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 /* Open FILENAME on the target, using FLAGS and MODE.  Return a
 208    target file descriptor, or -1 if an error occurs (and set
 209    *TARGET_ERRNO).  */
 210 static int
 211 inf_child_fileio_open (struct target_ops *self,
 212                        const char *filename, int flags, int mode,
 213                        int *target_errno)
 214 {
 215   int nat_flags;
 216   mode_t nat_mode;
 217   int fd;
 218
 219   if (fileio_to_host_openflags (flags, &nat_flags) == -1
 220       || fileio_to_host_mode (mode, &nat_mode) == -1)
 221     {
 222       *target_errno = FILEIO_EINVAL;
 223       return -1;
 224     }
 225
 226   fd = gdb_open_cloexec (filename, nat_flags, nat_mode);
 227   if (fd == -1)
 228     *target_errno = host_to_fileio_error (errno);
 229
 230   return fd;
 231 }
 232
 233 /* Write up to LEN bytes from WRITE_BUF to FD on the target.
 234    Return the number of bytes written, or -1 if an error occurs
 235    (and set *TARGET_ERRNO).  */
 236 static int
 237 inf_child_fileio_pwrite (struct target_ops *self,
 238                          int fd, const gdb_byte *write_buf, int len,
 239                          ULONGEST offset, int *target_errno)
 240 {
 241   int ret;
 242
 243 #ifdef HAVE_PWRITE
 244   ret = pwrite (fd, write_buf, len, (long) offset);
 245 #else
 246   ret = -1;
 247 #endif
 248   /* If we have no pwrite or it failed for this file, use lseek/write.  */
 249   if (ret == -1)
 250     {
 251       ret = lseek (fd, (long) offset, SEEK_SET);
 252       if (ret != -1)
 253         ret = write (fd, write_buf, len);
 254     }
 255
 256   if (ret == -1)
 257     *target_errno = host_to_fileio_error (errno);
 258
 259   return ret;
 260 }
 261
 262 /* Read up to LEN bytes FD on the target into READ_BUF.
 263    Return the number of bytes read, or -1 if an error occurs
 264    (and set *TARGET_ERRNO).  */
 265 static int
 266 inf_child_fileio_pread (struct target_ops *self,
 267                         int fd, gdb_byte *read_buf, int len,
 268                         ULONGEST offset, int *target_errno)
 269 {
 270   int ret;
 271
 272 #ifdef HAVE_PREAD
 273   ret = pread (fd, read_buf, len, (long) offset);
 274 #else
 275   ret = -1;
 276 #endif
 277   /* If we have no pread or it failed for this file, use lseek/read.  */
 278   if (ret == -1)
 279     {
 280       ret = lseek (fd, (long) offset, SEEK_SET);
 281       if (ret != -1)
 282         ret = read (fd, read_buf, len);
 283     }
 284
 285   if (ret == -1)
 286     *target_errno = host_to_fileio_error (errno);
 287
 288   return ret;
 289 }
 290
 291 /* Implementation of to_fileio_fstat.  */
 292 static int
 293 inf_child_fileio_fstat (struct target_ops *self, int fd,
 294                         struct stat *sb, int *target_errno)
 295 {
 296   int ret;
 297
 298   ret = fstat (fd, sb);
 299   if (ret == -1)
 300     *target_errno = host_to_fileio_error (errno);
 301
 302   return ret;
 303 }
 304
 305 /* Close FD on the target.  Return 0, or -1 if an error occurs
 306    (and set *TARGET_ERRNO).  */
 307 static int
 308 inf_child_fileio_close (struct target_ops *self, int fd, int *target_errno)
 309 {
 310   int ret;
 311
 312   ret = close (fd);
 313   if (ret == -1)
 314     *target_errno = host_to_fileio_error (errno);
 315
 316   return ret;
 317 }
 318
 319 /* Unlink FILENAME on the target.  Return 0, or -1 if an error
 320    occurs (and set *TARGET_ERRNO).  */
 321 static int
 322 inf_child_fileio_unlink (struct target_ops *self,
 323                          const char *filename, int *target_errno)
 324 {
 325   int ret;
 326
 327   ret = unlink (filename);
 328   if (ret == -1)
 329     *target_errno = host_to_fileio_error (errno);
 330
 331   return ret;
 332 }
 333
 334 /* Read value of symbolic link FILENAME on the target.  Return a
