diff --git a/cleonos/c/include/cleonos_syscall.h b/cleonos/c/include/cleonos_syscall.h
index fceaf9f..4eb7e74 100644
--- a/cleonos/c/include/cleonos_syscall.h
+++ b/cleonos/c/include/cleonos_syscall.h
@@ -18,6 +18,13 @@ typedef unsigned long long usize;
 #define CLEONOS_SIGCONT 18ULL
 #define CLEONOS_SIGSTOP 19ULL
 
+#define CLEONOS_O_RDONLY 0x0000ULL
+#define CLEONOS_O_WRONLY 0x0001ULL
+#define CLEONOS_O_RDWR   0x0002ULL
+#define CLEONOS_O_CREAT  0x0040ULL
+#define CLEONOS_O_TRUNC  0x0200ULL
+#define CLEONOS_O_APPEND 0x0400ULL
+
 typedef struct cleonos_proc_snapshot {
     u64 pid;
     u64 ppid;
@@ -107,6 +114,11 @@ typedef struct cleonos_proc_snapshot {
 #define CLEONOS_SYSCALL_STATS_ID_COUNT      69ULL
 #define CLEONOS_SYSCALL_STATS_RECENT_WINDOW 70ULL
 #define CLEONOS_SYSCALL_STATS_RECENT_ID     71ULL
+#define CLEONOS_SYSCALL_FD_OPEN             72ULL
+#define CLEONOS_SYSCALL_FD_READ             73ULL
+#define CLEONOS_SYSCALL_FD_WRITE            74ULL
+#define CLEONOS_SYSCALL_FD_CLOSE            75ULL
+#define CLEONOS_SYSCALL_FD_DUP              76ULL
 
 u64 cleonos_syscall(u64 id, u64 arg0, u64 arg1, u64 arg2);
 u64 cleonos_sys_log_write(const char *message, u64 length);
@@ -180,5 +192,10 @@ u64 cleonos_sys_stats_total(void);
 u64 cleonos_sys_stats_id_count(u64 id);
 u64 cleonos_sys_stats_recent_window(void);
 u64 cleonos_sys_stats_recent_id(u64 id);
+u64 cleonos_sys_fd_open(const char *path, u64 flags, u64 mode);
+u64 cleonos_sys_fd_read(u64 fd, void *out_buffer, u64 size);
+u64 cleonos_sys_fd_write(u64 fd, const void *buffer, u64 size);
+u64 cleonos_sys_fd_close(u64 fd);
+u64 cleonos_sys_fd_dup(u64 fd);
 
