Stage 21

clks/include/clks/fs.h

@@ -19,6 +19,12 @@ clks_bool clks_fs_stat(const char *path, struct clks_fs_node_info *out_info);
 const void *clks_fs_read_all(const char *path, u64 *out_size);
 u64 clks_fs_count_children(const char *dir_path);
 clks_bool clks_fs_get_child_name(const char *dir_path, u64 index, char *out_name, usize out_name_size);
+
+clks_bool clks_fs_mkdir(const char *path);
+clks_bool clks_fs_write_all(const char *path, const void *data, u64 size);
+clks_bool clks_fs_append(const char *path, const void *data, u64 size);
+clks_bool clks_fs_remove(const char *path);
+
 u64 clks_fs_node_count(void);
 
-#endif
+#endif

clks/kernel/fs.c

@@ -1,5 +1,6 @@
 #include <clks/boot.h>
 #include <clks/fs.h>
+#include <clks/heap.h>
 #include <clks/log.h>
 #include <clks/ramdisk.h>
 #include <clks/string.h>
@@ -8,6 +9,8 @@
 #define CLKS_FS_MAX_NODES 512U
 #define CLKS_FS_PATH_MAX  CLKS_RAMDISK_PATH_MAX
 
+#define CLKS_FS_NODE_FLAG_HEAP_DATA 0x0001U
+
 struct clks_fs_node {
     clks_bool used;
     enum clks_fs_node_type type;
@@ -26,6 +29,7 @@ struct clks_fs_build_stats {
 static struct clks_fs_node clks_fs_nodes[CLKS_FS_MAX_NODES];
 static u16 clks_fs_nodes_used = 0U;
 static clks_bool clks_fs_ready = CLKS_FALSE;
+static const u8 clks_fs_empty_file_data[1] = {0U};
 
 static clks_bool clks_fs_normalize_external_path(const char *path, char *out_internal, usize out_size) {
     usize in_pos = 0;
@@ -94,6 +98,33 @@ static clks_bool clks_fs_normalize_external_path(const char *path, char *out_int
     return CLKS_TRUE;
 }
 
+static clks_bool clks_fs_internal_in_temp_tree(const char *internal_path) {
+    if (internal_path == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    if (internal_path[0] != 't' ||
+        internal_path[1] != 'e' ||
+        internal_path[2] != 'm' ||
+        internal_path[3] != 'p') {
+        return CLKS_FALSE;
+    }
+
+    return (internal_path[4] == '\0' || internal_path[4] == '/') ? CLKS_TRUE : CLKS_FALSE;
+}
+
+static clks_bool clks_fs_internal_is_temp_file_path(const char *internal_path) {
+    if (clks_fs_internal_in_temp_tree(internal_path) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (internal_path[4] == '\0') {
+        return CLKS_FALSE;
+    }
+
+    return CLKS_TRUE;
+}
+
 static i32 clks_fs_find_node_by_internal(const char *internal_path) {
     u16 i;
 
@@ -176,12 +207,54 @@ static clks_bool clks_fs_split_parent(const char *internal_path, char *parent_ou
     return CLKS_TRUE;
 }
 
