From 10714a4659ec8b5f2123bfbeeacacc65f2b8fb91 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Thu, 13 Jun 2024 17:17:34 +0200
Subject: [PATCH] Make explicit flags optional for SYS_{READ,WRITE}2.

---
 src/syscall/debug.rs |  4 ++--
 src/syscall/mod.rs   | 16 ++++++++++++----
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/syscall/debug.rs b/src/syscall/debug.rs
index 5cfdefab01..1079d40d8d 100644
--- a/src/syscall/debug.rs
+++ b/src/syscall/debug.rs
@@ -71,9 +71,9 @@ pub fn format_call(a: usize, b: usize, c: usize, d: usize, e: usize, f: usize) -
         ),
         SYS_SENDFD => format!("sendfd({}, {}, {:#0x} {:#0x} {:#0x})", b, c, d, e, f,),
         SYS_READ => format!("read({}, {:#X}, {})", b, c, d),
-        SYS_READ2 => format!("read2({}, {:#X}, {}, {}, {:?})", b, c, d, e, RwFlags::from_bits_retain(f as u32)),
+        SYS_READ2 => format!("read2({}, {:#X}, {}, {}, {:?})", b, c, d, e, (f != usize::MAX).then_some(RwFlags::from_bits_retain(f as u32))),
         SYS_WRITE => format!("write({}, {:#X}, {})", b, c, d),
-        SYS_WRITE2 => format!("write2({}, {:#X}, {}, {}, {:?})", b, c, d, e, RwFlags::from_bits_retain(f as u32)),
+        SYS_WRITE2 => format!("write2({}, {:#X}, {}, {}, {:?})", b, c, d, e, (f != usize::MAX).then_some(RwFlags::from_bits_retain(f as u32))),
         SYS_LSEEK => format!(
             "lseek({}, {}, {} ({}))",
             b,
diff --git a/src/syscall/mod.rs b/src/syscall/mod.rs
index 32ee529414..4455e47747 100644
--- a/src/syscall/mod.rs
+++ b/src/syscall/mod.rs
@@ -84,8 +84,12 @@ pub fn syscall(
                 match a & SYS_ARG {
                     SYS_ARG_SLICE => match a {
                         SYS_WRITE2 => file_op_generic_ext(fd, |scheme, _, desc| {
-                            let flags = u32::try_from(f).ok().and_then(RwFlags::from_bits).ok_or(Error::new(EINVAL))?;
-                            scheme.kwriteoff(desc.number, UserSlice::ro(c, d)?, e as u64, desc.rw_flags(flags), desc.flags)
+                            let flags = if f == usize::MAX {
+                                None
+                            } else {
+                                Some(u32::try_from(f).ok().and_then(RwFlags::from_bits).ok_or(Error::new(EINVAL))?)
+                            };
+                            scheme.kwriteoff(desc.number, UserSlice::ro(c, d)?, e as u64, flags.map_or(desc.flags, |f| desc.rw_flags(f)), desc.flags)
                         }),
                         SYS_WRITE => sys_write(fd, UserSlice::ro(c, d)?),
                         SYS_FMAP => {
@@ -108,8 +112,12 @@ pub fn syscall(
                     },
                     SYS_ARG_MSLICE => match a {
                         SYS_READ2 => file_op_generic_ext(fd, |scheme, _, desc| {
-                            let flags = u32::try_from(f).ok().and_then(RwFlags::from_bits).ok_or(Error::new(EINVAL))?;
-                            scheme.kreadoff(desc.number, UserSlice::wo(c, d)?, e as u64, desc.rw_flags(flags), desc.flags)
+                            let flags = if f == usize::MAX {
+                                None
+                            } else {
+                                Some(u32::try_from(f).ok().and_then(RwFlags::from_bits).ok_or(Error::new(EINVAL))?)
+                            };
+                            scheme.kreadoff(desc.number, UserSlice::wo(c, d)?, e as u64, flags.map_or(desc.flags, |f| desc.rw_flags(f)), desc.flags)
                         }),
                         SYS_READ => sys_read(fd, UserSlice::wo(c, d)?),
                         SYS_FPATH => file_op_generic(fd, |scheme, number| {