 #endif
diff --git a/cleonos/c/src/syscall.c b/cleonos/c/src/syscall.c
index f4bd7a1..96059fa 100644
--- a/cleonos/c/src/syscall.c
+++ b/cleonos/c/src/syscall.c
@@ -310,3 +310,23 @@ u64 cleonos_sys_stats_recent_window(void) {
 u64 cleonos_sys_stats_recent_id(u64 id) {
     return cleonos_syscall(CLEONOS_SYSCALL_STATS_RECENT_ID, id, 0ULL, 0ULL);
 }
+
+u64 cleonos_sys_fd_open(const char *path, u64 flags, u64 mode) {
+    return cleonos_syscall(CLEONOS_SYSCALL_FD_OPEN, (u64)path, flags, mode);
+}
+
+u64 cleonos_sys_fd_read(u64 fd, void *out_buffer, u64 size) {
+    return cleonos_syscall(CLEONOS_SYSCALL_FD_READ, fd, (u64)out_buffer, size);
+}
+
+u64 cleonos_sys_fd_write(u64 fd, const void *buffer, u64 size) {
+    return cleonos_syscall(CLEONOS_SYSCALL_FD_WRITE, fd, (u64)buffer, size);
+}
+
+u64 cleonos_sys_fd_close(u64 fd) {
+    return cleonos_syscall(CLEONOS_SYSCALL_FD_CLOSE, fd, 0ULL, 0ULL);
+}
+
+u64 cleonos_sys_fd_dup(u64 fd) {
+    return cleonos_syscall(CLEONOS_SYSCALL_FD_DUP, fd, 0ULL, 0ULL);
+}
diff --git a/clks/include/clks/exec.h b/clks/include/clks/exec.h
index 76f1c75..2a98644 100644
--- a/clks/include/clks/exec.h
+++ b/clks/include/clks/exec.h
@@ -40,6 +40,11 @@ clks_bool clks_exec_spawn_path(const char *path, u64 *out_pid);
 clks_bool clks_exec_spawn_pathv(const char *path, const char *argv_line, const char *env_line, u64 *out_pid);
 u64 clks_exec_wait_pid(u64 pid, u64 *out_status);
 clks_bool clks_exec_request_exit(u64 status);
+u64 clks_exec_fd_open(const char *path, u64 flags, u64 mode);
+u64 clks_exec_fd_read(u64 fd, void *out_buffer, u64 size);
+u64 clks_exec_fd_write(u64 fd, const void *buffer, u64 size);
+u64 clks_exec_fd_close(u64 fd);
+u64 clks_exec_fd_dup(u64 fd);
 u64 clks_exec_current_pid(void);
 u32 clks_exec_current_tty(void);
 u64 clks_exec_current_argc(void);
diff --git a/clks/include/clks/syscall.h b/clks/include/clks/syscall.h
index 1808165..219491a 100644
--- a/clks/include/clks/syscall.h
+++ b/clks/include/clks/syscall.h
@@ -75,6 +75,11 @@
 #define CLKS_SYSCALL_STATS_ID_COUNT      69ULL
 #define CLKS_SYSCALL_STATS_RECENT_WINDOW 70ULL
 #define CLKS_SYSCALL_STATS_RECENT_ID     71ULL
+#define CLKS_SYSCALL_FD_OPEN             72ULL
+#define CLKS_SYSCALL_FD_READ             73ULL
+#define CLKS_SYSCALL_FD_WRITE            74ULL
+#define CLKS_SYSCALL_FD_CLOSE            75ULL
+#define CLKS_SYSCALL_FD_DUP              76ULL
 
 void clks_syscall_init(void);
 u64 clks_syscall_dispatch(void *frame_ptr);
diff --git a/clks/kernel/exec.c b/clks/kernel/exec.c
index 33afe23..a3b7f0d 100644
--- a/clks/kernel/exec.c
+++ b/clks/kernel/exec.c
@@ -4,6 +4,7 @@
 #include <clks/fs.h>
 #include <clks/heap.h>
 #include <clks/interrupts.h>
+#include <clks/keyboard.h>
 #include <clks/log.h>
 #include <clks/serial.h>
 #include <clks/string.h>
@@ -18,6 +19,7 @@ typedef u64 (*clks_exec_entry_fn)(void);
 #define CLKS_EXEC_PATH_MAX        192U
 #define CLKS_EXEC_ARG_LINE_MAX    256U
 #define CLKS_EXEC_ENV_LINE_MAX    512U
+#define CLKS_EXEC_FD_MAX           32U
 #define CLKS_EXEC_MAX_ARGS         24U
 #define CLKS_EXEC_MAX_ENVS         24U
 #define CLKS_EXEC_ITEM_MAX        128U
@@ -25,6 +27,19 @@ typedef u64 (*clks_exec_entry_fn)(void);
 #define CLKS_EXEC_DEFAULT_KILL_SIGNAL CLKS_EXEC_SIGNAL_TERM
 #define CLKS_EXEC_KERNEL_ADDR_BASE 0xFFFF800000000000ULL
 #define CLKS_EXEC_UNWIND_CTX_BYTES 56ULL
+#define CLKS_EXEC_FD_ACCESS_MASK 0x3ULL
+#define CLKS_EXEC_O_RDONLY       0x0000ULL
+#define CLKS_EXEC_O_WRONLY       0x0001ULL
+#define CLKS_EXEC_O_RDWR         0x0002ULL
+#define CLKS_EXEC_O_CREAT        0x0040ULL
+#define CLKS_EXEC_O_TRUNC        0x0200ULL
+#define CLKS_EXEC_O_APPEND       0x0400ULL
+
+enum clks_exec_fd_kind {
+    CLKS_EXEC_FD_KIND_NONE = 0,
+    CLKS_EXEC_FD_KIND_TTY = 1,
+    CLKS_EXEC_FD_KIND_FILE = 2,
+};
 
