/* The system call that is implemented in this file: * SYS_SIGCTL # signal handling functionality * * The parameters and types for this system call are: * SIG_REQUEST # request to perform (long) * SIG_PROC # process to signal/ pending (int) * SIG_CTXT_PTR # pointer to sigcontext structure (pointer) * SIG_FLAGS # flags for S_SIGRETURN call (int) * SIG_MAP # bit map with pending signals (long) * SIG_NUMBER # signal number to send to process (int) * * Supported request types are in the parameter SIG_REQUEST: * S_GETSIG # get a pending kernel signal * S_ENDSIG # signal has been processed * S_SENDSIG # deliver a POSIX-style signal * S_SIGRETURN # return from a POSIX-style signal * S_KILL # send a signal to a process */ #include "../kernel.h" #include "../system.h" #include #include INIT_ASSERT /* PM is ready to accept signals and repeatedly does a system call to get * one. Find a process with pending signals. If no signals are available, * return NONE in the process number field. */ PUBLIC int do_getsig(m_ptr) message *m_ptr; /* pointer to request message */ { register struct proc *rp; /* Find the next process with pending signals. */ for (rp = BEG_USER_ADDR; rp < END_PROC_ADDR; rp++) { if (rp->p_flags & PENDING) { m_ptr->SIG_PROC = proc_number(rp); m_ptr->SIG_MAP = rp->p_pending; sigemptyset(&rp->p_pending); /* ball is in PM's court */ rp->p_flags &= ~PENDING; /* blocked by SIG_PENDING */ return(OK); } } /* No process with pending signals was found. */ m_ptr->SIG_PROC = NONE; return(OK); } PUBLIC int do_endsig(m_ptr) message *m_ptr; /* pointer to request message */ { /* Finish up after a kernel type signal, caused by a SYS_KILL message or a * call to cause_sig by a task. This is called by the PM after processing a * signal it got with SYS_GETSIG. */ register struct proc *rp; rp = proc_addr(m_ptr->SIG_PROC); if (isemptyp(rp)) return(EINVAL); /* process already dead? */ /* PM has finished one kernel signal. Perhaps process is ready now? */ if (rp->p_pendcount != 0 && --rp->p_pendcount == 0 && (rp->p_flags &= ~SIG_PENDING) == 0) lock_ready(rp); return(OK); } PUBLIC int do_sigsend(m_ptr) message *m_ptr; /* pointer to request message */ { /* Handle sys_sigsend, POSIX-style signal handling. */ struct sigmsg smsg; register struct proc *rp; phys_bytes src_phys, dst_phys; struct sigcontext sc, *scp; struct sigframe fr, *frp; rp = proc_addr(m_ptr->SIG_PROC); assert(isuserp(rp)); /* Get the sigmsg structure into our address space. */ src_phys = umap_local(proc_addr(PM_PROC_NR), D, (vir_bytes) m_ptr->SIG_CTXT_PTR, (vir_bytes) sizeof(struct sigmsg)); assert(src_phys != 0); phys_copy(src_phys,vir2phys(&smsg),(phys_bytes) sizeof(struct sigmsg)); /* Compute the user stack pointer where sigcontext will be stored. */ scp = (struct sigcontext *) smsg.sm_stkptr - 1; /* Copy the registers to the sigcontext structure. */ kmemcpy(&sc.sc_regs, &rp->p_reg, sizeof(struct sigregs)); /* Finish the sigcontext initialization. */ sc.sc_flags = SC_SIGCONTEXT; sc.sc_mask = smsg.sm_mask; /* Copy the sigcontext structure to the user's stack. */ dst_phys = umap_local(rp, D, (vir_bytes) scp, (vir_bytes) sizeof(struct sigcontext)); if (dst_phys == 0) return(EFAULT); phys_copy(vir2phys(&sc), dst_phys, (phys_bytes) sizeof(struct sigcontext)); /* Initialize the sigframe structure. */ frp = (struct sigframe *) scp - 1; fr.sf_scpcopy = scp; fr.sf_retadr2= (void (*)()) rp->p_reg.pc; fr.sf_fp = rp->p_reg.fp; rp->p_reg.fp = (reg_t) &frp->sf_fp; fr.sf_scp = scp; fr.sf_code = 0; /* XXX - should be used for type of FP exception */ fr.sf_signo = smsg.sm_signo; fr.sf_retadr = (void (*)()) smsg.sm_sigreturn; /* Copy the sigframe structure to the user's stack. */ dst_phys = umap_local(rp, D, (vir_bytes) frp, (vir_bytes) sizeof(struct sigframe)); if (dst_phys == 0) return(EFAULT); phys_copy(vir2phys(&fr), dst_phys, (phys_bytes) sizeof(struct sigframe)); /* Reset user registers to execute the signal handler. */ rp->p_reg.sp = (reg_t) frp; rp->p_reg.pc = (reg_t) smsg.sm_sighandler; return(OK); } PUBLIC int do_sigreturn(m_ptr) message *m_ptr; /* pointer to request message */ { /* POSIX style signals require sys_sigreturn to put things in order before * the signalled process can resume execution */ struct sigcontext sc; register struct proc *rp; phys_bytes src_phys; rp = proc_addr(m_ptr->SIG_PROC); if (! isuserp(rp)) { kprintf("S_SIGRETURN: message source: %d; ", m_ptr->m_source); kprintf("got non-user process rp: %d\n", rp->p_nr); } assert(isuserp(rp)); /* Copy in the sigcontext structure. */ src_phys = umap_local(rp, D, (vir_bytes) m_ptr->SIG_CTXT_PTR, (vir_bytes) sizeof(struct sigcontext)); if (src_phys == 0) return(EFAULT); phys_copy(src_phys, vir2phys(&sc), (phys_bytes) sizeof(struct sigcontext)); /* Make sure that this is not just a jmp_buf. */ if ((sc.sc_flags & SC_SIGCONTEXT) == 0) return(EINVAL); /* Fix up only certain key registers if the compiler doesn't use * register variables within functions containing setjmp. */ if (sc.sc_flags & SC_NOREGLOCALS) { rp->p_reg.retreg = sc.sc_retreg; rp->p_reg.fp = sc.sc_fp; rp->p_reg.pc = sc.sc_pc; rp->p_reg.sp = sc.sc_sp; return(OK); } sc.sc_psw = rp->p_reg.psw; #if (CHIP == INTEL) /* Don't panic kernel if user gave bad selectors. */ sc.sc_cs = rp->p_reg.cs; sc.sc_ds = rp->p_reg.ds; sc.sc_es = rp->p_reg.es; #if _WORD_SIZE == 4 sc.sc_fs = rp->p_reg.fs; sc.sc_gs = rp->p_reg.gs; #endif #endif /* Restore the registers. */ kmemcpy(&rp->p_reg, (char *)&sc.sc_regs, sizeof(struct sigregs)); return(OK); } /*===========================================================================* * do_sigctl * *===========================================================================*/ PUBLIC int do_kill(m_ptr) message *m_ptr; /* pointer to request message */ { /* Handle sys_kill(). Cause a signal to be sent to a process via PM. * Note that this has nothing to do with the kill (2) system call, this * is how the FS (and possibly other servers) get access to cause_sig. */ cause_sig(m_ptr->SIG_PROC, m_ptr->SIG_NUMBER); return(OK); }