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
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
// Copyright 2015 Ted Mielczarek. See the COPYRIGHT
// file at the top-level directory of this distribution.

//! The state of a process.

use std::borrow::{Borrow, Cow};
use std::cell::RefCell;
use std::collections::{HashMap, HashSet};
use std::io;
use std::io::prelude::*;
use std::time::SystemTime;

use crate::op_analysis::MemoryAccess;
use minidump::system_info::PointerWidth;
use minidump::*;
use minidump_common::utils::basename;
use minidump_unwind::{CallStack, CallStackInfo, SymbolStats, SystemInfo};
use serde_json::json;

#[derive(Default)]
struct SerializationContext {
    pub pointer_width: Option<PointerWidth>,
}

std::thread_local! {
    static SERIALIZATION_CONTEXT: RefCell<SerializationContext> = Default::default();
}

#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, serde::Serialize)]
#[serde(into = "String")]
pub struct Address(pub u64);

impl From<u64> for Address {
    fn from(v: u64) -> Self {
        Address(v)
    }
}

impl From<Address> for u64 {
    fn from(a: Address) -> Self {
        a.0
    }
}

impl From<Address> for String {
    fn from(a: Address) -> Self {
        a.to_string()
    }
}

impl std::ops::Deref for Address {
    type Target = u64;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl std::ops::DerefMut for Address {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.0
    }
}

impl std::fmt::Display for Address {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        let pointer_width = SERIALIZATION_CONTEXT
            .with(|ctx| ctx.borrow().pointer_width.unwrap_or(PointerWidth::Unknown));
        match pointer_width {
            PointerWidth::Bits32 => write!(f, "{:#010x}", self.0),
            _ => write!(f, "{:#018x}", self.0),
        }
    }
}

pub type AddressOffset = Address;

#[derive(Debug, Clone, Default)]
pub struct LinuxStandardBase {
    pub id: String,
    pub release: String,
    pub codename: String,
    pub description: String,
}

impl From<MinidumpLinuxLsbRelease<'_>> for LinuxStandardBase {
    fn from(linux_standard_base: MinidumpLinuxLsbRelease) -> Self {
        let mut lsb = LinuxStandardBase::default();
        for (key, val) in linux_standard_base.iter() {
            match key.as_bytes() {
                b"DISTRIB_ID" | b"ID" => lsb.id = val.to_string_lossy().into_owned(),
                b"DISTRIB_RELEASE" | b"VERSION_ID" => {
                    lsb.release = val.to_string_lossy().into_owned()
                }
                b"DISTRIB_CODENAME" | b"VERSION_CODENAME" => {
                    lsb.codename = val.to_string_lossy().into_owned()
                }
                b"DISTRIB_DESCRIPTION" | b"PRETTY_NAME" => {
                    lsb.description = val.to_string_lossy().into_owned()
                }
                _ => {}
            }
        }
        lsb
    }
}

#[derive(Debug, Clone)]
pub struct LinuxProcStatus {
    pub pid: u32,
}

impl From<MinidumpLinuxProcStatus<'_>> for LinuxProcStatus {
    fn from(status: MinidumpLinuxProcStatus) -> Self {
        let pid = status
            .iter()
            .find(|entry| entry.0.as_bytes() == b"Pid")
            .map_or(0, |key_val| {
                key_val.1.to_string_lossy().parse::<u32>().unwrap_or(0)
            });
        LinuxProcStatus { pid }
    }
}

#[derive(Debug, Clone, PartialEq)]
pub enum Limit {
    Error,
    Unlimited,
    Limited(u64),
}

impl serde::Serialize for Limit {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        match *self {
            Limit::Error => serializer.serialize_str("err"),
            Limit::Unlimited => serializer.serialize_str("unlimited"),
            Limit::Limited(val) => serializer.serialize_u64(val),
        }
    }
}

#[derive(Debug, Clone)]
pub struct LinuxProcLimit {
    pub soft: Limit,
    pub hard: Limit,
    pub unit: String,
}