 enum clks_exec_proc_state {
     CLKS_EXEC_PROC_UNUSED = 0,
@@ -34,6 +49,15 @@ enum clks_exec_proc_state {
     CLKS_EXEC_PROC_STOPPED = 4,
 };
 
+struct clks_exec_fd_entry {
+    clks_bool used;
+    enum clks_exec_fd_kind kind;
+    u64 flags;
+    u64 offset;
+    u32 tty_index;
+    char path[CLKS_EXEC_PATH_MAX];
+};
+
 struct clks_exec_proc_record {
     clks_bool used;
     enum clks_exec_proc_state state;
@@ -57,6 +81,7 @@ struct clks_exec_proc_record {
     u64 last_fault_vector;
     u64 last_fault_error;
     u64 last_fault_rip;
+    struct clks_exec_fd_entry fds[CLKS_EXEC_FD_MAX];
 };
 
 #if defined(CLKS_ARCH_X86_64)
@@ -81,6 +106,8 @@ static u64 clks_exec_image_begin_stack[CLKS_EXEC_MAX_DEPTH];
 static u64 clks_exec_image_end_stack[CLKS_EXEC_MAX_DEPTH];
 static u32 clks_exec_pid_stack_depth = 0U;
 
+static struct clks_exec_proc_record *clks_exec_current_proc(void);
+
 static void clks_exec_serial_write_hex64(u64 value) {
     int nibble;
 
