57 lines
1.8 KiB
Rust
57 lines
1.8 KiB
Rust
// SPDX-License-Identifier: MPL-2.0
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use super::TidDirOps;
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use crate::{
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fs::{
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procfs::template::{FileOps, ProcFileBuilder},
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utils::{Inode, mkmod},
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},
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prelude::*,
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process::Process,
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};
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/// Represents the inode at `/proc/[pid]/task/[tid]/comm` (and also `/proc/[pid]/comm`).
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pub struct CommFileOps(Arc<Process>);
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impl CommFileOps {
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pub fn new_inode(dir: &TidDirOps, parent: Weak<dyn Inode>) -> Arc<dyn Inode> {
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let process_ref = dir.process_ref.clone();
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// Reference: <https://elixir.bootlin.com/linux/v6.16.5/source/fs/proc/base.c#L3336>
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ProcFileBuilder::new(Self(process_ref), mkmod!(a+r, u+w))
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.parent(parent)
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.build()
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.unwrap()
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}
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}
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impl FileOps for CommFileOps {
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fn read_at(&self, offset: usize, writer: &mut VmWriter) -> Result<usize> {
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let vmar_guard = self.0.lock_vmar();
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let Some(vmar) = vmar_guard.as_ref() else {
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// According to Linux behavior, return an empty string
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// if the process is a zombie process.
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return Ok(0);
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};
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let executable_file_name = vmar.process_vm().executable_file().name();
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let mut comm = executable_file_name.as_bytes().to_vec();
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comm.truncate(TASK_COMM_LEN - 1);
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comm.push(b'\n');
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let mut vm_reader = VmReader::from(&comm[offset.min(comm.len())..]);
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let bytes_read = writer.write_fallible(&mut vm_reader)?;
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Ok(bytes_read)
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}
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fn write_at(&self, _offset: usize, _reader: &mut VmReader) -> Result<usize> {
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warn!("writing to `/proc/[pid]/comm` is not supported");
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return_errno_with_message!(
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Errno::EOPNOTSUPP,
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"writing to `/proc/[pid]/comm` is not supported"
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);
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}
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}
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const TASK_COMM_LEN: usize = 16;
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