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utimensat

Implemented in Antinomie 0.7.0 · Syscall list

long utimensat(int dfd, const char *filename, struct __kernel_timespec *utimes, int flags);
Number (x86-64) 280
ABI common
Kernel entry point sys_utimensat

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

Sets the access and modification times of a file with nanosecond precision, relative to a directory descriptor.

Name Type Meaning
dfd (arg0) int Directory file descriptor that a relative path is resolved against, or AT_FDCWD (-100) for the current directory.
filename (arg1) const char * Path of the file, as a NUL-terminated string in user memory.
utimes (arg2) struct __kernel_timespec * Pointer to an array of two time values.
flags (arg3) int Option flags that change the behavior of the call.

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
-2 ENOENT A path component or the named object does not exist.
-1 EPERM The operation is not permitted for this process.

utimensat(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
filename (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
utimes (arg2) Entry the pointer itself, as a raw word args.2, args.raw[2]
↳ pointee Entry structure timespec[2] (fixed size) arg2.data always
flags (arg3) Entry raw scalar word; Syscall Trace also decodes it into flag names (nofollow_empty group), listing unknown bits separately args.3, args.flags
  • Result: ret, syscall.errno, syscall.success, syscall.duration_ns.
  • Argument words: args.dfd (arg0), args.filename (arg1), args.utimes (arg2), args.flags (arg3); 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 timespec[2] behind utimes (arg2): args.utimes.<member> for tv_nsec, tv_sec.

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.