sys/emulation/linux/i386/linux_ptrace.c

   1 /*
   2  * Copyright (c) 2001 Alexander Kabaev
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer
  10  *    in this position and unchanged.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. The name of the author may not be used to endorse or promote products
  15  *    derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * $FreeBSD: src/sys/i386/linux/linux_ptrace.c,v 1.7.4.3 2003/01/03 17:13:23 kan Exp $
  29  * $DragonFly: src/sys/emulation/linux/i386/linux_ptrace.c,v 1.15 2007/02/19 01:14:23 corecode Exp $
  30  */
  31
  32 #include "opt_cpu.h"
  33
  34 #include <sys/param.h>
  35 #include <sys/lock.h>
  36 #include <sys/proc.h>
  37 #include <sys/ptrace.h>
  38 #include <sys/systm.h>
  39
  40 #include <vm/vm.h>
  41 #include <vm/pmap.h>
  42 #include <vm/vm_map.h>
  43 #include <sys/user.h>
  44 #include <sys/reg.h>
  45
  46 #include <machine/md_var.h>
  47 #include <machine/pcb.h>
  48
  49 #include "linux.h"
  50 #include "linux_proto.h"
  51
  52 /*
  53  *   Linux ptrace requests numbers. Mostly identical to FreeBSD,
  54  *   except for MD ones and PT_ATTACH/PT_DETACH.
  55  */
  56 #define PTRACE_TRACEME          0
  57 #define PTRACE_PEEKTEXT         1
  58 #define PTRACE_PEEKDATA         2
  59 #define PTRACE_PEEKUSR          3
  60 #define PTRACE_POKETEXT         4
  61 #define PTRACE_POKEDATA         5
  62 #define PTRACE_POKEUSR          6
  63 #define PTRACE_CONT             7
  64 #define PTRACE_KILL             8
  65 #define PTRACE_SINGLESTEP       9
  66
  67 #define PTRACE_ATTACH           16
  68 #define PTRACE_DETACH           17
  69
  70 #define PTRACE_SYSCALL          24
  71
  72 #define PTRACE_GETREGS          12
  73 #define PTRACE_SETREGS          13
  74 #define PTRACE_GETFPREGS        14
  75 #define PTRACE_SETFPREGS        15
  76 #define PTRACE_GETFPXREGS       18
  77 #define PTRACE_SETFPXREGS       19
  78
  79 #define PTRACE_SETOPTIONS       21
  80
  81 /*
  82  * Linux keeps debug registers at the following
  83  * offset in the user struct
  84  */
  85 #define LINUX_DBREG_OFFSET      252
  86 #define LINUX_DBREG_SIZE        (8*sizeof(l_int))
  87
  88 static __inline__ int
  89 map_signum(int signum)
  90 {
  91
  92         if (signum > 0 && signum <= LINUX_SIGTBLSZ)
  93                 signum = linux_to_bsd_signal[_SIG_IDX(signum)];
  94         return ((signum == SIGSTOP)? 0 : signum);
  95 }
  96
  97 struct linux_pt_reg {
  98         l_long  ebx;
  99         l_long  ecx;
 100         l_long  edx;
 101         l_long  esi;
 102         l_long  edi;
 103         l_long  ebp;
 104         l_long  eax;
 105         l_int   xds;
 106         l_int   xes;
 107         l_int   xfs;
 108         l_int   xgs;
 109         l_long  orig_eax;
 110         l_long  eip;
 111         l_int   xcs;
 112         l_long  eflags;
 113         l_long  esp;
 114         l_int   xss;
 115 };
 116
 117 /*
 118  *   Translate i386 ptrace registers between Linux and FreeBSD formats.
