libos: Add FileSystem

libos/CMakeLists.txt

@@ -6,6 +6,7 @@ set(SOURCES
     ${HEADERS}
     src/ArgumentParser.cpp
     src/File.cpp
+    src/FileSystem.cpp
     src/Main.cpp
 )
 

libos/include/os/FileSystem.h

@@ -0,0 +1,21 @@
+#pragma once
+#include <luna/Result.h>
+#include <luna/StringView.h>
+#include <sys/types.h>
+
+namespace os
+{
+    namespace FileSystem
+    {
+        bool exists(StringView path);
+
+        bool is_directory(StringView path);
+
+        Result<void> create_directory(StringView path, mode_t mode);
+
+        Result<void> remove(StringView path);
+
+        Result<String> working_directory();
+        Result<String> home_directory();
+    }
+}

libos/src/FileSystem.cpp

@@ -0,0 +1,69 @@
+#include <luna/Ignore.h>
+#include <luna/String.h>
+#include <os/FileSystem.h>
+
+#include <errno.h>
+#include <pwd.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+namespace os::FileSystem
+{
+    bool exists(StringView path)
+    {
+        struct stat st;
+
+        if (stat(path.chars(), &st) < 0) return false;
+
+        return true;
+    }
+
+    bool is_directory(StringView path)
+    {
+        struct stat st;
+
+        if (stat(path.chars(), &st) < 0) return false;
+
+        return S_ISDIR(st.st_mode);
+    }
+
+    Result<void> create_directory(StringView path, mode_t mode)
+    {
+        long rc = syscall(SYS_mkdir, path.chars(), mode);
+        int _ignore = TRY(Result<int>::from_syscall(rc));
+
+        ignore(_ignore);
+
+        return {};
+    }
+
+    Result<void> remove(StringView path)
+    {
+        long rc = syscall(SYS_unlink, path.chars(), 0);
+        int _ignore = TRY(Result<int>::from_syscall(rc));
+
+        ignore(_ignore);
+
+        return {};
+    }
+
+    Result<String> working_directory()
+    {
+        char* ptr = getcwd(NULL, 0);
+        if (!ptr) return err(errno);
+        return String { ptr };
+    }
+
+    Result<String> home_directory()
+    {
+        char* home = getenv("HOME");
+        if (home) return String::from_cstring(home);
+
+        struct passwd* pw = getpwuid(getuid());
+        if (!pw) return err(ENOENT);
+
+        return String::from_cstring(pw->pw_dir);
+    }
+}