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
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
// Copyright 2021 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use crate::writer::{private::InspectTypeInternal, Error, Heap, Node, State};
use diagnostics_hierarchy::{DiagnosticsHierarchy, DiagnosticsHierarchyGetter};
use inspect_format::{constants, BlockContainer, Container};
use std::{borrow::Cow, cmp::max, fmt, sync::Arc};
use tracing::error;

#[cfg(target_os = "fuchsia")]
use fuchsia_zircon::{self as zx, AsHandleRef, HandleBased};

/// Root of the Inspect API. Through this API, further nodes can be created and inspect can be
/// served.
#[derive(Clone)]
pub struct Inspector {
    /// The root node.
    root_node: Arc<Node>,

    /// The storage backing the inspector. This is a VMO when working on Fuchsia.
    #[allow(dead_code)] // unused and meaningless in the host build.
    storage: Option<Arc<<Container as BlockContainer>::ShareableData>>,
}

impl fmt::Debug for Inspector {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        let tree = self.get_diagnostics_hierarchy();
        if fmt.alternate() {
            write!(fmt, "{:#?}", tree)
        } else {
            write!(fmt, "{:?}", tree)
        }
    }
}

impl DiagnosticsHierarchyGetter<String> for Inspector {
    fn get_diagnostics_hierarchy(&self) -> Cow<'_, DiagnosticsHierarchy> {
        let hierarchy = futures::executor::block_on(async move { crate::reader::read(self).await })
            .expect("failed to get hierarchy");
        Cow::Owned(hierarchy)
    }
}

#[cfg(target_os = "fuchsia")]
impl Inspector {
    /// Returns a duplicate of the underlying VMO for this Inspector.
    ///
    /// The duplicated VMO will be read-only, and is suitable to send to clients over FIDL.
    pub fn duplicate_vmo(&self) -> Option<zx::Vmo> {
        self.storage.as_ref().and_then(|vmo| {
            vmo.duplicate_handle(
                zx::Rights::BASIC | zx::Rights::READ | zx::Rights::MAP | zx::Rights::GET_PROPERTY,
            )
            .ok()
        })
    }

    /// This produces a copy-on-write VMO with a generation count marked as
    /// VMO_FROZEN. The resulting VMO is read-only.
    ///
    /// Failure
    /// This function returns `None` for failure. That can happen for
    /// a few reasons.
    ///   1) It is a semantic error to freeze a VMO while an atomic transaction
    ///      is in progress, because that transaction is supposed to be atomic.
    ///   2) VMO errors. This can include running out of space or debug assertions.
    ///
    /// Note: the generation count for the original VMO is updated immediately. Since
    /// the new VMO is page-by-page copy-on-write, at least the first page of the
    /// VMO will immediately do a true copy. The practical implications of this
    /// depend on implementation details like how large a VMO is versus page size.
    pub fn frozen_vmo_copy(&self) -> Option<zx::Vmo> {
        self.state()?.try_lock().ok().and_then(|mut state| state.frozen_vmo_copy().ok()).flatten()
    }

    /// Returns a VMO holding a copy of the data in this inspector.
    ///
    /// The copied VMO will be read-only.
    pub fn copy_vmo(&self) -> Option<zx::Vmo> {
        self.copy_vmo_data().and_then(|data| {
            if let Ok(vmo) = zx::Vmo::create(data.len() as u64) {
                vmo.write(&data, 0).ok().map(|_| vmo)
            } else {
                None
            }
        })
    }

    pub(crate) fn get_storage_handle(&self) -> Option<Arc<zx::Vmo>> {
        // We can'just share a reference to the underlying vec<u8> storage, so we copy the data
        self.storage.clone()
    }

    /// Returns Ok(()) if VMO is frozen, and the generation count if it is not.
    /// Very unsafe. Propagates unrelated errors by panicking.
    #[cfg(test)]
    pub fn is_frozen(&self) -> Result<(), u64> {
        use inspect_format::Block;
        let vmo = self.storage.as_ref().unwrap();
        let mut buffer: [u8; 16] = [0; 16];
        vmo.read(&mut buffer, 0).unwrap();
        let block = Block::new(&buffer, inspect_format::BlockIndex::EMPTY);
        if block.header_generation_count().unwrap() == constants::VMO_FROZEN {
            Ok(())
        } else {
            Err(block.header_generation_count().unwrap())
        }
    }
}

