gdb/gdbserver/low-linux.c

   1 /* Low level interface to ptrace, for the remote server for GDB.
   2    Copyright (C) 1995, 1996 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22 #include <sys/wait.h>
  23 #include "frame.h"
  24 #include "inferior.h"
  25
  26 #include <stdio.h>
  27 #include <sys/param.h>
  28 #include <sys/dir.h>
  29 #include <sys/user.h>
  30 #include <signal.h>
  31 #include <sys/ioctl.h>
  32 #if 0
  33 #include <sgtty.h>
  34 #endif
  35 #include <fcntl.h>
  36
  37 /***************Begin MY defs*********************/
  38 int quit_flag = 0;
  39 char registers[REGISTER_BYTES];
  40
  41 /* Index within `registers' of the first byte of the space for
  42    register N.  */
  43
  44
  45 char buf2[MAX_REGISTER_RAW_SIZE];
  46 /***************End MY defs*********************/
  47
  48 #include <sys/ptrace.h>
  49
  50 #if __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1)
  51 #include <sys/reg.h>
  52 #endif
  53
  54 extern char **environ;
  55 extern int errno;
  56 extern int inferior_pid;
  57 void quit (), perror_with_name ();
  58 int query ();
  59
  60 /* Start an inferior process and returns its pid.
  61    ALLARGS is a vector of program-name and args.
  62    ENV is the environment vector to pass.  */
  63
  64 int
  65 create_inferior (program, allargs)
  66      char *program;
  67      char **allargs;
  68 {
  69   int pid;
  70
  71   pid = fork ();
  72   if (pid < 0)
  73     perror_with_name ("fork");
  74
  75   if (pid == 0)
  76     {
  77       ptrace (PTRACE_TRACEME, 0, 0, 0);
  78
  79       execv (program, allargs);
  80
  81       fprintf (stderr, "Cannot exec %s: %s.\n", program,
  82                errno < sys_nerr ? sys_errlist[errno] : "unknown error");
  83       fflush (stderr);
  84       _exit (0177);
  85     }
  86
  87   return pid;
  88 }
  89
  90 /* Kill the inferior process.  Make us have no inferior.  */
  91
  92 void
  93 kill_inferior ()
  94 {
  95   if (inferior_pid == 0)
  96     return;
  97   ptrace (PTRACE_KILL, inferior_pid, 0, 0);
  98   wait (0);
  99 /*************inferior_died ();****VK**************/
 100 }
 101
 102 /* Return nonzero if the given thread is still alive.  */
 103 int
 104 mythread_alive (pid)
 105      int pid;
 106 {
 107   return 1;
 108 }
 109
 110 /* Wait for process, returns status */
 111
 112 unsigned char
 113 mywait (status)
 114      char *status;
 115 {
 116   int pid;
 117   union wait w;
 118
 119   pid = wait (&w);
 120   if (pid != inferior_pid)
 121     perror_with_name ("wait");
 122
 123   if (WIFEXITED (w))
 124     {
 125       fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
 126       *status = 'W';
 127       return ((unsigned char) WEXITSTATUS (w));
 128     }
 129   else if (!WIFSTOPPED (w))
 130     {
 131       fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
 132       *status = 'X';
 133       return ((unsigned char) WTERMSIG (w));
 134     }
 135
 136   fetch_inferior_registers (0);
 137
 138   *status = 'T';
 139   return ((unsigned char) WSTOPSIG (w));
 140 }
 141
 142 /* Resume execution of the inferior process.