+static clks_bool clks_fs_node_has_heap_data(u16 index) {
+    return ((clks_fs_nodes[index].reserved & CLKS_FS_NODE_FLAG_HEAP_DATA) != 0U) ? CLKS_TRUE : CLKS_FALSE;
+}
+
+static void clks_fs_node_set_heap_data(u16 index, clks_bool value) {
+    if (value == CLKS_TRUE) {
+        clks_fs_nodes[index].reserved |= CLKS_FS_NODE_FLAG_HEAP_DATA;
+    } else {
+        clks_fs_nodes[index].reserved &= (u16)(~CLKS_FS_NODE_FLAG_HEAP_DATA);
+    }
+}
+
+static void clks_fs_node_release_heap_data(u16 index) {
+    if (clks_fs_nodes[index].type != CLKS_FS_NODE_FILE) {
+        return;
+    }
+
+    if (clks_fs_node_has_heap_data(index) == CLKS_TRUE && clks_fs_nodes[index].data != CLKS_NULL) {
+        clks_kfree((void *)clks_fs_nodes[index].data);
+    }
+
+    clks_fs_node_set_heap_data(index, CLKS_FALSE);
+}
+
+static i32 clks_fs_alloc_slot(void) {
+    u16 i;
+
+    for (i = 0U; i < clks_fs_nodes_used; i++) {
+        if (clks_fs_nodes[i].used == CLKS_FALSE) {
+            return (i32)i;
+        }
+    }
+
+    if (clks_fs_nodes_used >= CLKS_FS_MAX_NODES) {
+        return -1;
+    }
+
+    clks_fs_nodes_used++;
+    return (i32)(clks_fs_nodes_used - 1U);
+}
+
 static i32 clks_fs_create_or_update_node(const char *internal_path,
                                          enum clks_fs_node_type type,
                                          u16 parent,
                                          const void *data,
                                          u64 size) {
     i32 existing;
+    i32 slot;
     usize path_len;
 
     if (internal_path == CLKS_NULL) {
@@ -208,25 +281,28 @@ static i32 clks_fs_create_or_update_node(const char *internal_path,
         if (type == CLKS_FS_NODE_FILE) {
             node->data = data;
             node->size = size;
+            node->reserved = 0U;
         }
 
+        node->used = CLKS_TRUE;
         return existing;
     }
 
-    if (clks_fs_nodes_used >= CLKS_FS_MAX_NODES) {
+    slot = clks_fs_alloc_slot();
+
+    if (slot < 0) {
         return -1;
     }
 
-    clks_fs_nodes[clks_fs_nodes_used].used = CLKS_TRUE;
-    clks_fs_nodes[clks_fs_nodes_used].type = type;
-    clks_fs_nodes[clks_fs_nodes_used].parent = parent;
-    clks_fs_nodes[clks_fs_nodes_used].reserved = 0U;
-    clks_fs_nodes[clks_fs_nodes_used].data = (type == CLKS_FS_NODE_FILE) ? data : CLKS_NULL;
-    clks_fs_nodes[clks_fs_nodes_used].size = (type == CLKS_FS_NODE_FILE) ? size : 0ULL;
-    clks_memcpy(clks_fs_nodes[clks_fs_nodes_used].path, internal_path, path_len + 1U);
+    clks_fs_nodes[(u16)slot].used = CLKS_TRUE;
+    clks_fs_nodes[(u16)slot].type = type;
+    clks_fs_nodes[(u16)slot].parent = parent;
+    clks_fs_nodes[(u16)slot].reserved = 0U;
+    clks_fs_nodes[(u16)slot].data = (type == CLKS_FS_NODE_FILE) ? data : CLKS_NULL;
+    clks_fs_nodes[(u16)slot].size = (type == CLKS_FS_NODE_FILE) ? size : 0ULL;
+    clks_memcpy(clks_fs_nodes[(u16)slot].path, internal_path, path_len + 1U);
 
-    clks_fs_nodes_used++;
-    return (i32)(clks_fs_nodes_used - 1U);
+    return slot;
 }
 
 static clks_bool clks_fs_ensure_root(void) {
@@ -372,6 +448,38 @@ static clks_bool clks_fs_ramdisk_visit(const struct clks_ramdisk_entry *entry, v
     return CLKS_TRUE;
 }
 
+static clks_bool clks_fs_build_file_payload(const void *data,
+                                            u64 size,
+                                            const void **out_data,
+                                            clks_bool *out_heap_owned) {
+    void *payload;
+
+    if (out_data == CLKS_NULL || out_heap_owned == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    if (size == 0ULL) {
+        *out_data = (const void *)clks_fs_empty_file_data;
+        *out_heap_owned = CLKS_FALSE;
+        return CLKS_TRUE;
+    }
+
+    if (data == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    payload = clks_kmalloc((usize)size);
+
+    if (payload == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    clks_memcpy(payload, data, (usize)size);
+    *out_data = (const void *)payload;
+    *out_heap_owned = CLKS_TRUE;
+    return CLKS_TRUE;
+}
+
 void clks_fs_init(void) {
     const struct limine_file *module;
     struct clks_fs_build_stats stats;
@@ -474,6 +582,10 @@ const void *clks_fs_read_all(const char *path, u64 *out_size) {
         *out_size = clks_fs_nodes[(u16)node_index].size;
     }
 
