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//! Load and unload kernel modules.
//!
//! For more details see
use std::ffi::CStr;
use std::os::unix::io::{AsFd, AsRawFd};
use crate::errno::Errno;
use crate::Result;
/// Loads a kernel module from a buffer.
///
/// It loads an ELF image into kernel space,
/// performs any necessary symbol relocations,
/// initializes module parameters to values provided by the caller,
/// and then runs the module's init function.
///
/// This function requires `CAP_SYS_MODULE` privilege.
///
/// The `module_image` argument points to a buffer containing the binary image
/// to be loaded. The buffer should contain a valid ELF image
/// built for the running kernel.
///
/// The `param_values` argument is a string containing space-delimited specifications
/// of the values for module parameters.
/// Each of the parameter specifications has the form:
///
/// `name[=value[,value...]]`
///
/// # Example
///
/// ```no_run
/// use std::fs::File;
/// use std::io::Read;
/// use std::ffi::CString;
/// use nix::kmod::init_module;
///
/// let mut f = File::open("mykernel.ko").unwrap();
/// let mut contents: Vec<u8> = Vec::new();
/// f.read_to_end(&mut contents).unwrap();
/// init_module(&mut contents, &CString::new("who=Rust when=Now,12").unwrap()).unwrap();
/// ```
///
/// See [`man init_module(2)`](https://man7.org/linux/man-pages/man2/init_module.2.html) for more information.
pub fn init_module(module_image: &[u8], param_values: &CStr) -> Result<()> {
let res = unsafe {
libc::syscall(
libc::SYS_init_module,
module_image.as_ptr(),
module_image.len(),
param_values.as_ptr(),
)
};
Errno::result(res).map(drop)
}
libc_bitflags!(
/// Flags used by the `finit_module` function.
pub struct ModuleInitFlags: libc::c_uint {
/// Ignore symbol version hashes.
MODULE_INIT_IGNORE_MODVERSIONS;
/// Ignore kernel version magic.
MODULE_INIT_IGNORE_VERMAGIC;
}
);
/// Loads a kernel module from a given file descriptor.
///
/// # Example
///
/// ```no_run
/// use std::fs::File;
/// use std::ffi::CString;
/// use nix::kmod::{finit_module, ModuleInitFlags};
///
/// let f = File::open("mymod.ko").unwrap();
/// finit_module(&f, &CString::new("").unwrap(), ModuleInitFlags::empty()).unwrap();
/// ```
///
/// See [`man init_module(2)`](https://man7.org/linux/man-pages/man2/init_module.2.html) for more information.
pub fn finit_module<Fd: AsFd>(
fd: Fd,
param_values: &CStr,
flags: ModuleInitFlags,
) -> Result<()> {
let res = unsafe {
libc::syscall(
libc::SYS_finit_module,
fd.as_fd().as_raw_fd(),
param_values.as_ptr(),
flags.bits(),
)
};
Errno::result(res).map(drop)
}
libc_bitflags!(
/// Flags used by `delete_module`.
///
/// for a detailed description how these flags work.
pub struct DeleteModuleFlags: libc::c_int {
/// `delete_module` will return immediately, with an error, if the module has a nonzero
/// reference count.
O_NONBLOCK;
/// `delete_module` will unload the module immediately, regardless of whether it has a
/// nonzero reference count.
O_TRUNC;
}
);
/// Unloads the kernel module with the given name.
///
/// # Example
///
/// ```no_run
/// use std::ffi::CString;
/// use nix::kmod::{delete_module, DeleteModuleFlags};
///
/// delete_module(&CString::new("mymod").unwrap(), DeleteModuleFlags::O_NONBLOCK).unwrap();
/// ```
///
/// See [`man delete_module(2)`](https://man7.org/linux/man-pages/man2/delete_module.2.html) for more information.
pub fn delete_module(name: &CStr, flags: DeleteModuleFlags) -> Result<()> {
let res = unsafe {
libc::syscall(libc::SYS_delete_module, name.as_ptr(), flags.bits())
};
Errno::result(res).map(drop)
}