tree-wide: remove Lennart's copyright lines

[elogind.git] / src / basic / io-util.c

diff --git a/src/basic/io-util.c b/src/basic/io-util.c
index ac8f93ff57a9b52a2775bfd57949e2208b4d2b8f..1f64cc933bd3e6ec1dc607d05806d7293fc803ee 100644 (file)
--- a/src/basic/io-util.c
+++ b/src/basic/io-util.c
@@ -1,34 +1,26 @@
-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
-  This file is part of systemd.
-
-  Copyright 2010 Lennart Poettering
-
-  systemd is free software; you can redistribute it and/or modify it
-  under the terms of the GNU Lesser General Public License as published by
-  the Free Software Foundation; either version 2.1 of the License, or
-  (at your option) any later version.
-
-  systemd is distributed in the hope that it will be useful, but
-  WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-  Lesser General Public License for more details.
-
-  You should have received a copy of the GNU Lesser General Public License
-  along with systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
+/* SPDX-License-Identifier: LGPL-2.1+ */
 
+#include <errno.h>
+#include <limits.h>
 #include <poll.h>
+#include <stdio.h>
+#include <time.h>
 #include <unistd.h>
 
 #include "io-util.h"
+#include "time-util.h"
 
 int flush_fd(int fd) {
         struct pollfd pollfd = {
                 .fd = fd,
                 .events = POLLIN,
         };
+        int count = 0;
+
+        /* 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];
@@ -43,7 +35,7 @@ int flush_fd(int fd) {
                         return -errno;
 
                 } else if (r == 0)
-                        return 0;
+                        return count;
 
                 l = read(fd, buf, sizeof(buf));
                 if (l < 0) {
@@ -52,11 +44,13 @@ int flush_fd(int fd) {
                                 continue;
 
                         if (errno == EAGAIN)
-                                return 0;
+                                return count;
 
                         return -errno;
                 } else if (l == 0)
-                        return 0;
+                        return count;
+
+                count += (int) l;
         }
 }
 
@@ -125,7 +119,7 @@ int loop_write(int fd, const void *buf, size_t nbytes, bool do_poll) {
         assert(fd >= 0);
         assert(buf);
 
-        if (nbytes > (size_t) SSIZE_MAX)
+        if (_unlikely_(nbytes > (size_t) SSIZE_MAX))
                 return -EINVAL;
 
         do {
@@ -191,7 +185,6 @@ int fd_wait_for_event(int fd, int event, usec_t t) {
         r = ppoll(&pollfd, 1, t == USEC_INFINITY ? NULL : timespec_store(&ts, t), NULL);
         if (r < 0)
                 return -errno;
-
         if (r == 0)
                 return 0;
 
@@ -246,7 +239,7 @@ ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length) {
                 } else if (n > 0)
                         q += n;
                 else
-                        q ++;
+                        q++;
         }
 
         if (q > w) {