sendto
Implemented in Antinomie 0.7.0 · Syscall list
Synopsis
Section titled “Synopsis”long sendto(int fd, void *buff, size_t len, unsigned int flags, struct sockaddr *addr, int addr_len);| Number (x86-64) | 44 |
| ABI | common |
| Kernel entry point | sys_sendto |
This is the raw kernel prototype from the pinned Linux 6.12.94 schema, not the libc wrapper.
Description
Section titled “Description”Sends data on a socket, optionally to an explicit destination address.
Arguments
Section titled “Arguments”| Name | Type | Meaning |
|---|---|---|
fd (arg0) |
int |
File descriptor to operate on. |
buff (arg1) |
void * |
Pointer to the data to send. |
len (arg2) |
size_t |
Number of bytes to send. |
flags (arg3) |
unsigned int |
Option flags that change the behavior of the call. |
addr (arg4) |
struct sockaddr * |
Pointer to the destination address, or NULL for a connected socket. |
addr_len (arg5) |
int |
Size of the destination address. |
Return value
Section titled “Return value”On success: The number of bytes transferred (see the description for what 0 means).
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. |
-104 |
ECONNRESET |
The connection was reset by the peer. |
-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 |
|
buff (arg1) |
Entry | the pointer itself, as a raw word | args.1, args.raw[1] |
|
| ↳ pointee | Entry | buffer; length min(len, MAX_RW_COUNT), taken from len (arg2) |
arg1.data |
always |
len (arg2) |
Entry | raw scalar word | args.2, args.len |
|
flags (arg3) |
Entry | raw scalar word; Syscall Trace also decodes it into flag names (message group), listing unknown bits separately |
args.3, args.flags |
|
addr (arg4) |
Entry | the pointer itself, as a raw word | args.4, args.raw[4] |
|
| ↳ pointee | Entry | socket address (sockaddr layout), length from addr_len (arg5) |
arg4.address |
the address pointer is not NULL |
addr_len (arg5) |
Entry | raw scalar word | args.5, args.addr_len |
Filter fields
Section titled “Filter fields”- Result:
ret,syscall.errno,syscall.success,syscall.duration_ns. - Argument words:
args.fd(arg0),args.buff(arg1),args.len(arg2),args.flags(arg3),args.addr(arg4),args.addr_len(arg5);args.0toargs.5by position. - Structure
sockaddrbehindaddr(arg4):args.addr.<member>forsa_family.
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.