starnix_core/syscalls/
misc.rs

1// Copyright 2021 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use crate::arch::{ARCH_NAME, ARCH_NAME32};
6use crate::mm::{MemoryAccessor, MemoryAccessorExt, PAGE_SIZE};
7use crate::security;
8use crate::task::CurrentTask;
9use crate::vfs::FsString;
10use fidl_fuchsia_buildinfo as buildinfo;
11use fuchsia_component::client::connect_to_protocol_sync;
12use starnix_logging::{log_error, track_stub};
13use starnix_sync::{Locked, Unlocked};
14use starnix_syscalls::decls::SyscallDecl;
15use starnix_syscalls::{SUCCESS, SyscallResult};
16use starnix_types::user_buffer::MAX_RW_COUNT;
17use starnix_uapi::auth::{CAP_SYS_ADMIN, CAP_SYS_MODULE};
18use starnix_uapi::errors::Errno;
19use starnix_uapi::personality::PersonalityFlags;
20use starnix_uapi::user_address::{MultiArchUserRef, UserAddress, UserCString, UserRef};
21use starnix_uapi::version::KERNEL_RELEASE;
22use starnix_uapi::{
23    EFAULT, GRND_NONBLOCK, GRND_RANDOM, c_char, errno, error, from_status_like_fdio, uapi, utsname,
24};
25
26uapi::check_arch_independent_layout! {
27    utsname {
28        sysname,
29        nodename,
30        release,
31        version,
32        machine,
33        domainname,
34    }
35}
36
37pub fn do_uname(
38    _locked: &mut Locked<Unlocked>,
39    current_task: &CurrentTask,
40    result: &mut utsname,
41) -> Result<(), Errno> {
42    fn init_array(fixed: &mut [c_char; 65], init: &[u8]) {
43        let len = init.len();
44        #[allow(
45            clippy::undocumented_unsafe_blocks,
46            reason = "Force documented unsafe blocks in Starnix"
47        )]
48        fixed[..len].copy_from_slice(zerocopy::transmute_ref!(init))
49    }
50
51    init_array(&mut result.sysname, b"Linux");
52    if current_task.thread_group().read().personality.contains(PersonalityFlags::UNAME26) {
53        init_array(&mut result.release, b"2.6.40-starnix");
54    } else {
55        init_array(&mut result.release, KERNEL_RELEASE.as_bytes());
56    }
57
58    let version = current_task.kernel().build_version.get_or_try_init(|| {
59        let proxy =
60            connect_to_protocol_sync::<buildinfo::ProviderMarker>().map_err(|_| errno!(ENOENT))?;
61        let buildinfo = proxy.get_build_info(zx::MonotonicInstant::INFINITE).map_err(|e| {
62            log_error!("FIDL error getting build info: {e}");
63            errno!(EIO)
64        })?;
65        Ok(buildinfo.version.unwrap_or_else(|| "starnix".to_string()))
66    })?;
67
68    init_array(&mut result.version, version.as_bytes());
69
70    let personality = current_task.thread_group().read().personality;
71    let machine = if personality.execution_domain() == (uapi::PER_LINUX32 as u32) {
72        ARCH_NAME32
73    } else {
74        ARCH_NAME
75    };
76    init_array(&mut result.machine, machine);
77
78    {
79        // Get the UTS namespace from the perspective of this task.
80        let task_state = current_task.read();
81        let uts_ns = task_state.uts_ns.read();
82        init_array(&mut result.nodename, uts_ns.hostname.as_slice());
83        init_array(&mut result.domainname, uts_ns.domainname.as_slice());
84    }
85    Ok(())
86}
87
88pub fn sys_uname(
89    locked: &mut Locked<Unlocked>,
90    current_task: &CurrentTask,
91    name: UserRef<utsname>,
92) -> Result<(), Errno> {
93    let mut result = utsname {
94        sysname: [0; 65],
95        nodename: [0; 65],
96        release: [0; 65],
97        version: [0; 65],
98        machine: [0; 65],
99        domainname: [0; 65],
100    };
101    do_uname(locked, current_task, &mut result)?;
102    current_task.write_object(name, &result)?;
103    Ok(())
104}
105
106pub fn sys_sysinfo(
107    _locked: &mut Locked<Unlocked>,
108    current_task: &CurrentTask,
109    info: MultiArchUserRef<uapi::sysinfo, uapi::arch32::sysinfo>,
110) -> Result<(), Errno> {
111    let page_size = zx::system_get_page_size();
112    let total_ram_pages = zx::system_get_physmem() / (page_size as u64);
113    let num_procs = current_task.kernel().pids.read().len();
114
115    track_stub!(TODO("https://fxbug.dev/297374270"), "compute system load");
116    let loads = [0; 3];
117
118    track_stub!(TODO("https://fxbug.dev/322874530"), "compute actual free ram usage");
119    let freeram = total_ram_pages / 8;
120
121    let result = uapi::sysinfo {
122        uptime: (zx::MonotonicInstant::get() - zx::MonotonicInstant::ZERO).into_seconds(),
123        loads,
124        totalram: total_ram_pages,
125        freeram,
126        procs: num_procs.try_into().map_err(|_| errno!(EINVAL))?,
127        mem_unit: page_size,
128        ..Default::default()
129    };
130
131    current_task.write_multi_arch_object(info, result)?;
132    Ok(())
133}
134
135// Used to read a hostname or domainname from task memory
136fn read_name(current_task: &CurrentTask, name: UserCString, len: u64) -> Result<FsString, Errno> {
137    const MAX_LEN: usize = 64;
138    let len = len as usize;
139
140    if len > MAX_LEN {
141        return error!(EINVAL);
142    }
143
144    // Read maximum characters and mark the null terminator.
