feat(vfs): 实现 SYS_PWRITEV 系统调用

kernel/src/filesystem/vfs/syscall/mod.rs

@@ -33,6 +33,7 @@ mod sys_openat;
 mod sys_pread64;
 mod sys_pselect6;
 mod sys_pwrite64;
+mod sys_pwritev;
 mod sys_read;
 mod sys_readlinkat;
 mod sys_readv;

kernel/src/filesystem/vfs/syscall/sys_pwritev.rs

@@ -0,0 +1,93 @@
+use alloc::string::ToString;
+use alloc::vec::Vec;
+
+use system_error::SystemError;
+
+use crate::arch::syscall::nr::SYS_PWRITEV;
+use crate::filesystem::vfs::iov::{IoVec, IoVecs};
+use crate::process::ProcessManager;
+use crate::syscall::table::{FormattedSyscallParam, Syscall};
+
+pub struct SysPwriteVHandle;
+
+impl Syscall for SysPwriteVHandle {
+    fn num_args(&self) -> usize {
+        4
+    }
+
+    /// ## Handle SYS_PWRITEV Call
+    /// ### Arguments
+    /// - `args` - System call arguments containing:
+    ///   - `fd`: File descriptor to write to
+    ///   - `iov`: Pointer to array of I/O vectors
+    ///   - `iov_count`: Number of elements in the I/O vector array
+    ///   - `offset`: at which the output operation is to be performed.
+    /// - `frame`: Trap frame representing the current CPU register state and execution context of the calling process.
+    ///   Used for accessing or modifying process state during syscall handling.
+    /// ### Return
+    /// - `Ok(usize)`: Number of bytes written
+    /// - `Err(SystemError)`: Error that occurred during the operation  
+    fn handle(
+        &self,
+        args: &[usize],
+        _frame: &mut crate::arch::interrupt::TrapFrame,
+    ) -> Result<usize, SystemError> {
+        // 从 args buffer 中获取想要的参数
+        let fd = Self::fd(args);
+        let iov = Self::iov(args);
+        let iov_count = Self::iov_count(args);
+        let offset = Self::offset(args);
+
+        // 将用户态传入的指向用户态应用的数据结构重新在内核栈上构造
+        let iovecs = unsafe { IoVecs::from_user(iov, iov_count, false) }?;
+        let data = iovecs.gather();
+
+        do_pwritev(fd, &data, offset)
+    }
+
+    fn entry_format(&self, args: &[usize]) -> Vec<FormattedSyscallParam> {
+        vec![
+            FormattedSyscallParam::new("fd:", Self::fd(args).to_string()),
+            FormattedSyscallParam::new("iov:", format!("{:#x}", Self::iov(args) as usize)),
+            FormattedSyscallParam::new("iov_count:", Self::iov_count(args).to_string()),
+            FormattedSyscallParam::new("offset:", Self::offset(args).to_string()),
+        ]
+    }
+}
+
+impl SysPwriteVHandle {
+    /// Extracts the file descriptor from system call arguments
+    fn fd(args: &[usize]) -> i32 {
+        args[0] as i32
+    }
+
+    /// Extracts the I/O vector pointer from system call arguments
+    fn iov(args: &[usize]) -> *const IoVec {
+        args[1] as *const IoVec
+    }
+
+    /// Extracts the I/O vector count from system call arguments
+    fn iov_count(args: &[usize]) -> usize {
+        args[2]
+    }
+
+    /// Extracts the offset at which the output operation is to be performed
+    fn offset(args: &[usize]) -> usize {
+        args[3]
+    }
+}
+
+pub fn do_pwritev(fd: i32, buf: &[u8], offset: usize) -> Result<usize, SystemError> {
+    let binding = ProcessManager::current_pcb().fd_table();
+    let fd_table_guard = binding.read();
+
+    let file = fd_table_guard
+        .get_file_by_fd(fd)
+        .ok_or(SystemError::EBADF)?;
+
+    // 释放 fd_table_guard 的读锁
+    drop(fd_table_guard);
+    file.pwrite(offset, buf.len(), buf)
+}
+
+syscall_table_macros::declare_syscall!(SYS_PWRITEV, SysPwriteVHandle);

user/apps/tests/syscall/gvisor/blocklists/write_test

@@ -1,4 +1,13 @@
-# 缺少pwritev而失败
+# 由于缺少SYS_RT_SIGTIMEDWAIT而失败
+WriteTest.WriteExceedsRLimit
+
+# 内核会报如下错误
+# src/arch/x86_64/mm/fault.rs:321 vma_access_error
 WriteTest.PartialWriteSIGSEGV
-# 缺少pwritev而失败
+# 内核会报如下错误
+# Location:
+#         File: src/mm/fault.rs
+#         Line: 675, Column: 24
+# Message:
+#         no cache_page in PageFaultMessage
 WriteTest.PartialWriteSIGBUS