[PATCH v3 02/11] android/hal: Add initial code for sending commands

[Szymon Janc <szymon.janc@tieto.com>]

This will be used by all HAL modules to send commands and get response
from daemon. In case of any protocol error abort.

If non-null fd pointer is passed auxiliary data with passed FD will be
received as part of response.
---
 android/hal-ipc.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 android/hal-ipc.h |   3 ++
 2 files changed, 110 insertions(+)

diff --git a/android/hal-ipc.c b/android/hal-ipc.c
index 6db67f2..5b77adf 100644
--- a/android/hal-ipc.c
+++ b/android/hal-ipc.c
@@ -37,6 +37,8 @@
 static int cmd_sk = -1;
 static int notif_sk = -1;
 
+static pthread_mutex_t cmd_sk_mutex = PTHREAD_MUTEX_INITIALIZER;
+
 static int accept_connection(int sk)
 {
 	int err;
@@ -135,3 +137,108 @@ void hal_ipc_cleanup(void)
 	close(notif_sk);
 	notif_sk = -1;
 }
+
+int hal_ipc_cmd(uint8_t service_id, uint8_t opcode, uint16_t len, void *param,
+					size_t rsp_len, void *rsp, int *fd)
+{
+	ssize_t ret;
+	struct msghdr msg;
+	struct iovec iv[2];
+	struct hal_msg_hdr hal_msg;
+	char cmsgbuf[CMSG_SPACE(sizeof(int))];
+
+	if (cmd_sk < 0)
+		return -EBADF;
+
+	memset(&msg, 0, sizeof(msg));
+	memset(&hal_msg, 0, sizeof(hal_msg));
+
+	hal_msg.service_id = service_id;
+	hal_msg.opcode = opcode;
+	hal_msg.len = len;
+
+	iv[0].iov_base = &hal_msg;
+	iv[0].iov_len = sizeof(hal_msg);
+
+	iv[1].iov_base = param;
+	iv[1].iov_len = len;
+
+	msg.msg_iov = iv;
+	msg.msg_iovlen = 2;
+
+	pthread_mutex_lock(&cmd_sk_mutex);
+
+	ret = sendmsg(cmd_sk, &msg, 0);
+	if (ret < 0) {
+		error("Sending command failed, aborting :%s", strerror(errno));
+		pthread_mutex_unlock(&cmd_sk_mutex);
+		exit(EXIT_FAILURE);
+	}
+
+	memset(&msg, 0, sizeof(msg));
+	memset(&hal_msg, 0, sizeof(hal_msg));
+
+	iv[0].iov_base = &hal_msg;
+	iv[0].iov_len = sizeof(hal_msg);
+
+	iv[1].iov_base = rsp;
+	iv[1].iov_len = rsp_len;
+
+	msg.msg_iov = iv;
+	msg.msg_iovlen = 2;
+
+	if (fd) {
+		memset(cmsgbuf, 0, sizeof(cmsgbuf));
+		msg.msg_control = cmsgbuf;
+		msg.msg_controllen = sizeof(cmsgbuf);
+	}
+
+	ret = recvmsg(cmd_sk, &msg, 0);
+	if (ret < 0) {
+		error("Receiving command response failed, aborting :%s",
+							strerror(errno));
+		pthread_mutex_unlock(&cmd_sk_mutex);
+		exit(EXIT_FAILURE);
+	}
+
+	pthread_mutex_unlock(&cmd_sk_mutex);
+
+	if (ret < (ssize_t) sizeof(hal_msg)) {
+		error("Too small response received(%zd bytes), aborting", ret);
+		exit(EXIT_FAILURE);
+	}
+
+	if (ret != (ssize_t) (sizeof(hal_msg) + hal_msg.len)) {
+		error("Malformed response received(%zd bytes), aborting", ret);
+		exit(EXIT_FAILURE);
+	}
+
+	if (hal_msg.opcode != opcode && hal_msg.opcode != HAL_MSG_OP_ERROR) {
+		error("Invalid opcode received (%u vs %u), aborting",
+						hal_msg.opcode, opcode);
+		exit(EXIT_FAILURE);
+	}
+
+	if (hal_msg.opcode == HAL_MSG_OP_ERROR) {
+		struct hal_msg_rsp_error *err = rsp;
+		return -err->status;
+	}
+
+	/* Receive auxiliary data in msg */
+	if (fd) {
+		struct cmsghdr *cmsg;
+
+		*fd = -1;
+
+		for (cmsg = CMSG_FIRSTHDR(&msg); !cmsg;
+					cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+			if (cmsg->cmsg_level == SOL_SOCKET
+					&& cmsg->cmsg_type == SCM_RIGHTS) {
+				memcpy(fd, CMSG_DATA(cmsg), sizeof(int));
+				break;
+			}
+		}
+	}
+
+	return hal_msg.len;
+}
diff --git a/android/hal-ipc.h b/android/hal-ipc.h
index 2f71668..3834e7d 100644
--- a/android/hal-ipc.h
+++ b/android/hal-ipc.h
@@ -17,3 +17,6 @@
 
 bool hal_ipc_init(void);
 void hal_ipc_cleanup(void);
+
+int hal_ipc_cmd(uint8_t service_id, uint8_t opcode, uint16_t len, void *param,
+					size_t rsp_len, void *rsp, int *fd);
-- 
1.8.4