sendmmsg
Implemented in Antinomie 0.7.0 · Syscall list
Synopsis
Section titled “Synopsis”long sendmmsg(int fd, struct mmsghdr *msg, unsigned int vlen, unsigned int flags);| Number (x86-64) | 307 |
| ABI | 64 |
| Kernel entry point | sys_sendmmsg |
This is the raw kernel prototype from the pinned Linux 6.12.94 schema, not the libc wrapper.
Description
Section titled “Description”Sends several messages on a socket in one call.
Arguments
Section titled “Arguments”| Name | Type | Meaning |
|---|---|---|
fd (arg0) |
int |
File descriptor to operate on. |
msg (arg1) |
struct mmsghdr * |
Pointer to a message structure. |
vlen (arg2) |
unsigned int |
Number of messages or vector entries. |
flags (arg3) |
unsigned int |
Option flags that change the behavior of the call. |
Return value
Section titled “Return value”On success: the number of messages sent.
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 |
|---|---|---|
-11 |
EAGAIN |
The call would block, or a resource is temporarily unavailable. |
-32 |
EPIPE |
The other end of a pipe or socket is closed. |
Man page
Section titled “Man page”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 |
|---|---|---|---|---|
fd (arg0) |
Entry | raw scalar word | args.0, args.fd |
|
msg (arg1) |
Entry | the pointer itself, as a raw word | args.1, args.raw[1] |
|
| ↳ pointee | Entry | per message (up to vlen, capped at 1,024): the mmsghdr, its iovec array and buffers, name and control data |
arg1.mmsg.* |
always |
vlen (arg2) |
Entry | raw scalar word | args.2, args.vlen |
|
flags (arg3) |
Entry | raw scalar word; Syscall Trace also decodes it into flag names (message group), listing unknown bits separately |
args.3, args.flags |
Filter fields
Section titled “Filter fields”- Result:
ret,syscall.errno,syscall.success,syscall.duration_ns. - Argument words:
args.fd(arg0),args.msg(arg1),args.vlen(arg2),args.flags(arg3);args.0toargs.5by position. - Structure
mmsghdr[]behindmsg(arg1):args.msg.<member>formsg_hdr.msg_control,msg_hdr.msg_controllen,msg_hdr.msg_flags,msg_hdr.msg_iov,msg_hdr.msg_iovlen,msg_hdr.msg_name,msg_hdr.msg_namelen,msg_len.
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.