199 lines
6.0 KiB
Rust
199 lines
6.0 KiB
Rust
/*
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* meli
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*
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* Copyright 2017-2018 Manos Pitsidianakis
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*
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* This file is part of meli.
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*
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* meli is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* meli is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with meli. If not, see <http://www.gnu.org/licenses/>.
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*/
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use std::fs;
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use std::fs::OpenOptions;
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use std::io::{Read, Write};
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use std::os::unix::fs::PermissionsExt;
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use std::path::PathBuf;
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use uuid::Uuid;
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enum FileType {
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Real,
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#[cfg(target_os = "linux")]
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Memory {
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fd: std::os::unix::io::RawFd,
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},
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}
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impl core::fmt::Debug for FileType {
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fn fmt(&self, fmt: &mut core::fmt::Formatter) -> core::fmt::Result {
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match self {
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FileType::Real => fmt.debug_struct("FileType::Real").finish(),
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#[cfg(target_os = "linux")]
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FileType::Memory { fd } => fmt
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.debug_struct(&format!("FileType::Memory({})", fd))
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.finish(),
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}
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}
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}
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#[derive(Debug)]
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pub struct MeliFile {
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backing: FileType,
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pub path: PathBuf,
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delete_on_drop: bool,
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}
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impl Drop for MeliFile {
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fn drop(&mut self) {
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if self.delete_on_drop {
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std::fs::remove_file(self.path()).unwrap_or_else(|_| {});
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}
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}
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}
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impl MeliFile {
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pub fn get_file(&self) -> std::fs::File {
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OpenOptions::new()
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.read(true)
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.write(true)
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.create(true)
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.open(&self.path)
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.unwrap()
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}
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pub fn path(&self) -> &PathBuf {
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&self.path
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}
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pub fn read_to_string(&self) -> String {
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let mut buf = Vec::new();
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let mut f = fs::File::open(&self.path)
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.unwrap_or_else(|_| panic!("Can't open {}", &self.path.display()));
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f.read_to_end(&mut buf)
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.unwrap_or_else(|_| panic!("Can't read {}", &self.path.display()));
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String::from_utf8(buf).unwrap()
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}
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/// Returned [`MeliFile`] will be deleted when dropped if delete_on_drop is set, so make sure to
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/// add it on [`Context'] `temp_files` to reap it later.
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pub fn create_temp_file(
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bytes: &[u8],
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filename: Option<&str>,
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path: Option<&PathBuf>,
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read_only: bool,
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delete_on_drop: bool,
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) -> MeliFile {
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#[cfg(target_os = "linux")]
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if delete_on_drop && read_only && filename.is_none() && path.is_none() {
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debug!("creating memfd");
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match MeliFile::create_mem_file(bytes) {
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Ok(f) => return f,
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Err(err) => {
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debug!("creating memfd failed {:?}", &err);
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melib::log(
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format!(
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"Could not memfd_create file of len {}: {}",
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bytes.len(),
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err
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),
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melib::LoggingLevel::DEBUG,
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);
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}
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}
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}
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let mut dir = std::env::temp_dir();
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let path = path.unwrap_or_else(|| {
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dir.push("meli");
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std::fs::DirBuilder::new()
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.recursive(true)
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.create(&dir)
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.unwrap();
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if let Some(filename) = filename {
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dir.push(filename)
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} else {
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let u = Uuid::new_v4();
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dir.push(u.to_hyphenated().to_string());
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}
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&dir
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});
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let mut f = std::fs::File::create(path).unwrap();
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let metadata = f.metadata().unwrap();
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let mut permissions = metadata.permissions();
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permissions.set_mode(0o600); // Read/write for owner only.
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f.set_permissions(permissions).unwrap();
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f.write_all(bytes).unwrap();
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f.flush().unwrap();
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MeliFile {
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backing: FileType::Real,
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path: path.clone(),
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delete_on_drop,
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}
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}
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#[cfg(target_os = "linux")]
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pub fn create_mem_file(bytes: &[u8]) -> melib::Result<MeliFile> {
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use std::convert::TryInto;
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use nix::fcntl::SealFlag;
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use nix::sys::memfd::{memfd_create, MemFdCreateFlag};
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use std::ffi::CStr;
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let name: &CStr = unsafe { CStr::from_bytes_with_nul_unchecked(&b"meli\0"[..]) };
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let len = bytes
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.len()
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.try_into()
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.map_err(|err| Box::new(err) as Box<dyn std::error::Error + Sync + Send + 'static>)?;
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let fd = debug!(memfd_create(
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name,
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MemFdCreateFlag::MFD_ALLOW_SEALING //| MemFdCreateFlag::MFD_CLOEXEC,
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))?;
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debug!(nix::unistd::ftruncate(fd, len))?;
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let addr = unsafe {
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debug!(nix::sys::mman::mmap(
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std::ptr::null_mut(),
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bytes.len(),
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nix::sys::mman::ProtFlags::PROT_WRITE,
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nix::sys::mman::MapFlags::MAP_SHARED,
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fd,
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0,
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))?
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};
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unsafe { std::ptr::copy_nonoverlapping(bytes.as_ptr(), addr as *mut u8, bytes.len()) };
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debug!(unsafe { nix::sys::mman::munmap(addr, bytes.len()) })?;
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debug!(nix::fcntl::fcntl(
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fd,
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nix::fcntl::FcntlArg::F_ADD_SEALS(
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SealFlag::F_SEAL_SHRINK
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| SealFlag::F_SEAL_GROW
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| SealFlag::F_SEAL_WRITE
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| SealFlag::F_SEAL_SEAL,
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),
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))?;
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Ok(MeliFile {
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backing: FileType::Memory { fd },
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path: PathBuf::from(format!(
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"/proc/{pid}/fd/{fd}",
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pid = std::process::id(),
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fd = fd
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)),
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delete_on_drop: true,
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})
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}
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}
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