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pidfd_send_signal

Implemented in Antinomie 0.7.0 · Syscall list

long pidfd_send_signal(int pidfd, int sig, siginfo_t *info, unsigned int flags);
Number (x86-64) 424
ABI common
Kernel entry point sys_pidfd_send_signal

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

Sends a signal to the process behind a pid file descriptor.

Name Type Meaning
pidfd (arg0) int File descriptor referring to a process.
sig (arg1) int Signal number.
info (arg2) siginfo_t * Pointer to an information structure.
flags (arg3) unsigned 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
-9 EBADF A file descriptor is not valid for this operation.
-1 EPERM The operation is not permitted for this process.

pidfd_send_signal(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
pidfd (arg0) Entry raw scalar word args.0, args.pidfd
sig (arg1) Entry raw scalar word args.1, args.sig
info (arg2) Entry the pointer itself, as a raw word args.2, args.raw[2]
↳ pointee Entry structure siginfo_t (128 bytes) signal.siginfo the pointer is not NULL
flags (arg3) Entry raw scalar word; Syscall Trace also decodes it into flag names (pidfd_signal group), listing unknown bits separately args.3, args.flags
  • Result: ret, syscall.errno, syscall.success, syscall.duration_ns.
  • Argument words: args.pidfd (arg0), args.sig (arg1), args.info (arg2), args.flags (arg3); args.0 to args.5 by position.
  • Structure siginfo_t[] behind info (arg2): args.info.<member> for _si_pad[0], _si_pad[10], _si_pad[11], _si_pad[12], _si_pad[13], _si_pad[14], _si_pad[15], _si_pad[16], _si_pad[17], _si_pad[18], _si_pad[19], _si_pad[1], _si_pad[20], _si_pad[21], _si_pad[22], _si_pad[23], _si_pad[24], _si_pad[25], _si_pad[26], _si_pad[27], _si_pad[28], _si_pad[29], _si_pad[2], _si_pad[30], _si_pad[31], _si_pad[3], _si_pad[4], _si_pad[5], _si_pad[6], _si_pad[7], _si_pad[8], _si_pad[9], si_code, si_errno, si_signo.

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.