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 <sys/mplock2.h>
  47
  48 #include <machine/md_var.h>
  49 #include <machine/pcb.h>
  50
  51 #include "linux.h"
  52 #include "linux_proto.h"
  53
  54 /*
  55  *   Linux ptrace requests numbers. Mostly identical to FreeBSD,
  56  *   except for MD ones and PT_ATTACH/PT_DETACH.
  57  */
  58 #define PTRACE_TRACEME          0
  59 #define PTRACE_PEEKTEXT         1
  60 #define PTRACE_PEEKDATA         2
  61 #define PTRACE_PEEKUSR          3
  62 #define PTRACE_POKETEXT         4
  63 #define PTRACE_POKEDATA         5
  64 #define PTRACE_POKEUSR          6
  65 #define PTRACE_CONT             7
  66 #define PTRACE_KILL             8
  67 #define PTRACE_SINGLESTEP       9
  68
  69 #define PTRACE_ATTACH           16
  70 #define PTRACE_DETACH           17
  71
  72 #define PTRACE_SYSCALL          24
  73
  74 #define PTRACE_GETREGS          12
  75 #define PTRACE_SETREGS          13
  76 #define PTRACE_GETFPREGS        14
  77 #define PTRACE_SETFPREGS        15
  78 #define PTRACE_GETFPXREGS       18
  79 #define PTRACE_SETFPXREGS       19
  80
  81 #define PTRACE_SETOPTIONS       21
  82
  83 /*
  84  * Linux keeps debug registers at the following
  85  * offset in the user struct
  86  */
  87 #define LINUX_DBREG_OFFSET      252
  88 #define LINUX_DBREG_SIZE        (8*sizeof(l_int))
  89
  90 static __inline__ int
  91 map_signum(int signum)
  92 {
  93
  94         if (signum > 0 && signum <= LINUX_SIGTBLSZ)
  95                 signum = linux_to_bsd_signal[_SIG_IDX(signum)];
  96         return ((signum == SIGSTOP)? 0 : signum);
  97 }
  98
  99 struct linux_pt_reg {
 100         l_long  ebx;
 101         l_long  ecx;
 102         l_long  edx;
 103         l_long  esi;
 104         l_long  edi;
 105         l_long  ebp;
 106         l_long  eax;
 107         l_int   xds;
 108         l_int   xes;
 109         l_int   xfs;
 110         l_int   xgs;
 111         l_long  orig_eax;
 112         l_long  eip;
 113         l_int   xcs;
 114         l_long  eflags;
 115         l_long  esp;
 116         l_int   xss;
 117 };
 118
 119 /*
 120  *   Translate i386 ptrace registers between Linux and FreeBSD formats.
 121  *   The translation is pretty straighforward, for all registers, but
 122  *   orig_eax on Linux side and r_trapno and r_err in FreeBSD
 123  */
 124 static void
 125 map_regs_to_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
 126 {
 127         linux_r->ebx = bsd_r->r_ebx;
 128         linux_r->ecx = bsd_r->r_ecx;
 129         linux_r->edx = bsd_r->r_edx;
 130         linux_r->esi = bsd_r->r_esi;
 131         linux_r->edi = bsd_r->r_edi;
 132         linux_r->ebp = bsd_r->r_ebp;
 133         linux_r->eax = bsd_r->r_eax;
 134         linux_r->xds = bsd_r->r_ds;
 135         linux_r->xes = bsd_r->r_es;
 136         linux_r->xfs = bsd_r->r_fs;
 137         linux_r->xgs = bsd_r->r_gs;
 138         linux_r->orig_eax = bsd_r->r_eax;
 139         linux_r->eip = bsd_r->r_eip;
 140         linux_r->xcs = bsd_r->r_cs;
 141         linux_r->eflags = bsd_r->r_eflags;
 142         linux_r->esp = bsd_r->r_esp;
 143         linux_r->xss = bsd_r->r_ss;
 144 }
 145
 146 static void
 147 map_regs_from_linux(struct reg *bsd_r, struct linux_pt_reg *linux_r)
 148 {
 149         bsd_r->r_ebx = linux_r->ebx;
 150         bsd_r->r_ecx = linux_r->ecx;
 151         bsd_r->r_edx = linux_r->edx;
 152         bsd_r->r_esi = linux_r->esi;
 153         bsd_r->r_edi = linux_r->edi;
 154         bsd_r->r_ebp = linux_r->ebp;
 155         bsd_r->r_eax = linux_r->eax;
 156         bsd_r->r_ds  = linux_r->xds;
 157         bsd_r->r_es  = linux_r->xes;
 158         bsd_r->r_fs  = linux_r->xfs;
 159         bsd_r->r_gs  = linux_r->xgs;
 160         bsd_r->r_eip = linux_r->eip;
 161         bsd_r->r_cs  = linux_r->xcs;
 162         bsd_r->r_eflags = linux_r->eflags;
 163         bsd_r->r_esp = linux_r->esp;
 164         bsd_r->r_ss = linux_r->xss;
 165 }
 166
 167 struct linux_pt_fpreg {
 168         l_long cwd;
 169         l_long swd;
 170         l_long twd;
 171         l_long fip;
 172         l_long fcs;
 173         l_long foo;
 174         l_long fos;
 175         l_long st_space[2*10];
 176 };
 177
 178 static void
 179 map_fpregs_to_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
 180 {
 181         linux_r->cwd = bsd_r->fpr_env[0];
 182         linux_r->swd = bsd_r->fpr_env[1];
