nc

Access system calls directly without std or libc.

• Documentation
• Release notes

Features:

• No glibc or musl required
• Access syscalls directly, via assembly
• No global errno variable, every function returns an errno instead
• Support latest kernel APIs, like io-uring and pidfd, introduced in linux 5.0+

Usage

Add this to Cargo.toml:

[dependencies]
nc = "0.9"

Examples

Get file stat:

let mut statbuf = nc::stat_t::default();
match unsafe { nc::stat("/etc/passwd", &mut statbuf) } {
    Ok(_) => println!("s: {:?}", statbuf),
    Err(errno) => eprintln!("Failed to get file status, got errno: {}", errno),
}

Get human-readable error string:

let errno = nc::EPERM;
println!("err: {:?}", nc::strerror(errno);

Fork process:

let pid = unsafe { nc::fork() };
match pid {
    Err(errno) => eprintln!("Failed to call fork(), err: {}", nc::strerror(errno)),
    Ok(0) => {
        // Child process
        println!("[child] pid: {}", unsafe { nc::getpid() });
        let args = ["ls", "-l", "-a"];
        let env = ["DISPLAY=wayland"];
        let ret = unsafe { nc::execve("/bin/ls", &args, &env) };
        assert!(ret.is_ok());
    }
    Ok(child_pid) => {
        // Parent process
        println!("[main] child pid is: {child_pid}");
    }
}

Kill self:

let pid = unsafe { nc::getpid() };
let ret = unsafe { nc::kill(pid, nc::SIGTERM) };
// Never reach here.
println!("ret: {:?}", ret);

Or handle signals:

fn handle_alarm(signum: i32) {
    assert_eq!(signum, nc::SIGALRM);
}

fn main() {
    let sa = nc::sigaction_t {
        sa_handler: handle_alarm as nc::sighandler_t,
        #[cfg(not(nc_has_sa_restorer))]
        sa_flags: nc::SA_RESTART,
        #[cfg(nc_has_sa_restorer)]
        sa_flags: nc::SA_RESTART | nc::SA_RESTORER,
        #[cfg(nc_has_sa_restorer)]
        sa_restorer: nc::restore::get_sa_restorer(),
        ..nc::sigaction_t::default()
    };
    let ret = unsafe { nc::rt_sigaction(nc::SIGALRM, Some(&sa), None) };
    assert!(ret.is_ok());
    let remaining = unsafe { nc::alarm(1) };
    let mask = nc::sigset_t::default();
    let ret = unsafe { nc::rt_sigsuspend(&mask) };
    assert!(ret.is_err());
    assert_eq!(ret, Err(nc::EINTR));
    assert_eq!(remaining, Ok(0));
}

Supported Operating Systems and Architectures

• linux
  • aarch64
  • arm
  • loongarch64
  • mips
  • mips64
  • mips64el
  • mipsel
  • powerpc64
  • powerpc64el
  • riscv64
  • s390x
  • x86
  • x86-64
• android
  • aarch64
• freebsd
  • x86-64
• netbsd
  • x86-64
• mac os
  • x86-64

Related projects

• nix
• relibc
• Linux Syscall Support
• syscall pkg in golang

License

This library is govered by Apache-2.0 License.