 143    If STEP is nonzero, single-step it.
 144    If SIGNAL is nonzero, give it that signal.  */
 145
 146 void
 147 myresume (step, signal)
 148      int step;
 149      int signal;
 150 {
 151   errno = 0;
 152   ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, inferior_pid, 1, signal);
 153   if (errno)
 154     perror_with_name ("ptrace");
 155 }
 156
 157
 158 #if !defined (offsetof)
 159 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 160 #endif
 161
 162 /* U_REGS_OFFSET is the offset of the registers within the u area.  */
 163 #if !defined (U_REGS_OFFSET)
 164 #define U_REGS_OFFSET \
 165   ptrace (PT_READ_U, inferior_pid, \
 166           (PTRACE_ARG3_TYPE) (offsetof (struct user, u_ar0)), 0) \
 167     - KERNEL_U_ADDR
 168 #endif
 169
 170 #ifndef TARGET_M68K
 171 /* this table must line up with REGISTER_NAMES in tm-i386v.h */
 172 /* symbols like 'EAX' come from <sys/reg.h> */
 173 static int regmap[] =
 174 {
 175   EAX, ECX, EDX, EBX,
 176   UESP, EBP, ESI, EDI,
 177   EIP, EFL, CS, SS,
 178   DS, ES, FS, GS,
 179 };
 180
 181 int
 182 i386_register_u_addr (blockend, regnum)
 183      int blockend;
 184      int regnum;
 185 {
 186 #if 0
 187   /* this will be needed if fp registers are reinstated */
 188   /* for now, you can look at them with 'info float'
 189    * sys5 wont let you change them with ptrace anyway
 190    */
 191   if (regnum >= FP0_REGNUM && regnum <= FP7_REGNUM)
 192     {
 193       int ubase, fpstate;
 194       struct user u;
 195       ubase = blockend + 4 * (SS + 1) - KSTKSZ;
 196       fpstate = ubase + ((char *) &u.u_fpstate - (char *) &u);
 197       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
 198     }
 199   else
 200 #endif
 201     return (blockend + 4 * regmap[regnum]);
 202
 203 }
 204 #else /* TARGET_M68K */
 205 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
 206 static int regmap[] =
 207 {
 208 #ifdef PT_D0
 209   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
 210   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
 211   PT_SR, PT_PC,
 212 #else
 213   14, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15,
 214   17, 18,
 215 #endif
 216 #ifdef PT_FP0
 217   PT_FP0, PT_FP1, PT_FP2, PT_FP3, PT_FP4, PT_FP5, PT_FP6, PT_FP7,
 218   PT_FPCR, PT_FPSR, PT_FPIAR
 219 #else
 220   21, 24, 27, 30, 33, 36, 39, 42, 45, 46, 47
 221 #endif
 222 };
 223
 224 /* BLOCKEND is the value of u.u_ar0, and points to the place where GS
 225    is stored.  */
 226
 227 int
 228 m68k_linux_register_u_addr (blockend, regnum)
 229      int blockend;
 230      int regnum;
 231 {
 232   return (blockend + 4 * regmap[regnum]);
 233 }
 234 #endif
 235
 236 CORE_ADDR
 237 register_addr (regno, blockend)
 238      int regno;
 239      CORE_ADDR blockend;
 240 {
 241   CORE_ADDR addr;
 242
 243   if (regno < 0 || regno >= ARCH_NUM_REGS)
 244     error ("Invalid register number %d.", regno);
 245
 246   REGISTER_U_ADDR (addr, blockend, regno);
 247
 248   return addr;
 249 }
 250
 251 /* Fetch one register.  */
 252
 253 static void
 254 fetch_register (regno)
 255      int regno;
 256 {
 257   register unsigned int regaddr;
 258   register int i;
 259
 260   /* Offset of registers within the u area.  */
 261   unsigned int offset;
 262
 263   offset = U_REGS_OFFSET;
 264
 265   regaddr = register_addr (regno, offset);
 266   for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
 267     {
 268       errno = 0;
 269       *(int *) &registers[regno * 4 + i] = ptrace (PTRACE_PEEKUSR, inferior_pid,
 270                                              (PTRACE_ARG3_TYPE) regaddr, 0);
 271       regaddr += sizeof (int);
 272       if (errno != 0)
 273         {
 274           /* Warning, not error, in case we are attached; sometimes the
 275              kernel doesn't let us at the registers.  */
 276           char *err = strerror (errno);
 277           char *msg = alloca (strlen (err) + 128);
 278           sprintf (msg, "reading register %d: %s", regno, err);
 279           error (msg);
 280           goto error_exit;
 281         }
 282     }
 283 error_exit:;
 284 }
 285
 286 /* Fetch all registers, or just one, from the child process.  */
 287
 288 void
 289 fetch_inferior_registers (regno)
 290      int regno;
 291 {
 292   if (regno == -1 || regno == 0)
 293     for (regno = 0; regno < NUM_REGS - NUM_FREGS; regno++)
 294       fetch_register (regno);
 295   else
 296     fetch_register (regno);
 297 }
 298
 299 /* Store our register values back into the inferior.