@@ -424,6 +451,188 @@ static u64 clks_exec_alloc_pid(void) {
     return pid;
 }
 
+static clks_bool clks_exec_fd_access_mode_valid(u64 flags) {
+    u64 mode = flags & CLKS_EXEC_FD_ACCESS_MASK;
+    return (mode == CLKS_EXEC_O_RDONLY || mode == CLKS_EXEC_O_WRONLY || mode == CLKS_EXEC_O_RDWR) ? CLKS_TRUE
+                                                                                                    : CLKS_FALSE;
+}
+
+static clks_bool clks_exec_fd_can_read(u64 flags) {
+    u64 mode = flags & CLKS_EXEC_FD_ACCESS_MASK;
+    return (mode == CLKS_EXEC_O_RDONLY || mode == CLKS_EXEC_O_RDWR) ? CLKS_TRUE : CLKS_FALSE;
+}
+
+static clks_bool clks_exec_fd_can_write(u64 flags) {
+    u64 mode = flags & CLKS_EXEC_FD_ACCESS_MASK;
+    return (mode == CLKS_EXEC_O_WRONLY || mode == CLKS_EXEC_O_RDWR) ? CLKS_TRUE : CLKS_FALSE;
+}
+
+static clks_bool clks_exec_path_is_dev_tty(const char *path) {
+    return (path != CLKS_NULL && clks_strcmp(path, "/dev/tty") == 0) ? CLKS_TRUE : CLKS_FALSE;
+}
+
+static void clks_exec_fd_init_defaults(struct clks_exec_proc_record *proc) {
+    if (proc == CLKS_NULL) {
+        return;
+    }
+
+    clks_memset(proc->fds, 0, sizeof(proc->fds));
+
+    proc->fds[0].used = CLKS_TRUE;
+    proc->fds[0].kind = CLKS_EXEC_FD_KIND_TTY;
+    proc->fds[0].flags = CLKS_EXEC_O_RDONLY;
+    proc->fds[0].offset = 0ULL;
+    proc->fds[0].tty_index = proc->tty_index;
+    proc->fds[0].path[0] = '\0';
+
+    proc->fds[1].used = CLKS_TRUE;
+    proc->fds[1].kind = CLKS_EXEC_FD_KIND_TTY;
+    proc->fds[1].flags = CLKS_EXEC_O_WRONLY;
+    proc->fds[1].offset = 0ULL;
+    proc->fds[1].tty_index = proc->tty_index;
+    proc->fds[1].path[0] = '\0';
+
+    proc->fds[2].used = CLKS_TRUE;
+    proc->fds[2].kind = CLKS_EXEC_FD_KIND_TTY;
+    proc->fds[2].flags = CLKS_EXEC_O_WRONLY;
+    proc->fds[2].offset = 0ULL;
+    proc->fds[2].tty_index = proc->tty_index;
+    proc->fds[2].path[0] = '\0';
+}
+
+static i32 clks_exec_fd_find_free(struct clks_exec_proc_record *proc) {
+    u32 i;
+
+    if (proc == CLKS_NULL) {
+        return -1;
+    }
+
+    for (i = 0U; i < CLKS_EXEC_FD_MAX; i++) {
+        if (proc->fds[i].used == CLKS_FALSE) {
+            return (i32)i;
+        }
+    }
+
+    return -1;
+}
+
+static struct clks_exec_fd_entry *clks_exec_fd_lookup(struct clks_exec_proc_record *proc, u64 fd) {
+    if (proc == CLKS_NULL || fd >= CLKS_EXEC_FD_MAX) {
+        return CLKS_NULL;
+    }
+
+    if (proc->fds[(u32)fd].used == CLKS_FALSE) {
+        return CLKS_NULL;
+    }
+
+    return &proc->fds[(u32)fd];
+}
+
+static u64 clks_exec_fd_file_read(struct clks_exec_fd_entry *entry, void *out_buffer, u64 size) {
+    const void *file_data;
+    u64 file_size = 0ULL;
+    u64 read_len;
+
+    if (entry == CLKS_NULL || out_buffer == CLKS_NULL || size == 0ULL) {
+        return 0ULL;
+    }
+
+    file_data = clks_fs_read_all(entry->path, &file_size);
+
+    if (file_data == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    if (entry->offset >= file_size) {
+        return 0ULL;
+    }
+
+    read_len = file_size - entry->offset;
+
+    if (read_len > size) {
+        read_len = size;
+    }
+
+    clks_memcpy(out_buffer, (const u8 *)file_data + (usize)entry->offset, (usize)read_len);
+    entry->offset += read_len;
+    return read_len;
+}
+
+static u64 clks_exec_fd_file_write(struct clks_exec_fd_entry *entry, const void *buffer, u64 size) {
+    const void *old_data = CLKS_NULL;
+    u64 old_size = 0ULL;
+    u64 write_pos;
+    u64 new_size;
+    void *merged = CLKS_NULL;
+    clks_bool ok;
+
+    if (entry == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    if (size == 0ULL) {
+        return 0ULL;
+    }
+
+    if (buffer == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    if ((entry->flags & CLKS_EXEC_O_APPEND) != 0ULL) {
+        if (clks_fs_append(entry->path, buffer, size) == CLKS_FALSE) {
+            return (u64)-1;
+        }
+
+        entry->offset += size;
+        return size;
+    }
+
+    old_data = clks_fs_read_all(entry->path, &old_size);
+
+    if (old_data == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    write_pos = entry->offset;
+
+    if (write_pos > (0xFFFFFFFFFFFFFFFFULL - size)) {
+        return (u64)-1;
+    }
+
+    new_size = write_pos + size;
+
+    if (new_size < old_size) {
+        new_size = old_size;
+    }
+
+    if (new_size == 0ULL) {
+        return 0ULL;
+    }
+
+    merged = clks_kmalloc((usize)new_size);
+
+    if (merged == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    clks_memset(merged, 0, (usize)new_size);
+
+    if (old_size > 0ULL) {
+        clks_memcpy(merged, old_data, (usize)old_size);
+    }
+
+    clks_memcpy((u8 *)merged + (usize)write_pos, buffer, (usize)size);
+    ok = clks_fs_write_all(entry->path, merged, new_size);
+    clks_kfree(merged);
+
+    if (ok == CLKS_FALSE) {
+        return (u64)-1;
+    }
+
+    entry->offset = write_pos + size;
+    return size;
+}
+
 static struct clks_exec_proc_record *clks_exec_prepare_proc_record(i32 slot,
                                                                     u64 pid,
                                                                     const char *path,
@@ -461,6 +670,7 @@ static struct clks_exec_proc_record *clks_exec_prepare_proc_record(i32 slot,
     proc->last_fault_vector = 0ULL;
     proc->last_fault_error = 0ULL;
     proc->last_fault_rip = 0ULL;
+    clks_exec_fd_init_defaults(proc);
 
