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msgctl

Partial in Antinomie 0.7.0 · Syscall list

long msgctl(int msqid, int cmd, struct msqid_ds *buf);
Number (x86-64) 71
ABI common
Kernel entry point sys_msgctl

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

Queries, changes or removes a System V message queue.

Name Type Meaning
msqid (arg0) int System V message queue id.
cmd (arg1) int Command or operation selector.
buf (arg2) struct msqid_ds * Pointer to a data buffer.

On success: a command-specific value, usually 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
-13 EACCES Permission denied.
-22 EINVAL An argument is invalid.
-1 EPERM The operation is not permitted for this process.

msgctl(2) on man7.org

Coverage mark: Partial. Known commands decode their structure. An unknown command records an ipc.unknown_selector “no decoder” gap.

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
msqid (arg0) Entry raw scalar word args.0, args.msqid
cmd (arg1) Entry raw scalar word args.1, args.cmd
buf (arg2) Entry the pointer itself, as a raw word args.2, args.raw[2]
↳ pointee Entry and exit by cmd: msqid64_ds or msginfo ipc.control input at entry for IPC_SET; output at exit when the result is 0 or greater for the query commands
  • Result: ret, syscall.errno, syscall.success, syscall.duration_ns.
  • Argument words: args.msqid (arg0), args.cmd (arg1), args.buf (arg2); args.0 to args.5 by position.
  • Structure msqid64_ds behind buf (arg2): args.buf.<member> for msg_cbytes, msg_ctime, msg_lrpid, msg_lspid, msg_perm.__pad2, msg_perm.cgid, msg_perm.cuid, msg_perm.gid, msg_perm.key, msg_perm.mode, msg_perm.seq, msg_perm.uid, msg_qbytes, msg_qnum, msg_rtime, msg_stime.

See Syscall Trace filter for the full syntax.

  • An unknown command records ipc.unknown_selector 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.