Function sys_open 

pub fn sys_open(_path: &str, _flags: u32) -> SyscallResult<u64>

Open a file or directory, returning a file descriptor.

Resolves the given path through the VeridianOS VFS (Virtual File System) and returns a new file descriptor for the opened file. The file descriptor is an index into the per-process file descriptor table and is valid until closed with sys_close.

The caller must hold a capability granting access to the target file or its parent directory. The required capability rights depend on the open flags: READ for O_RDONLY, WRITE for O_WRONLY or O_RDWR, and both for O_RDWR.

Arguments

• path - Path to the file or directory to open. Can be absolute (starting with /) or relative to the process’s current working directory. The path is resolved through the VFS layer (RamFS, DevFS, ProcFS, or BlockFS depending on the mount point).
• flags - Bitwise OR of open mode flags:
  • O_RDONLY (0x000) - Open for reading only.
  • O_WRONLY (0x001) - Open for writing only.
  • O_RDWR (0x002) - Open for reading and writing.
  • O_CREAT (0x100) - Create the file if it does not exist.
  • O_TRUNC (0x200) - Truncate the file to zero length if it exists.
  • O_APPEND (0x400) - Writes always append to end of file.
  • O_EXCL (0x800) - With O_CREAT, fail if the file already exists.

Returns

• Ok(fd) - A file descriptor (unsigned 64-bit integer) for the opened file. The descriptor is the lowest available unused fd in the process’s table.

Errors

• SyscallError::NotFound - The file does not exist and O_CREAT was not specified, or a path component does not exist.
• SyscallError::PermissionDenied - The caller lacks the required capability for the requested access mode.
• SyscallError::AlreadyExists - O_CREAT | O_EXCL was specified and the file already exists.
• SyscallError::InvalidArgument - The path is empty, contains null bytes, or flags contains an invalid combination.
• SyscallError::IoError - An I/O error occurred accessing the underlying storage.

Examples

use veridian_kernel::pkg::sdk::syscall_api::{sys_close, sys_open};

// Open an existing file for reading
let fd = sys_open("/etc/config.toml", 0x000).expect("open failed");

// Create a new file for writing (O_WRONLY | O_CREAT | O_TRUNC)
let fd_new = sys_open("/tmp/output.txt", 0x001 | 0x100 | 0x200).expect("create failed");

sys_close(fd).expect("close failed");
sys_close(fd_new).expect("close failed");