virtio: support dynamic device add

tools/hvisor.c

@@ -41,7 +41,8 @@ static void __attribute__((noreturn)) help(int exit_status) {
     printf("  zone start    <config.json>    Initialize an isolation zone\n");
     printf("  zone shutdown -id <zone_id>   Terminate a zone by ID\n");
     printf("  zone list                      List all active zones\n");
-    printf("  virtio start  <virtio.json>    Activate virtio devices\n\n");
+    printf("  virtio start  <virtio.json>    Activate virtio devices\n");
+    printf("  virtio add    <virtio.json>    Add virtio devices to daemon\n\n");
     printf("Options:\n");
     printf("  --id <zone_id>    Specify zone ID for shutdown\n");
     printf("  --help            Show this help message\n\n");
@@ -1128,6 +1129,8 @@ int main(int argc, char *argv[]) {
 
         if (strcmp(argv[2], "start") == 0) {
             err = virtio_start(argc, argv);
+        } else if (strcmp(argv[2], "add") == 0) {
+            err = virtio_add(argc, argv);
         } else {
             help(1);
         }

tools/virtio/devices/blk/virtio_blk.c

@@ -18,6 +18,7 @@
 #include <linux/fs.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/ioctl.h>
 #include <sys/param.h>
 #include <sys/stat.h>
@@ -337,6 +338,7 @@ static BlkDev *init_blk_dev(VirtIODevice *vdev) {
         vdev->dev = NULL;
         return NULL;
     }
+    dev->mutex_initialized = true;
 
     if (pthread_cond_init(&dev->cond, NULL) != 0) {
         log_error("failed to init blk cond");
@@ -345,6 +347,7 @@ static BlkDev *init_blk_dev(VirtIODevice *vdev) {
         vdev->dev = NULL;
         return NULL;
     }
+    dev->cond_initialized = true;
 
     return dev;
 }
@@ -464,11 +467,15 @@ static void virtio_blk_close(VirtIODevice *vdev) {
             pthread_cond_signal(&dev->cond);
             pthread_mutex_unlock(&dev->mtx);
             pthread_join(dev->tid, NULL);
+            dev->thread_started = false;
         }
-        pthread_mutex_destroy(&dev->mtx);
-        pthread_cond_destroy(&dev->cond);
+        if (dev->cond_initialized)
+            pthread_cond_destroy(&dev->cond);
+        if (dev->mutex_initialized)
+            pthread_mutex_destroy(&dev->mtx);
         if (dev->img_fd >= 0)
             close(dev->img_fd);
+        dev->img_fd = -1;
         free(dev);
         vdev->dev = NULL;
     }
@@ -512,7 +519,11 @@ static int virtio_blk_parse_params(const cJSON *json, void **out) {
         free(p);
         return -EINVAL;
     }
-    p->img_path = img->valuestring;
+    if (strlen(img->valuestring) >= sizeof(p->img_path)) {
+        free(p);
+        return -ENAMETOOLONG;
+    }
+    memcpy(p->img_path, img->valuestring, strlen(img->valuestring) + 1);
     *out = p;
     return 0;
 }

tools/virtio/devices/console/virtio_console.c

@@ -25,6 +25,8 @@ static uint8_t trashbuf[1024];
 
 static ConsoleDev *init_console_dev() {
     ConsoleDev *dev = (ConsoleDev *)malloc(sizeof(ConsoleDev));
+    if (!dev)
+        return NULL;
     dev->config.cols = 80;
     dev->config.rows = 25;
     dev->master_fd = -1;
@@ -96,25 +98,33 @@ static int virtio_console_init(VirtIODevice *vdev) {
     master_fd = posix_openpt(O_RDWR | O_NOCTTY);
     if (master_fd < 0) {
         log_error("Failed to open master pty, errno is %d", errno);
+        return -1;
     }
     if (grantpt(master_fd) < 0) {
         log_error("Failed to grant pty, errno is %d", errno);
+        close(master_fd);
+        return -1;
     }
     if (unlockpt(master_fd) < 0) {
         log_error("Failed to unlock pty, errno is %d", errno);
+        close(master_fd);
+        return -1;
     }
     dev->master_fd = master_fd;
 
     slave_name = ptsname(master_fd);
     if (slave_name == NULL) {
         log_error("Failed to get slave name, errno is %d", errno);
+        close(master_fd);
+        return -1;
     }
     log_info("char device redirected to %s", slave_name);
     // Open and keep a slave fd in this process. Without a slave peer,
     // master poll/epoll keeps reporting EPOLLHUP and can cause busy loops.
     slave_fd = open(slave_name, O_RDWR);
     if (slave_fd < 0) {
         log_error("Failed to open slave pty, errno is %d", errno);
+        close(master_fd);
         return -1;
     }
 
