kernel/vserver/signal.c

   1 /*
   2  *  linux/kernel/vserver/signal.c
   3  *
   4  *  Virtual Server: Signal Support
   5  *
   6  *  Copyright (C) 2003-2007  Herbert Pötzl
   7  *
   8  *  V0.01  broken out from vcontext V0.05
   9  *  V0.02  changed vcmds to vxi arg
  10  *  V0.03  adjusted siginfo for kill
  11  *
  12  */
  13
  14 #include <linux/sched.h>
  15
  16 #include <asm/errno.h>
  17 #include <asm/uaccess.h>
  18
  19 #include <linux/vs_context.h>
  20 #include <linux/vserver/signal_cmd.h>
  21
  22
  23 int vx_info_kill(struct vx_info *vxi, int pid, int sig)
  24 {
  25         int retval, count=0;
  26         struct task_struct *p;
  27         struct siginfo *sip = SEND_SIG_PRIV;
  28
  29         retval = -ESRCH;
  30         vxdprintk(VXD_CBIT(misc, 4),
  31                 "vx_info_kill(%p[#%d],%d,%d)*",
  32                 vxi, vxi->vx_id, pid, sig);
  33         read_lock(&tasklist_lock);
  34         switch (pid) {
  35         case  0:
  36         case -1:
  37                 for_each_process(p) {
  38                         int err = 0;
  39
  40                         if (vx_task_xid(p) != vxi->vx_id || p->pid <= 1 ||
  41                                 (pid && vxi->vx_initpid == p->pid))
  42                                 continue;
  43
  44                         err = group_send_sig_info(sig, sip, p);
  45                         ++count;
  46                         if (err != -EPERM)
  47                                 retval = err;
  48                 }
  49                 break;
  50
  51         case 1:
  52                 if (vxi->vx_initpid) {
  53                         pid = vxi->vx_initpid;
  54                         /* for now, only SIGINT to private init ... */
  55                         if (!vx_info_flags(vxi, VXF_STATE_ADMIN, 0) &&
  56                                 /* ... as long as there are tasks left */
  57                                 (atomic_read(&vxi->vx_tasks) > 1))
  58                                 sig = SIGINT;
  59                 }
  60                 /* fallthrough */
  61         default:
  62                 p = find_task_by_real_pid(pid);
  63                 if (p) {
  64                         if (vx_task_xid(p) == vxi->vx_id)
  65                                 retval = group_send_sig_info(sig, sip, p);
  66                 }
  67                 break;
  68         }
  69         read_unlock(&tasklist_lock);
  70         vxdprintk(VXD_CBIT(misc, 4),
  71                 "vx_info_kill(%p[#%d],%d,%d,%ld) = %d",
  72                 vxi, vxi->vx_id, pid, sig, (long)sip, retval);
  73         return retval;
  74 }
  75
  76 int vc_ctx_kill(struct vx_info *vxi, void __user *data)
  77 {
  78         struct vcmd_ctx_kill_v0 vc_data;
  79
  80         if (copy_from_user (&vc_data, data, sizeof(vc_data)))
  81                 return -EFAULT;
  82
  83         /* special check to allow guest shutdown */
  84         if (!vx_info_flags(vxi, VXF_STATE_ADMIN, 0) &&
  85                 /* forbid killall pid=0 when init is present */
  86                 (((vc_data.pid < 1) && vxi->vx_initpid) ||
  87                 (vc_data.pid > 1)))
  88                 return -EACCES;
  89
  90         return vx_info_kill(vxi, vc_data.pid, vc_data.sig);
  91 }
  92
  93
  94 static int __wait_exit(struct vx_info *vxi)
  95 {
  96         DECLARE_WAITQUEUE(wait, current);
  97         int ret = 0;
  98
  99         add_wait_queue(&vxi->vx_wait, &wait);
 100         set_current_state(TASK_INTERRUPTIBLE);
 101
 102 wait:
 103         if (vx_info_state(vxi,
 104                 VXS_SHUTDOWN|VXS_HASHED|VXS_HELPER) == VXS_SHUTDOWN)
 105                 goto out;
 106         if (signal_pending(current)) {
 107                 ret = -ERESTARTSYS;
 108                 goto out;
 109         }
 110         schedule();
 111         goto wait;
 112
 113 out:
 114         set_current_state(TASK_RUNNING);
 115         remove_wait_queue(&vxi->vx_wait, &wait);
 116         return ret;
 117 }
 118
 119
 120
 121 int vc_wait_exit(struct vx_info *vxi, void __user *data)
 122 {
 123         struct vcmd_wait_exit_v0 vc_data;
 124         int ret;
 125
 126         ret = __wait_exit(vxi);
 127         vc_data.reboot_cmd = vxi->reboot_cmd;
 128         vc_data.exit_code = vxi->exit_code;
 129
 130         if (copy_to_user (data, &vc_data, sizeof(vc_data)))
 131                 ret = -EFAULT;
 132         return ret;
 133 }
 134