     if (proc->argc < CLKS_EXEC_MAX_ARGS) {
         clks_exec_copy_path(proc->argv_items[proc->argc], CLKS_EXEC_ITEM_MAX, path);
@@ -965,6 +1175,215 @@ clks_bool clks_exec_request_exit(u64 status) {
     return CLKS_TRUE;
 }
 
+u64 clks_exec_fd_open(const char *path, u64 flags, u64 mode) {
+    struct clks_exec_proc_record *proc = clks_exec_current_proc();
+    struct clks_fs_node_info info;
+    i32 fd_slot;
+    u8 empty_payload = 0U;
+
+    (void)mode;
+
+    if (proc == CLKS_NULL || path == CLKS_NULL || path[0] != '/') {
+        return (u64)-1;
+    }
+
+    if (clks_strlen(path) >= CLKS_EXEC_PATH_MAX) {
+        return (u64)-1;
+    }
+
+    if (clks_exec_fd_access_mode_valid(flags) == CLKS_FALSE) {
+        return (u64)-1;
+    }
+
+    if (((flags & CLKS_EXEC_O_TRUNC) != 0ULL || (flags & CLKS_EXEC_O_APPEND) != 0ULL) &&
+        clks_exec_fd_can_write(flags) == CLKS_FALSE) {
+        return (u64)-1;
+    }
+
+    fd_slot = clks_exec_fd_find_free(proc);
+
+    if (fd_slot < 0) {
+        return (u64)-1;
+    }
+
+    if (clks_exec_path_is_dev_tty(path) == CLKS_TRUE) {
+        struct clks_exec_fd_entry *entry = &proc->fds[(u32)fd_slot];
+
+        clks_memset(entry, 0, sizeof(*entry));
+        entry->used = CLKS_TRUE;
+        entry->kind = CLKS_EXEC_FD_KIND_TTY;
+        entry->flags = flags;
+        entry->offset = 0ULL;
+        entry->tty_index = proc->tty_index;
+        entry->path[0] = '\0';
+        return (u64)fd_slot;
+    }
+
+    if (clks_fs_stat(path, &info) == CLKS_FALSE) {
+        if ((flags & CLKS_EXEC_O_CREAT) == 0ULL || clks_exec_fd_can_write(flags) == CLKS_FALSE) {
+            return (u64)-1;
+        }
+
+        if (clks_fs_write_all(path, &empty_payload, 0ULL) == CLKS_FALSE || clks_fs_stat(path, &info) == CLKS_FALSE) {
+            return (u64)-1;
+        }
+    }
+
+    if (info.type != CLKS_FS_NODE_FILE) {
+        return (u64)-1;
+    }
+
+    if ((flags & CLKS_EXEC_O_TRUNC) != 0ULL) {
+        if (clks_fs_write_all(path, &empty_payload, 0ULL) == CLKS_FALSE || clks_fs_stat(path, &info) == CLKS_FALSE) {
+            return (u64)-1;
+        }
+    }
+
+    {
+        struct clks_exec_fd_entry *entry = &proc->fds[(u32)fd_slot];
+
+        clks_memset(entry, 0, sizeof(*entry));
+        entry->used = CLKS_TRUE;
+        entry->kind = CLKS_EXEC_FD_KIND_FILE;
+        entry->flags = flags;
+        entry->offset = ((flags & CLKS_EXEC_O_APPEND) != 0ULL) ? info.size : 0ULL;
+        entry->tty_index = proc->tty_index;
+        clks_exec_copy_path(entry->path, sizeof(entry->path), path);
+    }
+
+    return (u64)fd_slot;
+}
+
+u64 clks_exec_fd_read(u64 fd, void *out_buffer, u64 size) {
+    struct clks_exec_proc_record *proc = clks_exec_current_proc();
+    struct clks_exec_fd_entry *entry;
+