+    if (clks_fs_nodes[(u16)node_index].size == 0ULL) {
+        return (const void *)clks_fs_empty_file_data;
+    }
+
     return clks_fs_nodes[(u16)node_index].data;
 }
 
@@ -563,10 +675,244 @@ clks_bool clks_fs_get_child_name(const char *dir_path, u64 index, char *out_name
     return CLKS_FALSE;
 }
 
+clks_bool clks_fs_mkdir(const char *path) {
+    char internal[CLKS_FS_PATH_MAX];
+    i32 node_index;
+
+    if (clks_fs_ready == CLKS_FALSE || path == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_normalize_external_path(path, internal, sizeof(internal)) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_internal_in_temp_tree(internal) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (internal[0] == '\0') {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_ensure_dir_hierarchy(internal) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    node_index = clks_fs_find_node_by_internal(internal);
+
+    if (node_index < 0) {
+        return CLKS_FALSE;
+    }
+
+    return (clks_fs_nodes[(u16)node_index].type == CLKS_FS_NODE_DIR) ? CLKS_TRUE : CLKS_FALSE;
+}
+
+clks_bool clks_fs_write_all(const char *path, const void *data, u64 size) {
+    char internal[CLKS_FS_PATH_MAX];
+    char parent[CLKS_FS_PATH_MAX];
+    const void *payload_data = CLKS_NULL;
+    clks_bool payload_heap_owned = CLKS_FALSE;
+    i32 parent_index;
+    i32 node_index;
+
+    if (clks_fs_ready == CLKS_FALSE || path == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_normalize_external_path(path, internal, sizeof(internal)) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_internal_is_temp_file_path(internal) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_split_parent(internal, parent, sizeof(parent)) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_internal_in_temp_tree(parent) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_ensure_dir_hierarchy(parent) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    parent_index = clks_fs_find_node_by_internal(parent);
+
+    if (parent_index < 0 || clks_fs_nodes[(u16)parent_index].type != CLKS_FS_NODE_DIR) {
+        return CLKS_FALSE;
+    }
+
+    node_index = clks_fs_find_node_by_internal(internal);
+
+    if (node_index >= 0 && clks_fs_nodes[(u16)node_index].type != CLKS_FS_NODE_FILE) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_build_file_payload(data, size, &payload_data, &payload_heap_owned) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (node_index >= 0) {
+        clks_fs_node_release_heap_data((u16)node_index);
+    }
+
+    node_index = clks_fs_create_or_update_node(
+        internal,
+        CLKS_FS_NODE_FILE,
+        (u16)parent_index,
+        payload_data,
+        size
+    );
+
+    if (node_index < 0) {
+        if (payload_heap_owned == CLKS_TRUE) {
+            clks_kfree((void *)payload_data);
+        }
+        return CLKS_FALSE;
+    }
+
+    clks_fs_node_set_heap_data((u16)node_index, payload_heap_owned);
+    return CLKS_TRUE;
+}
+
+clks_bool clks_fs_append(const char *path, const void *data, u64 size) {
+    char internal[CLKS_FS_PATH_MAX];
+    i32 node_index;
+    const void *old_data;
+    u64 old_size;
+    u64 new_size;
+    void *merged = CLKS_NULL;
+
