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Use safe nix API instead of libc (#12315)

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# Description
Where possible, this PR replaces usages of raw `libc` bindings to
instead use safe interfaces from the `nix` crate. Where not possible,
the `libc` version reexported through `nix` was used instead of having a
separate `libc` dependency.
This commit is contained in:
Ian Manske
2024-03-30 13:49:54 +00:00
committed by GitHub
parent 714a0ccd24
commit 251599c507
8 changed files with 103 additions and 128 deletions
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83
crates/nu-command/src/filesystem/util.rs
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@ -92,57 +92,40 @@ pub fn is_older(src: &Path, dst: &Path) -> Option<bool> {
#[cfg(unix)]
pub mod users {
use libc::{gid_t, uid_t};
use nix::unistd::{Gid, Group, Uid, User};
pub fn get_user_by_uid(uid: uid_t) -> Option<User> {
User::from_uid(Uid::from_raw(uid)).ok().flatten()
pub fn get_user_by_uid(uid: Uid) -> Option<User> {
User::from_uid(uid).ok().flatten()
}
pub fn get_group_by_gid(gid: gid_t) -> Option<Group> {
Group::from_gid(Gid::from_raw(gid)).ok().flatten()
pub fn get_group_by_gid(gid: Gid) -> Option<Group> {
Group::from_gid(gid).ok().flatten()
}
pub fn get_current_uid() -> uid_t {
Uid::current().as_raw()
pub fn get_current_uid() -> Uid {
Uid::current()
}
pub fn get_current_gid() -> gid_t {
Gid::current().as_raw()
pub fn get_current_gid() -> Gid {
Gid::current()
}
#[cfg(not(any(target_os = "linux", target_os = "freebsd", target_os = "android")))]
pub fn get_current_username() -> Option<String> {
User::from_uid(Uid::current())
.ok()
.flatten()
.map(|user| user.name)
get_user_by_uid(get_current_uid()).map(|user| user.name)
}
#[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "android"))]
pub fn current_user_groups() -> Option<Vec<Gid>> {
// SAFETY:
// if first arg is 0 then it ignores second argument and returns number of groups present for given user.
let ngroups = unsafe { libc::getgroups(0, core::ptr::null::<gid_t> as *mut _) };
let mut buff: Vec<gid_t> = vec![0; ngroups as usize];
// SAFETY:
// buff is the size of ngroups and getgroups reads max ngroups elements into buff
let found = unsafe { libc::getgroups(ngroups, buff.as_mut_ptr()) };
if found < 0 {
None
if let Ok(mut groups) = nix::unistd::getgroups() {
groups.sort_unstable_by_key(|id| id.as_raw());
groups.dedup();
Some(groups)
} else {
buff.truncate(found as usize);
buff.sort_unstable();
buff.dedup();
buff.into_iter()
.filter_map(|i| get_group_by_gid(i as gid_t))
.map(|group| group.gid)
.collect::<Vec<_>>()
.into()
None
}
}
/// Returns groups for a provided user name and primary group id.
///
/// # libc functions used
@ -159,19 +142,19 @@ pub mod users {
/// }
/// ```
#[cfg(not(any(target_os = "linux", target_os = "freebsd", target_os = "android")))]
pub fn get_user_groups(username: &str, gid: gid_t) -> Option<Vec<Gid>> {
pub fn get_user_groups(username: &str, gid: Gid) -> Option<Vec<Gid>> {
use nix::libc::{c_int, gid_t};
use std::ffi::CString;
// MacOS uses i32 instead of gid_t in getgrouplist for unknown reasons
#[cfg(target_os = "macos")]
let mut buff: Vec<i32> = vec![0; 1024];
#[cfg(not(target_os = "macos"))]
let mut buff: Vec<gid_t> = vec![0; 1024];
let Ok(name) = CString::new(username.as_bytes()) else {
return None;
};
let name = CString::new(username).ok()?;
let mut count = buff.len() as libc::c_int;
let mut count = buff.len() as c_int;
// MacOS uses i32 instead of gid_t in getgrouplist for unknown reasons
// SAFETY:
@ -182,11 +165,19 @@ pub mod users {
// The capacity for `*groups` is passed in as `*ngroups` which is the buffer max length/capacity (as we initialize with 0)
// Following reads from `*groups`/`buff` will only happen after `buff.truncate(*ngroups)`
#[cfg(target_os = "macos")]
let res =
unsafe { libc::getgrouplist(name.as_ptr(), gid as i32, buff.as_mut_ptr(), &mut count) };
let res = unsafe {
nix::libc::getgrouplist(
name.as_ptr(),
gid.as_raw() as i32,
buff.as_mut_ptr(),
&mut count,
)
};
#[cfg(not(target_os = "macos"))]
let res = unsafe { libc::getgrouplist(name.as_ptr(), gid, buff.as_mut_ptr(), &mut count) };
let res = unsafe {
nix::libc::getgrouplist(name.as_ptr(), gid.as_raw(), buff.as_mut_ptr(), &mut count)
};
if res < 0 {
None
@ -196,11 +187,13 @@ pub mod users {
buff.dedup();
// allow trivial cast: on macos i is i32, on linux it's already gid_t
#[allow(trivial_numeric_casts)]
buff.into_iter()
.filter_map(|i| get_group_by_gid(i as gid_t))
.map(|group| group.gid)
.collect::<Vec<_>>()
.into()
Some(
buff.into_iter()
.map(|id| Gid::from_raw(id as gid_t))
.filter_map(get_group_by_gid)
.map(|group| group.gid)
.collect(),
)
}
}
}