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b322121dd9
* feat(syscall): 添加syscall table的实现 - 实现syscall table - 为syscall table适配write/writev、read和readv系统调用 --------- Signed-off-by: longjin <longjin@DragonOS.org>
106 lines
3.3 KiB
Rust
106 lines
3.3 KiB
Rust
use system_error::SystemError;
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use crate::arch::syscall::nr::SYS_READ;
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use crate::process::ProcessManager;
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use crate::syscall::table::FormattedSyscallParam;
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use crate::syscall::table::Syscall;
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use crate::syscall::user_access::UserBufferWriter;
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use alloc::string::ToString;
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use alloc::vec::Vec;
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/// System call handler for the `read` syscall
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///
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/// This handler implements the `Syscall` trait to provide functionality for reading data from a file descriptor.
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pub struct SysReadHandle;
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impl Syscall for SysReadHandle {
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/// Returns the number of arguments expected by the `read` syscall
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fn num_args(&self) -> usize {
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3
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}
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/// Handles the `read` system call
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///
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/// Reads data from the specified file descriptor into a user buffer.
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///
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/// # Arguments
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/// * `args` - Array containing:
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/// - args[0]: File descriptor (i32)
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/// - args[1]: Pointer to user buffer (*mut u8)
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/// - args[2]: Length of data to read (usize)
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/// * `from_user` - Indicates if the call originates from user space
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///
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/// # Returns
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/// * `Ok(usize)` - Number of bytes successfully read
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/// * `Err(SystemError)` - Error code if operation fails
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fn handle(&self, args: &[usize], from_user: bool) -> Result<usize, SystemError> {
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let fd = Self::fd(args);
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let buf_vaddr = Self::buf(args);
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let len = Self::len(args);
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let mut user_buffer_writer = UserBufferWriter::new(buf_vaddr, len, from_user)?;
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let user_buf = user_buffer_writer.buffer(0)?;
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do_read(fd, user_buf)
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}
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/// Formats the syscall parameters for display/debug purposes
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///
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/// # Arguments
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/// * `args` - The raw syscall arguments
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///
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/// # Returns
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/// Vector of formatted parameters with descriptive names
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fn entry_format(&self, args: &[usize]) -> Vec<FormattedSyscallParam> {
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vec![
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FormattedSyscallParam::new("fd", Self::fd(args).to_string()),
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FormattedSyscallParam::new("buf", format!("{:#x}", Self::buf(args) as usize)),
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FormattedSyscallParam::new("len", Self::len(args).to_string()),
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]
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}
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}
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impl SysReadHandle {
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/// Extracts the file descriptor from syscall arguments
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fn fd(args: &[usize]) -> i32 {
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args[0] as i32
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}
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/// Extracts the buffer pointer from syscall arguments
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fn buf(args: &[usize]) -> *mut u8 {
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args[1] as *mut u8
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}
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/// Extracts the buffer length from syscall arguments
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fn len(args: &[usize]) -> usize {
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args[2]
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}
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}
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syscall_table_macros::declare_syscall!(SYS_READ, SysReadHandle);
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/// Internal implementation of the read operation
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///
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/// # Arguments
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/// * `fd` - File descriptor to read from
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/// * `buf` - Buffer to store read data
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///
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/// # Returns
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/// * `Ok(usize)` - Number of bytes successfully read
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/// * `Err(SystemError)` - Error code if operation fails
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pub(super) fn do_read(fd: i32, buf: &mut [u8]) -> Result<usize, SystemError> {
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let binding = ProcessManager::current_pcb().fd_table();
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let fd_table_guard = binding.read();
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let file = fd_table_guard.get_file_by_fd(fd);
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if file.is_none() {
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return Err(SystemError::EBADF);
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}
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// drop guard 以避免无法调度的问题
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drop(fd_table_guard);
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let file = file.unwrap();
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return file.read(buf.len(), buf);
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}
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