File and Directory Operations

open and openat

Supported functionality of open in SCML:

access_mode =
    O_RDONLY |
    O_WRONLY |
    O_RDWR;
creation_flags =
    O_CLOEXEC |
    O_DIRECTORY |
    O_EXCL |
    O_NOCTTY |
    O_NOFOLLOW |
    O_TRUNC;
status_flags =
    O_APPEND |
    O_ASYNC |
    O_DIRECT |
    O_LARGEFILE |
    O_NOATIME |
    O_NONBLOCK |
    O_SYNC;

// Open an existing file
open(
    path,
    flags = <access_mode> | <creation_flags> | <status_flags>,
);
openat(
    dirfd,
    path,
    flags = <access_mode> | <creation_flags> | <status_flags>,
);

// Create a new file
open(
    path,
    flags = O_CREAT | <access_mode> | <creation_flags> | <status_flags>,
    mode
);
openat(
    dirfd,
    path,
    flags = O_CREAT | <access_mode> | <creation_flags> | <status_flags>,
    mode
);

// Status flags that are meaningful with O_PATH
opath_valid_flags = O_CLOEXEC | O_DIRECTORY | O_NOFOLLOW;
// All other flags are ignored with O_PATH
opath_ignored_flags = O_CREAT | <creation_flags> | <status_flags>;
// Obtain a file descriptor to indicate a location in FS
open(
    path,
    flags = O_PATH | <opath_valid_flags> | <opath_ignored_flags>
);
openat(
    dirfd,
    path,
    flags = O_PATH | <opath_valid_flags> | <opath_ignored_flags>
);

// Create an unnamed file
// open(path, flags = O_TMPFILE | <creation_flags> | <status_flags>)

Silently-ignored flags:

• O_NOCTTY
• O_DSYNC
• O_SYNC
• O_LARGEFILE
• O_NOATIME
• O_NOCTTY

Partially-supported flags:

• O_PATH

Unsupported flags:

• O_TMPFILE

Supported and unsupported functionality of openat are the same as open. The SCML rules are omitted for brevity.

For more information, see the man page.

renameat2

Supported functionality in SCML:

// Rename a file, moving it between directories if required.
renameat2(olddirfd, oldpath, newdirfd, newpath, 0);

Unsupported flags:

• RENAME_EXCHANGE
• RENAME_NOREPLACE
• RENAME_WHITEOUT

For more information, see the man page.

lseek

Supported functionality in SCML:

// Set file offset
lseek(
    fd, offset,
    whence = SEEK_SET | SEEK_CUR | SEEK_END
);

Unsupported flags:

• SEEK_DATA
• SEEK_HOLE

For more information, see the man page.

newfstatat

Supported functionality in SCML:

// Retrieve file status by file descriptor
newfstatat(
    dirfd, path, statbuf,
    flags = AT_EMPTY_PATH | AT_SYMLINK_NOFOLLOW
);

Silently-ignored flags:

• AT_NO_AUTOMOUNT

For more information, see the man page.