From 74bfb930f2b3d4d7941bca0cab4cc7654456fb2b Mon Sep 17 00:00:00 2001
From: Bananymous <oskari.alaranta@bananymous.com>
Date: Wed, 25 Oct 2023 21:45:04 +0300
Subject: [PATCH] Kernel/LibC: Add syscall and wrapper for unlink

---
 kernel/include/kernel/Process.h |  1 +
 kernel/kernel/Process.cpp       | 22 +++++++++++++++++++++-
 kernel/kernel/Syscall.cpp       |  3 +++
 libc/include/sys/syscall.h      |  1 +
 libc/unistd.cpp                 |  5 +++++
 5 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/kernel/include/kernel/Process.h b/kernel/include/kernel/Process.h
index 54884377..95139aee 100644
--- a/kernel/include/kernel/Process.h
+++ b/kernel/include/kernel/Process.h
@@ -98,6 +98,7 @@ namespace Kernel
 		BAN::ErrorOr<long> sys_write(int fd, const void* buffer, size_t count);
 		BAN::ErrorOr<long> sys_create(const char*, mode_t);
 		BAN::ErrorOr<long> sys_create_dir(const char*, mode_t);
+		BAN::ErrorOr<long> sys_unlink(const char*);
 
 		BAN::ErrorOr<long> sys_chmod(const char*, mode_t);
 
diff --git a/kernel/kernel/Process.cpp b/kernel/kernel/Process.cpp
index b6edb963..e8bee629 100644
--- a/kernel/kernel/Process.cpp
+++ b/kernel/kernel/Process.cpp
@@ -634,7 +634,7 @@ namespace Kernel
 		auto directory = absolute_path.sv().substring(0, index);
 		auto file_name = absolute_path.sv().substring(index);
 
-		auto parent_inode = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, directory, O_WRONLY)).inode;
+		auto parent_inode = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, directory, O_EXEC | O_WRONLY)).inode;
 
 		if (Inode::Mode(mode).ifdir())
 			TRY(parent_inode->create_directory(file_name, mode, m_credentials.euid(), m_credentials.egid()));
@@ -762,6 +762,26 @@ namespace Kernel
 		return 0;
 	}
 
+	BAN::ErrorOr<long> Process::sys_unlink(const char* path)
+	{
+		LockGuard _(m_lock);
+		validate_string_access(path);
+		
+		auto absolute_path = TRY(absolute_path_of(path));
+
+		size_t index = absolute_path.size();
+		for (; index > 0; index--)
+			if (absolute_path[index - 1] == '/')
+				break;
+		auto directory = absolute_path.sv().substring(0, index);
+		auto file_name = absolute_path.sv().substring(index);
+
+		auto parent = TRY(VirtualFileSystem::get().file_from_absolute_path(m_credentials, directory, O_EXEC | O_WRONLY)).inode;
+		TRY(parent->unlink(file_name));
+
+		return 0;
+	}
+
 	BAN::ErrorOr<long> Process::sys_chmod(const char* path, mode_t mode)
 	{
 		if (mode & S_IFMASK)
diff --git a/kernel/kernel/Syscall.cpp b/kernel/kernel/Syscall.cpp
index 6b0a4249..ab7c3ce8 100644
--- a/kernel/kernel/Syscall.cpp
+++ b/kernel/kernel/Syscall.cpp
@@ -208,6 +208,9 @@ namespace Kernel
 		case SYS_CREATE_DIR:
 			ret = Process::current().sys_create_dir((const char*)arg1, (mode_t)arg2);
 			break;
+		case SYS_UNLINK:
+			ret = Process::current().sys_unlink((const char*)arg1);
+			break;
 		default:
 			dwarnln("Unknown syscall {}", syscall);
 			break;
diff --git a/libc/include/sys/syscall.h b/libc/include/sys/syscall.h
index 0daa6d7a..b6eacdf8 100644
--- a/libc/include/sys/syscall.h
+++ b/libc/include/sys/syscall.h
@@ -58,6 +58,7 @@ __BEGIN_DECLS
 #define SYS_CHMOD 55
 #define SYS_CREATE 56 // creat, mkfifo
 #define SYS_CREATE_DIR 57 // mkdir
+#define SYS_UNLINK 58
 
 __END_DECLS
 
diff --git a/libc/unistd.cpp b/libc/unistd.cpp
index b334b4d4..b118da95 100644
--- a/libc/unistd.cpp
+++ b/libc/unistd.cpp
@@ -210,6 +210,11 @@ void syncsync(int should_block)
 	syscall(SYS_SYNC, should_block);
 }
 
+int unlink(const char* path)
+{
+	return syscall(SYS_UNLINK, path);
+}
+
 pid_t getpid(void)
 {
 	return syscall(SYS_GET_PID);