#[derive(Debug, Clone)]
pub struct LinuxProcLimits {
    pub limits: HashMap<String, LinuxProcLimit>,
}

fn parse_limit(s: &str) -> Limit {
    match s.trim() {
        "unlimited" => Limit::Unlimited,
        val => Limit::Limited(val.parse::<u64>().unwrap_or(0)),
    }
}

impl From<MinidumpLinuxProcLimits<'_>> for LinuxProcLimits {
    fn from(limits: MinidumpLinuxProcLimits) -> Self {
        let hash: HashMap<String, LinuxProcLimit> = limits
            .iter()
            .filter(|l| !l.is_empty())
            .skip(1) // skip header
            .map(|line: &strings::LinuxOsStr| line.to_string_lossy())
            .map(|l| {
                l.split("  ")
                    .filter(|x| !x.is_empty())
                    .map(|x| x.to_string())
                    .collect::<Vec<String>>()
            })
            .map(|m| {
                let u = if m.len() == 3 {
                    "n/a".to_string()
                } else {
                    m[3].trim().to_string()
                };

                let name = m[0].trim().to_string();
                let lim = LinuxProcLimit {
                    soft: parse_limit(&m[1]),
                    hard: parse_limit(&m[2]),
                    unit: u,
                };

                (name, lim)
            })
            .collect();

        LinuxProcLimits { limits: hash }
    }
}

/// Info about an exception that may have occurred
///
/// May not be available if the minidump wasn't triggered by an exception, or if required
/// info about the exception is missing
#[derive(Debug, Clone)]
pub struct ExceptionInfo {
    /// a `CrashReason` describing the crash reason.
    pub reason: CrashReason,
    /// The memory address implicated in the crash.
    ///
    /// If the crash reason implicates memory, this is the memory address that
    /// caused the crash. For data access errors this will be the data address
    /// that caused the fault. For code errors, this will be the address of the
    /// instruction that caused the fault.
    pub address: Address,
    /// In certain circumstances, the previous `address` member may report a sub-optimal value
    /// for debugging purposes. If instruction analysis is able to successfully determine a
    /// more helpful value, it will be reported here.
    pub adjusted_address: Option<AdjustedAddress>,
    /// A string representing the crashing instruction (if available)
    pub instruction_str: Option<String>,
    /// A list of memory accesses performed by crashing instruction (if available)
    pub memory_accesses: Option<Vec<MemoryAccess>>,
    /// Possible valid addresses which are one flipped bit away from the crashing address or adjusted address.
    ///
    /// The original address was possibly the result of faulty hardware, alpha particles, etc.
    pub possible_bit_flips: Vec<PossibleBitFlip>,
}

/// Info about a memory address that was adjusted from its reported value
///
/// There will be situations where the memory address reported by the OS is sub-optimal for
/// debugging purposes, such as when an array is accidently indexed into with a null pointer base,
/// at which point the address might read something like `0x00001000` when the more-useful address
/// would just be zero.
///
/// If such a correction was made, this will be included in `ExceptionInfo`.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum AdjustedAddress {
    /// The original access was an Amd64 "non-canonical" address; actual address is provided here.
    NonCanonical(Address),
    /// The base pointer was null; offset from base is provided here.
    NullPointerWithOffset(AddressOffset),
}

#[derive(Debug, Clone, Default, PartialEq, Eq, serde::Serialize)]
pub struct BitFlipDetails {
    /// The bit flip caused a non-canonical address access.
    pub was_non_canonical: bool,
    /// The corrected address is null.
    pub is_null: bool,
    /// The original address was fairly low.
    ///
    /// This is only populated if `is_null` is true, and may indicate that a bit flip didn't occur
    /// (and the original value was merely a small value which is more likely to be produced by
    /// booleans, iteration, etc).
    pub was_low: bool,
    /// The number of registers near the corrected address.
    ///
    /// This will only be populated for sufficiently high addresses (to avoid high false positive
    /// rates).
    pub nearby_registers: u32,
    /// There are poison patterns in one or more registers.
    ///
    /// This may indicate that a bit flip _didn't_ occur, and instead there was a UAF.
    pub poison_registers: bool,
}

mod confidence {
    /* The hat from which these numbers are drawn.
           .~~~~`\~~\
          ;       ~~ \
          |           ;
      ,--------,______|---.
     /          \-----`    \
     `.__________`-_______-'
    */

    const HIGH: f32 = 0.90;
    const MEDIUM: f32 = 0.50;
    const LOW: f32 = 0.25;

    pub fn combine(values: &[f32]) -> f32 {
        1.0f32 - values.iter().map(|v| 1.0f32 - v).product::<f32>()
    }

    // TODO: do we want this at all, vs Option<f32> for confidence?
    // The only problem is there may not be a good way to display this (i.e. omitting a confidence
    // would potentially make those seem _stronger_).
    pub const BASELINE: f32 = LOW;

    pub const NON_CANONICAL: f32 = HIGH;
    pub const NULL: f32 = MEDIUM;
    pub const NEARBY_REGISTER: [f32; 4] = [MEDIUM, MEDIUM + 0.05, MEDIUM + 0.1, MEDIUM + 0.15];

