apps: Add ls

Istg Vector has a curse or something, the annoying and inexplicable bugs always end up in Vector.

apps/CMakeLists.txt

@@ -11,3 +11,4 @@ luna_app(cat.c cat)
 luna_app(edit.c edit)
 luna_app(sh.c sh)
 luna_app(date.c date)
+luna_app(ls.c ls)

apps/ls.c

@@ -0,0 +1,32 @@
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+
+int main(int argc, char** argv)
+{
+    const char* pathname;
+    if (argc == 1) pathname = "/";
+    else
+        pathname = argv[1];
+
+    DIR* dp = opendir(pathname);
+    if (!dp)
+    {
+        perror("opendir");
+        return 1;
+    }
+
+    int first_ent = 1;
+    do {
+        struct dirent* ent = readdir(dp);
+        if (!ent) break;
+        printf(first_ent ? "%s" : " %s", ent->d_name);
+        first_ent = 0;
+    } while (1);
+
+    putchar('\n');
+
+    closedir(dp);
+    return 0;
+}

kernel/src/fs/tmpfs/FileSystem.cpp

@@ -10,6 +10,7 @@ namespace TmpFS
     {
         SharedPtr<FileSystem> fs = TRY(adopt_shared_if_nonnull(new (std::nothrow) FileSystem()));
         SharedPtr<VFS::Inode> root = TRY(fs->create_dir_inode({}));
+        root->chmod(0755);
         fs->set_root(root);
         return (SharedPtr<VFS::FileSystem>)fs;
     }

libc/CMakeLists.txt

@@ -13,6 +13,7 @@ set(SOURCES
     src/ctype.cpp
     src/time.cpp
     src/init.cpp
+    src/dirent.cpp
     src/setjmp.cpp
     src/sys/stat.cpp
     src/sys/mman.cpp

libc/include/dirent.h

@@ -0,0 +1,32 @@
+/* dirent.h: Directory streams interface. */
+
+#ifndef _DIRENT_H
+#define _DIRENT_H
+
+#include <sys/types.h>
+
+typedef struct
+{
+    int _fd;
+} DIR;
+
+struct dirent
+{
+    ino_t d_ino;
+    char d_name[129];
+};
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    DIR* opendir(const char* path);
+    struct dirent* readdir(DIR* stream);
+    int closedir(DIR* stream);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

libc/src/dirent.cpp

@@ -0,0 +1,55 @@
+#include <bits/getdents.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+extern "C"
+{
+    DIR* opendir(const char* path)
+    {
+        DIR* dp = (DIR*)malloc(sizeof(DIR));
+        if (!dp) { return nullptr; }
+
+        // FIXME: Use O_DIRECTORY (validate that path is actually a directory)
+        int fd = open(path, O_RDONLY);
+        if (fd < 0)
+        {
+            free(dp);
+            return nullptr;
+        }
+
+        dp->_fd = fd;
+
+        return dp;
+    }
+
+    struct dirent* readdir(DIR* stream)
+    {
+        // FIXME: Very hackish, right now luna_dirent and dirent have the same layout.
+        static luna_dirent ent;
+
+        long rc = syscall(SYS_getdents, stream->_fd, &ent, 1);
+        if (rc < 0)
+        {
+            errno = -rc;
+            return nullptr;
+        }
+
+        // End-of-file (no more directory entries)
+        if (rc < 1) return nullptr;
+
+        return (struct dirent*)&ent;
+    }
+
+    int closedir(DIR* stream)
+    {
+        if (close(stream->_fd) < 0) return -1;
+
+        free(stream);
+
+        return 0;
+    }
+}

libluna/include/luna/Vector.h

@@ -106,13 +106,13 @@ template <typename T> class Vector
     const T& operator[](usize index) const
     {
         check(index < m_size);
-        return m_data[m_size];
+        return m_data[index];
     }
 
     T& operator[](usize index)
     {
         check(index < m_size);
-        return m_data[m_size];
+        return m_data[index];
     }
 
     Iterator begin()