1                 : /*
       2                 :  * Copyright 2010 The Native Client Authors. All rights reserved.
       3                 :  * Use of this source code is governed by a BSD-style license that can be
       4                 :  * found in the LICENSE file.
       5                 :  */
       6                 : 
       7                 : #include <signal.h>
       8                 : #include <string.h>
       9                 : #include <sys/ucontext.h>
      10                 : 
      11                 : #include "native_client/src/trusted/service_runtime/nacl_signal.h"
      12                 : 
      13                 : /*
      14                 :  * Definition of the POSIX ucontext_t for Linux can be found in:
      15                 :  * /usr/include/sys/ucontext.h
      16                 :  */
      17                 : 
      18                 : /*
      19                 :  * Fill a signal context structure from the raw platform dependent
      20                 :  * signal information.
      21                 :  */
      22          292091 : void NaClSignalContextFromHandler(struct NaClSignalContext *sig_ctx,
      23                 :                                   const void *raw_ctx) {
      24          292091 :   const ucontext_t *uctx = (const ucontext_t *) raw_ctx;
      25          292091 :   const mcontext_t *mctx = &uctx->uc_mcontext;
      26                 : 
      27          292091 :   memset(sig_ctx, 0, sizeof(*sig_ctx));
      28                 : 
      29          292091 :   sig_ctx->prog_ctr = mctx->gregs[REG_RIP];
      30          292091 :   sig_ctx->stack_ptr = mctx->gregs[REG_RSP];
      31                 : 
      32          292091 :   sig_ctx->rax = mctx->gregs[REG_RAX];
      33          292091 :   sig_ctx->rbx = mctx->gregs[REG_RBX];
      34          292091 :   sig_ctx->rcx = mctx->gregs[REG_RCX];
      35          292091 :   sig_ctx->rdx = mctx->gregs[REG_RDX];
      36          292091 :   sig_ctx->rsi = mctx->gregs[REG_RSI];
      37          292091 :   sig_ctx->rdi = mctx->gregs[REG_RDI];
      38          292091 :   sig_ctx->rbp = mctx->gregs[REG_RBP];
      39          292091 :   sig_ctx->r8  = mctx->gregs[REG_R8];
      40          292091 :   sig_ctx->r9  = mctx->gregs[REG_R9];
      41          292091 :   sig_ctx->r10 = mctx->gregs[REG_R10];
      42          292091 :   sig_ctx->r11 = mctx->gregs[REG_R11];
      43          292091 :   sig_ctx->r12 = mctx->gregs[REG_R12];
      44          292091 :   sig_ctx->r13 = mctx->gregs[REG_R13];
      45          292091 :   sig_ctx->r14 = mctx->gregs[REG_R14];
      46          292091 :   sig_ctx->r15 = mctx->gregs[REG_R15];
      47          292091 :   sig_ctx->flags = mctx->gregs[REG_EFL];
      48                 : 
      49                 :   /* Linux stores CS, GS, FS, PAD into one 64b word. */
      50          292091 :   sig_ctx->cs = (uint32_t) (mctx->gregs[REG_CSGSFS] & 0xFFFF);
      51          292091 :   sig_ctx->gs = (uint32_t) ((mctx->gregs[REG_CSGSFS] >> 16) & 0xFFFF);
      52          292091 :   sig_ctx->fs = (uint32_t) ((mctx->gregs[REG_CSGSFS] >> 32) & 0xFFFF);
      53                 : 
      54                 :   /*
      55                 :    * TODO(noelallen) Pull from current context, since they must be
      56                 :    * the same.
      57                 :    */
      58          292091 :   sig_ctx->ds = 0;
      59          292091 :   sig_ctx->ss = 0;
      60          292091 : }
      61                 : 
      62                 : 
      63                 : /*
      64                 :  * Update the raw platform dependent signal information from the
      65                 :  * signal context structure.
      66                 :  */
      67          276473 : void NaClSignalContextToHandler(void *raw_ctx,
      68                 :                                 const struct NaClSignalContext *sig_ctx) {
      69          276473 :   ucontext_t *uctx = (ucontext_t *) raw_ctx;
      70          276473 :   mcontext_t *mctx = &uctx->uc_mcontext;
      71                 : 
      72          276473 :   mctx->gregs[REG_RIP] = sig_ctx->prog_ctr;
      73          276473 :   mctx->gregs[REG_RSP] = sig_ctx->stack_ptr;
      74                 : 
      75          276473 :   mctx->gregs[REG_RAX] = sig_ctx->rax;
      76          276473 :   mctx->gregs[REG_RBX] = sig_ctx->rbx;
      77          276473 :   mctx->gregs[REG_RCX] = sig_ctx->rcx;
      78          276473 :   mctx->gregs[REG_RDX] = sig_ctx->rdx;
      79          276473 :   mctx->gregs[REG_RSI] = sig_ctx->rsi;
      80          276473 :   mctx->gregs[REG_RDI] = sig_ctx->rdi;
      81          276473 :   mctx->gregs[REG_RBP] = sig_ctx->rbp;
      82          276473 :   mctx->gregs[REG_R8]  = sig_ctx->r8;
      83          276473 :   mctx->gregs[REG_R9]  = sig_ctx->r9;
      84          276473 :   mctx->gregs[REG_R10] = sig_ctx->r10;
      85          276473 :   mctx->gregs[REG_R11] = sig_ctx->r11;
      86          276473 :   mctx->gregs[REG_R12] = sig_ctx->r12;
      87          276473 :   mctx->gregs[REG_R13] = sig_ctx->r13;
      88          276473 :   mctx->gregs[REG_R14] = sig_ctx->r14;
      89          276473 :   mctx->gregs[REG_R15] = sig_ctx->r15;
      90          276473 :   mctx->gregs[REG_EFL] = sig_ctx->flags;
      91                 : 
      92                 :   /* Linux stores CS, GS, FS, PAD into one 64b word. */
      93          552946 :   mctx->gregs[REG_CSGSFS] = ((uint64_t) (sig_ctx->cs & 0xFFFF))
      94          276473 :                           | (((uint64_t) (sig_ctx->gs & 0xFFFF)) << 16)
      95          276473 :                           | (((uint64_t) (sig_ctx->fs & 0xFFFF)) << 32);
      96                 : 
      97                 :   /*
      98                 :    * We do not support modification of DS & SS in 64b, so
      99                 :    * we do not push them back into the context.
     100                 :    */
     101          276473 : }
     102                 : 
     103                 : 
     104                 :