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-rw-r--r--src/basic/io-util.c5
-rw-r--r--src/basic/socket-util.c40
-rw-r--r--src/basic/socket-util.h2
3 files changed, 47 insertions, 0 deletions
diff --git a/src/basic/io-util.c b/src/basic/io-util.c
index 0037a37f2a..cc6dfa8c1b 100644
--- a/src/basic/io-util.c
+++ b/src/basic/io-util.c
@@ -33,6 +33,11 @@ int flush_fd(int fd) {
.events = POLLIN,
};
+ /* Read from the specified file descriptor, until POLLIN is not set anymore, throwing away everything
+ * read. Note that some file descriptors (notable IP sockets) will trigger POLLIN even when no data can be read
+ * (due to IP packet checksum mismatches), hence this function is only safe to be non-blocking if the fd used
+ * was set to non-blocking too. */
+
for (;;) {
char buf[LINE_MAX];
ssize_t l;
diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c
index 0f38f9a0f3..c634f1d564 100644
--- a/src/basic/socket-util.c
+++ b/src/basic/socket-util.c
@@ -23,6 +23,7 @@
#include <net/if.h>
#include <netdb.h>
#include <netinet/ip.h>
+#include <poll.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
@@ -970,3 +971,42 @@ fallback:
return (ssize_t) k;
}
+
+int flush_accept(int fd) {
+
+ struct pollfd pollfd = {
+ .fd = fd,
+ .events = POLLIN,
+ };
+ int r;
+
+
+ /* Similar to flush_fd() but flushes all incoming connection by accepting them and immediately closing them. */
+
+ for (;;) {
+ int cfd;
+
+ r = poll(&pollfd, 1, 0);
+ if (r < 0) {
+ if (errno == EINTR)
+ continue;
+
+ return -errno;
+
+ } else if (r == 0)
+ return 0;
+
+ cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
+ if (cfd < 0) {
+ if (errno == EINTR)
+ continue;
+
+ if (errno == EAGAIN)
+ return 0;
+
+ return -errno;
+ }
+
+ close(cfd);
+ }
+}
diff --git a/src/basic/socket-util.h b/src/basic/socket-util.h
index daa4b24a37..160f7c484b 100644
--- a/src/basic/socket-util.h
+++ b/src/basic/socket-util.h
@@ -135,6 +135,8 @@ int receive_one_fd(int transport_fd, int flags);
ssize_t next_datagram_size_fd(int fd);
+int flush_accept(int fd);
+
#define CMSG_FOREACH(cmsg, mh) \
for ((cmsg) = CMSG_FIRSTHDR(mh); (cmsg); (cmsg) = CMSG_NXTHDR((mh), (cmsg)))