coreutils/chroot/chroot.rs
2014-07-01 02:17:35 +02:00

214 lines
6.7 KiB
Rust

#![crate_id = "chroot#1.0.0"]
/*
* This file is part of the uutils coreutils package.
*
* (c) Vsevolod Velichko <torkvemada@sorokdva.net>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
#![feature(macro_rules)]
extern crate getopts;
extern crate libc;
use getopts::{optflag, optopt, getopts, usage};
use c_types::{get_pw_from_args, get_group};
use libc::funcs::posix88::unistd::{execvp, setuid, setgid};
#[path = "../common/util.rs"] mod util;
#[path = "../common/c_types.rs"] mod c_types;
extern {
fn chroot(path: *const libc::c_char) -> libc::c_int;
}
#[cfg(target_os = "macos")]
extern {
fn setgroups(size: libc::c_int, list: *const libc::gid_t) -> libc::c_int;
}
#[cfg(target_os = "linux")]
extern {
fn setgroups(size: libc::size_t, list: *const libc::gid_t) -> libc::c_int;
}
static NAME: &'static str = "chroot";
static VERSION: &'static str = "1.0.0";
pub fn uumain(args: Vec<String>) -> int {
let program = args.get(0);
let options = [
optopt("u", "user", "User (ID or name) to switch before running the program", "USER"),
optopt("g", "group", "Group (ID or name) to switch to", "GROUP"),
optopt("G", "groups", "Comma-separated list of groups to switch to", "GROUP1,GROUP2…"),
optopt("", "userspec", "Colon-separated user and group to switch to. \
Same as -u USER -g GROUP. \
Userspec has higher preference than -u and/or -g", "USER:GROUP"),
optflag("h", "help", "Show help"),
optflag("V", "version", "Show program's version")
];
let opts = match getopts(args.tail(), options) {
Ok(m) => m,
Err(f) => {
show_error!("{}", f);
help_menu(program.as_slice(), options);
return 1
}
};
if opts.opt_present("V") { version(); return 0 }
if opts.opt_present("h") { help_menu(program.as_slice(), options); return 0 }
if opts.free.len() == 0 {
println!("Missing operand: NEWROOT");
println!("Try `{:s} --help` for more information.", program.as_slice());
return 1
}
let defaultShell: &'static str = "/bin/sh";
let defaultOption: &'static str = "-i";
let userShell = std::os::getenv("SHELL");
let newroot = Path::new(opts.free.get(0).as_slice());
if !newroot.is_dir() {
crash!(1, "cannot change root directory to `{}`: no such directory", newroot.display());
}
let command: Vec<&str> = match opts.free.len() {
1 => {
let shell: &str = match userShell {
None => defaultShell,
Some(ref s) => s.as_slice()
};
vec!(shell, defaultOption)
}
_ => opts.free.slice(1, opts.free.len()).iter().map(|x| x.as_slice()).collect()
};
set_context(&newroot, &opts);
unsafe {
let executable = command.get(0).as_slice().to_c_str().unwrap();
let mut commandParts: Vec<*const i8> = command.iter().map(|x| x.to_c_str().unwrap()).collect();
commandParts.push(std::ptr::null());
execvp(executable as *const libc::c_char, commandParts.as_ptr() as *mut *const libc::c_char) as int
}
}
fn set_context(root: &Path, options: &getopts::Matches) {
let userspecStr = options.opt_str("userspec");
let userStr = options.opt_str("user").unwrap_or_default();
let groupStr = options.opt_str("group").unwrap_or_default();
let groupsStr = options.opt_str("groups").unwrap_or_default();
let userspec = match userspecStr {
Some(ref u) => {
let s: Vec<&str> = u.as_slice().split(':').collect();
if s.len() != 2 {
crash!(1, "invalid userspec: `{:s}`", u.as_slice())
};
s
}
None => Vec::new()
};
let user = if userspec.is_empty() { userStr.as_slice() } else { userspec.get(0).as_slice() };
let group = if userspec.is_empty() { groupStr.as_slice() } else { userspec.get(1).as_slice() };
enter_chroot(root);
set_groups_from_str(groupsStr.as_slice());
set_main_group(group);
set_user(user);
}
fn enter_chroot(root: &Path) {
let rootStr = root.display();
if !std::os::change_dir(root) {
crash!(1, "cannot chdir to {}", rootStr)
};
let err = unsafe {
chroot(".".to_c_str().unwrap() as *const libc::c_char)
};
if err != 0 {
crash!(1, "cannot chroot to {}: {:s}", rootStr, strerror(err).as_slice())
};
}
fn set_main_group(group: &str) {
if !group.is_empty() {
let group_id = match get_group(group) {
None => crash!(1, "no such group: {}", group),
Some(g) => g.gr_gid
};
let err = unsafe { setgid(group_id) };
if err != 0 {
crash!(1, "cannot set gid to {:u}: {:s}", group_id, strerror(err).as_slice())
}
}
}
#[cfg(target_os = "macos")]
fn set_groups(groups: Vec<libc::gid_t>) -> libc::c_int {
unsafe {
setgroups(groups.len() as libc::c_int,
groups.as_slice().as_ptr())
}
}
#[cfg(target_os = "linux")]
fn set_groups(groups: Vec<libc::gid_t>) -> libc::c_int {
unsafe {
setgroups(groups.len() as libc::size_t,
groups.as_slice().as_ptr())
}
}
fn set_groups_from_str(groups: &str) {
if !groups.is_empty() {
let groupsVec: Vec<libc::gid_t> = FromIterator::from_iter(
groups.split(',').map(
|x| match get_group(x) {
None => crash!(1, "no such group: {}", x),
Some(g) => g.gr_gid
})
);
let err = set_groups(groupsVec);
if err != 0 {
crash!(1, "cannot set groups: {:s}", strerror(err).as_slice())
}
}
}
fn set_user(user: &str) {
if !user.is_empty() {
let user_id = get_pw_from_args(&vec!(String::from_str(user))).unwrap().pw_uid;
let err = unsafe { setuid(user_id as libc::uid_t) };
if err != 0 {
crash!(1, "cannot set user to {:s}: {:s}", user, strerror(err).as_slice())
}
}
}
fn strerror(errno: i32) -> String {
unsafe {
let err = libc::funcs::c95::string::strerror(errno);
std::str::raw::from_c_str(err as *const i8)
}
}
fn version() {
println!("{} v{}", NAME, VERSION)
}
fn help_menu(program: &str, options: &[getopts::OptGroup]) {
version();
println!("Usage:");
println!(" {:s} [OPTION]… NEWROOT [COMMAND [ARG]…]", program);
println!("");
print!("{:s}", usage(
"Run COMMAND with root directory set to NEWROOT.\n\
If COMMAND is not specified, it defaults to '${SHELL} -i'. \
If ${SHELL} is not set, /bin/sh is used.", options))
}