1 files changed, 113 insertions, 0 deletions
diff --git a/src/lib/istream-unix.c b/src/lib/istream-unix.c
new file mode 100644
index 0000000..3a8fabd
--- /dev/null
+++ b/src/lib/istream-unix.c
@@ -0,0 +1,113 @@
+/* Copyright (c) 2014-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "fdpass.h"
+#include "istream-file-private.h"
+#include "istream-unix.h"
+
+struct unix_istream {
+	struct file_istream fstream;
+	bool next_read_fd;
+	int read_fd;
+};
+
+static void
+i_stream_unix_close(struct iostream_private *stream, bool close_parent)
+{
+	struct unix_istream *ustream =
+		container_of(stream, struct unix_istream,
+			     fstream.istream.iostream);
+
+	i_close_fd(&ustream->read_fd);
+	i_stream_file_close(stream, close_parent);
+}
+
+static ssize_t i_stream_unix_read(struct istream_private *stream)
+{
+	struct unix_istream *ustream =
+		container_of(stream, struct unix_istream, fstream.istream);
+	size_t size;
+	ssize_t ret;
+
+	if (!ustream->next_read_fd)
+		return i_stream_file_read(stream);
+
+	i_assert(ustream->read_fd == -1);
+	i_assert(ustream->fstream.skip_left == 0); /* not supported here.. */
+	if (!i_stream_try_alloc(stream, 1, &size))
+		return -2;
+
+	ret = fd_read(stream->fd, stream->w_buffer + stream->pos, size,
+		      &ustream->read_fd);
+	if (ustream->read_fd != -1)
+		ustream->next_read_fd = FALSE;
+
+	if (ret == 0) {
+		/* EOF */
+		stream->istream.eof = TRUE;
+		ustream->fstream.seen_eof = TRUE;
+		return -1;
+	}
+
+	if (unlikely(ret < 0)) {
+		if ((errno == EINTR || errno == EAGAIN) &&
+		    !stream->istream.blocking) {
+			return 0;
+		} else {
+			i_assert(errno != 0);
+			/* if we get EBADF for a valid fd, it means something's
+			   really wrong and we'd better just crash. */
+			i_assert(errno != EBADF);
+			stream->istream.stream_errno = errno;
+			return -1;
+		}
+	}
+	stream->pos += ret;
+	return ret;
+}
+
+struct istream *i_stream_create_unix(int fd, size_t max_buffer_size)
+{
+	struct unix_istream *ustream;
+	struct istream *input;
+
+	i_assert(fd != -1);
+
+	ustream = i_new(struct unix_istream, 1);
+	ustream->read_fd = -1;
+	input = i_stream_create_file_common(&ustream->fstream, fd, NULL,
+					    max_buffer_size, FALSE);
+	input->real_stream->iostream.close = i_stream_unix_close;
+	input->real_stream->read = i_stream_unix_read;
+	return input;
+}
+
+void i_stream_unix_set_read_fd(struct istream *input)
+{
+	struct unix_istream *ustream =
+		container_of(input->real_stream, struct unix_istream,
+			     fstream.istream);
+
+	ustream->next_read_fd = TRUE;
+}
+
+void i_stream_unix_unset_read_fd(struct istream *input)
+{
+	struct unix_istream *ustream =
+		container_of(input->real_stream, struct unix_istream,
+			     fstream.istream);
+
+	ustream->next_read_fd = FALSE;
+}
+
+int i_stream_unix_get_read_fd(struct istream *input)
+{
+	struct unix_istream *ustream =
+		container_of(input->real_stream, struct unix_istream,
+			     fstream.istream);
+	int fd;
+
+	fd = ustream->read_fd;
+	ustream->read_fd = -1;
+	return fd;
+}