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mount_setattr

Implemented in Antinomie 0.7.0 · Syscall list

long mount_setattr(int dfd, const char *path, unsigned int flags, struct mount_attr *uattr, size_t usize);
Number (x86-64) 442
ABI common
Kernel entry point sys_mount_setattr

This is the raw kernel prototype from the pinned Linux 6.12.94 schema, not the libc wrapper.

Changes the properties of a mount or a whole mount tree, such as read-only or id mapping.

Name Type Meaning
dfd (arg0) int Directory file descriptor that a relative path is resolved against, or AT_FDCWD (-100) for the current directory.
path (arg1) const char * Path, as a NUL-terminated string in user memory.
flags (arg2) unsigned int Option flags that change the behavior of the call.
uattr (arg3) struct mount_attr * Pointer to an attribute union.
usize (arg4) size_t Size of the attribute structure.

On success: 0.

In an Antinomie trace the Return column and the ret filter field show the raw kernel return value. On failure that is the negative errno, for example -2 for ENOENT, not the -1 plus errno that the libc wrapper gives. syscall.errno holds the positive errno and syscall.success is false.

Raw return Name Meaning
-22 EINVAL An argument is invalid.
-1 EPERM The operation is not permitted for this process.

mount_setattr(2) on man7.org

Coverage mark: Implemented. Every pointer argument has a capture rule in the pinned kernel patch and none of them records a “no decoder”, “address only” or “not observed” gap on any code path. Individual values can still be incomplete on a particular call; see the capture statuses.

Every call is recorded as an Entry record (the six argument words and the pointees copied at entry) and an Exit record (the return value and the pointees copied at exit).

Argument When How Recorded field key Condition
dfd (arg0) Entry raw scalar word args.0, args.dfd
path (arg1) Entry the pointer itself, as a raw word args.1, args.raw[1]
↳ pointee Entry NUL-terminated string, up to 4,096 bytes (PATH_MAX) arg1.path always
flags (arg2) Entry raw scalar word; Syscall Trace also decodes it into flag names (mount_setattr group), listing unknown bits separately args.2, args.flags
uattr (arg3) Entry the pointer itself, as a raw word args.3, args.raw[3]
↳ pointee Entry structure mount_attr, size from usize (arg4), versioned arg3.mount_attr always
usize (arg4) Entry raw scalar word args.4, args.usize
  • Result: ret, syscall.errno, syscall.success, syscall.duration_ns.
  • Argument words: args.dfd (arg0), args.path (arg1), args.flags (arg2), args.uattr (arg3), args.usize (arg4); args.0 to args.5 by position.
  • Captured strings: the args.<name> field of a path argument, and args.path, give the captured text instead of the pointer.
  • Structure mount_attr behind uattr (arg3): args.uattr.<member> for attr_clr, attr_set, propagation, userns_fd.

See Syscall Trace filter for the full syntax.

For what the capture statuses mean, see Capture statuses. For what is never recorded, see Known gaps.