145    let mut name = current_task.read_c_string_to_vec(name, MAX_LEN)?;
146
147    // Syscall may have specified an even smaller length, so trim to the requested length.
148    if len < name.len() {
149        name.truncate(len);
150    }
151    Ok(name)
152}
153
154pub fn sys_sethostname(
155    _locked: &mut Locked<Unlocked>,
156    current_task: &CurrentTask,
157    hostname: UserCString,
158    len: u64,
159) -> Result<SyscallResult, Errno> {
160    security::check_task_capable(current_task, CAP_SYS_ADMIN)?;
161
162    let hostname = read_name(current_task, hostname, len)?;
163
164    let task_state = current_task.read();
165    let mut uts_ns = task_state.uts_ns.write();
166    uts_ns.hostname = hostname;
167
168    Ok(SUCCESS)
169}
170
171pub fn sys_setdomainname(
172    _locked: &mut Locked<Unlocked>,
173    current_task: &CurrentTask,
174    domainname: UserCString,
175    len: u64,
176) -> Result<SyscallResult, Errno> {
177    security::check_task_capable(current_task, CAP_SYS_ADMIN)?;
178
179    let domainname = read_name(current_task, domainname, len)?;
180
181    let task_state = current_task.read();
182    let mut uts_ns = task_state.uts_ns.write();
183    uts_ns.domainname = domainname;
184
185    Ok(SUCCESS)
186}
187
188pub fn sys_getrandom(
189    _locked: &mut Locked<Unlocked>,
190    current_task: &CurrentTask,
191    start_addr: UserAddress,
192    size: usize,
193    flags: u32,
194) -> Result<usize, Errno> {
195    if flags & !(GRND_RANDOM | GRND_NONBLOCK) != 0 {
196        return error!(EINVAL);
197    }
198
199    // Copy random bytes in up-to-page-size chunks, stopping either when all the user-requested
200    // space has been written to or when we fault.
201    let mut bytes_written = 0;
202    let mut bounce_buffer = vec![0u8; std::cmp::min(*PAGE_SIZE as usize, size)];
203
204    let bytes_to_write = std::cmp::min(size, *MAX_RW_COUNT);
205
206    while bytes_written < bytes_to_write {
207        let chunk_start = start_addr.saturating_add(bytes_written);
208        let chunk_len = std::cmp::min(*PAGE_SIZE as usize, size - bytes_written);
209
210        let chunk = &mut bounce_buffer[..chunk_len];
211        starnix_crypto::cprng_draw(chunk);
212        match current_task.write_memory_partial(chunk_start, chunk) {
213            Ok(n) => {
214                bytes_written += n;
215
216                // If we didn't write the whole chunk then we faulted. Don't try to write any more.
217                if n < chunk_len {
218                    break;
219                }
220            }
221
222            // write_memory_partial fails if no bytes were written, but we might have
223            // written bytes already.
224            Err(e) if e.code.error_code() == EFAULT && bytes_written > 0 => break,
225            Err(e) => return Err(e),
226        }
227    }
228
229    Ok(bytes_written)
230}
231
232pub fn sys_sched_yield(
233    _locked: &mut Locked<Unlocked>,
234    _current_task: &CurrentTask,
235) -> Result<(), Errno> {
236    // SAFETY: This is unsafe because it is a syscall. zx_thread_legacy_yield is always safe.
237    let status = unsafe { zx::sys::zx_thread_legacy_yield(0) };
238    zx::Status::ok(status).map_err(|status| from_status_like_fdio!(status))
239}
240
241pub fn sys_unknown(
242    _locked: &mut Locked<Unlocked>,
243    #[allow(unused_variables)] current_task: &CurrentTask,
244    syscall_number: u64,
245) -> Result<SyscallResult, Errno> {
246    let decl = SyscallDecl::from_number(syscall_number, current_task.thread_state.arch_width());
247    track_stub!(TODO("https://fxbug.dev/322874143"), decl.name(), syscall_number);
248
249    // TODO(https://fxbug.dev/454657040) We should send SIGSYS once we have signals.
250    error!(ENOSYS)
251}
252
253pub fn sys_personality(
254    _locked: &mut Locked<Unlocked>,
255    current_task: &CurrentTask,
256    persona: u32,
257) -> Result<SyscallResult, Errno> {
258    let mut state = current_task.task.thread_group().write();
259    let previous_value = state.personality.update_from_syscall(persona);
260    Ok(previous_value.into())
261}
262
263pub fn sys_delete_module(
264    _locked: &mut Locked<Unlocked>,
265    current_task: &CurrentTask,
266    user_name: UserCString,
267    _flags: u32,
268) -> Result<SyscallResult, Errno> {
269    security::check_task_capable(current_task, CAP_SYS_MODULE)?;
270    // According to LTP test delete_module02.c
271    const MODULE_NAME_LEN: usize = 64 - std::mem::size_of::<u64>();
272    let _name = current_task.read_c_string_to_vec(user_name, MODULE_NAME_LEN)?;
273    // We don't ever have any modules loaded.
274    error!(ENOENT)
275}
276
277// Syscalls for arch32 usage
278#[cfg(target_arch = "aarch64")]
279mod arch32 {
280    pub use super::{sys_sysinfo as sys_arch32_sysinfo, sys_uname as sys_arch32_uname};
281}
282
283#[cfg(target_arch = "aarch64")]
284pub use arch32::*;
starnix_core/syscalls/misc.rs

starnix_core/syscalls/
misc.rs