+    if (proc == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    if (size == 0ULL) {
+        return 0ULL;
+    }
+
+    if (out_buffer == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    entry = clks_exec_fd_lookup(proc, fd);
+
+    if (entry == CLKS_NULL || clks_exec_fd_can_read(entry->flags) == CLKS_FALSE) {
+        return (u64)-1;
+    }
+
+    if (entry->kind == CLKS_EXEC_FD_KIND_TTY) {
+        u64 count = 0ULL;
+        char *dst = (char *)out_buffer;
+
+        while (count < size) {
+            char ch;
+
+            if (clks_keyboard_pop_char_for_tty(entry->tty_index, &ch) == CLKS_FALSE) {
+                break;
+            }
+
+            dst[count] = ch;
+            count++;
+        }
+
+        return count;
+    }
+
+    if (entry->kind == CLKS_EXEC_FD_KIND_FILE) {
+        return clks_exec_fd_file_read(entry, out_buffer, size);
+    }
+
+    return (u64)-1;
+}
+
+u64 clks_exec_fd_write(u64 fd, const void *buffer, u64 size) {
+    struct clks_exec_proc_record *proc = clks_exec_current_proc();
+    struct clks_exec_fd_entry *entry;
+
+    if (proc == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    if (size == 0ULL) {
+        return 0ULL;
+    }
+
+    if (buffer == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    entry = clks_exec_fd_lookup(proc, fd);
+
+    if (entry == CLKS_NULL || clks_exec_fd_can_write(entry->flags) == CLKS_FALSE) {
+        return (u64)-1;
+    }
+
+    if (entry->kind == CLKS_EXEC_FD_KIND_TTY) {
+        u64 i;
+        const char *src = (const char *)buffer;
+
+        for (i = 0ULL; i < size; i++) {
+            clks_tty_write_char(src[i]);
+        }
+
+        return size;
+    }
+
+    if (entry->kind == CLKS_EXEC_FD_KIND_FILE) {
+        return clks_exec_fd_file_write(entry, buffer, size);
+    }
+
+    return (u64)-1;
+}
+
+u64 clks_exec_fd_close(u64 fd) {
+    struct clks_exec_proc_record *proc = clks_exec_current_proc();
+    struct clks_exec_fd_entry *entry;
+
+    if (proc == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    entry = clks_exec_fd_lookup(proc, fd);
+
+    if (entry == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    clks_memset(entry, 0, sizeof(*entry));
+    return 0ULL;
+}
+
+u64 clks_exec_fd_dup(u64 fd) {
+    struct clks_exec_proc_record *proc = clks_exec_current_proc();
+    struct clks_exec_fd_entry *entry;
+    i32 fd_slot;
+
+    if (proc == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    entry = clks_exec_fd_lookup(proc, fd);
+
+    if (entry == CLKS_NULL) {
+        return (u64)-1;
+    }
+
+    fd_slot = clks_exec_fd_find_free(proc);
+
+    if (fd_slot < 0) {
+        return (u64)-1;
+    }
+
+    proc->fds[(u32)fd_slot] = *entry;
+    return (u64)fd_slot;
+}
+
 u64 clks_exec_current_pid(void) {
     i32 depth_index = clks_exec_current_depth_index();
 