+    if (clks_fs_ready == CLKS_FALSE || path == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    if (size > 0ULL && data == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_normalize_external_path(path, internal, sizeof(internal)) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_internal_is_temp_file_path(internal) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    node_index = clks_fs_find_node_by_internal(internal);
+
+    if (node_index < 0) {
+        return clks_fs_write_all(path, data, size);
+    }
+
+    if (clks_fs_nodes[(u16)node_index].type != CLKS_FS_NODE_FILE) {
+        return CLKS_FALSE;
+    }
+
+    old_data = clks_fs_nodes[(u16)node_index].data;
+    old_size = clks_fs_nodes[(u16)node_index].size;
+
+    if (old_size > (0xFFFFFFFFFFFFFFFFULL - size)) {
+        return CLKS_FALSE;
+    }
+
+    new_size = old_size + size;
+
+    if (new_size == 0ULL) {
+        return clks_fs_write_all(path, clks_fs_empty_file_data, 0ULL);
+    }
+
+    merged = clks_kmalloc((usize)new_size);
+
+    if (merged == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    if (old_size > 0ULL && old_data != CLKS_NULL) {
+        clks_memcpy(merged, old_data, (usize)old_size);
+    }
+
+    if (size > 0ULL) {
+        clks_memcpy((u8 *)merged + (usize)old_size, data, (usize)size);
+    }
+    if (clks_fs_write_all(path, merged, new_size) == CLKS_FALSE) {
+        clks_kfree(merged);
+        return CLKS_FALSE;
+    }
+
+    clks_kfree(merged);
+    return CLKS_TRUE;
+}
+
+clks_bool clks_fs_remove(const char *path) {
+    char internal[CLKS_FS_PATH_MAX];
+    i32 node_index;
+    u16 i;
+
+    if (clks_fs_ready == CLKS_FALSE || path == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_normalize_external_path(path, internal, sizeof(internal)) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_internal_in_temp_tree(internal) == CLKS_FALSE) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_strcmp(internal, "temp") == 0) {
+        return CLKS_FALSE;
+    }
+
+    node_index = clks_fs_find_node_by_internal(internal);
+
+    if (node_index < 0) {
+        return CLKS_FALSE;
+    }
+
+    if (clks_fs_nodes[(u16)node_index].type == CLKS_FS_NODE_DIR) {
+        for (i = 0U; i < clks_fs_nodes_used; i++) {
+            if (clks_fs_nodes[i].used == CLKS_FALSE) {
+                continue;
+            }
+
+            if (clks_fs_nodes[i].parent == (u16)node_index) {
+                return CLKS_FALSE;
+            }
+        }
+    }
+
+    clks_fs_node_release_heap_data((u16)node_index);
+
+    clks_fs_nodes[(u16)node_index].used = CLKS_FALSE;
+    clks_fs_nodes[(u16)node_index].type = CLKS_FS_NODE_FILE;
+    clks_fs_nodes[(u16)node_index].parent = 0U;
+    clks_fs_nodes[(u16)node_index].reserved = 0U;
+    clks_fs_nodes[(u16)node_index].data = CLKS_NULL;
+    clks_fs_nodes[(u16)node_index].size = 0ULL;
+    clks_fs_nodes[(u16)node_index].path[0] = '\0';
+
+    return CLKS_TRUE;
+}
+
 u64 clks_fs_node_count(void) {
+    u16 i;
+    u64 used = 0ULL;
+
     if (clks_fs_ready == CLKS_FALSE) {
         return 0ULL;
     }
 
-    return (u64)clks_fs_nodes_used;
-}
+    for (i = 0U; i < clks_fs_nodes_used; i++) {
+        if (clks_fs_nodes[i].used == CLKS_TRUE) {
+            used++;
+        }
+    }
+
+    return used;
+}

clks/kernel/kmain.c

@@ -96,7 +96,7 @@ void clks_kernel_main(void) {
         clks_tty_init();
     }
 
-    clks_log(CLKS_LOG_INFO, "BOOT", "CLEONOS STAGE18 START");
+    clks_log(CLKS_LOG_INFO, "BOOT", "CLEONOS Stage21 START");
 