#[cfg(not(target_os = "fuchsia"))]
impl Inspector {
    pub(crate) fn duplicate_vmo(&self) -> Option<<Container as BlockContainer>::Data> {
        // We don't support getting a duplicate handle to the data on the host so we lock and copy
        // the udnerlying data.
        self.copy_vmo_data()
    }

    pub(crate) fn get_storage_handle(&self) -> Option<Vec<u8>> {
        // We can'just share a reference to the underlying vec<u8> storage, so we copy the data
        self.copy_vmo_data()
    }
}

impl Default for Inspector {
    fn default() -> Self {
        Inspector::new(InspectorConfig::default())
    }
}

impl Inspector {
    /// Initializes a new Inspect VMO object with the
    /// [`default maximum size`][constants::DEFAULT_VMO_SIZE_BYTES].
    pub fn new(conf: InspectorConfig) -> Self {
        conf.build()
    }

    /// Returns a copy of the bytes stored in the VMO for this inspector.
    ///
    /// The output will be truncated to only those bytes that are needed to accurately read the
    /// stored data.
    pub fn copy_vmo_data(&self) -> Option<Vec<u8>> {
        self.root_node.inner.inner_ref().and_then(|inner_ref| inner_ref.state.copy_vmo_bytes())
    }

    pub fn max_size(&self) -> Option<usize> {
        self.state()?.try_lock().ok().map(|state| state.stats().maximum_size)
    }

    /// True if the Inspector was created successfully (it's not No-Op)
    pub fn is_valid(&self) -> bool {
        // It is only necessary to check the root_node, because:
        //   1) If the Inspector was created as a no-op, the root node is not valid.
        //   2) If the creation of the Inspector failed, then the root_node is invalid. This
        //      is because `Inspector::new_root` returns the VMO and root node as a pair.
        self.root_node.is_valid()
    }

    /// Returns the root node of the inspect hierarchy.
    pub fn root(&self) -> &Node {
        &self.root_node
    }

    /// Takes a function to execute as under a single lock of the Inspect VMO. This function
    /// receives a reference to the root of the inspect hierarchy.
    pub fn atomic_update<F, R>(&self, update_fn: F) -> R
    where
        F: FnOnce(&Node) -> R,
    {
        self.root().atomic_update(update_fn)
    }

    pub(crate) fn state(&self) -> Option<State> {
        self.root().inner.inner_ref().map(|inner_ref| inner_ref.state.clone())
    }
}

/// Classic builder pattern object for constructing an `Inspector`.
pub struct InspectorConfig {
    is_no_op: bool,
    size: usize,
    storage: Option<Arc<<Container as BlockContainer>::ShareableData>>,
}

impl Default for InspectorConfig {
    /// A default Inspector:
    ///     * Fully functional
    ///     * Size: `constants::DEFAULT_VMO_SIZE_BYTES`
    ///
    /// Because the default is so cheap to construct, there is
    /// no "empty" `InspectorConfig`.
    fn default() -> Self {
        Self { is_no_op: false, size: constants::DEFAULT_VMO_SIZE_BYTES, storage: None }
    }
}

impl InspectorConfig {
    /// A read-only Inspector.
    pub fn no_op(mut self) -> Self {
        self.is_no_op = true;
        self
    }

    /// Size of the VMO.
    pub fn size(mut self, max_size: usize) -> Self {
        self.size = max_size;
        self
    }

    fn create_no_op(self) -> Inspector {
        return Inspector { storage: self.storage, root_node: Arc::new(Node::new_no_op()) };
    }

    fn adjusted_buffer_size(max_size: usize) -> usize {
        let mut size = max(constants::MINIMUM_VMO_SIZE_BYTES, max_size);
        // If the size is not a multiple of 4096, round up.
        if size % constants::MINIMUM_VMO_SIZE_BYTES != 0 {
            size =
                (1 + size / constants::MINIMUM_VMO_SIZE_BYTES) * constants::MINIMUM_VMO_SIZE_BYTES;
        }

        size
    }
}

#[cfg(target_os = "fuchsia")]
impl InspectorConfig {
    /// An Inspector with a readable VMO.
    /// Implicitly no-op.
    pub fn vmo(mut self, vmo: Arc<zx::Vmo>) -> Self {
        self.storage = Some(vmo);
        self.no_op()
    }

    fn build(self) -> Inspector {
        if self.is_no_op {
            return self.create_no_op();
        }

        match Self::new_root(self.size) {
            Ok((storage, root_node)) => {
                Inspector { storage: Some(storage), root_node: Arc::new(root_node) }
            }
            Err(e) => {
                error!("Failed to create root node. Error: {:?}", e);
                return self.create_no_op();
            }
        }
    }

