stackpulse 0.7.1

Linux perf_event stack sampling with native unwinding, symbolization, and compact spooling
Documentation 
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

//! Shared ELF section data and metadata types.

use memmap2::Mmap;
use std::fmt;
use std::ops::Deref;
use std::ops::Range;
use std::sync::Arc;

use super::LoadSegment;

#[derive(Clone)]
pub(crate) struct ElfSectionData {
    storage: ElfSectionStorage,
    range: Range<usize>,
}

#[derive(Clone)]
enum ElfSectionStorage {
    Owned(Arc<[u8]>),
    Mmap(Arc<Mmap>),
}

impl ElfSectionData {
    #[must_use]
    pub(crate) fn owned(data: impl Into<Arc<[u8]>>) -> Self {
        let data = data.into();
        Self {
            range: 0..data.len(),
            storage: ElfSectionStorage::Owned(data),
        }
    }

    pub(crate) fn owned_range(data: Arc<[u8]>, range: Range<usize>) -> Option<Self> {
        (range.start <= range.end && range.end <= data.len()).then_some(Self {
            storage: ElfSectionStorage::Owned(data),
            range,
        })
    }

    pub(crate) fn mmap(mmap: Arc<Mmap>, range: Range<usize>) -> Option<Self> {
        (range.start <= range.end && range.end <= mmap.len()).then_some(Self {
            storage: ElfSectionStorage::Mmap(mmap),
            range,
        })
    }
}

impl Deref for ElfSectionData {
    type Target = [u8];

    fn deref(&self) -> &Self::Target {
        match &self.storage {
            ElfSectionStorage::Owned(data) => &data[self.range.clone()],
            ElfSectionStorage::Mmap(mmap) => &mmap[self.range.clone()],
        }
    }
}

impl AsRef<[u8]> for ElfSectionData {
    fn as_ref(&self) -> &[u8] {
        self
    }
}

impl fmt::Debug for ElfSectionData {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("ElfSectionData")
            .field("len", &self.len())
            .finish()
    }
}

impl PartialEq for ElfSectionData {
    fn eq(&self, other: &Self) -> bool {
        self.deref() == other.deref()
    }
}

impl Eq for ElfSectionData {}

/// ELF section addresses and data needed for DWARF unwinding.
///
/// `eh_frame` and `eh_frame_hdr` clone cheaply so multiple mappings of the same
/// library share storage.
#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) struct ElfSectionInfo {
    /// Base stated virtual address from the first PT_LOAD segment.
    pub(crate) base_svma: u64,

    /// .text section range (SVMA)
    pub(crate) text_svma: Option<Range<u64>>,

    /// .text section range in file-offset space.
    pub(crate) text_file_range: Option<Range<u64>>,

    /// .text section data.
    pub(crate) text: Option<ElfSectionData>,

    /// .eh_frame section address (SVMA)
    pub(crate) eh_frame_svma: Option<u64>,

    /// .eh_frame section data
    pub(crate) eh_frame: Option<ElfSectionData>,

    /// .eh_frame_hdr section address (SVMA)
    pub(crate) eh_frame_hdr_svma: Option<u64>,

    /// .eh_frame_hdr section data
    pub(crate) eh_frame_hdr: Option<ElfSectionData>,

    /// .got section range (SVMA)
    pub(crate) got_svma: Option<Range<u64>>,

    /// PT_LOAD segments sorted by file offset.
    pub(crate) load_segments: Box<[LoadSegment]>,
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::test_support::mmap_from_bytes;

    #[test]
    fn mmap_section_data_validates_and_slices_ranges() {
        let mmap = mmap_from_bytes(&[10, 20, 30, 40, 50]);

        let section = ElfSectionData::mmap(mmap.clone(), 1..4).expect("valid mmap range");

        assert_eq!(&*section, &[20, 30, 40]);
        assert_eq!(section, ElfSectionData::owned(vec![20_u8, 30, 40]));
        let start = 4;
        let end = 1;
        assert!(ElfSectionData::mmap(mmap.clone(), start..end).is_none());
        assert!(ElfSectionData::mmap(mmap, 0..6).is_none());
    }
}