linux_module/iface-syscall.c

   1 /*
   2  * Linux interface for control of the fast system call
   3  * exiting utility
   4  *
   5  * (c) Kyle C. Hale 2012
   6  *
   7  */
   8
   9 #include <linux/uaccess.h>
  10 #include <linux/module.h>
  11
  12 #include <gears/syscall_hijack.h>
  13
  14 #include "palacios.h"
  15 #include "vm.h"
  16 #include "linux-exts.h"
  17
  18 #include "iface-syscall.h"
  19
  20
  21 static int vm_syscall_ctrl (struct v3_guest * guest, unsigned int cmd, unsigned long arg, void * priv_data) {
  22     struct v3_syscall_cmd syscall_cmd;
  23     int ret;
  24
  25     if (copy_from_user(&syscall_cmd, (void __user *)arg, sizeof(struct v3_syscall_cmd))) {
  26         ERROR("palacios: error copying syscall command from userspace\n");
  27         return -EFAULT;
  28     }
  29
  30     switch (syscall_cmd.cmd) {
  31
  32         case SYSCALL_OFF: {
  33             ret = v3_syscall_off(guest->v3_ctx, syscall_cmd.syscall_nr);
  34             if (ret < 0) {
  35                 ERROR("palacios: error deactivating syscall exiting for syscall nr: %d\n", syscall_cmd.syscall_nr);
  36             }
  37             break;
  38         }
  39         case SYSCALL_ON: {
  40             ret = v3_syscall_on(guest->v3_ctx, syscall_cmd.syscall_nr);
  41             if (ret < 0) {
  42                 ERROR("palacios: error activating syscall exiting for syscall nr: %d\n", syscall_cmd.syscall_nr);
  43             }
  44             break;
  45         }
  46         case SYSCALL_STAT: {
  47             ret = v3_syscall_stat(guest->v3_ctx, syscall_cmd.syscall_nr);
  48             if (ret == SYSCALL_OFF)
  49                 INFO("palacios: exiting for syscall #%d is OFF\n", syscall_cmd.syscall_nr);
  50             else if (ret == SYSCALL_ON)
  51                 INFO("palacios: exiting for syscall #%d is ON\n", syscall_cmd.syscall_nr);
  52             else
  53                 INFO("palacios: error stating syscall nr: %d\n", syscall_cmd.syscall_nr);
  54             break;
  55         }
  56         default:
  57             ERROR("palacios: error - invalid syscall command\n");
  58             return -1;
  59     }
  60
  61     return ret;
  62 }
  63
  64
  65 static int init_syscall_ctrl (void) {
  66     return 0;
  67 }
  68
  69
  70 static int deinit_syscall_ctrl (void) {
  71     return 0;
  72 }
  73
  74
  75 static int guest_init_syscall_ctrl (struct v3_guest * guest, void ** vm_data) {
  76     add_guest_ctrl(guest, V3_VM_SYSCALL_CTRL, vm_syscall_ctrl, NULL);
  77     return 0;
  78 }
  79
  80
  81 static int guest_deinit_syscall_ctrl (struct v3_guest * guest, void * vm_data) {
  82     remove_guest_ctrl(guest, V3_VM_SYSCALL_CTRL);
  83     return 0;
  84 }
  85
  86
  87 static struct linux_ext syscall_ctrl_ext = {
  88     .name = "SYSCALL_CTRL",
  89     .init = init_syscall_ctrl,
  90     .deinit = deinit_syscall_ctrl,
  91     .guest_init = guest_init_syscall_ctrl,
  92     .guest_deinit = guest_deinit_syscall_ctrl
  93 };
  94
  95 register_extension(&syscall_ctrl_ext);