minix/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  *      m_sigcalls.endpt        # process to call signal handler
   6  *      m_sigcalls.sigctx       # pointer to sigcontext structure
   7  *
   8  */
   9
  10 #include "kernel/system.h"
  11 #include <signal.h>
  12 #include <string.h>
  13
  14 #if USE_SIGSEND
  15
  16 /*===========================================================================*
  17  *                            do_sigsend                                     *
  18  *===========================================================================*/
  19 int do_sigsend(struct proc * caller, message * m_ptr)
  20 {
  21 /* Handle sys_sigsend, POSIX-style signal handling. */
  22
  23   struct sigmsg smsg;
  24   register struct proc *rp;
  25   struct sigframe_sigcontext fr, *frp;
  26   int proc_nr, r;
  27 #if defined(__i386__)
  28   reg_t new_fp;
  29 #endif
  30
  31   if (!isokendpt(m_ptr->m_sigcalls.endpt, &proc_nr)) return EINVAL;
  32   if (iskerneln(proc_nr)) return EPERM;
  33   rp = proc_addr(proc_nr);
  34
  35   /* Get the sigmsg structure into our address space.  */
  36   if ((r = data_copy_vmcheck(caller, caller->p_endpoint,
  37                 (vir_bytes)m_ptr->m_sigcalls.sigctx, KERNEL,
  38                 (vir_bytes)&smsg, (phys_bytes) sizeof(struct sigmsg))) != OK)
  39         return r;
  40
  41   /* WARNING: the following code may be run more than once even for a single
  42    * signal delivery. Do not change registers here. See the comment below.
  43    */
  44
  45   /* Compute the user stack pointer where sigframe will start. */
  46   smsg.sm_stkptr = arch_get_sp(rp);
  47   frp = (struct sigframe_sigcontext *) smsg.sm_stkptr - 1;
  48
  49   /* Copy the registers to the sigcontext structure. */
  50   memset(&fr, 0, sizeof(fr));
  51   fr.sf_scp = &frp->sf_sc;
  52
  53 #if defined(__i386__)
  54   fr.sf_sc.sc_gs = rp->p_reg.gs;
  55   fr.sf_sc.sc_fs = rp->p_reg.fs;
  56   fr.sf_sc.sc_es = rp->p_reg.es;
  57   fr.sf_sc.sc_ds = rp->p_reg.ds;
  58   fr.sf_sc.sc_edi = rp->p_reg.di;
  59   fr.sf_sc.sc_esi = rp->p_reg.si;
  60   fr.sf_sc.sc_ebp = rp->p_reg.fp;
  61   fr.sf_sc.sc_ebx = rp->p_reg.bx;
  62   fr.sf_sc.sc_edx = rp->p_reg.dx;
  63   fr.sf_sc.sc_ecx = rp->p_reg.cx;
  64   fr.sf_sc.sc_eax = rp->p_reg.retreg;
  65   fr.sf_sc.sc_eip = rp->p_reg.pc;
  66   fr.sf_sc.sc_cs = rp->p_reg.cs;
  67   fr.sf_sc.sc_eflags = rp->p_reg.psw;
  68   fr.sf_sc.sc_esp = rp->p_reg.sp;
  69   fr.sf_sc.sc_ss = rp->p_reg.ss;
  70   fr.sf_fp = rp->p_reg.fp;
  71   fr.sf_signum = smsg.sm_signo;
  72   new_fp = (reg_t) &frp->sf_fp;
  73   fr.sf_scpcopy = fr.sf_scp;
  74   fr.sf_ra_sigreturn = smsg.sm_sigreturn;
  75   fr.sf_ra= rp->p_reg.pc;
  76
  77   fr.sf_sc.trap_style = rp->p_seg.p_kern_trap_style;
  78
  79   if (fr.sf_sc.trap_style == KTS_NONE) {
  80         printf("do_sigsend: sigsend an unsaved process\n");
  81         return EINVAL;
  82   }
  83
  84   if (proc_used_fpu(rp)) {
  85         /* save the FPU context before saving it to the sig context */