    // Detractors
    pub const POISON: f32 = MEDIUM;
    pub const ORIGINAL_LOW: f32 = MEDIUM;
}

impl BitFlipDetails {
    /// Calculate a confidence level between 0 and 1 pertaining to the bit flip likelihood.
    pub fn confidence(&self) -> f32 {
        use confidence::*;
        let mut values = Vec::with_capacity(4);
        values.push(BASELINE);

        if self.was_non_canonical {
            values.push(NON_CANONICAL);
        }

        if self.is_null {
            let mut val = NULL;
            if self.was_low {
                val *= ORIGINAL_LOW;
            }
            values.push(val);
        }

        if self.nearby_registers > 0 {
            let nearby = std::cmp::min(self.nearby_registers as usize, NEARBY_REGISTER.len()) - 1;
            values.push(NEARBY_REGISTER[nearby]);
        }

        let mut ret = combine(&values);

        if self.poison_registers {
            ret *= POISON;
        }
        ret
    }
}

#[derive(Debug, Clone, PartialEq, serde::Serialize)]
pub struct PossibleBitFlip {
    /// The un-bit-flipped (potentially correct) address.
    pub address: Address,
    /// The register which held the bit-flipped address, if from a register at all.
    pub source_register: Option<&'static str>,
    /// Heuristics related to the determination of the bit flip.
    pub details: BitFlipDetails,
    /// A confidence level for the bit flip, derived from the details.
    pub confidence: Option<f32>,
}

/// The maximum distance between addresses to consider them "nearby" when calculating bit flip
/// heuristics with regard to register contents.
const NEARBY_REGISTER_DISTANCE: u64 = 1 << 12;

/// The cutoff for addresses considered "low".
const LOW_ADDRESS_CUTOFF: u64 = NEARBY_REGISTER_DISTANCE * 2;

impl PossibleBitFlip {
    pub fn new(address: u64, source_register: Option<&'static str>) -> Self {
        PossibleBitFlip {
            address: address.into(),
            source_register,
            details: Default::default(),
            confidence: None,
        }
    }

    pub fn calculate_heuristics(
        &mut self,
        original_address: u64,
        was_non_canonical: bool,
        context: Option<&MinidumpContext>,
    ) {
        self.details.is_null = self.address.0 == 0;
        self.details.was_low = self.details.is_null && original_address <= LOW_ADDRESS_CUTOFF;
        self.details.was_non_canonical = was_non_canonical;

        self.details.nearby_registers = 0;
        self.details.poison_registers = false;
        if let Some(context) = context {
            let register_size = context.register_size();

            let is_repeated = match register_size {
                2 => |addr: u64| addr == (addr & 0xff) * 0x0101,
                4 => |addr: u64| addr == (addr & 0xff) * 0x01010101,
                8 => |addr: u64| addr == (addr & 0xff) * 0x0101010101010101,
                other => {
                    tracing::warn!("unsupported register size: {other}");
                    |_| false
                }
            };

            // Don't calculate nearby registers for low addresses, there will be a high false
            // positive rate.
            let should_calculate_nearby_registers = self.address.0 > LOW_ADDRESS_CUTOFF;

            for (_, addr) in context.valid_registers() {
                if should_calculate_nearby_registers
                    && self.address.0.abs_diff(addr) <= NEARBY_REGISTER_DISTANCE
                {
                    self.details.nearby_registers += 1;
                }

                if !self.details.poison_registers && is_repeated(addr) {
                    // Poison patterns from
                    // https://searchfox.org/mozilla-central/rev/3002762e41363de8ee9ca80196d55e79651bcb6b/js/src/util/Poison.h#52
                    //
                    // 0xa5 from xmalloc/jemalloc
                    // 0xe5 from mozilla jemalloc
                    // (https://searchfox.org/mozilla-central/source/memory/build/mozjemalloc.cpp#1412)
                    match (addr & 0xff) as u8 {
                        0x2b | 0x2d | 0x2f | 0x49 | 0x4b | 0x4d | 0x4f | 0x6b | 0x8b | 0x9b
                        | 0x9f | 0xa5 | 0xbb | 0xcc | 0xcd | 0xce | 0xdb | 0xe5 => {
                            self.details.poison_registers = true;
                        }
                        _ => (),
                    }
                }
            }
        }

