev_full(QIO_CHANNEL(pr_mgr->ioc), &iov, 1,
                                            nfds ? &fd : NULL, nfds, errp);

        if (n_written <= 0) {
            assert(n_written != QIO_CHANNEL_ERR_BLOCK);
            object_unref(OBJECT(pr_mgr->ioc));
            pr_mgr->ioc = NULL;
            pr_manager_send_status_changed_event(pr_mgr);
            return n_written < 0 ? -EINVAL : 0;
        }

        nfds = 0;
        buf += n_written;
        sz -= n_written;
    }

    return 0;
}

/* Called with lock held.  */
static int pr_manager_helper_initialize(PRManagerHelper *pr_mgr,
                                        Error **errp)
{
    char *path = g_strdup(pr_mgr->path);
    SocketAddress saddr = {
        .type = SOCKET_ADDRESS_TYPE_UNIX,
        .u.q_unix.path = path
    };
    QIOChannelSocket *sioc = qio_channel_socket_new();
    Error *local_err = NULL;

    uint32_t flags;
    int r;

    assert(!pr_mgr->ioc);
    qio_channel_set_name(QIO_CHANNEL(sioc), "pr-manager-helper");
    qio_channel_socket_connect_sync(sioc,
                                    &saddr,
                                    &local_err);
    g_free(path);
    if (local_err) {
        object_unref(OBJECT(sioc));
        error_propagate(errp, local_err);
        return -ENOTCONN;
    }

    qio_channel_set_delay(QIO_CHANNEL(sioc), false);
    pr_mgr->ioc = QIO_CHANNEL(sioc);

    /* A simple feature negotation protocol, even though there is
     * no optional feature right now.
     */
    r = pr_manager_helper_read(pr_mgr, &flags, sizeof(flags), errp);
    if (r < 0) {
        goto out_close;
    }

    flags = 0;
    r = pr_manager_helper_write(pr_mgr, -1, &flags, sizeof(flags), errp);
    if (r < 0) {
        goto out_close;
    }

    pr_manager_send_status_changed_event(pr_mgr);
    return 0;

out_close:
    object_unref(OBJECT(pr_mgr->ioc));
    pr_mgr->ioc = NULL;
    return r;
}

static int pr_manager_helper_run(PRManager *p,
                                 int fd, struct sg_io_hdr *io_hdr)
{
    PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(p);

    uint32_t len;
    PRHelperResponse resp;
    int ret;
    int expected_dir;
    int attempts;
    uint8_t cdb[PR_HELPER_CDB_SIZE] = { 0 };

    if (!io_hdr->cmd_len || io_hdr->cmd_len > PR_HELPER_CDB_SIZE) {
        return -EINVAL;
    }

    memcpy(cdb, io_hdr->cmdp, io_hdr->cmd_len);
    assert(cdb[0] == PERSISTENT_RESERVE_OUT || cdb[0] == PERSISTENT_RESERVE_IN);
    expected_dir =
        (cdb[0] == PERSISTENT_RESERVE_OUT ? SG_DXFER_TO_DEV : SG_DXFER_FROM_DEV);
    if (io_hdr->dxfer_direction != expected_dir) {
        return -EINVAL;
    }

    len = scsi_cdb_xfer(cdb);
    if (io_hdr->dxfer_len < len || len > PR_HELPER_DATA_SIZE) {
        return -EINVAL;
    }

    qemu_mutex_lock(&pr_mgr->lock);

    /* Try to reconnect while sending the CDB.  */
    for (attempts = 0; attempts < PR_MAX_RECONNECT_ATTEMPTS; attempts++) {
        if (!pr_mgr->ioc) {
            ret = pr_manager_helper_initialize(pr_mgr, NULL);
            if (ret < 0) {
                qemu_mutex_unlock(&pr_mgr->lock);
                g_usleep(G_USEC_PER_SEC);
                qemu_mutex_lock(&pr_mgr->lock);
                continue;
            }
        }

        ret = pr_manager_helper_write(pr_mgr, fd, cdb, ARRAY_SIZE(cdb), NULL);
        if (ret >= 0) {
            break;
        }
    }
    if (ret < 0) {
        goto out;
    }

