epoll_ctl
Partial in Antinomie 0.7.0 · Syscall list
Synopsis
Section titled “Synopsis”long epoll_ctl(int epfd, int op, int fd, struct epoll_event *event);| Number (x86-64) | 233 |
| ABI | common |
| Kernel entry point | sys_epoll_ctl |
This is the raw kernel prototype from the pinned Linux 6.12.94 schema, not the libc wrapper.
Description
Section titled “Description”Adds, changes or removes a file descriptor in an epoll instance, with the events of interest.
Arguments
Section titled “Arguments”| Name | Type | Meaning |
|---|---|---|
epfd (arg0) |
int |
File descriptor of an epoll instance. |
op (arg1) |
int |
Operation selector. |
fd (arg2) |
int |
File descriptor to operate on. |
event (arg3) |
struct epoll_event * |
Pointer to an event structure. |
Return value
Section titled “Return value”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.
Common errors
Section titled “Common errors”| Raw return | Name | Meaning |
|---|---|---|
-9 |
EBADF |
A file descriptor is not valid for this operation. |
-17 |
EEXIST |
The object already exists. |
-2 |
ENOENT |
A path component or the named object does not exist. |
Man page
Section titled “Man page”Captured by Antinomie
Section titled “Captured by Antinomie”Coverage mark: Partial. The epoll_event is decoded for EPOLL_CTL_ADD and EPOLL_CTL_MOD. Any other operation (except EPOLL_CTL_DEL, which has none) records it with the “no decoder” status.
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 |
|---|---|---|---|---|
epfd (arg0) |
Entry | raw scalar word | args.0, args.epfd |
|
op (arg1) |
Entry | raw scalar word | args.1, args.op |
|
fd (arg2) |
Entry | raw scalar word | args.2, args.fd |
|
event (arg3) |
Entry | the pointer itself, as a raw word | args.3, args.raw[3] |
|
| ↳ pointee | Entry | structure epoll_event (12 bytes) |
arg3.epoll_event |
op is not EPOLL_CTL_DEL; status “no decoder” if op is not ADD or MOD |
Filter fields
Section titled “Filter fields”- Result:
ret,syscall.errno,syscall.success,syscall.duration_ns. - Argument words:
args.epfd(arg0),args.op(arg1),args.fd(arg2),args.event(arg3);args.0toargs.5by position. - Structure
epoll_event[]behindevent(arg3):args.event.<member>fordata,events.
See Syscall Trace filter for the full syntax.
Known gaps
Section titled “Known gaps”- An
opother than ADD, MOD or DEL records the event pointer with the “no decoder” status. - See the coverage mark above for the code paths that record a gap.
For what the capture statuses mean, see Capture statuses. For what is never recorded, see Known gaps.