 119  *   The translation is pretty straighforward, for all registers, but
 120  *   orig_eax on Linux side and r_trapno and r_err in FreeBSD
 121  */
 122 static void
 123 map_regs_to_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
 124 {
 125         linux_r->ebx = bsd_r->r_ebx;
 126         linux_r->ecx = bsd_r->r_ecx;
 127         linux_r->edx = bsd_r->r_edx;
 128         linux_r->esi = bsd_r->r_esi;
 129         linux_r->edi = bsd_r->r_edi;
 130         linux_r->ebp = bsd_r->r_ebp;
 131         linux_r->eax = bsd_r->r_eax;
 132         linux_r->xds = bsd_r->r_ds;
 133         linux_r->xes = bsd_r->r_es;
 134         linux_r->xfs = bsd_r->r_fs;
 135         linux_r->xgs = bsd_r->r_gs;
 136         linux_r->orig_eax = bsd_r->r_eax;
 137         linux_r->eip = bsd_r->r_eip;
 138         linux_r->xcs = bsd_r->r_cs;
 139         linux_r->eflags = bsd_r->r_eflags;
 140         linux_r->esp = bsd_r->r_esp;
 141         linux_r->xss = bsd_r->r_ss;
 142 }
 143
 144 static void
 145 map_regs_from_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
 146 {
 147         bsd_r->r_ebx = linux_r->ebx;
 148         bsd_r->r_ecx = linux_r->ecx;
 149         bsd_r->r_edx = linux_r->edx;
 150         bsd_r->r_esi = linux_r->esi;
 151         bsd_r->r_edi = linux_r->edi;
 152         bsd_r->r_ebp = linux_r->ebp;
 153         bsd_r->r_eax = linux_r->eax;
 154         bsd_r->r_ds  = linux_r->xds;
 155         bsd_r->r_es  = linux_r->xes;
 156         bsd_r->r_fs  = linux_r->xfs;
 157         bsd_r->r_gs  = linux_r->xgs;
 158         bsd_r->r_eip = linux_r->eip;
 159         bsd_r->r_cs  = linux_r->xcs;
 160         bsd_r->r_eflags = linux_r->eflags;
 161         bsd_r->r_esp = linux_r->esp;
 162         bsd_r->r_ss = linux_r->xss;
 163 }
 164
 165 struct linux_pt_fpreg {
 166         l_long cwd;
 167         l_long swd;
 168         l_long twd;
 169         l_long fip;
 170         l_long fcs;
 171         l_long foo;
 172         l_long fos;
 173         l_long st_space[2*10];
 174 };
 175
 176 static void
 177 map_fpregs_to_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
 178 {
 179         linux_r->cwd = bsd_r->fpr_env[0];
 180         linux_r->swd = bsd_r->fpr_env[1];
 181         linux_r->twd = bsd_r->fpr_env[2];
 182         linux_r->fip = bsd_r->fpr_env[3];
 183         linux_r->fcs = bsd_r->fpr_env[4];
 184         linux_r->foo = bsd_r->fpr_env[5];
 185         linux_r->fos = bsd_r->fpr_env[6];
 186         bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(linux_r->st_space));
 187 }
 188
 189 static void
 190 map_fpregs_from_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
 191 {
 192         bsd_r->fpr_env[0] = linux_r->cwd;
 193         bsd_r->fpr_env[1] = linux_r->swd;
 194         bsd_r->fpr_env[2] = linux_r->twd;
 195         bsd_r->fpr_env[3] = linux_r->fip;
 196         bsd_r->fpr_env[4] = linux_r->fcs;
 197         bsd_r->fpr_env[5] = linux_r->foo;
 198         bsd_r->fpr_env[6] = linux_r->fos;
 199         bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(bsd_r->fpr_acc));
 200 }
 201
 202 struct linux_pt_fpxreg {
 203         l_ushort        cwd;
 204         l_ushort        swd;
 205         l_ushort        twd;
 206         l_ushort        fop;
 207         l_long          fip;
 208         l_long          fcs;
 209         l_long          foo;
 210         l_long          fos;
 211         l_long          mxcsr;
 212         l_long          reserved;
 213         l_long          st_space[32];
 214         l_long          xmm_space[32];
 215         l_long          padding[56];
 216 };
 217
 218 #ifndef CPU_DISABLE_SSE
 219 static int
 220 linux_proc_read_fpxregs(struct lwp *lp, struct linux_pt_fpxreg *fpxregs)
 221 {
 222         int error;
 223
 224         error = 0;
 225         if (cpu_fxsr == 0)
 226                 error = EIO;
 227         else
 228                 bcopy(&lp->lwp_thread->td_pcb->pcb_save.sv_xmm,