 300    If REGNO is -1, do this for all registers.
 301    Otherwise, REGNO specifies which register (so we can save time).  */
 302
 303 void
 304 store_inferior_registers (regno)
 305      int regno;
 306 {
 307   register unsigned int regaddr;
 308   register int i;
 309   unsigned int offset = U_REGS_OFFSET;
 310
 311   if (regno >= 0)
 312     {
 313 #if 0
 314       if (CANNOT_STORE_REGISTER (regno))
 315         return;
 316 #endif
 317       regaddr = register_addr (regno, offset);
 318       errno = 0;
 319 #if 0
 320       if (regno == PCOQ_HEAD_REGNUM || regno == PCOQ_TAIL_REGNUM)
 321         {
 322           scratch = *(int *) &registers[REGISTER_BYTE (regno)] | 0x3;
 323           ptrace (PT_WUREGS, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 324                   scratch, 0);
 325           if (errno != 0)
 326             {
 327               /* Error, even if attached.  Failing to write these two
 328                  registers is pretty serious.  */
 329               sprintf (buf, "writing register number %d", regno);
 330               perror_with_name (buf);
 331             }
 332         }
 333       else
 334 #endif
 335         for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
 336           {
 337             errno = 0;
 338             ptrace (PTRACE_POKEUSR, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 339                     *(int *) &registers[REGISTER_BYTE (regno) + i]);
 340             if (errno != 0)
 341               {
 342                 /* Warning, not error, in case we are attached; sometimes the
 343                    kernel doesn't let us at the registers.  */
 344                 char *err = strerror (errno);
 345                 char *msg = alloca (strlen (err) + 128);
 346                 sprintf (msg, "writing register %d: %s",
 347                          regno, err);
 348                 error (msg);
 349                 return;
 350               }
 351             regaddr += sizeof (int);
 352           }
 353     }
 354   else
 355     for (regno = 0; regno < NUM_REGS - NUM_FREGS; regno++)
 356       store_inferior_registers (regno);
 357 }
 358
 359 /* NOTE! I tried using PTRACE_READDATA, etc., to read and write memory
 360    in the NEW_SUN_PTRACE case.
 361    It ought to be straightforward.  But it appears that writing did
 362    not write the data that I specified.  I cannot understand where
 363    it got the data that it actually did write.  */
 364
 365 /* Copy LEN bytes from inferior's memory starting at MEMADDR
 366    to debugger memory starting at MYADDR.  */
 367
 368 void
 369 read_inferior_memory (memaddr, myaddr, len)
 370      CORE_ADDR memaddr;
 371      char *myaddr;
 372      int len;
 373 {
 374   register int i;
 375   /* Round starting address down to longword boundary.  */
 376   register CORE_ADDR addr = memaddr & -sizeof (int);
 377   /* Round ending address up; get number of longwords that makes.  */
 378   register int count
 379   = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
 380   /* Allocate buffer of that many longwords.  */
 381   register int *buffer = (int *) alloca (count * sizeof (int));
 382
 383   /* Read all the longwords */
 384   for (i = 0; i < count; i++, addr += sizeof (int))
 385     {
 386       buffer[i] = ptrace (PTRACE_PEEKTEXT, inferior_pid, addr, 0);
 387     }
 388
 389   /* Copy appropriate bytes out of the buffer.  */
 390   memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (int) - 1)), len);
 391 }
 392
 393 /* Copy LEN bytes of data from debugger memory at MYADDR
 394    to inferior's memory at MEMADDR.
 395    On failure (cannot write the inferior)
 396    returns the value of errno.  */
 397
 398 int
 399 write_inferior_memory (memaddr, myaddr, len)
 400      CORE_ADDR memaddr;
 401      char *myaddr;
 402      int len;
 403 {
 404   register int i;
 405   /* Round starting address down to longword boundary.  */
 406   register CORE_ADDR addr = memaddr & -sizeof (int);
 407   /* Round ending address up; get number of longwords that makes.  */
 408   register int count
 409   = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
 410   /* Allocate buffer of that many longwords.  */
 411   register int *buffer = (int *) alloca (count * sizeof (int));
 412   extern int errno;
 413
 414   /* Fill start and end extra bytes of buffer with existing memory data.  */
 415
 416   buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid, addr, 0);
 417
 418   if (count > 1)
 419     {
 420       buffer[count - 1]
 421         = ptrace (PTRACE_PEEKTEXT, inferior_pid,
 422                   addr + (count - 1) * sizeof (int), 0);
 423     }
 424
 425   /* Copy data to be written over corresponding part of buffer */
 426
 427   memcpy ((char *) buffer + (memaddr & (sizeof (int) - 1)), myaddr, len);
 428
 429   /* Write the entire buffer.  */
 430
 431   for (i = 0; i < count; i++, addr += sizeof (int))
 432     {
 433       errno = 0;
 434       ptrace (PTRACE_POKETEXT, inferior_pid, addr, buffer[i]);
 435       if (errno)
 436         return errno;
 437     }
 438
 439   return 0;
 440 }
 441 \f
 442 void
 443 initialize ()
 444 {
 445   inferior_pid = 0;
 446 }
 447
 448 int
 449 have_inferior_p ()
 450 {
 451   return inferior_pid != 0;
 452 }