     if (boot_fb == CLKS_NULL) {
         clks_log(CLKS_LOG_WARN, "VIDEO", "NO FRAMEBUFFER FROM LIMINE");

clks/kernel/shell.c

@@ -23,6 +23,7 @@ static char clks_shell_line[CLKS_SHELL_LINE_MAX];
 static usize clks_shell_line_len = 0U;
 static usize clks_shell_cursor = 0U;
 static usize clks_shell_rendered_len = 0U;
+static char clks_shell_cwd[CLKS_SHELL_PATH_MAX] = "/";
 
 static char clks_shell_history[CLKS_SHELL_HISTORY_MAX][CLKS_SHELL_LINE_MAX];
 static u32 clks_shell_history_count = 0U;
@@ -390,11 +391,178 @@ static clks_bool clks_shell_resolve_exec_path(const char *arg, char *out_path, u
     return CLKS_TRUE;
 }
 
+static clks_bool clks_shell_path_push_component(char *path, usize path_size, usize *io_len, const char *component, usize comp_len) {
+    if (path == CLKS_NULL || io_len == CLKS_NULL || component == CLKS_NULL || comp_len == 0U) {
+        return CLKS_FALSE;
+    }
+
+    if (*io_len == 1U) {
+        if (*io_len + comp_len >= path_size) {
+            return CLKS_FALSE;
+        }
+
+        clks_memcpy(path + 1U, component, comp_len);
+        *io_len = 1U + comp_len;
+        path[*io_len] = '\0';
+        return CLKS_TRUE;
+    }
+
+    if (*io_len + 1U + comp_len >= path_size) {
+        return CLKS_FALSE;
+    }
+
+    path[*io_len] = '/';
+    clks_memcpy(path + *io_len + 1U, component, comp_len);
+    *io_len += (1U + comp_len);
+    path[*io_len] = '\0';
+    return CLKS_TRUE;
+}
+
+static void clks_shell_path_pop_component(char *path, usize *io_len) {
+    if (path == CLKS_NULL || io_len == CLKS_NULL) {
+        return;
+    }
+
+    if (*io_len <= 1U) {
+        path[0] = '/';
+        path[1] = '\0';
+        *io_len = 1U;
+        return;
+    }
+
+    while (*io_len > 1U && path[*io_len - 1U] != '/') {
+        (*io_len)--;
+    }
+
+    if (*io_len > 1U) {
+        (*io_len)--;
+    }
+
+    path[*io_len] = '\0';
+}
+
+static clks_bool clks_shell_path_parse_into(const char *src, char *out_path, usize out_size, usize *io_len) {
+    usize i = 0U;
+
+    if (src == CLKS_NULL || out_path == CLKS_NULL || io_len == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    if (src[0] == '/') {
+        i = 1U;
+    }
+
+    while (src[i] != '\0') {
+        usize start;
+        usize len;
+
+        while (src[i] == '/') {
+            i++;
+        }
+
+        if (src[i] == '\0') {
+            break;
+        }
+
+        start = i;
+
+        while (src[i] != '\0' && src[i] != '/') {
+            i++;
+        }
+
+        len = i - start;
+
+        if (len == 1U && src[start] == '.') {
+            continue;
+        }
+
+        if (len == 2U && src[start] == '.' && src[start + 1U] == '.') {
+            clks_shell_path_pop_component(out_path, io_len);
+            continue;
+        }
+
+        if (clks_shell_path_push_component(out_path, out_size, io_len, src + start, len) == CLKS_FALSE) {
+            return CLKS_FALSE;
+        }
+    }
+
+    return CLKS_TRUE;
+}
+
+static clks_bool clks_shell_resolve_path(const char *arg, char *out_path, usize out_size) {
+    usize len = 1U;
+
+    if (out_path == CLKS_NULL || out_size < 2U) {
+        return CLKS_FALSE;
+    }
+
+    out_path[0] = '/';
+    out_path[1] = '\0';
+
+    if (arg == CLKS_NULL || arg[0] == '\0') {
+        return clks_shell_path_parse_into(clks_shell_cwd, out_path, out_size, &len);
+    }
+
+    if (arg[0] != '/') {
+        if (clks_shell_path_parse_into(clks_shell_cwd, out_path, out_size, &len) == CLKS_FALSE) {
+            return CLKS_FALSE;
+        }
+    }
+
+    return clks_shell_path_parse_into(arg, out_path, out_size, &len);
+}
+
+static clks_bool clks_shell_split_first_and_rest(const char *arg,
+                                                 char *out_first,
+                                                 usize out_first_size,
+                                                 const char **out_rest) {
+    usize i = 0U;
+    usize p = 0U;
+
+    if (arg == CLKS_NULL || out_first == CLKS_NULL || out_first_size == 0U || out_rest == CLKS_NULL) {
+        return CLKS_FALSE;
+    }
+
+    out_first[0] = '\0';
+    *out_rest = "";
+
+    while (arg[i] != '\0' && clks_shell_is_space(arg[i]) == CLKS_TRUE) {
+        i++;
+    }
+
+    if (arg[i] == '\0') {
+        return CLKS_FALSE;
+    }
+
+    while (arg[i] != '\0' && clks_shell_is_space(arg[i]) == CLKS_FALSE) {
+        if (p + 1U < out_first_size) {
+            out_first[p++] = arg[i];
+        }
+        i++;
+    }
+
+    out_first[p] = '\0';
+
+    while (arg[i] != '\0' && clks_shell_is_space(arg[i]) == CLKS_TRUE) {
+        i++;
+    }
+
+    *out_rest = &arg[i];
+    return CLKS_TRUE;
+}
+
 static void clks_shell_cmd_help(void) {
     clks_shell_writeln("commands:");
     clks_shell_writeln("  help");
     clks_shell_writeln("  ls [dir]");
     clks_shell_writeln("  cat <file>");
+    clks_shell_writeln("  pwd");
+    clks_shell_writeln("  cd [dir]");
+    clks_shell_writeln("  mkdir <dir>      (/temp only)");
+    clks_shell_writeln("  touch <file>     (/temp only)");
+    clks_shell_writeln("  write <file> <text>   (/temp only)");
+    clks_shell_writeln("  append <file> <text>  (/temp only)");
+    clks_shell_writeln("  rm <path>        (/temp only)");
     clks_shell_writeln("  exec <path|name>");
     clks_shell_writeln("  clear");
     clks_shell_writeln("  kbdstat");
@@ -403,12 +571,18 @@ static void clks_shell_cmd_help(void) {
 
