gdb/hppab-nat.c

   1 /* Machine-dependent hooks for the unix child process stratum.  This
   2    code is for the HP PA-RISC cpu.
   3
   4    Copyright 1986, 1987, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
   5
   6    Contributed by the Center for Software Science at the
   7    University of Utah (pa-gdb-bugs@cs.utah.edu).
   8
   9 This file is part of GDB.
  10
  11 This program is free software; you can redistribute it and/or modify
  12 it under the terms of the GNU General Public License as published by
  13 the Free Software Foundation; either version 2 of the License, or
  14 (at your option) any later version.
  15
  16 This program is distributed in the hope that it will be useful,
  17 but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 GNU General Public License for more details.
  20
  21 You should have received a copy of the GNU General Public License
  22 along with this program; if not, write to the Free Software
  23 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  24
  25 #include "defs.h"
  26 #include "inferior.h"
  27 #include "target.h"
  28 #include <sys/ptrace.h>
  29
  30 #ifndef PT_ATTACH
  31 #define PT_ATTACH PTRACE_ATTACH
  32 #endif
  33
  34 #ifndef PT_DETACH
  35 #define PT_DETACH PTRACE_DETACH
  36 #endif
  37
  38 /* This function simply calls ptrace with the given arguments.
  39    It exists so that all calls to ptrace are isolated in this
  40    machine-dependent file. */
  41
  42 int
  43 call_ptrace (request, pid, addr, data)
  44      int request, pid;
  45      PTRACE_ARG3_TYPE addr;
  46      int data;
  47 {
  48   return ptrace (request, pid, addr, data, 0);
  49 }
  50
  51 /* Use an extra level of indirection for ptrace calls.
  52    This lets us breakpoint usefully on call_ptrace.   It also
  53    allows us to pass an extra argument to ptrace without
  54    using an ANSI-C specific macro.  */
  55
  56 #define ptrace call_ptrace
  57
  58 void
  59 kill_inferior ()
  60 {
  61   if (inferior_pid == 0)
  62     return;
  63   ptrace (PT_KILL, inferior_pid, (PTRACE_ARG3_TYPE) 0, 0);
  64   wait ((int *)0);
  65   target_mourn_inferior ();
  66 }
  67
  68 #ifdef ATTACH_DETACH
  69
  70 /* Start debugging the process whose number is PID.  */
  71 int
  72 attach (pid)
  73      int pid;
  74 {
  75   errno = 0;
  76   ptrace (PT_ATTACH, pid, (PTRACE_ARG3_TYPE) 0, 0);
  77   if (errno)
  78     perror_with_name ("ptrace");
  79   attach_flag = 1;
  80   return pid;
  81 }
  82
  83 /* Stop debugging the process whose number is PID
  84    and continue it with signal number SIGNAL.
  85    SIGNAL = 0 means just continue it.  */
  86
  87 void
  88 detach (signal)
  89      int signal;
  90 {
  91   errno = 0;
  92   ptrace (PT_DETACH, inferior_pid, (PTRACE_ARG3_TYPE) 1, signal);
  93   if (errno)
  94     perror_with_name ("ptrace");
  95   attach_flag = 0;
  96 }
  97 #endif /* ATTACH_DETACH */
  98 \f
  99
 100
 101 /* KERNEL_U_ADDR is the amount to subtract from u.u_ar0
 102    to get the offset in the core file of the register values.  */
 103 #if defined (KERNEL_U_ADDR_BSD)
 104 /* Get kernel_u_addr using BSD-style nlist().  */
 105 CORE_ADDR kernel_u_addr;
 106
 107 #include <a.out.gnu.h>          /* For struct nlist */
 108
 109 void
 110 _initialize_kernel_u_addr ()
 111 {
 112   struct nlist names[2];
 113
 114   names[0].n_un.n_name = "_u";
 115   names[1].n_un.n_name = NULL;
 116   if (nlist ("/vmunix", names) == 0)
 117     kernel_u_addr = names[0].n_value;
 118   else
 119     fatal ("Unable to get kernel u area address.");
 120 }
 121 #endif /* KERNEL_U_ADDR_BSD.  */
 122
 123 #if defined (KERNEL_U_ADDR_HPUX)
 124 /* Get kernel_u_addr using HPUX-style nlist().  */
 125 CORE_ADDR kernel_u_addr;
 126
 127 struct hpnlist {
 128         char *          n_name;
 129         long            n_value;