        self.confidence = Some(self.details.confidence());
    }
}

/// The state of a process as recorded by a `Minidump`.
#[derive(Debug, Clone)]
pub struct ProcessState {
    /// The PID of the process.
    pub process_id: Option<u32>,
    /// When the minidump was written.
    pub time: SystemTime,
    /// When the process started, if available
    pub process_create_time: Option<SystemTime>,
    /// Known code signing certificates (module name => cert name)
    pub cert_info: HashMap<String, String>,
    /// Info about the exception that triggered the dump (if one did)
    pub exception_info: Option<ExceptionInfo>,
    /// A string describing an assertion that was hit, if present.
    pub assertion: Option<String>,
    /// The index of the thread that requested a dump be written.
    /// If a dump was produced as a result of a crash, this
    /// will point to the thread that crashed.  If the dump was produced as
    /// by user code without crashing, and the dump contains extended Breakpad
    /// information, this will point to the thread that requested the dump.
    /// If the dump was not produced as a result of an exception and no
    /// extended Breakpad information is present, this field will be
    /// `None`.
    pub requesting_thread: Option<usize>,
    /// Stacks for each thread (except possibly the exception handler
    /// thread) at the time of the crash.
    pub threads: Vec<CallStack>,
    // TODO:
    // thread_memory_regions
    /// Information about the system on which the minidump was written.
    pub system_info: SystemInfo,
    /// Linux Standard Base Info
    pub linux_standard_base: Option<LinuxStandardBase>,
    /// Linux Proc Limits
    pub linux_proc_limits: Option<LinuxProcLimits>,
    pub mac_crash_info: Option<Vec<RawMacCrashInfo>>,
    pub mac_boot_args: Option<MinidumpMacBootargs>,
    /// The modules that were loaded into the process represented by the
    /// `ProcessState`.
    pub modules: MinidumpModuleList,
    pub unloaded_modules: MinidumpUnloadedModuleList,
    pub handles: Option<MinidumpHandleDataStream>,
    // modules_without_symbols
    // modules_with_corrupt_symbols
    // exploitability
    pub unknown_streams: Vec<MinidumpUnknownStream>,
    pub unimplemented_streams: Vec<MinidumpUnimplementedStream>,
    pub symbol_stats: HashMap<String, SymbolStats>,
}

fn json_registers(ctx: &MinidumpContext) -> serde_json::Value {
    let registers: Cow<HashSet<&str>> = match ctx.valid {
        MinidumpContextValidity::All => {
            let gpr = ctx.general_purpose_registers();
            let set: HashSet<&str> = gpr.iter().cloned().collect();
            Cow::Owned(set)
        }
        MinidumpContextValidity::Some(ref which) => Cow::Borrowed(which),
    };

    let mut output = serde_json::Map::new();
    for &reg in ctx.general_purpose_registers() {
        if registers.contains(reg) {
            let reg_val = ctx.format_register(reg);
            output.insert(String::from(reg), json!(reg_val));
        }
    }
    json!(output)
}

fn eq_some<T: PartialEq>(opt: Option<T>, val: T) -> bool {
    match opt {
        Some(v) => v == val,
        None => false,
    }
}

impl ProcessState {
    /// `true` if the minidump was written in response to a process crash.
    pub fn crashed(&self) -> bool {
        self.exception_info.is_some()
    }
    /// Write a human-readable description of the process state to `f`.
    ///
    /// This is very verbose, it implements the output format used by
    /// minidump_stackwalk.
    pub fn print<T: Write>(&self, f: &mut T) -> io::Result<()> {
        self.print_internal(f, false)
    }

    /// Write a brief human-readable description of the process state to `f`.
    ///
    /// Only includes the summary at the top and a backtrace of the crashing thread.
    pub fn print_brief<T: Write>(&self, f: &mut T) -> io::Result<()> {
        self.print_internal(f, true)
    }

    fn print_internal<T: Write>(&self, f: &mut T, brief: bool) -> io::Result<()> {
        self.set_print_context();

        writeln!(f, "Operating system: {}", self.system_info.os.long_name())?;
        if let Some(ref ver) = self.system_info.format_os_version() {
            writeln!(f, "                  {ver}")?;
        }
        writeln!(f, "CPU: {}", self.system_info.cpu)?;
        if let Some(ref info) = self.system_info.cpu_info {
            writeln!(f, "     {info}")?;
        }
        writeln!(
            f,
            "     {} CPU{}",
            self.system_info.cpu_count,
            if self.system_info.cpu_count > 1 {
                "s"
            } else {
                ""
            }
        )?;
        if let Some(ref lsb) = self.linux_standard_base {
            writeln!(
                f,
                "Linux {} {} - {} ({})",
                lsb.id, lsb.release, lsb.codename, lsb.description
            )?;
        }
        writeln!(f)?;

