X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=snprintf%2Fpatient_write.c;h=aa59ba1457d92ece99df4ac4daa7acc001d31e12;hb=9fe043d73a3e2112f859ce1fa489021a96efecc9;hp=9bd2913f58ecbed3a9e56f4e6b5481d974f1d9d6;hpb=49705576d8779e3fa2b3efc4294bc03261f76935;p=deliverable%2Flttng-ust.git

diff --git a/snprintf/patient_write.c b/snprintf/patient_write.c
index 9bd2913f..aa59ba14 100644
--- a/snprintf/patient_write.c
+++ b/snprintf/patient_write.c
@@ -22,6 +22,9 @@
 /* write() */
 #include <unistd.h>
 
+/* writev() */
+#include <sys/uio.h>
+
 /* send() */
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -58,6 +61,52 @@ 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;