From 9e729593e82918f65da752b4fca4a522630a672f Mon Sep 17 00:00:00 2001
From: Zhenchen Wang <m202372036@hust.edu.cn>
Date: Fri, 11 Apr 2025 14:29:14 +0000
Subject: [PATCH] Add syscall faccessat2

Signed-off-by: Zhenchen Wang <m202372036@hust.edu.cn>
---
 docs/src/kernel/linux-compatibility.md |  1 +
 kernel/src/syscall/access.rs           | 23 +++++++++++++++++++++--
 kernel/src/syscall/arch/riscv.rs       |  1 +
 kernel/src/syscall/arch/x86.rs         |  3 ++-
 4 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/docs/src/kernel/linux-compatibility.md b/docs/src/kernel/linux-compatibility.md
index 5a1befe1..6be7115b 100644
--- a/docs/src/kernel/linux-compatibility.md
+++ b/docs/src/kernel/linux-compatibility.md
@@ -342,6 +342,7 @@ provided by Linux on x86-64 architecture.
 | 328	  | pwritev2         | ✅              |
 | 332     | statx            | ✅              |
 | 435	  | clone3           | ✅              |
+| 439     | faccessat2       | ✅              |
 
 ## File Systems
 
diff --git a/kernel/src/syscall/access.rs b/kernel/src/syscall/access.rs
index fbddaecd..ac5631a1 100644
--- a/kernel/src/syscall/access.rs
+++ b/kernel/src/syscall/access.rs
@@ -30,8 +30,23 @@ pub fn sys_access(path_ptr: Vaddr, mode: u16, ctx: &Context) -> Result<SyscallRe
     do_faccessat(AT_FDCWD, path_ptr, mode, 0, ctx)
 }
 
+pub fn sys_faccessat2(
+    dirfd: FileDesc,
+    path_ptr: Vaddr,
+    mode: u16,
+    flags: u32,
+    ctx: &Context,
+) -> Result<SyscallReturn> {
+    debug!(
+        "faccessat2: dirfd = {}, path_ptr = {:#x}, mode = {:o}, flags = {}",
+        dirfd, path_ptr, mode, flags
+    );
+
+    do_faccessat(dirfd, path_ptr, mode, flags, ctx)
+}
+
 bitflags! {
-    struct FaccessatFlags: i32 {
+    struct FaccessatFlags: u32 {
         const AT_EACCESS = 0x200;
         const AT_SYMLINK_NOFOLLOW = 0x100;
         const AT_EMPTY_PATH = 0x1000;
@@ -52,7 +67,7 @@ pub fn do_faccessat(
     dirfd: FileDesc,
     path_ptr: Vaddr,
     mode: u16,
-    flags: i32,
+    flags: u32,
     ctx: &Context,
 ) -> Result<SyscallReturn> {
     let mode = AccessMode::from_bits(mode)
@@ -66,6 +81,10 @@ pub fn do_faccessat(
         dirfd, path, mode, flags
     );
 
+    if path.is_empty() && !flags.contains(FaccessatFlags::AT_EMPTY_PATH) {
+        return_errno_with_message!(Errno::ENOENT, "path is empty");
+    }
+
     let dentry = {
         let path = path.to_string_lossy();
         let fs_path = FsPath::new(dirfd, path.as_ref())?;
diff --git a/kernel/src/syscall/arch/riscv.rs b/kernel/src/syscall/arch/riscv.rs
index e9a25e52..87688222 100644
--- a/kernel/src/syscall/arch/riscv.rs
+++ b/kernel/src/syscall/arch/riscv.rs
@@ -296,4 +296,5 @@ impl_syscall_nums_and_dispatch_fn! {
     SYS_UTIMENSAT = 412          => sys_utimensat(args[..4]);
     SYS_SEMTIMEDOP = 420         => sys_semtimedop(args[..4]);
     SYS_CLONE3 = 435             => sys_clone3(args[..2], &user_ctx);
+    SYS_FACCESSAT2 = 439         => sys_faccessat2(arg[..4]);
 }
diff --git a/kernel/src/syscall/arch/x86.rs b/kernel/src/syscall/arch/x86.rs
index b9556780..16fba25a 100644
--- a/kernel/src/syscall/arch/x86.rs
+++ b/kernel/src/syscall/arch/x86.rs
@@ -2,7 +2,7 @@
 
 use crate::syscall::{
     accept::{sys_accept, sys_accept4},
-    access::{sys_access, sys_faccessat},
+    access::{sys_access, sys_faccessat, sys_faccessat2},
     alarm::sys_alarm,
     arch_prctl::sys_arch_prctl,
     bind::sys_bind,
@@ -362,4 +362,5 @@ impl_syscall_nums_and_dispatch_fn! {
     SYS_PWRITEV2 = 328         => sys_pwritev2(args[..5]);
     SYS_STATX = 332            => sys_statx(args[..5]);
     SYS_CLONE3 = 435           => sys_clone3(args[..2], &user_ctx);
+    SYS_FACCESSAT2 = 439       => sys_faccessat2(args[..4]);
 }