        if let Some(ref crash_info) = self.exception_info {
            writeln!(f, "Crash reason:  {}", crash_info.reason)?;

            if let Some(adjusted_address) = &crash_info.adjusted_address {
                writeln!(f, "Crash address: {} **", crash_info.address)?;
                match adjusted_address {
                    AdjustedAddress::NonCanonical(address) => {
                        writeln!(f, "    ** Non-canonical address detected: {address}")?
                    }
                    AdjustedAddress::NullPointerWithOffset(offset) => {
                        writeln!(f, "    ** Null pointer detected with offset: {offset}")?
                    }
                }
            } else {
                writeln!(f, "Crash address: {}", crash_info.address)?;
            }

            if let Some(ref crashing_instruction_str) = crash_info.instruction_str {
                writeln!(f, "Crashing instruction: `{crashing_instruction_str}`")?;
            }

            if let Some(ref memory_accesses) = crash_info.memory_accesses {
                if !memory_accesses.is_empty() {
                    writeln!(f, "Memory accessed by instruction:")?;
                    for (idx, access) in memory_accesses.iter().enumerate() {
                        writeln!(f, "  {idx}. Address: {}", Address(access.address))?;
                        if let Some(size) = access.size {
                            writeln!(f, "     Size: {size}")?;
                        } else {
                            writeln!(f, "     Size: Unknown")?;
                        }
                        if access.is_likely_guard_page {
                            writeln!(f, "     This address falls in a likely guard page.")?;
                        }
                    }
                } else {
                    writeln!(f, "No memory accessed by instruction")?;
                }
            }

            if !crash_info.possible_bit_flips.is_empty() {
                writeln!(f, "Crashing address may be the result of a flipped bit:")?;
                let mut bit_flips_with_confidence = crash_info
                    .possible_bit_flips
                    .iter()
                    .map(|b| (b.confidence.unwrap_or_default(), b))
                    .collect::<Vec<_>>();
                // Sort by confidence (descending), then address (ascending).
                bit_flips_with_confidence.sort_unstable_by(|(conf_a, bf_a), (conf_b, bf_b)| {
                    conf_a
                        .total_cmp(conf_b)
                        .reverse()
                        .then_with(|| bf_a.address.cmp(&bf_b.address))
                });
                for (idx, (confidence, b)) in bit_flips_with_confidence.iter().enumerate() {
                    writeln!(
                        f,
                        "  {idx}. Valid address: {register}{addr} ({confidence:.3})",
                        addr = b.address,
                        register = match b.source_register {
                            None => Default::default(),
                            Some(name) => format!("{name}="),
                        }
                    )?;
                }
            }
        } else {
            writeln!(f, "No crash")?;
        }

        if let Some(ref assertion) = self.assertion {
            writeln!(f, "Assertion: {assertion}")?;
        }
        if let Some(ref info) = self.mac_crash_info {
            writeln!(f, "Mac Crash Info:")?;
            for (idx, record) in info.iter().enumerate() {
                writeln!(f, "  Record {idx}")?;
                if let Some(val) = record.thread() {
                    writeln!(f, "    thread: 0x{val}")?;
                }
                if let Some(val) = record.dialog_mode() {
                    writeln!(f, "    dialog mode: 0x{val}")?;
                }
                if let Some(val) = record.abort_cause() {
                    writeln!(f, "    abort_cause: 0x{val}")?;
                }

                if let Some(val) = record.module_path() {
                    writeln!(f, "    module: {val}")?;
                }
                if let Some(val) = record.message() {
                    writeln!(f, "    message: {val}")?;
                }
                if let Some(val) = record.signature_string() {
                    writeln!(f, "    signature string: {val}")?;
                }
                if let Some(val) = record.backtrace() {
                    writeln!(f, "    backtrace: {val}")?;
                }
                if let Some(val) = record.message2() {
                    writeln!(f, "    message2: {val}")?;
                }
            }
            writeln!(f)?;
        }
        if let Some(ref info) = self.mac_boot_args {
            writeln!(
                f,
                "Mac Boot Args: {}",
                info.bootargs.as_deref().unwrap_or("")
            )?;
            writeln!(f)?;
        }
        if let Some(ref time) = self.process_create_time {
            let uptime = self.time.duration_since(*time).unwrap_or_default();
            writeln!(f, "Process uptime: {} seconds", uptime.as_secs())?;
        } else {
            writeln!(f, "Process uptime: not available")?;
        }
        writeln!(f)?;

        if let Some(requesting_thread) = self.requesting_thread {
            let stack = &self.threads[requesting_thread];
            writeln!(
                f,
                "Thread {} {} ({})",
                requesting_thread,
                stack.thread_name.as_deref().unwrap_or(""),
                if self.crashed() {
                    "crashed"
                } else {
                    "requested dump, did not crash"
                }
            )?;
            stack.print(f)?;
            writeln!(f)?;
        }