 183         linux_r->twd = bsd_r->fpr_env[2];
 184         linux_r->fip = bsd_r->fpr_env[3];
 185         linux_r->fcs = bsd_r->fpr_env[4];
 186         linux_r->foo = bsd_r->fpr_env[5];
 187         linux_r->fos = bsd_r->fpr_env[6];
 188         bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(linux_r->st_space));
 189 }
 190
 191 static void
 192 map_fpregs_from_linux(struct fpreg *bsd_r, struct linux_pt_fpreg *linux_r)
 193 {
 194         bsd_r->fpr_env[0] = linux_r->cwd;
 195         bsd_r->fpr_env[1] = linux_r->swd;
 196         bsd_r->fpr_env[2] = linux_r->twd;
 197         bsd_r->fpr_env[3] = linux_r->fip;
 198         bsd_r->fpr_env[4] = linux_r->fcs;
 199         bsd_r->fpr_env[5] = linux_r->foo;
 200         bsd_r->fpr_env[6] = linux_r->fos;
 201         bcopy(bsd_r->fpr_acc, linux_r->st_space, sizeof(bsd_r->fpr_acc));
 202 }
 203
 204 struct linux_pt_fpxreg {
 205         l_ushort        cwd;
 206         l_ushort        swd;
 207         l_ushort        twd;
 208         l_ushort        fop;
 209         l_long          fip;
 210         l_long          fcs;
 211         l_long          foo;
 212         l_long          fos;
 213         l_long          mxcsr;
 214         l_long          reserved;
 215         l_long          st_space[32];
 216         l_long          xmm_space[32];
 217         l_long          padding[56];
 218 };
 219
 220 #ifndef CPU_DISABLE_SSE
 221 static int
 222 linux_proc_read_fpxregs(struct lwp *lp, struct linux_pt_fpxreg *fpxregs)
 223 {
 224         int error;
 225
 226         error = 0;
 227         if (cpu_fxsr == 0)
 228                 error = EIO;
 229         else
 230                 bcopy(&lp->lwp_thread->td_pcb->pcb_save.sv_xmm,
 231                     fpxregs, sizeof(*fpxregs));
 232         return (error);
 233 }
 234
 235 static int
 236 linux_proc_write_fpxregs(struct lwp *lp, struct linux_pt_fpxreg *fpxregs)
 237 {
 238         int error;
 239
 240         error = 0;
 241         if (cpu_fxsr == 0)
 242                 error = EIO;
 243         else
 244                 bcopy(fpxregs, &lp->lwp_thread->td_pcb->pcb_save.sv_xmm,
 245                     sizeof(*fpxregs));
 246         return (error);
 247 }
 248 #endif
 249
 250 /*
 251  * MPALMOSTSAFE
 252  */
 253 int
 254 sys_linux_ptrace(struct linux_ptrace_args *uap)
 255 {
 256         struct thread *td = curthread;
 257         struct proc *curp = td->td_proc;
 258         union {
 259                 struct linux_pt_reg     reg;
 260                 struct linux_pt_fpreg   fpreg;
 261                 struct linux_pt_fpxreg  fpxreg;
 262         } r;
 263         union {
 264                 struct reg              bsd_reg;
 265                 struct fpreg            bsd_fpreg;
 266                 struct dbreg            bsd_dbreg;
 267         } u;
 268         void *addr;
 269         pid_t pid;
 270         int error, req;
 271
 272         error = 0;
 273
 274         /* by default, just copy data intact */
 275         req  = uap->req;
 276         pid  = (pid_t)uap->pid;
 277         addr = (void *)uap->addr;
 278
 279         get_mplock();
 280
 281         switch (req) {
 282         case PTRACE_TRACEME:
 283         case PTRACE_POKETEXT:
 284         case PTRACE_POKEDATA:
 285         case PTRACE_KILL:
 286                 error = kern_ptrace(curp, req, pid, addr, uap->data,
 287                                     &uap->sysmsg_iresult);
 288                 break;
 289         case PTRACE_PEEKTEXT:
 290         case PTRACE_PEEKDATA: {
 291                 /* need to preserve return value, use dummy */
 292                 l_int rval = 0;
 293                 error = kern_ptrace(curp, req, pid, addr, 0, &rval);
 294                 if (error == 0) {
 295                         error = copyout(&rval, (caddr_t)uap->data, sizeof(l_int));
 296                 }
 297                 break;
 298         }
 299         case PTRACE_DETACH:
 300                 error = kern_ptrace(curp, PT_DETACH, pid, (void *)1,
 301                                     map_signum(uap->data),
 302                                     &uap->sysmsg_iresult);
 303                 break;
 304         case PTRACE_SINGLESTEP:
 305         case PTRACE_CONT:
 306                 error = kern_ptrace(curp, req, pid, (void *)1,
 307                                     map_signum(uap->data),
 308                                     &uap->sysmsg_iresult);