    /* After sending the CDB, any communications failure causes the
     * command to fail.  The failure is transient, retrying the command
     * will invoke pr_manager_helper_initialize again.
     */
    if (expected_dir == SG_DXFER_TO_DEV) {
        io_hdr->resid = io_hdr->dxfer_len - len;
        ret = pr_manager_helper_write(pr_mgr, -1, io_hdr->dxferp, len, NULL);
        if (ret < 0) {
            goto out;
        }
    }
    ret = pr_manager_helper_read(pr_mgr, &resp, sizeof(resp), NULL);
    if (ret < 0) {
        goto out;
    }

    resp.result = be32_to_cpu(resp.result);
    resp.sz = be32_to_cpu(resp.sz);
    if (io_hdr->dxfer_direction == SG_DXFER_FROM_DEV) {
        assert(resp.sz <= io_hdr->dxfer_len);
        ret = pr_manager_helper_read(pr_mgr, io_hdr->dxferp, resp.sz, NULL);
        if (ret < 0) {
            goto out;
        }
        io_hdr->resid = io_hdr->dxfer_len - resp.sz;
    } else {
        assert(resp.sz == 0);
    }

    io_hdr->status = resp.result;
    if (resp.result == CHECK_CONDITION) {
        io_hdr->driver_status = SG_ERR_DRIVER_SENSE;
        io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, PR_HELPER_SENSE_SIZE);
        memcpy(io_hdr->sbp, resp.sense, io_hdr->sb_len_wr);
    }

out:
    if (ret < 0) {
        int sense_len = scsi_build_sense(io_hdr->sbp,
                                         SENSE_CODE(LUN_COMM_FAILURE));
        io_hdr->driver_status = SG_ERR_DRIVER_SENSE;
        io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, sense_len);
        io_hdr->status = CHECK_CONDITION;
    }
    qemu_mutex_unlock(&pr_mgr->lock);
    return ret;
}

static bool pr_manager_helper_is_connected(PRManager *p)
{
    PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(p);
    bool result;

    qemu_mutex_lock(&pr_mgr->lock);
    result = (pr_mgr->ioc != NULL);
    qemu_mutex_unlock(&pr_mgr->lock);

    return result;
}

static void pr_manager_helper_complete(UserCreatable *uc, Error **errp)
{
    PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(uc);

    qemu_mutex_lock(&pr_mgr->lock);
    pr_manager_helper_initialize(pr_mgr, errp);
    qemu_mutex_unlock(&pr_mgr->lock);
}

static char *get_path(Object *obj, Error **errp)
{
    PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj);

    return g_strdup(pr_mgr->path);
}

static void set_path(Object *obj, const char *str, Error **errp)
{
    PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj);

    g_free(pr_mgr->path);
    pr_mgr->path = g_strdup(str);
}

static void pr_manager_helper_instance_finalize(Object *obj)
{
    PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj);

    object_unref(OBJECT(pr_mgr->ioc));
    qemu_mutex_destroy(&pr_mgr->lock);
}

static void pr_manager_helper_instance_init(Object *obj)
{
    PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(obj);

    qemu_mutex_init(&pr_mgr->lock);
}

static void pr_manager_helper_class_init(ObjectClass *klass,
                                         void *class_data G_GNUC_UNUSED)
{
    PRManagerClass *prmgr_klass = PR_MANAGER_CLASS(klass);
    UserCreatableClass *uc_klass = USER_CREATABLE_CLASS(klass);

    object_class_property_add_str(klass, "path", get_path, set_path);
    uc_klass->complete = pr_manager_helper_complete;
    prmgr_klass->run = pr_manager_helper_run;
    prmgr_klass->is_connected = pr_manager_helper_is_connected;
}

static const TypeInfo pr_manager_helper_info = {
    .parent = TYPE_PR_MANAGER,
    .name = TYPE_PR_MANAGER_HELPER,
    .instance_size = sizeof(PRManagerHelper),
    .instance_init = pr_manager_helper_instance_init,
    .instance_finalize = pr_manager_helper_instance_finalize,
    .class_init = pr_manager_helper_class_init,
};

static void pr_manager_helper_register_types(void)
{
    type_register_static(&pr_manager_helper_info);
}

type_init(pr_manager_helper_register_types);