 static void clks_shell_cmd_ls(const char *arg) {
     struct clks_fs_node_info info;
-    const char *path = arg;
+    char path[CLKS_SHELL_PATH_MAX];
+    const char *target = arg;
     u64 count;
     u64 i;
 
-    if (path == CLKS_NULL || path[0] == '\0') {
-        path = "/";
+    if (target == CLKS_NULL || target[0] == '\0') {
+        target = ".";
+    }
+
+    if (clks_shell_resolve_path(target, path, sizeof(path)) == CLKS_FALSE) {
+        clks_shell_writeln("ls: invalid path");
+        return;
     }
 
     if (clks_fs_stat(path, &info) == CLKS_FALSE || info.type != CLKS_FS_NODE_DIR) {
@@ -439,6 +613,7 @@ static void clks_shell_cmd_cat(const char *arg) {
     const void *data;
     u64 size = 0ULL;
     u64 copy_len;
+    char path[CLKS_SHELL_PATH_MAX];
     char out[CLKS_SHELL_CAT_LIMIT + 1U];
 
     if (arg == CLKS_NULL || arg[0] == '\0') {
@@ -446,7 +621,12 @@ static void clks_shell_cmd_cat(const char *arg) {
         return;
     }
 
-    data = clks_fs_read_all(arg, &size);
+    if (clks_shell_resolve_path(arg, path, sizeof(path)) == CLKS_FALSE) {
+        clks_shell_writeln("cat: invalid path");
+        return;
+    }
+
+    data = clks_fs_read_all(path, &size);
 
     if (data == CLKS_NULL) {
         clks_shell_writeln("cat: file not found");
@@ -469,6 +649,143 @@ static void clks_shell_cmd_cat(const char *arg) {
     }
 }
 
+static void clks_shell_cmd_pwd(void) {
+    clks_shell_writeln(clks_shell_cwd);
+}
+
+static void clks_shell_cmd_cd(const char *arg) {
+    struct clks_fs_node_info info;
+    char path[CLKS_SHELL_PATH_MAX];
+    const char *target = arg;
+
+    if (target == CLKS_NULL || target[0] == '\0') {
+        target = "/";
+    }
+
+    if (clks_shell_resolve_path(target, path, sizeof(path)) == CLKS_FALSE) {
+        clks_shell_writeln("cd: invalid path");
+        return;
+    }
+
+    if (clks_fs_stat(path, &info) == CLKS_FALSE || info.type != CLKS_FS_NODE_DIR) {
+        clks_shell_writeln("cd: directory not found");
+        return;
+    }
+
+    clks_shell_copy_line(clks_shell_cwd, sizeof(clks_shell_cwd), path);
+}
+
+static void clks_shell_cmd_mkdir(const char *arg) {
+    char path[CLKS_SHELL_PATH_MAX];
+
+    if (arg == CLKS_NULL || arg[0] == '\0') {
+        clks_shell_writeln("mkdir: directory path required");
+        return;
+    }
+
+    if (clks_shell_resolve_path(arg, path, sizeof(path)) == CLKS_FALSE) {
+        clks_shell_writeln("mkdir: invalid path");
+        return;
+    }
+
+    if (clks_fs_mkdir(path) == CLKS_FALSE) {
+        clks_shell_writeln("mkdir: failed (only /temp writable)");
+    }
+}
+
+static void clks_shell_cmd_touch(const char *arg) {
+    static const char empty_data[1] = {'\0'};
+    char path[CLKS_SHELL_PATH_MAX];
+
+    if (arg == CLKS_NULL || arg[0] == '\0') {
+        clks_shell_writeln("touch: file path required");