 229                     fpxregs, sizeof(*fpxregs));
 230         return (error);
 231 }
 232
 233 static int
 234 linux_proc_write_fpxregs(struct lwp *lp, struct linux_pt_fpxreg *fpxregs)
 235 {
 236         int error;
 237
 238         error = 0;
 239         if (cpu_fxsr == 0)
 240                 error = EIO;
 241         else
 242                 bcopy(fpxregs, &lp->lwp_thread->td_pcb->pcb_save.sv_xmm,
 243                     sizeof(*fpxregs));
 244         return (error);
 245 }
 246 #endif
 247
 248 /*
 249  * MPALMOSTSAFE
 250  */
 251 int
 252 sys_linux_ptrace(struct linux_ptrace_args *uap)
 253 {
 254         struct thread *td = curthread;
 255         struct proc *curp = td->td_proc;
 256         union {
 257                 struct linux_pt_reg     reg;
 258                 struct linux_pt_fpreg   fpreg;
 259                 struct linux_pt_fpxreg  fpxreg;
 260         } r;
 261         union {
 262                 struct reg              bsd_reg;
 263                 struct fpreg            bsd_fpreg;
 264                 struct dbreg            bsd_dbreg;
 265         } u;
 266         void *addr;
 267         pid_t pid;
 268         int error, req;
 269         struct proc *p = NULL;  /* held process */
 270
 271         error = 0;
 272
 273         /* by default, just copy data intact */
 274         req  = uap->req;
 275         pid  = (pid_t)uap->pid;
 276         addr = (void *)uap->addr;
 277
 278         switch (req) {
 279         case PTRACE_TRACEME:
 280         case PTRACE_POKETEXT:
 281         case PTRACE_POKEDATA:
 282         case PTRACE_KILL:
 283                 error = kern_ptrace(curp, req, pid, addr, uap->data,
 284                                     &uap->sysmsg_iresult);
 285                 break;
 286         case PTRACE_PEEKTEXT:
 287         case PTRACE_PEEKDATA: {
 288                 /* need to preserve return value, use dummy */
 289                 l_int rval = 0;
 290                 error = kern_ptrace(curp, req, pid, addr, 0, &rval);
 291                 if (error == 0) {
 292                         error = copyout(&rval, (caddr_t)uap->data, sizeof(l_int));
 293                 }
 294                 break;
 295         }
 296         case PTRACE_DETACH:
 297                 error = kern_ptrace(curp, PT_DETACH, pid, (void *)1,
 298                                     map_signum(uap->data),
 299                                     &uap->sysmsg_iresult);
 300                 break;
 301         case PTRACE_SINGLESTEP:
 302         case PTRACE_CONT:
 303                 error = kern_ptrace(curp, req, pid, (void *)1,
 304                                     map_signum(uap->data),
 305                                     &uap->sysmsg_iresult);
 306                 break;
 307         case PTRACE_ATTACH:
 308                 error = kern_ptrace(curp, PT_ATTACH, pid, addr, uap->data,
 309                                     &uap->sysmsg_iresult);
 310                 break;
 311         case PTRACE_GETREGS:
 312                 /* Linux is using data where FreeBSD is using addr */
 313                 error = kern_ptrace(curp, PT_GETREGS, pid, &u.bsd_reg, 0,
 314                                     &uap->sysmsg_iresult);
 315                 if (error == 0) {
 316                         map_regs_to_linux(&u.bsd_reg, &r.reg);
 317                         error = copyout(&r.reg, (void *)uap->data,
 318                                         sizeof(r.reg));
 319                 }
 320                 break;
 321         case PTRACE_SETREGS:
 322                 /* Linux is using data where FreeBSD is using addr */
 323                 error = copyin((caddr_t)uap->data, &r.reg, sizeof(r.reg));
 324                 if (error == 0) {
 325                         map_regs_from_linux(&u.bsd_reg, &r.reg);
 326                         error = kern_ptrace(curp, PT_SETREGS, pid, &u.bsd_reg,
