poll

Implemented in Antinomie 0.7.0 · Syscall list

Synopsis

long poll(struct pollfd *ufds, unsigned int nfds, int timeout);

Number (x86-64)	7
ABI	common
Kernel entry point	sys_poll

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

Description

Waits until one of a set of file descriptors becomes ready for I/O, or a timeout expires. Each entry lists the events asked for and receives the events found.

Arguments

Name	Type	Meaning
ufds (arg0)	struct pollfd *	Pointer to an array of pollfd structures.
nfds (arg1)	unsigned int	Number of entries in the array.
timeout (arg2)	int	Timeout, as a pointer to a time structure or a value in the unit the call uses.

Return value

On success: the number of descriptors with events, 0 on timeout.

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

Raw return	Name	Meaning
-14	EFAULT	A pointer argument points outside the accessible address space.
-4	EINTR	The call was interrupted by a signal.
-22	EINVAL	An argument is invalid.

Man page

poll(2) on man7.org

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

Argument	When	How	Recorded field key	Condition
ufds (arg0)	Entry	the pointer itself, as a raw word	args.0, args.raw[0]
↳ pointee	Entry and exit	array of pollfd, count from nfds (arg1); “invalid extent” if above the descriptor limit	arg0.pollfd	at exit when the result is 0 or greater, or the call was interrupted
nfds (arg1)	Entry	raw scalar word	args.1, args.nfds
timeout (arg2)	Entry	raw scalar word	args.2, args.timeout

Filter fields

• Result: ret, syscall.errno, syscall.success, syscall.duration_ns.
• Argument words: args.ufds (arg0), args.nfds (arg1), args.timeout (arg2); args.0 to args.5 by position.
• Structure pollfd[] behind ufds (arg0): args.ufds.<member> for events, fd, revents.

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.