+        return;
+    }
+
+    if (clks_shell_resolve_path(arg, path, sizeof(path)) == CLKS_FALSE) {
+        clks_shell_writeln("touch: invalid path");
+        return;
+    }
+
+    if (clks_fs_write_all(path, empty_data, 0ULL) == CLKS_FALSE) {
+        clks_shell_writeln("touch: failed (only /temp writable)");
+    }
+}
+
+static void clks_shell_cmd_write(const char *arg) {
+    char path_arg[CLKS_SHELL_PATH_MAX];
+    char abs_path[CLKS_SHELL_PATH_MAX];
+    const char *payload;
+    u64 payload_len;
+
+    if (arg == CLKS_NULL || arg[0] == '\0') {
+        clks_shell_writeln("write: usage write <file> <text>");
+        return;
+    }
+
+    if (clks_shell_split_first_and_rest(arg, path_arg, sizeof(path_arg), &payload) == CLKS_FALSE) {
+        clks_shell_writeln("write: usage write <file> <text>");
+        return;
+    }
+
+    if (clks_shell_resolve_path(path_arg, abs_path, sizeof(abs_path)) == CLKS_FALSE) {
+        clks_shell_writeln("write: invalid path");
+        return;
+    }
+
+    payload_len = clks_strlen(payload);
+
+    if (clks_fs_write_all(abs_path, payload, payload_len) == CLKS_FALSE) {
+        clks_shell_writeln("write: failed (only /temp writable)");
+    }
+}
+
+static void clks_shell_cmd_append(const char *arg) {
+    char path_arg[CLKS_SHELL_PATH_MAX];
+    char abs_path[CLKS_SHELL_PATH_MAX];
+    const char *payload;
+    u64 payload_len;
+
+    if (arg == CLKS_NULL || arg[0] == '\0') {
+        clks_shell_writeln("append: usage append <file> <text>");
+        return;
+    }
+
+    if (clks_shell_split_first_and_rest(arg, path_arg, sizeof(path_arg), &payload) == CLKS_FALSE) {
+        clks_shell_writeln("append: usage append <file> <text>");
+        return;
+    }
+
+    if (clks_shell_resolve_path(path_arg, abs_path, sizeof(abs_path)) == CLKS_FALSE) {
+        clks_shell_writeln("append: invalid path");
+        return;
+    }
+
+    payload_len = clks_strlen(payload);
+
+    if (clks_fs_append(abs_path, payload, payload_len) == CLKS_FALSE) {
+        clks_shell_writeln("append: failed (only /temp writable)");
+    }
+}
+
+static void clks_shell_cmd_rm(const char *arg) {
+    char path[CLKS_SHELL_PATH_MAX];
+
+    if (arg == CLKS_NULL || arg[0] == '\0') {
+        clks_shell_writeln("rm: path required");
+        return;
+    }
+
+    if (clks_shell_resolve_path(arg, path, sizeof(path)) == CLKS_FALSE) {
+        clks_shell_writeln("rm: invalid path");
+        return;
+    }
+
+    if (clks_fs_remove(path) == CLKS_FALSE) {
+        clks_shell_writeln("rm: failed (only /temp writable; dir must be empty)");
+    }
+}
+
 static void clks_shell_cmd_exec(const char *arg) {
     char path[CLKS_SHELL_PATH_MAX];
     u64 status = (u64)-1;
@@ -540,6 +857,41 @@ static void clks_shell_execute_line(const char *line) {
         return;
     }
 
