kernel/system/do_sigsend.c

   1 /* The kernel call that is implemented in this file:
   2  *   m_type:    SYS_SIGSEND
   3  *
   4  * The parameters for this kernel call are:
   5  *     m2_i1:   SIG_ENDPT       # process to call signal handler
   6  *     m2_p1:   SIG_CTXT_PTR    # pointer to sigcontext structure
   7  *     m2_i3:   SIG_FLAGS       # flags for S_SIGRETURN call
   8  *
   9  */
  10
  11 #include "kernel/system.h"
  12 #include <signal.h>
  13 #include <string.h>
  14
  15 #if USE_SIGSEND
  16
  17 /*===========================================================================*
  18  *                            do_sigsend                                     *
  19  *===========================================================================*/
  20 int do_sigsend(struct proc * caller, message * m_ptr)
  21 {
  22 /* Handle sys_sigsend, POSIX-style signal handling. */
  23
  24   struct sigmsg smsg;
  25   register struct proc *rp;
  26   struct sigcontext sc, *scp;
  27   struct sigframe fr, *frp;
  28   int proc_nr, r;
  29
  30   if (!isokendpt(m_ptr->SIG_ENDPT, &proc_nr)) return(EINVAL);
  31   if (iskerneln(proc_nr)) return(EPERM);
  32   rp = proc_addr(proc_nr);
  33
  34   /* Get the sigmsg structure into our address space.  */
  35   if((r=data_copy_vmcheck(caller, caller->p_endpoint,
  36                 (vir_bytes) m_ptr->SIG_CTXT_PTR, KERNEL, (vir_bytes) &smsg,
  37                 (phys_bytes) sizeof(struct sigmsg))) != OK)
  38         return r;
  39
  40   /* Compute the user stack pointer where sigcontext will be stored. */
  41   smsg.sm_stkptr = arch_get_sp(rp);
  42   scp = (struct sigcontext *) smsg.sm_stkptr - 1;
  43
  44   /* Copy the registers to the sigcontext structure. */
  45   memcpy(&sc.sc_regs, (char *) &rp->p_reg, sizeof(sigregs));
  46
  47 #if defined(__i386__)
  48   sc.trap_style = rp->p_seg.p_kern_trap_style;
  49
  50   if(sc.trap_style == KTS_NONE) {
  51         printf("do_sigsend: sigsend an unsaved process\n");
  52         return EINVAL;
  53   }
  54
  55     if(proc_used_fpu(rp)) {
  56             /* save the FPU context before saving it to the sig context */
  57             save_fpu(rp);
  58             memcpy(&sc.sc_fpu_state, rp->p_seg.fpu_state, FPU_XFP_SIZE);
  59     }
  60 #endif
  61
  62   /* Finish the sigcontext initialization. */
  63   sc.sc_mask = smsg.sm_mask;
  64   sc.sc_flags = rp->p_misc_flags & MF_FPU_INITIALIZED;
  65
  66   /* Copy the sigcontext structure to the user's stack. */
  67   if((r=data_copy_vmcheck(caller, KERNEL, (vir_bytes) &sc, m_ptr->SIG_ENDPT,
  68         (vir_bytes) scp, (vir_bytes) sizeof(struct sigcontext))) != OK)
  69       return r;
  70
  71   /* Initialize the sigframe structure. */
  72   frp = (struct sigframe *) scp - 1;
  73   fr.sf_scpcopy = scp;
  74   fr.sf_retadr2= (void (*)()) rp->p_reg.pc;
  75   fr.sf_fp = rp->p_reg.fp;
  76   rp->p_reg.fp = (reg_t) &frp->sf_fp;
  77   fr.sf_scp = scp;
  78
  79   fpu_sigcontext(rp, &fr, &sc);
  80
  81   fr.sf_signo = smsg.sm_signo;
  82   fr.sf_retadr = (void (*)()) smsg.sm_sigreturn;
  83
  84 #if defined(__arm__)
  85   /* use the ARM link register to set the return address from the signal
  86    * handler
  87    */
  88   rp->p_reg.lr = (reg_t) fr.sf_retadr;
  89   if(rp->p_reg.lr & 1) { printf("sigsend: LSB LR makes no sense.\n"); }
  90
  91   /* pass signal handler parameters in registers */
  92   rp->p_reg.retreg = (reg_t) fr.sf_signo;
  93   rp->p_reg.r1 = (reg_t) fr.sf_code;
  94   rp->p_reg.r2 = (reg_t) fr.sf_scp;
  95   rp->p_misc_flags |= MF_CONTEXT_SET;
  96 #endif
  97
  98   /* Copy the sigframe structure to the user's stack. */
  99   if((r=data_copy_vmcheck(caller, KERNEL, (vir_bytes) &fr,
 100         m_ptr->SIG_ENDPT, (vir_bytes) frp,
 101       (vir_bytes) sizeof(struct sigframe))) != OK)
 102       return r;
 103
 104   /* Reset user registers to execute the signal handler. */
 105   rp->p_reg.sp = (reg_t) frp;
 106   rp->p_reg.pc = (reg_t) smsg.sm_sighandler;
 107
 108   /* Signal handler should get clean FPU. */
 109   rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
 110
 111   if(!RTS_ISSET(rp, RTS_PROC_STOP)) {
 112         printf("system: warning: sigsend a running process\n");
 113         printf("caller stack: ");
 114         proc_stacktrace(caller);
 115   }
 116
 117   return(OK);
 118 }
 119
 120 #endif /* USE_SIGSEND */
 121