@@ -247,4 +257,4 @@ static void virtio_console_free_params(void *params) { (void)params; }
 const struct virtio_config_ops virtio_console_config_ops = {
     .parse = virtio_console_parse_params,
     .free = virtio_console_free_params,
-};
+};

tools/virtio/devices/net/virtio_net.c

@@ -25,7 +25,9 @@
 #include <unistd.h>
 
 static NetDev *init_net_dev(const uint8_t mac[]) {
-    NetDev *dev = malloc(sizeof(NetDev));
+    NetDev *dev = calloc(1, sizeof(NetDev));
+    if (!dev)
+        return NULL;
     memcpy(dev->config.mac, mac, sizeof(dev->config.mac));
     dev->config.status = VIRTIO_NET_S_LINK_UP;
     dev->tapfd = -1;
@@ -321,8 +323,12 @@ static void virtio_net_close(VirtIODevice *vdev) {
     if (dev) {
         if (dev->tapfd >= 0)
             close(dev->tapfd);
-        remove_event(dev->event);
-        free(dev->event);
+        dev->tapfd = -1;
+        if (dev->event) {
+            remove_event(dev->event);
+            free(dev->event);
+            dev->event = NULL;
+        }
         free(dev->in_iov);
         free(dev->out_iov);
         free(dev);
@@ -369,7 +375,11 @@ static int virtio_net_parse_params(const cJSON *json, void **out) {
         free(p);
         return -EINVAL;
     }
-    p->tap = tap->valuestring;
+    if (strlen(tap->valuestring) >= sizeof(p->tap)) {
+        free(p);
+        return -ENAMETOOLONG;
+    }
+    memcpy(p->tap, tap->valuestring, strlen(tap->valuestring) + 1);
 
     cJSON *mac_json = cJSON_GetObjectItem(json, "mac");
     if (cJSON_GetArraySize(mac_json) != 6) {

tools/virtio/include/virtio.h

@@ -263,10 +263,10 @@ void handle_virtio_requests();
 
 int virtio_init();
 
-int create_virtio_device_from_json(const cJSON *device_json, int zone_id);
-
 int virtio_start_from_json(char *json_path);
 
 int virtio_start(int argc, char *argv[]);
 
+int virtio_add(int argc, char *argv[]);
+
 #endif /* __HVISOR_VIRTIO_H */

tools/virtio/include/virtio_blk.h

@@ -11,6 +11,7 @@
 #ifndef _HVISOR_VIRTIO_BLK_H
 #define _HVISOR_VIRTIO_BLK_H
 #include "virtio.h"
+#include <limits.h>
 #include <linux/virtio_blk.h>
 #include <pthread.h>
 #include <stdbool.h>
@@ -39,14 +40,16 @@ typedef struct virtio_blk_dev {
     pthread_cond_t cond;
     bool close;
     bool thread_started;
+    bool mutex_initialized;
+    bool cond_initialized;
     bool reset; // Device reset in progress: worker must not touch the vq
     bool worker_paused; // Worker parked in reset wait; vq not touched
     struct iovec out_buf[VIRTQUEUE_BLK_MAX_SIZE];
     struct iovec in_buf[VIRTQUEUE_BLK_MAX_SIZE];
 } BlkDev;
 
 struct virtio_blk_init_params {
-    const char *img_path;
+    char img_path[PATH_MAX];
 };
 
 extern const struct virtio_device_ops virtio_blk_ops;

tools/virtio/include/virtio_net.h

@@ -13,6 +13,7 @@
 #include "event_monitor.h"
 #include "virtio.h"
 #include <linux/virtio_net.h>
+#include <net/if.h>
 
 // Queue idx for virtio net.
 #define NET_QUEUE_RX 0
@@ -25,7 +26,7 @@
 
 struct virtio_net_init_params {
     uint8_t mac[6];
-    const char *tap;
+    char tap[IFNAMSIZ];
 };
 
 // Max iov entries for a single descriptor chain.  Each descriptor in the