 327                                             0, &uap->sysmsg_iresult);
 328                 }
 329                 break;
 330         case PTRACE_GETFPREGS:
 331                 /* Linux is using data where FreeBSD is using addr */
 332                 error = kern_ptrace(curp, PT_GETFPREGS, pid, &u.bsd_fpreg,
 333                                     0, &uap->sysmsg_iresult);
 334                 if (error == 0) {
 335                         map_fpregs_to_linux(&u.bsd_fpreg, &r.fpreg);
 336                         error = copyout(&r.fpreg, (caddr_t)uap->data,
 337                             sizeof(r.fpreg));
 338                 }
 339                 break;
 340         case PTRACE_SETFPREGS:
 341                 /* Linux is using data where FreeBSD is using addr */
 342                 error = copyin((caddr_t)uap->data, &r.fpreg, sizeof(r.fpreg));
 343                 if (error == 0) {
 344                         map_fpregs_from_linux(&u.bsd_fpreg, &r.fpreg);
 345                         error = kern_ptrace(curp, PT_SETFPREGS, pid,
 346                                             &u.bsd_fpreg,
 347                                             0, &uap->sysmsg_iresult);
 348                 }
 349                 break;
 350         case PTRACE_SETFPXREGS:
 351 #ifndef CPU_DISABLE_SSE
 352                 error = copyin((caddr_t)uap->data, &r.fpxreg,
 353                     sizeof(r.fpxreg));
 354                 if (error)
 355                         break;
 356 #endif
 357                 /* FALL THROUGH */
 358         case PTRACE_GETFPXREGS: {
 359 #ifndef CPU_DISABLE_SSE
 360                 struct proc *p;
 361                 struct lwp *lp;
 362
 363                 if (sizeof(struct linux_pt_fpxreg) != sizeof(struct savexmm)) {
 364                         static int once = 0;
 365                         if (!once) {
 366                                 kprintf("linux: savexmm != linux_pt_fpxreg\n");
 367                                 once = 1;
 368                         }
 369                         error = EIO;
 370                         break;
 371                 }
 372
 373                 if ((p = pfind(uap->pid)) == NULL) {
 374                         error = ESRCH;
 375                         break;
 376                 }
 377
 378                 if (!PRISON_CHECK(curp->p_ucred, p->p_ucred)) {
 379                         error = ESRCH;
 380                         goto fail;
 381                 }
 382
 383                 /* System processes can't be debugged. */
 384                 if ((p->p_flag & P_SYSTEM) != 0) {
 385                         error = EINVAL;
 386                         goto fail;
 387                 }
 388
 389                 /* not being traced... */
 390                 if ((p->p_flag & P_TRACED) == 0) {
 391                         error = EPERM;
 392                         goto fail;
 393                 }
 394
 395                 /* not being traced by YOU */
 396                 if (p->p_pptr != curp) {
 397                         error = EBUSY;
 398                         goto fail;
 399                 }
 400
 401                 /* not currently stopped */
 402                 if ((p->p_flag & (P_TRACED|P_WAITED)) == 0) {
 403                         error = EBUSY;
 404                         goto fail;
 405                 }
 406
 407                 /* XXX lwp */
 408                 lp = FIRST_LWP_IN_PROC(p);
 409
 410                 if (req == PTRACE_GETFPXREGS) {
 411                         LWPHOLD(lp);
 412                         error = linux_proc_read_fpxregs(lp, &r.fpxreg);
 413                         LWPRELE(lp);
 414                         if (error == 0)
 415                                 error = copyout(&r.fpxreg, (caddr_t)uap->data,
 416                                     sizeof(r.fpxreg));
 417                 } else {
