gdb/inf-child.c

   1 /* Base/prototype target for default child (native) targets.
   2
   3    Copyright (C) 1988-2015 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 /* This file provides a common base class/target that all native
  21    target implementations extend, by calling inf_child_target to get a
  22    new prototype target and then overriding target methods as
  23    necessary.  */
  24
  25 #include "defs.h"
  26 #include "regcache.h"
  27 #include "memattr.h"
  28 #include "symtab.h"
  29 #include "target.h"
  30 #include "inferior.h"
  31 #include <sys/stat.h>
  32 #include "inf-child.h"
  33 #include "fileio.h"
  34 #include "agent.h"
  35 #include "gdb_wait.h"
  36 #include "filestuff.h"
  37
  38 #include <sys/types.h>
  39 #include <fcntl.h>
  40 #include <unistd.h>
  41
  42 /* A pointer to what is returned by inf_child_target.  Used by
  43    inf_child_open to push the most-derived target in reaction to
  44    "target native".  */
  45 static struct target_ops *inf_child_ops = NULL;
  46
  47 /* Helper function for child_wait and the derivatives of child_wait.
  48    HOSTSTATUS is the waitstatus from wait() or the equivalent; store our
  49    translation of that in OURSTATUS.  */
  50 void
  51 store_waitstatus (struct target_waitstatus *ourstatus, int hoststatus)
  52 {
  53   if (WIFEXITED (hoststatus))
  54     {
  55       ourstatus->kind = TARGET_WAITKIND_EXITED;
  56       ourstatus->value.integer = WEXITSTATUS (hoststatus);
  57     }
  58   else if (!WIFSTOPPED (hoststatus))
  59     {
  60       ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
  61       ourstatus->value.sig = gdb_signal_from_host (WTERMSIG (hoststatus));
  62     }
  63   else
  64     {
  65       ourstatus->kind = TARGET_WAITKIND_STOPPED;
  66       ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (hoststatus));
  67     }
  68 }
  69
  70 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  71    for all registers.  */
  72
  73 static void
  74 inf_child_fetch_inferior_registers (struct target_ops *ops,
  75                                     struct regcache *regcache, int regnum)
  76 {
  77   if (regnum == -1)
  78     {
  79       for (regnum = 0;
  80            regnum < gdbarch_num_regs (get_regcache_arch (regcache));
  81            regnum++)
  82         regcache_raw_supply (regcache, regnum, NULL);
  83     }
  84   else
  85     regcache_raw_supply (regcache, regnum, NULL);
  86 }
  87
  88 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
  89    this for all registers (including the floating point registers).  */
  90
  91 static void
  92 inf_child_store_inferior_registers (struct target_ops *ops,
  93                                     struct regcache *regcache, int regnum)
  94 {
  95 }
  96
  97 static void
  98 inf_child_post_attach (struct target_ops *self, int pid)
  99 {
 100   /* This target doesn't require a meaningful "post attach" operation
 101      by a debugger.  */
 102 }
 103
 104 /* Get ready to modify the registers array.  On machines which store
 105    individual registers, this doesn't need to do anything.  On
 106    machines which store all the registers in one fell swoop, this
 107    makes sure that registers contains all the registers from the
 108    program being debugged.  */
 109
 110 static void
 111 inf_child_prepare_to_store (struct target_ops *self,
 112                             struct regcache *regcache)
 113 {
 114 }
 115
 116 /* True if the user did "target native".  In that case, we won't
 117    unpush the child target automatically when the last inferior is
 118    gone.  */
 119 static int inf_child_explicitly_opened;
 120
 121 /* See inf-child.h.  */
 122
 123 void
 124 inf_child_open_target (struct target_ops *target, const char *arg,
 125                        int from_tty)
 126 {
 127   target_preopen (from_tty);
 128   push_target (target);
 129   inf_child_explicitly_opened = 1;
 130   if (from_tty)
 131     printf_filtered ("Done.  Use the \"run\" command to start a process.\n");
 132 }
 133
 134 static void
 135 inf_child_open (const char *arg, int from_tty)
 136 {
 137   inf_child_open_target (inf_child_ops, arg, from_tty);
 138 }
 139
 140 /* Implement the to_disconnect target_ops method.  */
 141
 142 static void
 143 inf_child_disconnect (struct target_ops *target, const char *args, int from_tty)
 144 {
 145   if (args != NULL)
