From 56846e2ddde98b6db7cbda456e905291a5cdb74b Mon Sep 17 00:00:00 2001
From: Tulio A M Mendes <tadryanom@hotmail.com>
Date: Wed, 11 Feb 2026 23:40:17 -0300
Subject: [PATCH] feat: fsync/fdatasync syscall stubs (no-op, POSIX compliance)

---
 include/syscall.h            | 10 ++++++++++
 src/kernel/syscall.c         | 10 ++++++++++
 user/ulibc/include/syscall.h |  2 ++
 user/ulibc/include/unistd.h  |  2 ++
 user/ulibc/src/unistd.c      |  8 ++++++++
 5 files changed, 32 insertions(+)

diff --git a/include/syscall.h b/include/syscall.h
index 170396d..3e3a36e 100644
--- a/include/syscall.h
+++ b/include/syscall.h
@@ -91,6 +91,16 @@ enum {
 
     SYSCALL_CLONE     = 67,
     SYSCALL_GETTID    = 68,
+
+    SYSCALL_FSYNC     = 69,
+    SYSCALL_FDATASYNC = 70,
+    SYSCALL_SIGPENDING = 71,
+    SYSCALL_PREAD     = 72,
+    SYSCALL_PWRITE    = 73,
+    SYSCALL_ACCESS    = 74,
+    SYSCALL_UMASK     = 75,
+    SYSCALL_SETUID    = 76,
+    SYSCALL_SETGID    = 77,
 };
 
 #endif
diff --git a/src/kernel/syscall.c b/src/kernel/syscall.c
index 4e42df9..8f0b4ea 100644
--- a/src/kernel/syscall.c
+++ b/src/kernel/syscall.c
@@ -2200,6 +2200,16 @@ void syscall_handler(struct registers* regs) {
         return;
     }
 
+    if (syscall_no == SYSCALL_FSYNC || syscall_no == SYSCALL_FDATASYNC) {
+        int fd = (int)regs->ebx;
+        if (!current_process || fd < 0 || fd >= PROCESS_MAX_FILES || !current_process->files[fd]) {
+            regs->eax = (uint32_t)-EBADF;
+        } else {
+            regs->eax = 0;
+        }
+        return;
+    }
+
     /* ---- Socket syscalls ---- */
     socket_syscall_dispatch(regs, syscall_no);
     /* If socket dispatch handled it, eax is set and we return.
diff --git a/user/ulibc/include/syscall.h b/user/ulibc/include/syscall.h
index 3671aed..ec1e847 100644
--- a/user/ulibc/include/syscall.h
+++ b/user/ulibc/include/syscall.h
@@ -51,6 +51,8 @@ enum {
     SYS_SET_THREAD_AREA = 57,
     SYS_CLONE = 67,
     SYS_GETTID = 68,
+    SYS_FSYNC = 69,
+    SYS_FDATASYNC = 70,
 };
 
 /* Raw syscall wrappers — up to 5 args via INT 0x80 */
diff --git a/user/ulibc/include/unistd.h b/user/ulibc/include/unistd.h
index fe873cf..70a818f 100644
--- a/user/ulibc/include/unistd.h
+++ b/user/ulibc/include/unistd.h
@@ -33,6 +33,8 @@ int     setsid(void);
 int     setpgid(int pid, int pgid);
 int     getpgrp(void);
 int     gettid(void);
+int     fsync(int fd);
+int     fdatasync(int fd);
 void*   brk(void* addr);
 
 void    _exit(int status) __attribute__((noreturn));
diff --git a/user/ulibc/src/unistd.c b/user/ulibc/src/unistd.c
index 2ae0979..06ce1b6 100644
--- a/user/ulibc/src/unistd.c
+++ b/user/ulibc/src/unistd.c
@@ -86,6 +86,14 @@ int gettid(void) {
     return _syscall0(SYS_GETTID);
 }
 
+int fsync(int fd) {
+    return __syscall_ret(_syscall1(SYS_FSYNC, fd));
+}
+
+int fdatasync(int fd) {
+    return __syscall_ret(_syscall1(SYS_FDATASYNC, fd));
+}
+
 void* brk(void* addr) {
     return (void*)_syscall1(SYS_BRK, (int)addr);
 }
-- 
2.43.0