  86         save_fpu(rp);
  87         memcpy(&fr.sf_sc.sc_fpu_state, rp->p_seg.fpu_state, FPU_XFP_SIZE);
  88   }
  89 #endif
  90
  91 #if defined(__arm__)
  92   fr.sf_sc.sc_spsr = rp->p_reg.psr;
  93   fr.sf_sc.sc_r0 = rp->p_reg.retreg;
  94   fr.sf_sc.sc_r1 = rp->p_reg.r1;
  95   fr.sf_sc.sc_r2 = rp->p_reg.r2;
  96   fr.sf_sc.sc_r3 = rp->p_reg.r3;
  97   fr.sf_sc.sc_r4 = rp->p_reg.r4;
  98   fr.sf_sc.sc_r5 = rp->p_reg.r5;
  99   fr.sf_sc.sc_r6 = rp->p_reg.r6;
 100   fr.sf_sc.sc_r7 = rp->p_reg.r7;
 101   fr.sf_sc.sc_r8 = rp->p_reg.r8;
 102   fr.sf_sc.sc_r9 = rp->p_reg.r9;
 103   fr.sf_sc.sc_r10 = rp->p_reg.r10;
 104   fr.sf_sc.sc_r11 = rp->p_reg.fp;
 105   fr.sf_sc.sc_r12 = rp->p_reg.r12;
 106   fr.sf_sc.sc_usr_sp = rp->p_reg.sp;
 107   fr.sf_sc.sc_usr_lr = rp->p_reg.lr;
 108   fr.sf_sc.sc_svc_lr = 0;       /* ? */
 109   fr.sf_sc.sc_pc = rp->p_reg.pc;        /* R15 */
 110 #endif
 111
 112   /* Finish the sigcontext initialization. */
 113   fr.sf_sc.sc_mask = smsg.sm_mask;
 114   fr.sf_sc.sc_flags = rp->p_misc_flags & MF_FPU_INITIALIZED;
 115   fr.sf_sc.sc_magic = SC_MAGIC;
 116
 117   /* Initialize the sigframe structure. */
 118   fpu_sigcontext(rp, &fr, &fr.sf_sc);
 119
 120   /* Copy the sigframe structure to the user's stack. */
 121   if ((r = data_copy_vmcheck(caller, KERNEL, (vir_bytes)&fr,
 122                 m_ptr->m_sigcalls.endpt, (vir_bytes)frp,
 123                 (vir_bytes)sizeof(struct sigframe_sigcontext))) != OK)
 124       return r;
 125
 126   /* WARNING: up to the statement above, the code may run multiple times, since
 127    * copying out the frame/context may fail with VMSUSPEND the first time. For
 128    * that reason, changes to process registers *MUST* be deferred until after
 129    * this last copy -- otherwise, these changes will be made several times,
 130    * possibly leading to corrupted process state.
 131    */
 132
 133   /* Reset user registers to execute the signal handler. */
 134   rp->p_reg.sp = (reg_t) frp;
 135   rp->p_reg.pc = (reg_t) smsg.sm_sighandler;
 136
 137 #if defined(__i386__)
 138   rp->p_reg.fp = new_fp;
 139 #elif defined(__arm__)
 140   /* use the ARM link register to set the return address from the signal
 141    * handler
 142    */
 143   rp->p_reg.lr = (reg_t) smsg.sm_sigreturn;
 144   if(rp->p_reg.lr & 1) { printf("sigsend: LSB LR makes no sense.\n"); }
 145
 146   /* pass signal handler parameters in registers */
 147   rp->p_reg.retreg = (reg_t) smsg.sm_signo;
 148   rp->p_reg.r1 = 0;     /* sf_code */
 149   rp->p_reg.r2 = (reg_t) fr.sf_scp;
 150   rp->p_misc_flags |= MF_CONTEXT_SET;
 151 #endif
 152
 153   /* Signal handler should get clean FPU. */
 154   rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
 155
 156   if(!RTS_ISSET(rp, RTS_PROC_STOP)) {
 157         printf("system: warning: sigsend a running process\n");
 158         printf("caller stack: ");
 159         proc_stacktrace(caller);
 160   }
 161
 162   return OK;
 163 }
 164
 165 #endif /* USE_SIGSEND */
 166