 146     error (_("Argument given to \"disconnect\"."));
 147
 148   /* This offers to detach/kill current inferiors, and then pops all
 149      targets.  */
 150   target_preopen (from_tty);
 151 }
 152
 153 /* Implement the to_close target_ops method.  */
 154
 155 static void
 156 inf_child_close (struct target_ops *target)
 157 {
 158   /* In case we were forcibly closed.  */
 159   inf_child_explicitly_opened = 0;
 160 }
 161
 162 void
 163 inf_child_mourn_inferior (struct target_ops *ops)
 164 {
 165   generic_mourn_inferior ();
 166   inf_child_maybe_unpush_target (ops);
 167 }
 168
 169 /* See inf-child.h.  */
 170
 171 void
 172 inf_child_maybe_unpush_target (struct target_ops *ops)
 173 {
 174   if (!inf_child_explicitly_opened && !have_inferiors ())
 175     unpush_target (ops);
 176 }
 177
 178 static void
 179 inf_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
 180 {
 181   /* This target doesn't require a meaningful "post startup inferior"
 182      operation by a debugger.  */
 183 }
 184
 185 static int
 186 inf_child_follow_fork (struct target_ops *ops, int follow_child,
 187                        int detach_fork)
 188 {
 189   /* This target doesn't support following fork or vfork events.  */
 190   return 0;
 191 }
 192
 193 static int
 194 inf_child_can_run (struct target_ops *self)
 195 {
 196   return 1;
 197 }
 198
 199 static char *
 200 inf_child_pid_to_exec_file (struct target_ops *self, int pid)
 201 {
 202   /* This target doesn't support translation of a process ID to the
 203      filename of the executable file.  */
 204   return NULL;
 205 }
 206
 207 /* Implementation of to_fileio_open.  */
 208
 209 static int
 210 inf_child_fileio_open (struct target_ops *self,
 211                        struct inferior *inf, const char *filename,
 212                        int flags, int mode, int *target_errno)
 213 {
 214   int nat_flags;
 215   mode_t nat_mode;
 216   int fd;
 217
 218   if (fileio_to_host_openflags (flags, &nat_flags) == -1
 219       || fileio_to_host_mode (mode, &nat_mode) == -1)
 220     {
 221       *target_errno = FILEIO_EINVAL;
 222       return -1;
 223     }
 224
 225   fd = gdb_open_cloexec (filename, nat_flags, nat_mode);
 226   if (fd == -1)
 227     *target_errno = host_to_fileio_error (errno);
 228
 229   return fd;
 230 }
 231
 232 /* Implementation of to_fileio_pwrite.  */
 233
 234 static int
 235 inf_child_fileio_pwrite (struct target_ops *self,
 236                          int fd, const gdb_byte *write_buf, int len,
 237                          ULONGEST offset, int *target_errno)
 238 {
 239   int ret;
 240
 241 #ifdef HAVE_PWRITE
 242   ret = pwrite (fd, write_buf, len, (long) offset);
 243 #else
 244   ret = -1;
 245 #endif
 246   /* If we have no pwrite or it failed for this file, use lseek/write.  */
 247   if (ret == -1)
 248     {
 249       ret = lseek (fd, (long) offset, SEEK_SET);
 250       if (ret != -1)
 251         ret = write (fd, write_buf, len);
 252     }
 253
 254   if (ret == -1)
 255     *target_errno = host_to_fileio_error (errno);
 256
 257   return ret;
 258 }
 259
 260 /* Implementation of to_fileio_pread.  */
 261
 262 static int
 263 inf_child_fileio_pread (struct target_ops *self,
 264                         int fd, gdb_byte *read_buf, int len,
 265                         ULONGEST offset, int *target_errno)
 266 {
 267   int ret;
 268
 269 #ifdef HAVE_PREAD
 270   ret = pread (fd, read_buf, len, (long) offset);
 271 #else
 272   ret = -1;
 273 #endif
 274   /* If we have no pread or it failed for this file, use lseek/read.  */
 275   if (ret == -1)
 276     {
 277       ret = lseek (fd, (long) offset, SEEK_SET);
 278       if (ret != -1)
 279         ret = read (fd, read_buf, len);
 280     }
 281
 282   if (ret == -1)
 283     *target_errno = host_to_fileio_error (errno);
 284
 285   return ret;
 286 }
 287
 288 /* Implementation of to_fileio_fstat.  */
 289
 290 static int
 291 inf_child_fileio_fstat (struct target_ops *self, int fd,
 292                         struct stat *sb, int *target_errno)
 293 {
 294   int ret;
 295
 296   ret = fstat (fd, sb);
 297   if (ret == -1)
 298     *target_errno = host_to_fileio_error (errno);
 299
 300   return ret;
 301 }
 302
 303 /* Implementation of to_fileio_close.  */
 304
 305 static int
 306 inf_child_fileio_close (struct target_ops *self, int fd, int *target_errno)
 307 {
 308   int ret;
 309
