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

starnix_modules_syscalls/
misc.rs
