implement ls, rmdir and mkdir

errors/errno.fugu

@@ -1451,4 +1451,5 @@ errors shelly SHELLY_ERR_ {
     failure WRITE                "String write failed",
     failure SPAWN_RPC                 "Spawn RPC failed",
     failure PS_RPC                    "ps RPC failed",
+    failure FILE_NOT_FOUND            "file not found",
 };

usr/shelly/shelly_cmd.c

@@ -1,4 +1,6 @@
 #include <stdlib.h>
+#include <fs/fs.h>
+#include <fs/dirent.h>
 #include "shelly.h"
 
 __attribute__((__used__))
@@ -41,9 +43,36 @@ static errval_t shelly_cmd_help(char * line) {
 }
 
 static errval_t shelly_cmd_ls(char * line) {
-    // errval_t err;
+    errval_t err;
 
-    return SYS_ERR_OK;
+    fs_dirhandle_t dh;
+    err = opendir(line, &dh);
+    if (err_is_fail(err)) {
+        return err;
+    }
+
+    if (dh == NULL) {
+        return SHELLY_ERR_FILE_NOT_FOUND;
+    }
+
+    char buf[256];
+
+    do {
+        char *name;
+        err = readdir(dh, &name);
+        if (err_no(err) == FS_ERR_INDEX_BOUNDS) {
+            break;
+        } else if (err_is_fail(err)) {
+            goto err_out;
+        }
+        snprintf(buf, 256, "%s\n\r", name);
+        err = shelly_write_str(buf);
+        if (err_is_fail(err)) goto err_out;
+    } while(err_is_ok(err));
+
+    return closedir(dh);
+    err_out:
+    return err;
 }
 
 static errval_t shelly_cmd_cat(char * line) {
@@ -62,15 +91,11 @@ static errval_t shelly_cmd_cat(char * line) {
 }
 
 static errval_t shelly_cmd_mkdir(char * line) {
-    // errval_t err;
+    return mkdir(line);
-
-    return SYS_ERR_OK;
 }
 
 static errval_t shelly_cmd_rmdir(char * line) {
-    // errval_t err;
+    return rmdir(line);
-
-    return SYS_ERR_OK;
 }
 
 static errval_t shelly_cmd_echo(char * line) {