    /// Allocates a new VMO and initializes it.
    fn new_root(
        max_size: usize,
    ) -> Result<(Arc<<Container as BlockContainer>::ShareableData>, Node), Error> {
        let size = Self::adjusted_buffer_size(max_size);
        let (container, vmo) = Container::read_and_write(size).map_err(Error::AllocateVmo)?;
        let cname = std::ffi::CString::new("InspectHeap").unwrap();
        vmo.set_name(&cname).map_err(Error::AllocateVmo)?;
        let vmo = Arc::new(vmo);
        let heap = Heap::new(container).map_err(|e| Error::CreateHeap(Box::new(e)))?;
        let state =
            State::create(heap, vmo.clone()).map_err(|e| Error::CreateState(Box::new(e)))?;
        Ok((vmo, Node::new_root(state)))
    }
}

#[cfg(not(target_os = "fuchsia"))]
impl InspectorConfig {
    fn build(self) -> Inspector {
        if self.is_no_op {
            return self.create_no_op();
        }

        match Self::new_root(self.size) {
            Ok((root_node, storage)) => {
                Inspector { storage: Some(storage), root_node: Arc::new(root_node) }
            }
            Err(e) => {
                error!("Failed to create root node. Error: {:?}", e);
                self.create_no_op()
            }
        }
    }

    fn new_root(
        max_size: usize,
    ) -> Result<(Node, Arc<<Container as BlockContainer>::ShareableData>), Error> {
        let size = Self::adjusted_buffer_size(max_size);
        let (container, storage) = Container::read_and_write(size).unwrap();
        let heap = Heap::new(container).map_err(|e| Error::CreateHeap(Box::new(e)))?;
        let state = State::create(heap, Arc::new(storage.clone()))
            .map_err(|e| Error::CreateState(Box::new(e)))?;
        Ok((Node::new_root(state), Arc::new(storage)))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::assert_update_is_atomic;
    use futures::FutureExt;

    #[fuchsia::test]
    fn debug_impl() {
        let inspector = Inspector::default();
        inspector.root().record_int("name", 5);

        assert_eq!(
            format!("{:?}", &inspector),
            "DiagnosticsHierarchy { name: \
            \"root\", properties: [Int(\"name\", 5)], children: [], missing: [] }"
        );

        let pretty = r#"DiagnosticsHierarchy {
    name: "root",
    properties: [
        Int(
            "name",
            5,
        ),
    ],
    children: [],
    missing: [],
}"#;
        assert_eq!(format!("{:#?}", &inspector), pretty);

        let two = inspector.root().create_child("two");
        two.record_lazy_child("two_child", || {
            let insp = Inspector::default();
            insp.root().record_double("double", 1.0);

            async move { Ok(insp) }.boxed()
        });

        let pretty = r#"DiagnosticsHierarchy {
    name: "root",
    properties: [
        Int(
            "name",
            5,
        ),
    ],
    children: [
        DiagnosticsHierarchy {
            name: "two",
            properties: [],
            children: [
                DiagnosticsHierarchy {
                    name: "two_child",
                    properties: [
                        Double(
                            "double",
                            1.0,
                        ),
                    ],
                    children: [],
                    missing: [],
                },
            ],
            missing: [],
        },
    ],
    missing: [],
}"#;
        assert_eq!(format!("{:#?}", &inspector), pretty);
    }

    #[fuchsia::test]
    fn inspector_new() {
        let test_object = Inspector::default();
        assert_eq!(test_object.max_size().unwrap(), constants::DEFAULT_VMO_SIZE_BYTES);
    }

    #[fuchsia::test]
    fn inspector_copy_data() {
        let test_object = Inspector::default();

        assert_eq!(test_object.max_size().unwrap(), constants::DEFAULT_VMO_SIZE_BYTES);

        // The copy will be a single page, since that is all that is used.
        assert_eq!(test_object.copy_vmo_data().unwrap().len(), 4096);
    }