diff --git a/clks/kernel/syscall.c b/clks/kernel/syscall.c
index 6d0e493..c0cc5fb 100644
--- a/clks/kernel/syscall.c
+++ b/clks/kernel/syscall.c
@@ -32,7 +32,7 @@
 #define CLKS_SYSCALL_KDBG_STACK_WINDOW_BYTES (128ULL * 1024ULL)
 #define CLKS_SYSCALL_KERNEL_SYMBOL_FILE "/system/kernel.sym"
 #define CLKS_SYSCALL_KERNEL_ADDR_BASE 0xFFFF800000000000ULL
-#define CLKS_SYSCALL_STATS_MAX_ID     CLKS_SYSCALL_STATS_RECENT_ID
+#define CLKS_SYSCALL_STATS_MAX_ID     CLKS_SYSCALL_FD_DUP
 #define CLKS_SYSCALL_STATS_RING_SIZE  256U
 
 struct clks_syscall_frame {
@@ -210,6 +210,40 @@ static u64 clks_syscall_kbd_get_char(void) {
     return (u64)(u8)ch;
 }
 
+static u64 clks_syscall_fd_open(u64 arg0, u64 arg1, u64 arg2) {
+    char path[CLKS_SYSCALL_PATH_MAX];
+
+    if (clks_syscall_copy_user_string(arg0, path, sizeof(path)) == CLKS_FALSE) {
+        return (u64)-1;
+    }
+
+    return clks_exec_fd_open(path, arg1, arg2);
+}
+
+static u64 clks_syscall_fd_read(u64 arg0, u64 arg1, u64 arg2) {
+    if (arg2 > 0ULL && arg1 == 0ULL) {
+        return (u64)-1;
+    }
+
+    return clks_exec_fd_read(arg0, (void *)arg1, arg2);
+}
+
+static u64 clks_syscall_fd_write(u64 arg0, u64 arg1, u64 arg2) {
+    if (arg2 > 0ULL && arg1 == 0ULL) {
+        return (u64)-1;
+    }
+
+    return clks_exec_fd_write(arg0, (const void *)arg1, arg2);
+}
+
+static u64 clks_syscall_fd_close(u64 arg0) {
+    return clks_exec_fd_close(arg0);
+}
+
+static u64 clks_syscall_fd_dup(u64 arg0) {
+    return clks_exec_fd_dup(arg0);
+}
+
 static clks_bool clks_syscall_procfs_is_root(const char *path) {
     return (path != CLKS_NULL && clks_strcmp(path, "/proc") == 0) ? CLKS_TRUE : CLKS_FALSE;
 }
@@ -1786,6 +1820,16 @@ u64 clks_syscall_dispatch(void *frame_ptr) {
             return clks_syscall_stats_recent_window();
         case CLKS_SYSCALL_STATS_RECENT_ID:
             return clks_syscall_stats_recent_id(frame->rbx);
+        case CLKS_SYSCALL_FD_OPEN:
+            return clks_syscall_fd_open(frame->rbx, frame->rcx, frame->rdx);
+        case CLKS_SYSCALL_FD_READ:
+            return clks_syscall_fd_read(frame->rbx, frame->rcx, frame->rdx);
+        case CLKS_SYSCALL_FD_WRITE:
+            return clks_syscall_fd_write(frame->rbx, frame->rcx, frame->rdx);
+        case CLKS_SYSCALL_FD_CLOSE:
+            return clks_syscall_fd_close(frame->rbx);
+        case CLKS_SYSCALL_FD_DUP:
+            return clks_syscall_fd_dup(frame->rbx);
         default:
             return (u64)-1;
     }
diff --git a/docs/syscall.md b/docs/syscall.md
index 7251117..bffabd0 100644
--- a/docs/syscall.md
+++ b/docs/syscall.md
@@ -83,7 +83,7 @@ u64 cleonos_syscall(u64 id, u64 arg0, u64 arg1, u64 arg2);
 - `/proc/<pid>`：指定 PID 快照文本
 - `/proc` 为只读；写入类 syscall 不支持。
 