+    if (clks_shell_streq(cmd, "pwd") == CLKS_TRUE) {
+        clks_shell_cmd_pwd();
+        return;
+    }
+
+    if (clks_shell_streq(cmd, "cd") == CLKS_TRUE) {
+        clks_shell_cmd_cd(arg);
+        return;
+    }
+
+    if (clks_shell_streq(cmd, "mkdir") == CLKS_TRUE) {
+        clks_shell_cmd_mkdir(arg);
+        return;
+    }
+
+    if (clks_shell_streq(cmd, "touch") == CLKS_TRUE) {
+        clks_shell_cmd_touch(arg);
+        return;
+    }
+
+    if (clks_shell_streq(cmd, "write") == CLKS_TRUE) {
+        clks_shell_cmd_write(arg);
+        return;
+    }
+
+    if (clks_shell_streq(cmd, "append") == CLKS_TRUE) {
+        clks_shell_cmd_append(arg);
+        return;
+    }
+
+    if (clks_shell_streq(cmd, "rm") == CLKS_TRUE) {
+        clks_shell_cmd_rm(arg);
+        return;
+    }
+
     if (clks_shell_streq(cmd, "exec") == CLKS_TRUE || clks_shell_streq(cmd, "run") == CLKS_TRUE) {
         clks_shell_cmd_exec(arg);
         return;
@@ -686,10 +1038,12 @@ static void clks_shell_handle_char(char ch) {
         clks_shell_render_line();
     }
 }
+
 void clks_shell_init(void) {
     clks_shell_reset_line();
     clks_shell_history_count = 0U;
     clks_shell_history_cancel_nav();
+    clks_shell_copy_line(clks_shell_cwd, sizeof(clks_shell_cwd), "/");
 
     if (clks_tty_ready() == CLKS_FALSE) {
         clks_shell_ready = CLKS_FALSE;
@@ -702,6 +1056,7 @@ void clks_shell_init(void) {
     clks_shell_writeln("");
     clks_shell_writeln("CLeonOS interactive shell ready");
     clks_shell_writeln("type 'help' for commands");
+    clks_shell_writeln("/temp is writable in kernel shell mode");
     clks_shell_prompt();
 
     clks_log(CLKS_LOG_INFO, "SHELL", "INTERACTIVE LOOP ONLINE");