 309                 break;
 310         case PTRACE_ATTACH:
 311                 error = kern_ptrace(curp, PT_ATTACH, pid, addr, uap->data,
 312                                     &uap->sysmsg_iresult);
 313                 break;
 314         case PTRACE_GETREGS:
 315                 /* Linux is using data where FreeBSD is using addr */
 316                 error = kern_ptrace(curp, PT_GETREGS, pid, &u.bsd_reg, 0,
 317                                     &uap->sysmsg_iresult);
 318                 if (error == 0) {
 319                         map_regs_to_linux(&u.bsd_reg, &r.reg);
 320                         error = copyout(&r.reg, (void *)uap->data,
 321                                         sizeof(r.reg));
 322                 }
 323                 break;
 324         case PTRACE_SETREGS:
 325                 /* Linux is using data where FreeBSD is using addr */
 326                 error = copyin((caddr_t)uap->data, &r.reg, sizeof(r.reg));
 327                 if (error == 0) {
 328                         map_regs_from_linux(&u.bsd_reg, &r.reg);
 329                         error = kern_ptrace(curp, PT_SETREGS, pid, &u.bsd_reg,
 330                                             0, &uap->sysmsg_iresult);
 331                 }
 332                 break;
 333         case PTRACE_GETFPREGS:
 334                 /* Linux is using data where FreeBSD is using addr */
 335                 error = kern_ptrace(curp, PT_GETFPREGS, pid, &u.bsd_fpreg,
 336                                     0, &uap->sysmsg_iresult);
 337                 if (error == 0) {
 338                         map_fpregs_to_linux(&u.bsd_fpreg, &r.fpreg);
 339                         error = copyout(&r.fpreg, (caddr_t)uap->data,
 340                             sizeof(r.fpreg));
 341                 }
 342                 break;
 343         case PTRACE_SETFPREGS:
 344                 /* Linux is using data where FreeBSD is using addr */
 345                 error = copyin((caddr_t)uap->data, &r.fpreg, sizeof(r.fpreg));
 346                 if (error == 0) {
 347                         map_fpregs_from_linux(&u.bsd_fpreg, &r.fpreg);
 348                         error = kern_ptrace(curp, PT_SETFPREGS, pid,
 349                                             &u.bsd_fpreg,
 350                                             0, &uap->sysmsg_iresult);
 351                 }
 352                 break;
 353         case PTRACE_SETFPXREGS:
 354 #ifndef CPU_DISABLE_SSE
 355                 error = copyin((caddr_t)uap->data, &r.fpxreg,
 356                     sizeof(r.fpxreg));
 357                 if (error)
 358                         break;
 359 #endif
 360                 /* FALL THROUGH */
 361         case PTRACE_GETFPXREGS: {
 362 #ifndef CPU_DISABLE_SSE
 363                 struct proc *p;
 364                 struct lwp *lp;
 365
 366                 if (sizeof(struct linux_pt_fpxreg) != sizeof(struct savexmm)) {
 367                         static int once = 0;
 368                         if (!once) {
 369                                 kprintf("linux: savexmm != linux_pt_fpxreg\n");
 370                                 once = 1;
 371                         }
 372                         error = EIO;
 373                         break;
 374                 }
 375
 376                 if ((p = pfind(uap->pid)) == NULL) {
 377                         error = ESRCH;
 378                         break;
 379                 }
 380
 381                 if (!PRISON_CHECK(curp->p_ucred, p->p_ucred)) {
 382                         error = ESRCH;
 383                         goto fail;
 384                 }
 385
 386                 /* System processes can't be debugged. */
 387                 if ((p->p_flag & P_SYSTEM) != 0) {
 388                         error = EINVAL;
 389                         goto fail;
 390                 }
 391
 392                 /* not being traced... */
 393                 if ((p->p_flag & P_TRACED) == 0) {
 394                         error = EPERM;
 395                         goto fail;
 396                 }
 397
 398                 /* not being traced by YOU */
 399                 if (p->p_pptr != curp) {
 400                         error = EBUSY;
 401                         goto fail;
 402                 }
 403
 404                 /* not currently stopped */
 405                 if ((p->p_flag & (P_TRACED|P_WAITED)) == 0) {
