stats.rs

 1// SPDX-License-Identifier: GPL-2.0
 2
 3// Copyright (C) 2025 Google LLC.
 4
 5//! Keep track of statistics for binder_logs.
 6
 7use crate::defs::*;
 8use core::sync::atomic::{AtomicU32, Ordering::Relaxed};
 9use kernel::{ioctl::_IOC_NR, seq_file::SeqFile, seq_print};
10
11const BC_COUNT: usize = _IOC_NR(BC_REPLY_SG) as usize + 1;
12const BR_COUNT: usize = _IOC_NR(BR_TRANSACTION_PENDING_FROZEN) as usize + 1;
13
14pub(crate) static GLOBAL_STATS: BinderStats = BinderStats::new();
15
16pub(crate) struct BinderStats {
17    bc: [AtomicU32; BC_COUNT],
18    br: [AtomicU32; BR_COUNT],
19}
20
21impl BinderStats {
22    pub(crate) const fn new() -> Self {
23        #[expect(clippy::declare_interior_mutable_const)]
24        const ZERO: AtomicU32 = AtomicU32::new(0);
25
26        Self {
27            bc: [ZERO; BC_COUNT],
28            br: [ZERO; BR_COUNT],
29        }
30    }
31
32    pub(crate) fn inc_bc(&self, bc: u32) {
33        let idx = _IOC_NR(bc) as usize;
34        if let Some(bc_ref) = self.bc.get(idx) {
35            bc_ref.fetch_add(1, Relaxed);
36        }
37    }
38
39    pub(crate) fn inc_br(&self, br: u32) {
40        let idx = _IOC_NR(br) as usize;
41        if let Some(br_ref) = self.br.get(idx) {
42            br_ref.fetch_add(1, Relaxed);
43        }
44    }
45
46    pub(crate) fn debug_print(&self, prefix: &str, m: &SeqFile) {
47        for (i, cnt) in self.bc.iter().enumerate() {
48            let cnt = cnt.load(Relaxed);
49            if cnt > 0 {
50                seq_print!(m, "{}{}: {}\n", prefix, command_string(i), cnt);
51            }
52        }
53        for (i, cnt) in self.br.iter().enumerate() {
54            let cnt = cnt.load(Relaxed);
55            if cnt > 0 {
56                seq_print!(m, "{}{}: {}\n", prefix, return_string(i), cnt);
57            }
58        }
59    }
60}
61
62mod strings {
63    use core::str::from_utf8_unchecked;
64    use kernel::str::{CStr, CStrExt as _};
65
66    extern "C" {
67        static binder_command_strings: [*const u8; super::BC_COUNT];
68        static binder_return_strings: [*const u8; super::BR_COUNT];
69    }
70
71    pub(super) fn command_string(i: usize) -> &'static str {
72        // SAFETY: Accessing `binder_command_strings` is always safe.
73        let c_str_ptr = unsafe { binder_command_strings[i] };
74        // SAFETY: The `binder_command_strings` array only contains nul-terminated strings.
75        let bytes = unsafe { CStr::from_char_ptr(c_str_ptr) }.to_bytes();
76        // SAFETY: The `binder_command_strings` array only contains strings with ascii-chars.
77        unsafe { from_utf8_unchecked(bytes) }
78    }
79
80    pub(super) fn return_string(i: usize) -> &'static str {
81        // SAFETY: Accessing `binder_return_strings` is always safe.
82        let c_str_ptr = unsafe { binder_return_strings[i] };
83        // SAFETY: The `binder_command_strings` array only contains nul-terminated strings.
84        let bytes = unsafe { CStr::from_char_ptr(c_str_ptr) }.to_bytes();
85        // SAFETY: The `binder_command_strings` array only contains strings with ascii-chars.
86        unsafe { from_utf8_unchecked(bytes) }
87    }
88}
89use strings::{command_string, return_string};