ipc_recv (nr 507)

Receive a message from an IPC channel (blocking).

Signature

ipc_recv(fd: i32, msg_ptr: *mut IpcMessage, flags: u32) → 0 or -errno

Arguments

Arg	Register	Description
fd	rdi	Channel recv-end fd (from `ipc_create`)
msg_ptr	rsi	Pointer to `IpcMessage` buffer for received message
flags	rdx	`IPC_NONBLOCK` (0x1) for non-blocking mode

Return value

On success, writes the received message to msg_ptr and returns 0.

Errors

Error	Condition
EFAULT	`msg_ptr` is invalid
EBADF	`fd` is not a valid channel recv-end
EPIPE	Send end has been closed and channel is empty
EAGAIN	`IPC_NONBLOCK` set and no message available
EMFILE	fd table full during fd transfer installation

Description

Receives a message from the channel. If no message is available and IPC_NONBLOCK is not set, the calling thread blocks until a sender posts a message.

If the received message carries file descriptors (msg.fds entries != -1), the transferred fd objects are installed in the receiver’s fd table and the fds array is rewritten with the new fd numbers before being copied to user memory.

For async (non-blocking, multiplexed) receiving, use OP_IPC_RECV via io_submit instead.

Implementation

osl/src/ipc.rs — sys_ipc_recv

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