 130         unsigned char   n_type;
 131         unsigned char   n_length;
 132         short           n_almod;
 133         short           n_unused;
 134 };
 135 static struct hpnlist nl[] = {{ "_u", -1, }, { (char *) 0, }};
 136
 137 /* read the value of the u area from the hp-ux kernel */
 138 void
 139 _initialize_kernel_u_addr ()
 140 {
 141     struct user u;
 142     nlist ("/hp-ux", &nl);
 143     kernel_u_addr = nl[0].n_value;
 144 }
 145 #endif /* KERNEL_U_ADDR_HPUX.  */
 146
 147 #if !defined (offsetof)
 148 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 149 #endif
 150
 151 /* U_REGS_OFFSET is the offset of the registers within the u area.  */
 152 #if !defined (U_REGS_OFFSET)
 153 #define U_REGS_OFFSET \
 154   ptrace (PT_READ_U, inferior_pid, \
 155           (PTRACE_ARG3_TYPE) (offsetof (struct user, u_ar0)), 0) \
 156     - KERNEL_U_ADDR
 157 #endif
 158
 159 /* Fetch one register.  */
 160
 161 static void
 162 fetch_register (regno)
 163      int regno;
 164 {
 165   register unsigned int regaddr;
 166   char buf[MAX_REGISTER_RAW_SIZE];
 167   register int i;
 168
 169   /* Offset of registers within the u area.  */
 170   unsigned int offset;
 171
 172   offset = U_REGS_OFFSET;
 173
 174   regaddr = register_addr (regno, offset);
 175   for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (int))
 176     {
 177       errno = 0;
 178       *(int *) &buf[i] = ptrace (PT_RUREGS, inferior_pid,
 179                                  (PTRACE_ARG3_TYPE) regaddr, 0);
 180       regaddr += sizeof (int);
 181       if (errno != 0)
 182         {
 183           /* Warning, not error, in case we are attached; sometimes the
 184              kernel doesn't let us at the registers.  */
 185           char *err = safe_strerror (errno);
 186           char *msg = alloca (strlen (err) + 128);
 187           sprintf (msg, "reading register %s: %s", reg_names[regno], err);
 188           warning (msg);
 189           goto error_exit;
 190         }
 191     }
 192   supply_register (regno, buf);
 193  error_exit:;
 194 }
 195
 196 /* Fetch all registers, or just one, from the child process.  */
 197
 198 void
 199 fetch_inferior_registers (regno)
 200      int regno;
 201 {
 202   if (regno == -1)
 203     for (regno = 0; regno < NUM_REGS; regno++)
 204       fetch_register (regno);
 205   else
 206     fetch_register (regno);
 207 }
 208
 209 /* Store our register values back into the inferior.
 210    If REGNO is -1, do this for all registers.
 211    Otherwise, REGNO specifies which register (so we can save time).  */
 212
 213 void
 214 store_inferior_registers (regno)
 215      int regno;
 216 {
 217   register unsigned int regaddr;
 218   extern char registers[];
 219   register int i;
 220
 221   unsigned int offset = U_REGS_OFFSET;
 222
 223   if (regno >= 0)
 224     {
 225       regaddr = register_addr (regno, offset);
 226       for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof(int))
 227         {
 228           errno = 0;
 229           ptrace (PT_WUREGS, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 230                   *(int *) &registers[REGISTER_BYTE (regno) + i]);
 231           if (errno != 0)
 232             {
 233               char *err = safe_strerror (errno);
 234               char *msg = alloca (strlen (err) + 128);
 235               sprintf (msg, "writing register %s: %s", reg_names[regno], err);
 236               warning (msg);
 237             }
 238           regaddr += sizeof(int);
 239         }
 240     }
 241   else
 242     {
 243       for (regno = 0; regno < NUM_REGS; regno++)
 244         {
 245           if (CANNOT_STORE_REGISTER (regno))
 246             continue;
 247           store_inferior_registers (regno);
 248         }
 249     }
 250   return;
 251 }
 252
 253 /* Resume execution of process PID.
