X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;ds=sidebyside;f=snprintf%2Fpatient_write.c;h=4f344ec97d1af588e877142f02822abbb40f9588;hb=c0c0989ab70574e09b2f7e8b48c2da6af664a849;hp=9bd2913f58ecbed3a9e56f4e6b5481d974f1d9d6;hpb=b4051ad8c170901d5297e1b3005b24e63cb0ab1e;p=lttng-ust.git

diff --git a/snprintf/patient_write.c b/snprintf/patient_write.c
index 9bd2913f..4f344ec9 100644
--- a/snprintf/patient_write.c
+++ b/snprintf/patient_write.c
@@ -1,20 +1,8 @@
 /*
- * Copyright (C) 2009  Pierre-Marc Fournier
- * Copyright (C) 2011  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * SPDX-License-Identifier: LGPL-2.1-or-later
  *
- * This library 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.
- *
- * This library 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 this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ * Copyright (C) 2009 Pierre-Marc Fournier
+ * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  */
 
 #include <stddef.h>
@@ -22,6 +10,9 @@
 /* write() */
 #include <unistd.h>
 
+/* writev() */
+#include <sys/uio.h>
+
 /* send() */
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -58,6 +49,52 @@ ssize_t patient_write(int fd, const void *buf, size_t count)
 	return bufc-(const char *)buf;
 }
 
+/*
+ * The `struct iovec *iov` is not `const` because we modify it to support
+ * partial writes.
+ */
+ssize_t patient_writev(int fd, struct iovec *iov, int iovcnt)
+{
+	ssize_t written, total_written = 0;
+	int curr_element_idx = 0;
+
+	for(;;) {
+		written = writev(fd, iov + curr_element_idx,
+				iovcnt - curr_element_idx);
+		if (written == -1 && errno == EINTR) {
+			continue;
+		}
+		if (written <= 0) {
+			return written;
+		}
+
+		total_written += written;
+
+		/*
+		 * If it's not the last element in the vector and we have
+		 * written more than the current element size, then increment
+		 * the current element index until we reach the element that
+		 * was partially written.
+		 */
+		while (curr_element_idx < iovcnt &&
+				written >= iov[curr_element_idx].iov_len) {
+			written -= iov[curr_element_idx].iov_len;
+			curr_element_idx++;
+		}
+
+		/* Maybe we are done. */
+		if (curr_element_idx >= iovcnt) {
+			break;
+		}
+
+		/* Update the current element base and size. */
+		iov[curr_element_idx].iov_base += written;
+		iov[curr_element_idx].iov_len -= written;
+	}
+
+	return total_written;
+}
+
 ssize_t patient_send(int fd, const void *buf, size_t count, int flags)
 {
 	const char *bufc = (const char *) buf;