devctl commands for getting device info

kernel/syscall/devctl.c

@@ -52,6 +52,44 @@ int32_t SYSCALL5(sys_devctl, devh1, cmd1, buffer1, len1, extra1) {
         goto done;
       }
     } break;
+    case DEVCTL_DEVLS_SZ: {
+      size_t n = 0;
+      spinlock_acquire(&DEVTABLE.spinlock);
+      for (size_t i = 0; i < LEN(DEVTABLE.devs); i++) {
+        if (DEVTABLE.devs[i]._hshtbstate == HSHTB_TAKEN) {
+          n++;
+        }
+      }
+      spinlock_release(&DEVTABLE.spinlock);
+      ret = n;
+    } break;
+    case DEVCTL_DEVLS_STAT: {
+      DevStat *devstat = (DevStat *)buffer1;
+      size_t idx = (size_t)len1;
+
+      if (devstat == NULL) {
+        ret = E_INVALIDARGUMENT;
+        goto done;
+      }
+
+      devstat->present = false;
+
+      spinlock_acquire(&DEVTABLE.spinlock);
+      for (size_t i = 0; i < LEN(DEVTABLE.devs); i++) {
+        if (i == idx && DEVTABLE.devs[i]._hshtbstate == HSHTB_TAKEN) {
+          Dev *dev = &DEVTABLE.devs[i];
+          hal_memcpy(devstat->name, dev->ident, sizeof(dev->ident));
+          for (size_t j = 0; j < DEV_FNS_MAX; j++) {
+            if (dev->fns[j] != NULL) {
+              devstat->nfns++;
+            }
+          }
+          devstat->present = true;
+          break;
+        }
+      }
+      spinlock_release(&DEVTABLE.spinlock);
+    } break;
     default: {
       if (devh == NULL) {
         ret = E_INVALIDARGUMENT;