 254    If STEP is nonzero, single-step it.
 255    If SIGNAL is nonzero, give it that signal.  */
 256
 257 void
 258 child_resume (pid, step, signal)
 259      int pid;
 260      int step;
 261      int signal;
 262 {
 263   errno = 0;
 264
 265   if (pid == -1)
 266     pid = inferior_pid;
 267
 268   /* An address of (PTRACE_ARG3_TYPE) 1 tells ptrace to continue from where
 269      it was. (If GDB wanted it to start some other way, we have already
 270      written a new PC value to the child.)  */
 271
 272   if (step)
 273     ptrace (PT_STEP, pid, (PTRACE_ARG3_TYPE) 1, signal);
 274   else
 275     ptrace (PT_CONTINUE, pid, (PTRACE_ARG3_TYPE) 1, signal);
 276
 277   if (errno)
 278     perror_with_name ("ptrace");
 279 }
 280
 281 /* NOTE! I tried using PTRACE_READDATA, etc., to read and write memory
 282    in the NEW_SUN_PTRACE case.
 283    It ought to be straightforward.  But it appears that writing did
 284    not write the data that I specified.  I cannot understand where
 285    it got the data that it actually did write.  */
 286
 287 /* Copy LEN bytes to or from inferior's memory starting at MEMADDR
 288    to debugger memory starting at MYADDR.   Copy to inferior if
 289    WRITE is nonzero.
 290
 291    Returns the length copied, which is either the LEN argument or zero.
 292    This xfer function does not do partial moves, since child_ops
 293    doesn't allow memory operations to cross below us in the target stack
 294    anyway.  */
 295
 296 int
 297 child_xfer_memory (memaddr, myaddr, len, write, target)
 298      CORE_ADDR memaddr;
 299      char *myaddr;
 300      int len;
 301      int write;
 302      struct target_ops *target;         /* ignored */
 303 {
 304   register int i;
 305   /* Round starting address down to longword boundary.  */
 306   register CORE_ADDR addr = memaddr & - sizeof (int);
 307   /* Round ending address up; get number of longwords that makes.  */
 308   register int count
 309     = (((memaddr + len) - addr) + sizeof (int) - 1) / sizeof (int);
 310   /* Allocate buffer of that many longwords.  */
 311   register int *buffer = (int *) alloca (count * sizeof (int));
 312
 313   if (write)
 314     {
 315       /* Fill start and end extra bytes of buffer with existing memory data.  */
 316
 317       if (addr != memaddr || len < (int)sizeof (int)) {
 318         /* Need part of initial word -- fetch it.  */
 319         buffer[0] = ptrace (PT_READ_I, inferior_pid, (PTRACE_ARG3_TYPE) addr,
 320                             0);
 321       }
 322
 323       if (count > 1)            /* FIXME, avoid if even boundary */
 324         {
 325           buffer[count - 1]
 326             = ptrace (PT_READ_I, inferior_pid,
 327                       (PTRACE_ARG3_TYPE) (addr + (count - 1) * sizeof (int)),
 328                       0);
 329         }
 330
 331       /* Copy data to be written over corresponding part of buffer */
 332
 333       memcpy ((char *) buffer + (memaddr & (sizeof (int) - 1)), myaddr, len);
 334
 335       /* Write the entire buffer.  */
 336
 337       for (i = 0; i < count; i++, addr += sizeof (int))
 338         {
 339           errno = 0;
 340           ptrace (PT_WRITE_D, inferior_pid, (PTRACE_ARG3_TYPE) addr,
 341                   buffer[i]);
 342           if (errno)
 343             {
 344               /* Using the appropriate one (I or D) is necessary for
 345                  Gould NP1, at least.  */
 346               errno = 0;
 347               ptrace (PT_WRITE_I, inferior_pid, (PTRACE_ARG3_TYPE) addr,
 348                       buffer[i]);
 349             }
 350           if (errno)
 351             return 0;
 352         }
 353     }
 354   else
 355     {
 356       /* Read all the longwords */
 357       for (i = 0; i < count; i++, addr += sizeof (int))
 358         {
 359           errno = 0;
 360           buffer[i] = ptrace (PT_READ_I, inferior_pid,
 361                               (PTRACE_ARG3_TYPE) addr, 0);
 362           if (errno)
 363             return 0;
 364           QUIT;
 365         }
 366
 367       /* Copy appropriate bytes out of the buffer.  */
 368       memcpy (myaddr, (char *) buffer + (memaddr & (sizeof (int) - 1)), len);
 369     }
 370   return len;
 371 }
 372