 406                         error = EBUSY;
 407                         goto fail;
 408                 }
 409
 410                 /* XXX lwp */
 411                 lp = FIRST_LWP_IN_PROC(p);
 412
 413                 if (req == PTRACE_GETFPXREGS) {
 414                         LWPHOLD(lp);
 415                         error = linux_proc_read_fpxregs(lp, &r.fpxreg);
 416                         LWPRELE(lp);
 417                         if (error == 0)
 418                                 error = copyout(&r.fpxreg, (caddr_t)uap->data,
 419                                     sizeof(r.fpxreg));
 420                 } else {
 421                         /* clear dangerous bits exactly as Linux does*/
 422                         r.fpxreg.mxcsr &= 0xffbf;
 423                         LWPHOLD(lp);
 424                         error = linux_proc_write_fpxregs(lp, &r.fpxreg);
 425                         LWPRELE(lp);
 426                 }
 427                 break;
 428
 429         fail:
 430 #else
 431                 error = EIO;
 432 #endif
 433                 break;
 434         }
 435         case PTRACE_PEEKUSR:
 436         case PTRACE_POKEUSR: {
 437                 error = EIO;
 438
 439                 /* check addr for alignment */
 440                 if (uap->addr < 0 || uap->addr & (sizeof(l_int) - 1))
 441                         break;
 442                 /*
 443                  * Allow linux programs to access register values in
 444                  * user struct. We simulate this through PT_GET/SETREGS
 445                  * as necessary.
 446                  */
 447                 if (uap->addr < sizeof(struct linux_pt_reg)) {
 448                         error = kern_ptrace(curp, PT_GETREGS, pid, &u.bsd_reg,
 449                                             0, &uap->sysmsg_iresult);
 450                         if (error != 0)
 451                                 break;
 452
 453                         map_regs_to_linux(&u.bsd_reg, &r.reg);
 454                         if (req == PTRACE_PEEKUSR) {
 455                                 error = copyout((char *)&r.reg + uap->addr,
 456                                     (caddr_t)uap->data, sizeof(l_int));
 457                                 break;
 458                         }
 459
 460                         *(l_int *)((char *)&r.reg + uap->addr) =
 461                             (l_int)uap->data;
 462
 463                         map_regs_from_linux(&u.bsd_reg, &r.reg);
 464                         error = kern_ptrace(curp, PT_SETREGS, pid, &u.bsd_reg,
 465                                             0, &uap->sysmsg_iresult);
 466                 }
 467
 468                 /*
 469                  * Simulate debug registers access
 470                  */
 471                 if (uap->addr >= LINUX_DBREG_OFFSET &&
 472                     uap->addr <= LINUX_DBREG_OFFSET + LINUX_DBREG_SIZE) {
 473                         error = kern_ptrace(curp, PT_GETDBREGS, pid,
 474                                             &u.bsd_dbreg,
 475                                             0, &uap->sysmsg_iresult);
 476                         if (error != 0)
 477                                 break;
 478
 479                         uap->addr -= LINUX_DBREG_OFFSET;
 480                         if (req == PTRACE_PEEKUSR) {
 481                                 error = copyout((char *)&u.bsd_dbreg +
 482                                     uap->addr, (caddr_t)uap->data,
 483                                     sizeof(l_int));
 484                                 break;
 485                         }
 486
 487                         *(l_int *)((char *)&u.bsd_dbreg + uap->addr) =
 488                              uap->data;
 489                         error = kern_ptrace(curp, PT_SETDBREGS, pid,
 490                                             &u.bsd_dbreg,
 491                                             0, &uap->sysmsg_iresult);
 492                 }
 493
 494                 break;
 495         }
 496         case PTRACE_SYSCALL:
 497                 /* fall through */
 498         default:
 499                 kprintf("linux: ptrace(%u, ...) not implemented\n",
 500                     (unsigned int)uap->req);
 501                 error = EINVAL;
 502                 break;
 503         }
 504
 505         rel_mplock();
 506         return (error);
 507 }