    #[fuchsia::test]
    fn no_op() {
        let inspector = Inspector::new(InspectorConfig::default().size(4096));
        // Make the VMO full.
        let nodes = (0..84)
            .map(|i| inspector.root().create_child(format!("test-{}", i)))
            .collect::<Vec<Node>>();

        assert!(nodes.iter().all(|node| node.is_valid()));
        let no_op_node = inspector.root().create_child("no-op-child");
        assert!(!no_op_node.is_valid());
    }

    #[fuchsia::test]
    fn inspector_new_with_size() {
        let test_object = Inspector::new(InspectorConfig::default().size(8192));
        assert_eq!(test_object.max_size().unwrap(), 8192);

        // If size is not a multiple of 4096, it'll be rounded up.
        let test_object = Inspector::new(InspectorConfig::default().size(10000));
        assert_eq!(test_object.max_size().unwrap(), 12288);

        // If size is less than the minimum size, the minimum will be set.
        let test_object = Inspector::new(InspectorConfig::default().size(2000));
        assert_eq!(test_object.max_size().unwrap(), 4096);
    }

    #[fuchsia::test]
    async fn atomic_update() {
        let insp = Inspector::default();
        assert_update_is_atomic!(insp, |n| {
            n.record_int("", 1);
            n.record_int("", 2);
            n.record_uint("", 3);
            n.record_string("", "abcd");
        });
    }
}

// These tests exercise Fuchsia-specific APIs for Inspector.
#[cfg(all(test, target_os = "fuchsia"))]
mod fuchsia_tests {
    use super::*;
    use std::ffi::CString;

    #[fuchsia::test]
    fn inspector_duplicate_vmo() {
        let test_object = Inspector::default();
        assert_eq!(
            test_object.storage.as_ref().unwrap().get_size().unwrap(),
            constants::DEFAULT_VMO_SIZE_BYTES as u64
        );
        assert_eq!(
            test_object.duplicate_vmo().unwrap().get_size().unwrap(),
            constants::DEFAULT_VMO_SIZE_BYTES as u64
        );
    }

    #[fuchsia::test]
    fn inspector_new_root() {
        // Note, the small size we request should be rounded up to a full 4kB page.
        let (vmo, root_node) = InspectorConfig::new_root(100).unwrap();
        assert_eq!(vmo.get_size().unwrap(), 4096);
        let inner = root_node.inner.inner_ref().unwrap();
        assert_eq!(*inner.block_index, 0);
        assert_eq!(CString::new("InspectHeap").unwrap(), vmo.get_name().expect("Has name"));
    }

    #[fuchsia::test]
    fn freeze_vmo_works() {
        let inspector = Inspector::default();
        let initial = inspector
            .state()
            .unwrap()
            .with_current_header(|header| header.header_generation_count().unwrap());
        let vmo = inspector.frozen_vmo_copy();

        let is_frozen_result = inspector.is_frozen();
        assert!(is_frozen_result.is_err());

        assert_eq!(initial + 2, is_frozen_result.err().unwrap());
        assert!(is_frozen_result.err().unwrap() % 2 == 0);

        let frozen_insp =
            Inspector::new(InspectorConfig::default().no_op().vmo(Arc::new(vmo.unwrap())));
        assert!(frozen_insp.is_frozen().is_ok());
    }

    #[fuchsia::test]
    fn transactions_block_freezing() {
        let inspector = Inspector::default();
        inspector.atomic_update(|_| assert!(inspector.frozen_vmo_copy().is_none()));
    }

    #[fuchsia::test]
    fn transactions_block_copying() {
        let inspector = Inspector::default();
        inspector.atomic_update(|_| assert!(inspector.copy_vmo().is_none()));
        inspector.atomic_update(|_| assert!(inspector.copy_vmo_data().is_none()));
    }

    #[fuchsia::test]
    fn inspector_new_with_size() {
        let test_object = Inspector::new(InspectorConfig::default().size(8192));
        assert_eq!(test_object.max_size().unwrap(), 8192);

        assert_eq!(
            CString::new("InspectHeap").unwrap(),
            test_object.storage.as_ref().unwrap().get_name().expect("Has name")
        );

        // If size is not a multiple of 4096, it'll be rounded up.
        let test_object = Inspector::new(InspectorConfig::default().size(10000));
        assert_eq!(test_object.max_size().unwrap(), 12288);

        // If size is less than the minimum size, the minimum will be set.
        let test_object = Inspector::new(InspectorConfig::default().size(2000));
        assert_eq!(test_object.max_size().unwrap(), 4096);
    }
}