libdaemon: Split daemon-shared.[hc] into daemon-io.[hc] and config-util.[hc].

1 files changed, 99 insertions, 0 deletions

diff --git a/libdaemon/client/daemon-io.c b/libdaemon/client/daemon-io.c
new file mode 100644
index 000000000..4af9343f8
--- /dev/null
+++ b/libdaemon/client/daemon-io.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2011-2012 Red Hat, Inc.
+ *
+ * This file is part of LVM2.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "daemon-io.h"
+#include "dm-logging.h"
+#include "libdevmapper.h"
+
+/*
+ * Read a single message from a (socket) filedescriptor. Messages are delimited
+ * by blank lines. This call will block until all of a message is received. The
+ * memory will be allocated from heap. Upon error, all memory is freed and the
+ * buffer pointer is set to NULL.
+ *
+ * See also write_buffer about blocking (read_buffer has identical behaviour).
+ */
+int read_buffer(int fd, char **buffer) {
+	int bytes = 0;
+	int buffersize = 32;
+	char *new;
+	*buffer = dm_malloc(buffersize + 1);
+
+	while (1) {
+		int result = read(fd, (*buffer) + bytes, buffersize - bytes);
+		if (result > 0) {
+			bytes += result;
+			if (!strncmp((*buffer) + bytes - 4, "\n##\n", 4)) {
+				*(*buffer + bytes - 4) = 0;
+				break; /* success, we have the full message now */
+			}
+			if (bytes == buffersize) {
+				buffersize += 1024;
+				if (!(new = realloc(*buffer, buffersize + 1)))
+					goto fail;
+				*buffer = new;
+			}
+			continue;
+		}
+		if (result == 0) {
+			errno = ECONNRESET;
+			goto fail; /* we should never encounter EOF here */
+		}
+		if (result < 0 && errno != EAGAIN && errno != EWOULDBLOCK && errno != EINTR)
+			goto fail;
+		/* TODO call select here if we encountered EAGAIN/EWOULDBLOCK/EINTR */
+	}
+	return 1;
+fail:
+	dm_free(*buffer);
+	*buffer = NULL;
+	return 0;
+}
+
+/*
+ * Write a buffer to a filedescriptor. Keep trying. Blocks (even on
+ * SOCK_NONBLOCK) until all of the write went through.
+ *
+ * TODO use select on EWOULDBLOCK/EAGAIN/EINTR to avoid useless spinning
+ */
+int write_buffer(int fd, const char *buffer, int length) {
+	static const char terminate[] = "\n##\n";
+	int done = 0;
+	int written = 0;
+write:
+	while (1) {
+		int result = write(fd, buffer + written, length - written);
+		if (result > 0)
+			written += result;
+		if (result < 0 && errno != EWOULDBLOCK && errno != EAGAIN && errno != EINTR)
+			return 0; /* too bad */
+		if (written == length) {
+			if (done)
+				return 1;
+			else
+				break; /* done */
+		}
+	}
+
+	buffer = terminate;
+	length = 4;
+	written = 0;
+	done = 1;
+	goto write;
+}