open_by_handle_at
Implemented in Antinomie 0.7.0 · Syscall list
Synopsis
Section titled “Synopsis”long open_by_handle_at(int mountdirfd, struct file_handle *handle, int flags);| Number (x86-64) | 304 |
| ABI | common |
| Kernel entry point | sys_open_by_handle_at |
This is the raw kernel prototype from the pinned Linux 6.12.94 schema, not the libc wrapper.
Description
Section titled “Description”Opens a file from a handle made by name_to_handle_at. It needs the capability to bypass permission checks.
Arguments
Section titled “Arguments”| Name | Type | Meaning |
|---|---|---|
mountdirfd (arg0) |
int |
Descriptor of a directory on the mount. |
handle (arg1) |
struct file_handle * |
Pointer to a file_handle structure. |
flags (arg2) |
int |
Option flags that change the behavior of the call. |
Return value
Section titled “Return value”On success: A new file descriptor (a non-negative number).
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.
Common errors
Section titled “Common errors”| Raw return | Name | Meaning |
|---|---|---|
-116 |
ESTALE |
The file handle is stale. |
-1 |
EPERM |
The operation is not permitted for this process. |
Man page
Section titled “Man page”open_by_handle_at(2) on man7.org
Captured by Antinomie
Section titled “Captured by Antinomie”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).
Arguments
Section titled “Arguments”| Argument | When | How | Recorded field key | Condition |
|---|---|---|---|---|
mountdirfd (arg0) |
Entry | raw scalar word | args.0, args.mountdirfd |
|
handle (arg1) |
Entry | the pointer itself, as a raw word | args.1, args.raw[1] |
|
| ↳ pointee | Entry | structure file_handle header |
handle.header |
always |
| ↳ pointee | Entry | the handle bytes, length from the header’s handle_bytes up to 128 |
handle.bytes |
always |
flags (arg2) |
Entry | raw scalar word; Syscall Trace also decodes it into flag names (open group), listing unknown bits separately |
args.2, args.flags |
Filter fields
Section titled “Filter fields”- Result:
ret,syscall.errno,syscall.success,syscall.duration_ns. - Argument words:
args.mountdirfd(arg0),args.handle(arg1),args.flags(arg2);args.0toargs.5by position.
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.