1 | /* The kernel call that is implemented in this file:
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2 | * m_type: SYS_SIGRETURN
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3 | *
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4 | * The parameters for this kernel call are:
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5 | * m2_i1: SIG_ENDPT # process returning from handler
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6 | * m2_p1: SIG_CTXT_PTR # pointer to sigcontext structure
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7 | *
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8 | */
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9 |
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10 | #include "../system.h"
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11 | #include <string.h>
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12 | #include <signal.h>
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13 | #include <sys/sigcontext.h>
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14 |
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15 | #if USE_SIGRETURN
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16 |
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17 | /*===========================================================================*
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18 | * do_sigreturn *
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19 | *===========================================================================*/
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20 | PUBLIC int do_sigreturn(m_ptr)
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21 | message *m_ptr; /* pointer to request message */
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22 | {
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23 | /* POSIX style signals require sys_sigreturn to put things in order before
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24 | * the signalled process can resume execution
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25 | */
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26 | struct sigcontext sc;
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27 | register struct proc *rp;
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28 | phys_bytes src_phys;
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29 | int proc;
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30 |
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31 | if (! isokendpt(m_ptr->SIG_ENDPT, &proc)) return(EINVAL);
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32 | if (iskerneln(proc)) return(EPERM);
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33 | rp = proc_addr(proc);
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34 |
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35 | /* Copy in the sigcontext structure. */
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36 | src_phys = umap_local(rp, D, (vir_bytes) m_ptr->SIG_CTXT_PTR,
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37 | (vir_bytes) sizeof(struct sigcontext));
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38 | if (src_phys == 0) return(EFAULT);
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39 | phys_copy(src_phys, vir2phys(&sc), (phys_bytes) sizeof(struct sigcontext));
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40 |
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41 | /* Make sure that this is not just a jump buffer. */
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42 | if ((sc.sc_flags & SC_SIGCONTEXT) == 0) return(EINVAL);
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43 |
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44 | /* Fix up only certain key registers if the compiler doesn't use
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45 | * register variables within functions containing setjmp.
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46 | */
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47 | if (sc.sc_flags & SC_NOREGLOCALS) {
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48 | rp->p_reg.retreg = sc.sc_retreg;
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49 | rp->p_reg.fp = sc.sc_fp;
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50 | rp->p_reg.pc = sc.sc_pc;
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51 | rp->p_reg.sp = sc.sc_sp;
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52 | return(OK);
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53 | }
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54 | sc.sc_psw = rp->p_reg.psw;
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55 |
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56 | #if (CHIP == INTEL)
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57 | /* Don't panic kernel if user gave bad selectors. */
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58 | sc.sc_cs = rp->p_reg.cs;
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59 | sc.sc_ds = rp->p_reg.ds;
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60 | sc.sc_es = rp->p_reg.es;
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61 | #if _WORD_SIZE == 4
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62 | sc.sc_fs = rp->p_reg.fs;
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63 | sc.sc_gs = rp->p_reg.gs;
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64 | #endif
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65 | #endif
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66 |
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67 | /* Restore the registers. */
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68 | memcpy(&rp->p_reg, &sc.sc_regs, sizeof(struct sigregs));
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69 | return(OK);
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70 | }
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71 | #endif /* USE_SIGRETURN */
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72 |
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