        // We're done if this is a brief report!
        if brief {
            return Ok(());
        }

        for (i, stack) in self.threads.iter().enumerate() {
            if eq_some(self.requesting_thread, i) {
                // Don't print the requesting thread again,
                continue;
            }
            if stack.info == CallStackInfo::DumpThreadSkipped {
                continue;
            }
            writeln!(
                f,
                "Thread {} {}",
                i,
                stack.thread_name.as_deref().unwrap_or("")
            )?;
            stack.print(f)?;
        }
        write!(
            f,
            "
Loaded modules:
"
        )?;
        let main_address = self.modules.main_module().map(|m| m.base_address());
        for module in self.modules.by_addr() {
            // TODO: missing symbols, corrupt symbols
            let full_name = module.code_file();
            let name = basename(&full_name);
            write!(
                f,
                "{:#010x} - {:#010x}  {}  {}",
                module.base_address(),
                module.base_address() + module.size() - 1,
                name,
                module.version().unwrap_or(Cow::Borrowed("???"))
            )?;
            if eq_some(main_address, module.base_address()) {
                write!(f, "  (main)")?;
            }
            if let Some(cert) = self.cert_info.get(name) {
                write!(f, " ({cert})")?;
            }
            writeln!(f)?;
        }
        write!(
            f,
            "
Unloaded modules:
"
        )?;
        for module in self.unloaded_modules.by_addr() {
            let full_name = module.code_file();
            let name = basename(&full_name);
            write!(
                f,
                "{:#010x} - {:#010x}  {}",
                module.base_address(),
                module.base_address() + module.size() - 1,
                basename(&module.code_file()),
            )?;
            if let Some(cert) = self.cert_info.get(name) {
                write!(f, " ({cert})")?;
            }
            writeln!(f)?;
        }
        if !self.unimplemented_streams.is_empty() {
            write!(
                f,
                "
Unimplemented streams encountered:
"
            )?;
            for stream in &self.unimplemented_streams {
                writeln!(
                    f,
                    "Stream 0x{:08x} {:?} ({}) @ 0x{:08x}",
                    stream.stream_type as u32,
                    stream.stream_type,
                    stream.vendor,
                    stream.location.rva,
                )?;
            }
        }
        if !self.unknown_streams.is_empty() {
            write!(
                f,
                "
Unknown streams encountered:
"
            )?;
            for stream in &self.unknown_streams {
                writeln!(
                    f,
                    "Stream 0x{:08x} ({}) @ 0x{:08x}",
                    stream.stream_type, stream.vendor, stream.location.rva,
                )?;
            }
        }
        Ok(())
    }

    /// Outputs json in a schema compatible with mozilla's Socorro crash reporting servers.
    ///
    /// See the top level documentation of this library for the stable JSON schema.
    pub fn print_json<T: Write>(&self, f: &mut T, pretty: bool) -> Result<(), serde_json::Error> {
        // See ../json-schema.md for details on this format.

        self.set_print_context();

        let sys = &self.system_info;

        fn json_hex(address: u64) -> String {
            Address(address).to_string()
        }

