gdb/linux-nat-trad.c

   1 /* Generic GNU/Linux target using traditional ptrace register access.
   2
   3    Copyright (C) 1988-2018 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "linux-nat-trad.h"
  22
  23 #include "nat/gdb_ptrace.h"
  24 #include "inf-ptrace.h"
  25
  26 /* Fetch register REGNUM from the inferior.  */
  27
  28 void
  29 linux_nat_trad_target::fetch_register (struct regcache *regcache, int regnum)
  30 {
  31   struct gdbarch *gdbarch = regcache->arch ();
  32   CORE_ADDR addr;
  33   size_t size;
  34   PTRACE_TYPE_RET *buf;
  35   pid_t pid;
  36   int i;
  37
  38   /* This isn't really an address, but ptrace thinks of it as one.  */
  39   addr = register_u_offset (gdbarch, regnum, 0);
  40   if (addr == (CORE_ADDR)-1
  41       || gdbarch_cannot_fetch_register (gdbarch, regnum))
  42     {
  43       regcache_raw_supply (regcache, regnum, NULL);
  44       return;
  45     }
  46
  47   pid = get_ptrace_pid (regcache_get_ptid (regcache));
  48
  49   size = register_size (gdbarch, regnum);
  50   gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0);
  51   buf = (PTRACE_TYPE_RET *) alloca (size);
  52
  53   /* Read the register contents from the inferior a chunk at a time.  */
  54   for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++)
  55     {
  56       errno = 0;
  57       buf[i] = ptrace (PT_READ_U, pid, (PTRACE_TYPE_ARG3)(uintptr_t)addr, 0);
  58       if (errno != 0)
  59         error (_("Couldn't read register %s (#%d): %s."),
  60                gdbarch_register_name (gdbarch, regnum),
  61                regnum, safe_strerror (errno));
  62
  63       addr += sizeof (PTRACE_TYPE_RET);
  64     }
  65   regcache_raw_supply (regcache, regnum, buf);
  66 }
  67
  68 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  69    for all registers.  */
  70
  71 void
  72 linux_nat_trad_target::fetch_registers (struct regcache *regcache, int regnum)
  73 {
  74   if (regnum == -1)
  75     for (regnum = 0;
  76          regnum < gdbarch_num_regs (regcache->arch ());
  77          regnum++)
  78       fetch_register (regcache, regnum);
  79   else
  80     fetch_register (regcache, regnum);
  81 }
  82
  83 /* Store register REGNUM into the inferior.  */
  84
  85 void
  86 linux_nat_trad_target::store_register (const struct regcache *regcache,
  87                                        int regnum)
  88 {
  89   struct gdbarch *gdbarch = regcache->arch ();
  90   CORE_ADDR addr;
  91   size_t size;
  92   PTRACE_TYPE_RET *buf;
  93   pid_t pid;
  94   int i;
  95
  96   /* This isn't really an address, but ptrace thinks of it as one.  */
  97   addr = register_u_offset (gdbarch, regnum, 1);
  98   if (addr == (CORE_ADDR)-1
  99       || gdbarch_cannot_store_register (gdbarch, regnum))
 100     return;
 101
 102   pid = get_ptrace_pid (regcache_get_ptid (regcache));
 103
 104   size = register_size (gdbarch, regnum);
 105   gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0);
 106   buf = (PTRACE_TYPE_RET *) alloca (size);
 107
 108   /* Write the register contents into the inferior a chunk at a time.  */
 109   regcache_raw_collect (regcache, regnum, buf);
 110   for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++)
 111     {
 112       errno = 0;
 113       ptrace (PT_WRITE_U, pid, (PTRACE_TYPE_ARG3)(uintptr_t)addr, buf[i]);
 114       if (errno != 0)
 115         error (_("Couldn't write register %s (#%d): %s."),
 116                gdbarch_register_name (gdbarch, regnum),
 117                regnum, safe_strerror (errno));
 118
 119       addr += sizeof (PTRACE_TYPE_RET);
 120     }
 121 }
 122
 123 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
 124    this for all registers.  */
 125
 126 void
 127 linux_nat_trad_target::store_registers (struct regcache *regcache, int regnum)
 128 {
 129   if (regnum == -1)
 130     for (regnum = 0;
 131          regnum < gdbarch_num_regs (regcache->arch ());
 132          regnum++)
 133       store_register (regcache, regnum);
 134   else
 135     store_register (regcache, regnum);
 136 }