git: a43b745aaf4f - main - linux sendfile: Fix handling of non-blocking sockets

From: Mark Johnston <markj_at_FreeBSD.org>
Date: Wed, 13 Nov 2024 14:16:36 UTC
The branch main has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=a43b745aaf4f5bbc96875d2ab3ec9bea8024eda4

commit a43b745aaf4f5bbc96875d2ab3ec9bea8024eda4
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2024-11-13 14:15:47 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2024-11-13 14:15:47 +0000

    linux sendfile: Fix handling of non-blocking sockets
    
    FreeBSD sendfile() may perform a partial transfer and return EAGAIN if
    the socket is non-blocking.  Linux sendfile() expects no error in this
    case, so squash EAGAIN.
    
    PR:             282495
    Tested by:      pieter@krikkit.xyz
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D47447
---
 sys/compat/linux/linux_socket.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/compat/linux/linux_socket.c b/sys/compat/linux/linux_socket.c
index 15431bf3127c..6c6751ad30a8 100644
--- a/sys/compat/linux/linux_socket.c
+++ b/sys/compat/linux/linux_socket.c
@@ -2538,6 +2538,13 @@ sendfile_sendfile(struct thread *td, struct file *fp, l_int out,
 		current_offset = *offset;
 	error = fo_sendfile(fp, out, NULL, NULL, current_offset, count,
 	    sbytes, 0, td);
+	if (error == EAGAIN && *sbytes > 0) {
+		/*
+		 * The socket is non-blocking and we didn't finish sending.
+		 * Squash the error, since that's what Linux does.
+		 */
+		error = 0;
+	}
 	if (error == 0) {
 		current_offset += *sbytes;
 		if (offset != NULL)