 335    null-terminated string allocated via xmalloc, or NULL if an error
 336    occurs (and set *TARGET_ERRNO).  */
 337 static char *
 338 inf_child_fileio_readlink (struct target_ops *self,
 339                            const char *filename, int *target_errno)
 340 {
 341   /* We support readlink only on systems that also provide a compile-time
 342      maximum path length (PATH_MAX), at least for now.  */
 343 #if defined (PATH_MAX)
 344   char buf[PATH_MAX];
 345   int len;
 346   char *ret;
 347
 348   len = readlink (filename, buf, sizeof buf);
 349   if (len < 0)
 350     {
 351       *target_errno = host_to_fileio_error (errno);
 352       return NULL;
 353     }
 354
 355   ret = xmalloc (len + 1);
 356   memcpy (ret, buf, len);
 357   ret[len] = '\0';
 358   return ret;
 359 #else
 360   *target_errno = FILEIO_ENOSYS;
 361   return NULL;
 362 #endif
 363 }
 364
 365 static int
 366 inf_child_use_agent (struct target_ops *self, int use)
 367 {
 368   if (agent_loaded_p ())
 369     {
 370       use_agent = use;
 371       return 1;
 372     }
 373   else
 374     return 0;
 375 }
 376
 377 static int
 378 inf_child_can_use_agent (struct target_ops *self)
 379 {
 380   return agent_loaded_p ();
 381 }
 382
 383 /* Default implementation of the to_can_async_p and
 384    to_supports_non_stop methods.  */
 385
 386 static int
 387 return_zero (struct target_ops *ignore)
 388 {
 389   return 0;
 390 }
 391
 392 struct target_ops *
 393 inf_child_target (void)
 394 {
 395   struct target_ops *t = XCNEW (struct target_ops);
 396
 397   t->to_shortname = "native";
 398   t->to_longname = "Native process";
 399   t->to_doc = "Native process (started by the \"run\" command).";
 400   t->to_open = inf_child_open;
 401   t->to_close = inf_child_close;
 402   t->to_disconnect = inf_child_disconnect;
 403   t->to_post_attach = inf_child_post_attach;
 404   t->to_fetch_registers = inf_child_fetch_inferior_registers;
 405   t->to_store_registers = inf_child_store_inferior_registers;
 406   t->to_prepare_to_store = inf_child_prepare_to_store;
 407   t->to_insert_breakpoint = memory_insert_breakpoint;
 408   t->to_remove_breakpoint = memory_remove_breakpoint;
 409   t->to_terminal_init = child_terminal_init;
 410   t->to_terminal_inferior = child_terminal_inferior;
 411   t->to_terminal_ours_for_output = child_terminal_ours_for_output;
 412   t->to_terminal_ours = child_terminal_ours;
 413   t->to_terminal_info = child_terminal_info;
 414   t->to_post_startup_inferior = inf_child_post_startup_inferior;
 415   t->to_follow_fork = inf_child_follow_fork;
 416   t->to_can_run = inf_child_can_run;
 417   /* We must default these because they must be implemented by any
 418      target that can run.  */
 419   t->to_can_async_p = return_zero;
 420   t->to_supports_non_stop = return_zero;
 421   t->to_pid_to_exec_file = inf_child_pid_to_exec_file;
 422   t->to_stratum = process_stratum;
 423   t->to_has_all_memory = default_child_has_all_memory;
 424   t->to_has_memory = default_child_has_memory;
 425   t->to_has_stack = default_child_has_stack;
 426   t->to_has_registers = default_child_has_registers;
 427   t->to_has_execution = default_child_has_execution;
 428   t->to_fileio_open = inf_child_fileio_open;
 429   t->to_fileio_pwrite = inf_child_fileio_pwrite;
 430   t->to_fileio_pread = inf_child_fileio_pread;
 431   t->to_fileio_fstat = inf_child_fileio_fstat;
 432   t->to_fileio_close = inf_child_fileio_close;
 433   t->to_fileio_unlink = inf_child_fileio_unlink;
 434   t->to_fileio_readlink = inf_child_fileio_readlink;
 435   t->to_magic = OPS_MAGIC;
 436   t->to_use_agent = inf_child_use_agent;
 437   t->to_can_use_agent = inf_child_can_use_agent;
 438
 439   /* Store a pointer so we can push the most-derived target from
 440      inf_child_open.  */
 441   inf_child_ops = t;
 442
 443   return t;
 444 }