 310   ret = close (fd);
 311   if (ret == -1)
 312     *target_errno = host_to_fileio_error (errno);
 313
 314   return ret;
 315 }
 316
 317 /* Implementation of to_fileio_unlink.  */
 318
 319 static int
 320 inf_child_fileio_unlink (struct target_ops *self,
 321                          struct inferior *inf, const char *filename,
 322                          int *target_errno)
 323 {
 324   int ret;
 325
 326   ret = unlink (filename);
 327   if (ret == -1)
 328     *target_errno = host_to_fileio_error (errno);
 329
 330   return ret;
 331 }
 332
 333 /* Implementation of to_fileio_readlink.  */
 334
 335 static char *
 336 inf_child_fileio_readlink (struct target_ops *self,
 337                            struct inferior *inf, const char *filename,
 338                            int *target_errno)
 339 {
 340   /* We support readlink only on systems that also provide a compile-time
 341      maximum path length (PATH_MAX), at least for now.  */
 342 #if defined (PATH_MAX)
 343   char buf[PATH_MAX];
 344   int len;
 345   char *ret;
 346
 347   len = readlink (filename, buf, sizeof buf);
 348   if (len < 0)
 349     {
 350       *target_errno = host_to_fileio_error (errno);
 351       return NULL;
 352     }
 353
 354   ret = xmalloc (len + 1);
 355   memcpy (ret, buf, len);
 356   ret[len] = '\0';
 357   return ret;
 358 #else
 359   *target_errno = FILEIO_ENOSYS;
 360   return NULL;
 361 #endif
 362 }
 363
 364 static int
 365 inf_child_use_agent (struct target_ops *self, int use)
 366 {
 367   if (agent_loaded_p ())
 368     {
 369       use_agent = use;
 370       return 1;
 371     }
 372   else
 373     return 0;
 374 }
 375
 376 static int
 377 inf_child_can_use_agent (struct target_ops *self)
 378 {
 379   return agent_loaded_p ();
 380 }
 381
 382 /* Default implementation of the to_can_async_p and
 383    to_supports_non_stop methods.  */
 384
 385 static int
 386 return_zero (struct target_ops *ignore)
 387 {
 388   return 0;
 389 }
 390
 391 struct target_ops *
 392 inf_child_target (void)
 393 {
 394   struct target_ops *t = XCNEW (struct target_ops);
 395
 396   t->to_shortname = "native";
 397   t->to_longname = "Native process";
 398   t->to_doc = "Native process (started by the \"run\" command).";
 399   t->to_open = inf_child_open;
 400   t->to_close = inf_child_close;
 401   t->to_disconnect = inf_child_disconnect;
 402   t->to_post_attach = inf_child_post_attach;
 403   t->to_fetch_registers = inf_child_fetch_inferior_registers;
 404   t->to_store_registers = inf_child_store_inferior_registers;
 405   t->to_prepare_to_store = inf_child_prepare_to_store;
 406   t->to_insert_breakpoint = memory_insert_breakpoint;
 407   t->to_remove_breakpoint = memory_remove_breakpoint;
 408   t->to_terminal_init = child_terminal_init;
 409   t->to_terminal_inferior = child_terminal_inferior;
 410   t->to_terminal_ours_for_output = child_terminal_ours_for_output;
 411   t->to_terminal_ours = child_terminal_ours;
 412   t->to_terminal_info = child_terminal_info;
 413   t->to_post_startup_inferior = inf_child_post_startup_inferior;
 414   t->to_follow_fork = inf_child_follow_fork;
 415   t->to_can_run = inf_child_can_run;
 416   /* We must default these because they must be implemented by any
 417      target that can run.  */
 418   t->to_can_async_p = return_zero;
 419   t->to_supports_non_stop = return_zero;
 420   t->to_pid_to_exec_file = inf_child_pid_to_exec_file;
 421   t->to_stratum = process_stratum;
 422   t->to_has_all_memory = default_child_has_all_memory;
 423   t->to_has_memory = default_child_has_memory;
 424   t->to_has_stack = default_child_has_stack;
 425   t->to_has_registers = default_child_has_registers;
 426   t->to_has_execution = default_child_has_execution;
 427   t->to_fileio_open = inf_child_fileio_open;
 428   t->to_fileio_pwrite = inf_child_fileio_pwrite;
 429   t->to_fileio_pread = inf_child_fileio_pread;
 430   t->to_fileio_fstat = inf_child_fileio_fstat;
 431   t->to_fileio_close = inf_child_fileio_close;
 432   t->to_fileio_unlink = inf_child_fileio_unlink;
 433   t->to_fileio_readlink = inf_child_fileio_readlink;
 434   t->to_magic = OPS_MAGIC;
 435   t->to_use_agent = inf_child_use_agent;
 436   t->to_can_use_agent = inf_child_can_use_agent;
 437
 438   /* Store a pointer so we can push the most-derived target from
 439      inf_child_open.  */
 440   inf_child_ops = t;
 441
 442   return t;
 443 }