        let mut output = json!({
            // Currently unused, we either produce no output or successful output.
            // OK | ERROR_* | SYMBOL_SUPPLIER_INTERRUPTED
            "status": "OK",
            "system_info": {
                // Linux | Windows NT | Mac OS X
                "os": sys.os.long_name(),
                "os_ver": sys.format_os_version(),
                // x86 | amd64 | arm | ppc | sparc
                "cpu_arch": sys.cpu.to_string(),
                "cpu_info": sys.cpu_info,
                "cpu_count": sys.cpu_count,
                // optional, print as hex string
                "cpu_microcode_version": sys.cpu_microcode_version.map(|num| format!("{num:#x}")),
            },
            "crash_info": {
                "type": self.exception_info.as_ref().map(|info| info.reason).map(|reason| reason.to_string()),
                "address": self.exception_info.as_ref().map(|info| info.address),
                "adjusted_address": self.exception_info.as_ref().map(|info| {
                    info.adjusted_address.as_ref().map(|adjusted| match adjusted {
                        AdjustedAddress::NonCanonical(address) => json!({
                            "kind": "non-canonical",
                            "address": address,
                        }),
                        AdjustedAddress::NullPointerWithOffset(offset) => json!({
                            "kind": "null-pointer",
                            "offset": offset,
                        }),
                    })
                }),
                "instruction": self.exception_info.as_ref().map(|info| info.instruction_str.as_ref()),
                "memory_accesses": self.exception_info.as_ref().and_then(|info| {
                    info.memory_accesses.as_ref().map(|accesses| {
                        accesses.iter().map(|access| {
                            let mut map = json!({
                                "address": json_hex(access.address),
                                "size": access.size,
                            });
                            // Only add the `is_likely_guard_page` field when it is affirmative.
                            if access.is_likely_guard_page {
                                map["is_likely_guard_page"] = true.into();
                            }
                            map
                        }).collect::<Vec<_>>()
                    })
                }),
                "possible_bit_flips": self.exception_info.as_ref().and_then(|info| {
                    (!info.possible_bit_flips.is_empty()).then_some(&info.possible_bit_flips)
                }),
                // thread index | null
                "crashing_thread": self.requesting_thread,
                "assertion": self.assertion,
            },
            // optional
            "lsb_release": self.linux_standard_base.as_ref().map(|lsb| json!({
                "id": lsb.id,
                "release": lsb.release,
                "codename": lsb.codename,
                "description": lsb.description,
            })),
            // optional
            "proc_limits": self.linux_proc_limits.as_ref().map(|limits| json!({
                "limits": limits.limits.iter().map(|limit| json!({
                    "name": limit.0,
                    "soft": limit.1.soft,
                    "hard": limit.1.hard,
                    "unit": limit.1.unit,
                })).collect::<Vec<_>>()
            })),
            // optional
            "mac_crash_info": self.mac_crash_info.as_ref().map(|info| json!({
                "num_records": info.len(),
                // All of these fields are optional
                "records": info.iter().map(|record| json!({
                    "thread": record.thread().copied().map(json_hex),
                    "dialog_mode": record.dialog_mode().copied().map(json_hex),
                    "abort_cause": record.abort_cause().copied().map(json_hex),

                    "module": record.module_path(),
                    "message": record.message(),
                    "signature_string": record.signature_string(),
                    "backtrace": record.backtrace(),
                    "message2": record.message2(),
                })).collect::<Vec<_>>()
            })),
            // optional
            "mac_boot_args": self.mac_boot_args.as_ref().map(|info| info.bootargs.as_ref()),

            // the first module is always the main one
            "main_module": 0,
            // [UNSTABLE:evil_json]
            "modules_contains_cert_info": !self.cert_info.is_empty(),
            "modules": self.modules.iter().map(|module| {
                let full_name = module.code_file();
                let name = basename(&full_name);

                // Gather statistics on the module's symbols
                let stats = self.symbol_stats.get(name);
                let had_stats = stats.is_some();
                let default = SymbolStats::default();
                let stats = stats.unwrap_or(&default);
                // Resolve debug file and debug id from extra debug info if present
                let debug_file;
                let debug_id;
                let debug_file_cow = module.debug_file().unwrap_or(Cow::Borrowed(""));
                if let Some(debug_info) = &stats.extra_debug_info {
                    debug_file = debug_info.debug_file.as_str();
                    debug_id = debug_info.debug_identifier;
                } else {
                    debug_file = debug_file_cow.borrow();
                    debug_id = module.debug_identifier().unwrap_or_default();
                }
                // Only consider the symbols "missing" if the symbolizer
                // actually has statistics on them (implying it *tried* to
                // get the symbols but failed.)
                let missing_symbols = had_stats && !stats.loaded_symbols;
                json!({
                    "base_addr": json_hex(module.raw.base_of_image),
                    // filename | empty string
                    "debug_file": basename(debug_file),
                    // [[:xdigit:]]{33} | empty string
                    "debug_id": debug_id.breakpad().to_string(),
                    "end_addr": json_hex(module.raw.base_of_image + module.raw.size_of_image as u64),
                    "filename": &name,
                    "code_id": module.code_identifier().unwrap_or_default().as_str(),
                    "version": module.version(),
                    // [UNSTABLE:evil_json]
                    "cert_subject": self.cert_info.get(name),