 418                         /* clear dangerous bits exactly as Linux does*/
 419                         r.fpxreg.mxcsr &= 0xffbf;
 420                         LWPHOLD(lp);
 421                         error = linux_proc_write_fpxregs(lp, &r.fpxreg);
 422                         LWPRELE(lp);
 423                 }
 424                 break;
 425
 426         fail:
 427 #else
 428                 error = EIO;
 429 #endif
 430                 break;
 431         }
 432         case PTRACE_PEEKUSR:
 433         case PTRACE_POKEUSR: {
 434                 error = EIO;
 435
 436                 /* check addr for alignment */
 437                 if (uap->addr < 0 || uap->addr & (sizeof(l_int) - 1))
 438                         break;
 439                 /*
 440                  * Allow linux programs to access register values in
 441                  * user struct. We simulate this through PT_GET/SETREGS
 442                  * as necessary.
 443                  */
 444                 if (uap->addr < sizeof(struct linux_pt_reg)) {
 445                         error = kern_ptrace(curp, PT_GETREGS, pid, &u.bsd_reg,
 446                                             0, &uap->sysmsg_iresult);
 447                         if (error != 0)
 448                                 break;
 449
 450                         map_regs_to_linux(&u.bsd_reg, &r.reg);
 451                         if (req == PTRACE_PEEKUSR) {
 452                                 error = copyout((char *)&r.reg + uap->addr,
 453                                     (caddr_t)uap->data, sizeof(l_int));
 454                                 break;
 455                         }
 456
 457                         *(l_int *)((char *)&r.reg + uap->addr) =
 458                             (l_int)uap->data;
 459
 460                         map_regs_from_linux(&u.bsd_reg, &r.reg);
 461                         error = kern_ptrace(curp, PT_SETREGS, pid, &u.bsd_reg,
 462                                             0, &uap->sysmsg_iresult);
 463                 }
 464
 465                 /*
 466                  * Simulate debug registers access
 467                  */
 468                 if (uap->addr >= LINUX_DBREG_OFFSET &&
 469                     uap->addr <= LINUX_DBREG_OFFSET + LINUX_DBREG_SIZE) {
 470                         error = kern_ptrace(curp, PT_GETDBREGS, pid,
 471                                             &u.bsd_dbreg,
 472                                             0, &uap->sysmsg_iresult);
 473                         if (error != 0)
 474                                 break;
 475
 476                         uap->addr -= LINUX_DBREG_OFFSET;
 477                         if (req == PTRACE_PEEKUSR) {
 478                                 error = copyout((char *)&u.bsd_dbreg +
 479                                     uap->addr, (caddr_t)uap->data,
 480                                     sizeof(l_int));
 481                                 break;
 482                         }
 483
 484                         *(l_int *)((char *)&u.bsd_dbreg + uap->addr) =
 485                              uap->data;
 486                         error = kern_ptrace(curp, PT_SETDBREGS, pid,
 487                                             &u.bsd_dbreg,
 488                                             0, &uap->sysmsg_iresult);
 489                 }
 490
 491                 break;
 492         }
 493         case PTRACE_SYSCALL:
 494                 /* fall through */
 495         default:
 496                 kprintf("linux: ptrace(%u, ...) not implemented\n",
 497                     (unsigned int)uap->req);
 498                 error = EINVAL;
 499                 break;
 500         }
 501
 502         /*
 503          * Release held proces (if any) before returning.
 504          */
 505         if (p)
 506                 PRELE(p);
 507         return (error);
 508 }