proka_exec/
sections.rs

1//! The definitions of section entry.
2use crate::{HEADER_SIZE, SECTION_SIZE};
3
4/// A section entry.
5#[repr(C, packed)]
6#[derive(Debug, Clone, Copy)]
7pub struct Section {
8    /// The section name (16 bytes max).
9    pub name: [u8; 16],
10
11    /// Assign is this section loadable
12    pub is_loadable: bool,
13
14    /// Assign is this section executable
15    pub is_execable: bool,
16
17    /// The offset of the section start.
18    pub base: u32,
19
20    /// The length of the section.
21    pub length: u32,
22
23    /// Reserved bits
24    pub _reserved: [u8; 6]
25}
26
27impl Section {
28    /// Convert this object to array.
29    #[inline]
30    pub const fn to_array(&self) -> [u8; SECTION_SIZE] {
31        // SAFETY: used `#[repr(C)]`
32        unsafe { core::ptr::read(self as *const Self as *const [u8; SECTION_SIZE]) }
33    }
34
35    /// Validate is this section not corrupted.
36    #[inline]
37    pub fn validate(&self) -> bool {
38        // If the section is loadable, its base must 4KiB
39        // aligned.
40        let align_ok = if self.is_loadable {
41            (self.base & 0xfff) == 0
42        } else {
43            true
44        };
45
46        // Cannot executable if unloadable
47        let perm_ok = !(self.is_execable && !self.is_loadable);
48
49        align_ok && perm_ok
50    }
51}
52
53/// The iterator of each sections
54#[derive(Debug, Clone, Copy)]
55pub(crate) struct SectionIter {
56    pub buf: &'static [u8],
57    pub total: u16,
58    pub current: u16,
59}
60
61// Iterator implementations
62impl Iterator for SectionIter {
63    type Item = Section;
64
65    fn next(&mut self) -> Option<Self::Item> {
66        let base = HEADER_SIZE + self.current as usize * SECTION_SIZE;
67        let buf = &self.buf[base..base + SECTION_SIZE];
68
69        // Check: is current over than total
70        if self.current >= self.total {
71            return None;
72        }
73
74        // Now convert it
75        let section = unsafe { *(buf.as_ptr() as *const Section) };
76        Some(section)
77    }
78}
proka_exec/sections.rs

proka_exec/
sections.rs
