Create system calls for truncate and write

kernel/include/vfs/vfs.hpp

@@ -29,6 +29,8 @@ int64_t statfs(const char* mount_point, statfs_info& info);
 int64_t mkdir(const char* file);
 int64_t rm(const char* file);
 int64_t read(size_t fd, char* buffer, size_t count, size_t offset = 0);
+int64_t write(size_t fd, char* buffer, size_t count, size_t offset = 0);
+int64_t truncate(size_t fd, size_t size);
 int64_t entries(size_t fd, char* buffer, size_t size);
 int64_t mounts(char* buffer, size_t size);
 

kernel/src/system_calls.cpp

@@ -140,6 +140,22 @@ void sc_read(interrupt::syscall_regs* regs){
     regs->rax = vfs::read(fd, buffer, max, offset);
 }
 
+void sc_write(interrupt::syscall_regs* regs){
+    auto fd = regs->rbx;
+    auto buffer = reinterpret_cast<char*>(regs->rcx);
+    auto max = regs->rdx;
+    auto offset = regs->rsi;
+
+    regs->rax = vfs::write(fd, buffer, max, offset);
+}
+
+void sc_truncate(interrupt::syscall_regs* regs){
+    auto fd = regs->rbx;
+    auto size = regs->rcx;
+
+    regs->rax = vfs::truncate(fd, size);
+}
+
 void sc_entries(interrupt::syscall_regs* regs){
     auto fd = regs->rbx;
     auto buffer = reinterpret_cast<char*>(regs->rcx);
@@ -305,6 +321,14 @@ void system_call_entry(interrupt::syscall_regs* regs){
             sc_statfs(regs);
             break;
 
+        case 311:
+            sc_write(regs);
+            break;
+
+        case 312:
+            sc_truncate(regs);
+            break;
+
         case 400:
             sc_datetime(regs);
             break;

kernel/src/vfs/vfs.cpp

@@ -304,6 +304,48 @@ int64_t vfs::read(size_t fd, char* buffer, size_t count, size_t offset){
     return read;
 }
 
+int64_t vfs::write(size_t fd, char* buffer, size_t count, size_t offset){
+    if(!scheduler::has_handle(fd)){
+        return -std::ERROR_INVALID_FILE_DESCRIPTOR;
+    }
+
+    auto path = scheduler::get_handle(fd);
+
+    if(path.empty()){
+        return -std::ERROR_INVALID_FILE_PATH;
+    }
+
+    auto& fs = get_fs(path);
+    auto fs_path = get_fs_path(path, fs);
+
+    size_t written = 0;
+    auto result = fs.file_system->write(fs_path, buffer, count, offset, written);
+
+    if(result > 0){
+        return -result;
+    }
+
+    return written;
+}
+
+int64_t vfs::truncate(size_t fd, size_t size){
+    if(!scheduler::has_handle(fd)){
+        return -std::ERROR_INVALID_FILE_DESCRIPTOR;
+    }
+
+    auto path = scheduler::get_handle(fd);
+
+    if(path.empty()){
+        return -std::ERROR_INVALID_FILE_PATH;
+    }
+
+    auto& fs = get_fs(path);
+    auto fs_path = get_fs_path(path, fs);
+
+    auto result = fs.file_system->truncate(fs_path, size);
+    return result > 0 ? -result : 0;
+}
+
 int64_t vfs::direct_read(const std::string& file_path, std::string& content){
     auto path = get_path(file_path.c_str());
     auto& fs = get_fs(path);