Add setgroups

src/backend/libc/process/syscalls.rs

@@ -711,3 +711,12 @@ pub(crate) fn getgroups(buf: &mut [Gid]) -> io::Result<usize> {
 
     unsafe { ret_usize(c::getgroups(len, buf.as_mut_ptr().cast()) as isize) }
 }
+
+#[cfg(linux_kernel)]
+#[inline]
+pub(crate) fn setgroups(groups: &[crate::ugid::Gid]) -> io::Result<()> {
+    syscall! {
+        fn setgroups(size: c::size_t, list: *const c::gid_t) via SYS_setgroups -> c::c_int
+    }
+    ret(unsafe { setgroups(groups.len(), groups.as_ptr().cast()) })
+}

src/backend/linux_raw/process/syscalls.rs

@@ -11,7 +11,7 @@ use crate::backend::c;
 use crate::backend::conv::slice_mut;
 use crate::backend::conv::{
     by_mut, by_ref, c_int, c_uint, negative_pid, pass_usize, raw_fd, ret, ret_c_int,
-    ret_c_int_infallible, ret_c_uint, ret_infallible, ret_owned_fd, ret_usize, size_of,
+    ret_c_int_infallible, ret_c_uint, ret_infallible, ret_owned_fd, ret_usize, size_of, slice,
     slice_just_addr, zero,
 };
 use crate::fd::{AsRawFd, BorrowedFd, OwnedFd, RawFd};
@@ -601,3 +601,9 @@ pub(crate) fn getgroups(buf: &mut [Gid]) -> io::Result<usize> {
         ))
     }
 }
+
+#[inline]
+pub(crate) fn setgroups(gids: &[crate::ugid::Gid]) -> io::Result<()> {
+    let (addr, len) = slice(gids);
+    unsafe { ret(syscall_readonly!(__NR_setgroups, len, addr)) }
+}

src/process/id.rs

@@ -230,3 +230,15 @@ pub fn getgroups() -> io::Result<Vec<Gid>> {
         buffer.resize(buffer.capacity(), Gid::ROOT);
     }
 }
+
+/// `setgroups(groups)`-Sets the supplementary group IDs for the calling process.
+///
+/// # References
+/// - [Linux]
+///
+/// [Linux]: https://man7.org/linux/man-pages/man2/setgroups.2.html
+#[cfg(linux_kernel)]
+#[inline]
+pub fn set_groups(groups: &[Gid]) -> io::Result<()> {
+    backend::process::syscalls::setgroups(groups)
+}