[dpdk-dev,V17,3/4] eal/linux: uevent parse and process

diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c b/lib/librte_eal/linuxapp/eal/eal_dev.c
index 5ab5830..6466329 100644
--- a/lib/librte_eal/linuxapp/eal/eal_dev.c
+++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
@@ -2,19 +2,204 @@ 
  * Copyright(c) 2018 Intel Corporation
  */
 
-#include <rte_log.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <linux/netlink.h>
+
 #include <rte_dev.h>
+#include <rte_log.h>
+#include <rte_malloc.h>
+#include <rte_interrupts.h>
+
+#include "eal_private.h"
+
+static struct rte_intr_handle intr_handle = {.fd = -1 };
+static bool monitor_started;
+
+#define EAL_UEV_MSG_LEN 4096
+#define EAL_UEV_MSG_ELEM_LEN 128
+
+/* identify the system layer which event exposure from */
+enum eal_dev_event_subsystem {
+	EAL_DEV_EVENT_SUBSYSTEM_PCI, /* PCI bus device event */
+	EAL_DEV_EVENT_SUBSYSTEM_UIO, /* UIO driver device event */
+	EAL_DEV_EVENT_SUBSYSTEM_MAX
+};
+
+static int
+dev_uev_monitor_create(int netlink_fd)
+{
+	struct sockaddr_nl addr;
+	int ret;
+	int size = 64 * 1024;
+	int nonblock = 1;
+
+	memset(&addr, 0, sizeof(addr));
+	addr.nl_family = AF_NETLINK;
+	addr.nl_pid = 0;
+	addr.nl_groups = 0xffffffff;
+
+	if (bind(netlink_fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
+		RTE_LOG(ERR, EAL, "Failed to bind socket for netlink fd.\n");
+		goto err;
+	}
+
+	setsockopt(netlink_fd, SOL_SOCKET, SO_PASSCRED, &size, sizeof(size));
+
+	ret = ioctl(netlink_fd, FIONBIO, &nonblock);
+	if (ret != 0) {
+		RTE_LOG(ERR, EAL, "ioctl(FIONBIO) failed.\n");
+		goto err;
+	}
+	return 0;
+err:
+	close(netlink_fd);
+	return -1;
+}
+
+static void
+dev_uev_parse(const char *buf, struct rte_dev_event *event, int length)
+{
+	char action[EAL_UEV_MSG_ELEM_LEN];
+	char subsystem[EAL_UEV_MSG_ELEM_LEN];
+	char pci_slot_name[EAL_UEV_MSG_ELEM_LEN];
+	int i = 0;
+
+	memset(action, 0, EAL_UEV_MSG_ELEM_LEN);
+	memset(subsystem, 0, EAL_UEV_MSG_ELEM_LEN);
+	memset(pci_slot_name, 0, EAL_UEV_MSG_ELEM_LEN);
+
+	while (i < length) {
+		for (; i < length; i++) {
+			if (*buf)
+				break;
+			buf++;
+		}
+		if (!strncmp(buf, "ACTION=", 7)) {
+			buf += 7;
+			i += 7;
+			snprintf(action, sizeof(action), "%s", buf);
+		} else if (!strncmp(buf, "SUBSYSTEM=", 10)) {
+			buf += 10;
+			i += 10;
+			snprintf(subsystem, sizeof(subsystem), "%s", buf);
+		} else if (!strncmp(buf, "PCI_SLOT_NAME=", 14)) {
+			buf += 14;
+			i += 14;
+			snprintf(pci_slot_name, sizeof(subsystem), "%s", buf);
+			event->devname = strdup(pci_slot_name);
+		}
+		for (; i < length; i++) {
+			if (*buf == '\0')
+				break;
+			buf++;
+		}
+	}
+
+	if (!strncmp(subsystem, "uio", 3))
+		event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_UIO;
+	else if (!strncmp(subsystem, "pci", 3))
+		event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_PCI;
+	if (!strncmp(action, "add", 3))
+		event->type = RTE_DEV_EVENT_ADD;
+	if (!strncmp(action, "remove", 6))
+		event->type = RTE_DEV_EVENT_REMOVE;
+}
+
+static int
+dev_uev_receive(int fd, struct rte_dev_event *uevent)
+{
+	int ret;
+	char buf[EAL_UEV_MSG_LEN];
+
+	memset(uevent, 0, sizeof(struct rte_dev_event));
+	memset(buf, 0, EAL_UEV_MSG_LEN);
+
+	ret = recv(fd, buf, EAL_UEV_MSG_LEN, MSG_DONTWAIT);
+	if (ret < 0) {
+		RTE_LOG(ERR, EAL,
+			"Socket read error(%d): %s.\n",
+			errno, strerror(errno));
+		return -1;
+	} else if (ret == 0)
+		/* connection closed */
+		return -1;
+
+	dev_uev_parse(buf, uevent, EAL_UEV_MSG_LEN);
+
+	return 0;
+}
+
+static void
+dev_uev_process(__rte_unused void *param)
+{
+	struct rte_dev_event uevent;
+
+	if (dev_uev_receive(intr_handle.fd, &uevent))
+		return;
+
+	if (uevent.devname)
+		dev_callback_process(uevent.devname, uevent.type);
+}
 
 int __rte_experimental
 rte_dev_event_monitor_start(void)
 {
-	/* TODO: start uevent monitor for linux */
+	int ret;
+
+	if (monitor_started)
+		return 0;
+
+	intr_handle.fd = socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC |
+			SOCK_NONBLOCK,
+			NETLINK_KOBJECT_UEVENT);
+	if (intr_handle.fd < 0) {
+		RTE_LOG(ERR, EAL, "create uevent fd failed.\n");
+		return -1;
+	}
+	intr_handle.type = RTE_INTR_HANDLE_DEV_EVENT;
+
+	ret = dev_uev_monitor_create(intr_handle.fd);
+
+	if (ret) {
+		RTE_LOG(ERR, EAL, "error create device event monitor.\n");
+		return -1;
+	}
+
+	ret = rte_intr_callback_register(&intr_handle, dev_uev_process, NULL);
+
+	if (ret) {
+		RTE_LOG(ERR, EAL, "fail to register uevent callback.\n");
+		return -1;
+	}
+
+	monitor_started = true;
+
 	return 0;
 }
 
 int __rte_experimental
 rte_dev_event_monitor_stop(void)
 {
-	/* TODO: stop uevent monitor for linux */
+	int ret;
+
+	if (!monitor_started)
+		return 0;
+
+	ret = rte_intr_callback_unregister(&intr_handle, dev_uev_process,
+					   (void *)-1);
+	if (ret) {
+		RTE_LOG(ERR, EAL, "fail to unregister uevent callback.");
+		return ret;
+	}
+
+	close(intr_handle.fd);
+	intr_handle.fd = -1;
+	monitor_started = false;
 	return 0;
 }
diff --git a/lib/librte_eal/linuxapp/eal/meson.build b/lib/librte_eal/linuxapp/eal/meson.build
index 03974ff..b222571 100644
--- a/lib/librte_eal/linuxapp/eal/meson.build
+++ b/lib/librte_eal/linuxapp/eal/meson.build
@@ -18,6 +18,7 @@  env_sources = files('eal_alarm.c',
 		'eal_vfio_mp_sync.c',
 		'eal.c',
 		'eal_memory.c',
+		'eal_dev.c',
 )
 
 if has_libnuma == 1