xio: add ioexact operations

Break this out so that we only need to have sigint non-static where
it is really needed.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/ioexact.c b/ioexact.c
new file mode 100644
index 0000000..1600784
--- /dev/null
+++ b/ioexact.c
@@ -0,0 +1,53 @@
+#include <errno.h>
+#include <unistd.h>
+#include <signal.h>
+
+#include "ioexact.h"
+
+extern volatile sig_atomic_t sigint;
+
+ssize_t read_exact(int fd, void *buf, size_t len, int mayexit)
+{
+	ssize_t num = 0, written;
+
+	while (len > 0 && !sigint) {
+		if ((written = read(fd, buf, len)) < 0) {
+			if (errno == EAGAIN && num > 0)
+				continue;
+			if (mayexit)
+				return -1;
+			else
+				continue;
+		}
+		if (!written)
+			return 0;
+		len -= written;
+		buf += written;
+		num += written;
+	}
+
+	return num;
+}
+
+ssize_t write_exact(int fd, void *buf, size_t len, int mayexit)
+{
+	ssize_t num = 0, written;
+
+	while (len > 0 && !sigint) {
+		if ((written = write(fd, buf, len)) < 0) {
+			if (errno == EAGAIN && num > 0)
+				continue;
+			if (mayexit)
+				return -1;
+			else
+				continue;
+		}
+		if (!written)
+			return 0;
+		len -= written;
+		buf += written;
+		num += written;
+	}
+
+	return num;
+}