                    // These are all just metrics for debugging minidump-processor's execution

                    // optional, if mdsw looked for the file and it doesn't exist
                    "missing_symbols": missing_symbols,
                    // optional, if mdsw looked for the file and it does exist
                    "loaded_symbols": stats.loaded_symbols,
                    // optional, if mdsw found a file that has parse errors
                    "corrupt_symbols": stats.corrupt_symbols,
                    // optional, url of symbol file
                    "symbol_url": stats.symbol_url,
                })
            }).collect::<Vec<_>>(),
            "pid": self.process_id,
            "thread_count": self.threads.len(),
            "threads": self.threads.iter().map(|thread| json!({
                "frame_count": thread.frames.len(),
                // optional
                "last_error_value": thread.last_error_value.map(|error| error.to_string()),
                // optional
                "thread_name": thread.thread_name,
                "frames": thread.frames.iter().enumerate().map(|(idx, frame)| json!({
                    "frame": idx,
                    // optional
                    "module": frame.module.as_ref().map(|module| basename(&module.name)),
                    // optional
                    "function": frame.function_name,
                    // optional
                    "file": frame.source_file_name,
                    // optional
                    "line": frame.source_line,
                    "offset": json_hex(frame.instruction),
                    // optional
                    "inlines": if !frame.inlines.is_empty() {
                        Some(frame.inlines.iter().map(|frame| {
                            json!({
                                "function": frame.function_name,
                                "file": frame.source_file_name,
                                "line": frame.source_line,
                            })
                        }).collect::<Vec<_>>())
                    } else {
                        None
                    },
                    // optional
                    "module_offset": frame
                        .module
                        .as_ref()
                        .map(|module| frame.instruction - module.raw.base_of_image)
                        .map(json_hex),
                    // optional
                    "unloaded_modules": if frame.unloaded_modules.is_empty() {
                        None
                    } else {
                        Some(frame.unloaded_modules.iter().map(|(module, offsets)| json!({
                            "module": module,
                            "offsets": offsets.iter().copied().map(json_hex).collect::<Vec<_>>(),
                        })).collect::<Vec<_>>())
                    },
                    // optional
                    "function_offset": frame
                        .function_base
                        .map(|func_base| frame.instruction - func_base)
                        .map(json_hex),
                    "missing_symbols": frame.function_name.is_none(),
                    // none | scan | cfi_scan | frame_pointer | cfi | context | prewalked
                    "trust": frame.trust.as_str()
                })).collect::<Vec<_>>(),
            })).collect::<Vec<_>>(),

            "unloaded_modules": self.unloaded_modules.iter().map(|module| json!({
                "base_addr": json_hex(module.raw.base_of_image),
                "code_id": module.code_identifier().unwrap_or_default().as_str(),
                "end_addr": json_hex(module.raw.base_of_image + module.raw.size_of_image as u64),
                "filename": module.name,
                "cert_subject": self.cert_info.get(&module.name),
            })).collect::<Vec<_>>(),
            "handles": self.handles.as_ref().map(|handles| handles.iter().map(|handle| json!({
                "handle": handle.raw.handle(),
                "type_name": handle.type_name,
                "object_name": handle.object_name
            })).collect::<Vec<_>>()),
        });

        if let Some(requesting_thread) = self.requesting_thread {
            // Copy the crashing thread into a top-level "crashing_thread" field and:
            // * Add a "threads_index" field to indicate which thread it was
            // * Add a "registers" field to its first frame
            //
            // Note that we currently make crashing_thread a strict superset
            // of a normal "threads" entry, while the original schema strips
            // many of the fields here. We don't to keep things more uniform.

            // We can't do any of this work if we don't have at least one frame.
            if let Some(f) = self.threads[requesting_thread].frames.first() {
                let registers = json_registers(&f.context);

                // Yuck, spidering through json...
                let mut thread = output.get_mut("threads").unwrap().as_array().unwrap()
                    [requesting_thread]
                    .clone();
                let thread_obj = thread.as_object_mut().unwrap();
                let frames = thread_obj
                    .get_mut("frames")
                    .unwrap()
                    .as_array_mut()
                    .unwrap();
                let frame = frames[0].as_object_mut().unwrap();

                frame.insert(String::from("registers"), registers);
                thread_obj.insert(String::from("threads_index"), json!(requesting_thread));

                output
                    .as_object_mut()
                    .unwrap()
                    .insert(String::from("crashing_thread"), thread);
            }
        }

        if pretty {
            serde_json::to_writer_pretty(f, &output)
        } else {
            serde_json::to_writer(f, &output)
        }
    }

    fn set_print_context(&self) {
        SERIALIZATION_CONTEXT.with(|ctx| {
            ctx.borrow_mut().pointer_width = Some(self.system_info.cpu.pointer_width());
        });
    }
}