-## 4. Syscall 列表（0~71）
+## 4. Syscall 列表（0~76）
 
 ### 0 `CLEONOS_SYSCALL_LOG_WRITE`
 
@@ -557,6 +557,53 @@ u64 cleonos_syscall(u64 id, u64 arg0, u64 arg1, u64 arg2);
 - `arg0`: `u64 id`
 - 返回：指定 syscall ID 在“最近窗口”中的出现次数（ID 越界返回 `0`）
 
+### 72 `CLEONOS_SYSCALL_FD_OPEN`
+
+- 参数：
+- `arg0`: `const char *path`
+- `arg1`: `u64 flags`
+- `arg2`: `u64 mode`（当前保留）
+- 返回：成功返回 `fd`，失败返回 `-1`
+- 说明：
+- 当前支持普通文件与 `/dev/tty`。
+- 默认进程会预置 `fd 0/1/2`（stdin/stdout/stderr）。
+- 标志位兼容子集：`O_RDONLY/O_WRONLY/O_RDWR/O_CREAT/O_TRUNC/O_APPEND`。
+
+### 73 `CLEONOS_SYSCALL_FD_READ`
+
+- 参数：
+- `arg0`: `u64 fd`
+- `arg1`: `void *out_buffer`
+- `arg2`: `u64 size`
+- 返回：读取字节数；错误返回 `-1`
+- 说明：
+- 对 `tty fd`（如 stdin）为非阻塞读取：无输入时返回 `0`。
+- 对文件 fd 为顺序读取，内部维护偏移。
+
+### 74 `CLEONOS_SYSCALL_FD_WRITE`
+
+- 参数：
+- `arg0`: `u64 fd`
+- `arg1`: `const void *buffer`
+- `arg2`: `u64 size`
+- 返回：写入字节数；错误返回 `-1`
+- 说明：
+- `tty fd` 输出到终端。
+- 文件 fd 支持顺序写；`O_APPEND` 下始终追加。
+
+### 75 `CLEONOS_SYSCALL_FD_CLOSE`
+
+- 参数：
+- `arg0`: `u64 fd`
+- 返回：成功 `0`，失败 `-1`
+
+### 76 `CLEONOS_SYSCALL_FD_DUP`
+
+- 参数：
+- `arg0`: `u64 oldfd`
+- 返回：新 fd；失败 `-1`
+- 说明：当前为“按值复制”语义（复制 flags/offset/目标对象）。
+
 ## 5. 用户态封装函数
 
 用户态封装位于：
@@ -581,6 +628,7 @@ u64 cleonos_syscall(u64 id, u64 arg0, u64 arg1, u64 arg2);
 - `cleonos_sys_proc_count()` / `cleonos_sys_proc_pid_at()` / `cleonos_sys_proc_snapshot()` / `cleonos_sys_proc_kill()`
 - `cleonos_sys_kdbg_sym()` / `cleonos_sys_kdbg_bt()` / `cleonos_sys_kdbg_regs()`
 - `cleonos_sys_stats_total()` / `cleonos_sys_stats_id_count()` / `cleonos_sys_stats_recent_window()` / `cleonos_sys_stats_recent_id()`
+- `cleonos_sys_fd_open()` / `cleonos_sys_fd_read()` / `cleonos_sys_fd_write()` / `cleonos_sys_fd_close()` / `cleonos_sys_fd_dup()`
 
 ## 6. 开发注意事项
 
@@ -591,6 +639,6 @@ u64 cleonos_syscall(u64 id, u64 arg0, u64 arg1, u64 arg2);
 
 ## 7. Wine 兼容说明
 
-- `wine/cleonos_wine_lib/runner.py` 目前以 syscall `0..67` 为主，新增 ID 需同步适配后才能完整观测统计类接口。
+- `wine/cleonos_wine_lib/runner.py` 目前以 syscall `0..67` 为主；`68..76`（stats/fd）需同步适配后才能完整覆盖。
 - Wine 在运行时崩溃场景下会生成与内核一致格式的“信号编码退出状态”，可通过 `WAITPID` 读取。
 - Wine 当前音频 syscall 为占位实现：`AUDIO_AVAILABLE=0`，`AUDIO_PLAY_TONE=0`，`AUDIO_STOP=1`。