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 "common-remote-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
 208 /* Target file operations.  */
 209
 210 static int
 211 inf_child_fileio_open_flags_to_host (int fileio_open_flags, int *open_flags_p)
 212 {
 213   int open_flags = 0;
 214
 215   if (fileio_open_flags & ~FILEIO_O_SUPPORTED)
 216     return -1;
 217
 218   if (fileio_open_flags & FILEIO_O_CREAT)
 219     open_flags |= O_CREAT;
 220   if (fileio_open_flags & FILEIO_O_EXCL)
 221     open_flags |= O_EXCL;
 222   if (fileio_open_flags & FILEIO_O_TRUNC)
 223     open_flags |= O_TRUNC;
 224   if (fileio_open_flags & FILEIO_O_APPEND)
 225     open_flags |= O_APPEND;
 226   if (fileio_open_flags & FILEIO_O_RDONLY)
 227     open_flags |= O_RDONLY;
 228   if (fileio_open_flags & FILEIO_O_WRONLY)
 229     open_flags |= O_WRONLY;
 230   if (fileio_open_flags & FILEIO_O_RDWR)
 231     open_flags |= O_RDWR;
 232 /* On systems supporting binary and text mode, always open files in
 233    binary mode. */
 234 #ifdef O_BINARY
 235   open_flags |= O_BINARY;
 236 #endif
 237
 238   *open_flags_p = open_flags;
 239   return 0;
 240 }
 241
 242 /* Open FILENAME on the target, using FLAGS and MODE.  Return a
 243    target file descriptor, or -1 if an error occurs (and set
 244    *TARGET_ERRNO).  */
 245 static int
 246 inf_child_fileio_open (struct target_ops *self,
 247                        const char *filename, int flags, int mode,
 248                        int *target_errno)
 249 {
 250   int nat_flags;
 251   int fd;
 252
 253   if (inf_child_fileio_open_flags_to_host (flags, &nat_flags) == -1)
 254     {
 255       *target_errno = FILEIO_EINVAL;
 256       return -1;
 257     }
 258
 259   /* We do not need to convert MODE, since the fileio protocol uses
 260      the standard values.  */
 261   fd = gdb_open_cloexec (filename, nat_flags, mode);
 262   if (fd == -1)
 263     *target_errno = remote_fileio_to_fio_error (errno);
 264
 265   return fd;
 266 }
 267
 268 /* Write up to LEN bytes from WRITE_BUF to FD on the target.
 269    Return the number of bytes written, or -1 if an error occurs
 270    (and set *TARGET_ERRNO).  */
 271 static int
 272 inf_child_fileio_pwrite (struct target_ops *self,
 273                          int fd, const gdb_byte *write_buf, int len,
 274                          ULONGEST offset, int *target_errno)
 275 {
 276   int ret;
 277
 278 #ifdef HAVE_PWRITE
 279   ret = pwrite (fd, write_buf, len, (long) offset);
 280 #else
 281   ret = -1;
 282 #endif
 283   /* If we have no pwrite or it failed for this file, use lseek/write.  */
 284   if (ret == -1)
 285     {
 286       ret = lseek (fd, (long) offset, SEEK_SET);
 287       if (ret != -1)
 288         ret = write (fd, write_buf, len);
 289     }
 290
 291   if (ret == -1)
 292     *target_errno = remote_fileio_to_fio_error (errno);
 293
 294   return ret;
 295 }
 296
 297 /* Read up to LEN bytes FD on the target into READ_BUF.
 298    Return the number of bytes read, or -1 if an error occurs
 299    (and set *TARGET_ERRNO).  */
 300 static int
 301 inf_child_fileio_pread (struct target_ops *self,
 302                         int fd, gdb_byte *read_buf, int len,
 303                         ULONGEST offset, int *target_errno)
 304 {
 305   int ret;
 306
 307 #ifdef HAVE_PREAD
 308   ret = pread (fd, read_buf, len, (long) offset);
 309 #else
 310   ret = -1;
 311 #endif
 312   /* If we have no pread or it failed for this file, use lseek/read.  */
 313   if (ret == -1)
 314     {
 315       ret = lseek (fd, (long) offset, SEEK_SET);
 316       if (ret != -1)
 317         ret = read (fd, read_buf, len);
 318     }
 319
 320   if (ret == -1)
 321     *target_errno = remote_fileio_to_fio_error (errno);
 322
 323   return ret;
 324 }
 325
 326 /* Implementation of to_fileio_fstat.  */
 327 static int
 328 inf_child_fileio_fstat (struct target_ops *self, int fd,
 329                         struct stat *sb, int *target_errno)
 330 {
 331   int ret;
 332
 333   ret = fstat (fd, sb);
 334   if (ret == -1)
 335     *target_errno = remote_fileio_to_fio_error (errno);
 336
 337   return ret;
 338 }
 339
 340 /* Close FD on the target.  Return 0, or -1 if an error occurs
 341    (and set *TARGET_ERRNO).  */
 342 static int
 343 inf_child_fileio_close (struct target_ops *self, int fd, int *target_errno)
 344 {
 345   int ret;
 346
 347   ret = close (fd);
 348   if (ret == -1)
 349     *target_errno = remote_fileio_to_fio_error (errno);
 350
 351   return ret;
 352 }
 353
 354 /* Unlink FILENAME on the target.  Return 0, or -1 if an error
 355    occurs (and set *TARGET_ERRNO).  */
 356 static int
 357 inf_child_fileio_unlink (struct target_ops *self,
 358                          const char *filename, int *target_errno)
 359 {
 360   int ret;
 361
 362   ret = unlink (filename);
 363   if (ret == -1)
 364     *target_errno = remote_fileio_to_fio_error (errno);
 365
 366   return ret;
 367 }
 368
 369 /* Read value of symbolic link FILENAME on the target.  Return a
 370    null-terminated string allocated via xmalloc, or NULL if an error
 371    occurs (and set *TARGET_ERRNO).  */
 372 static char *
 373 inf_child_fileio_readlink (struct target_ops *self,
 374                            const char *filename, int *target_errno)
 375 {
 376   /* We support readlink only on systems that also provide a compile-time
 377      maximum path length (PATH_MAX), at least for now.  */
 378 #if defined (PATH_MAX)
 379   char buf[PATH_MAX];
 380   int len;
 381   char *ret;
 382
 383   len = readlink (filename, buf, sizeof buf);
 384   if (len < 0)
 385     {
 386       *target_errno = remote_fileio_to_fio_error (errno);
 387       return NULL;
 388     }
 389
 390   ret = xmalloc (len + 1);
 391   memcpy (ret, buf, len);
 392   ret[len] = '\0';
 393   return ret;
 394 #else
 395   *target_errno = FILEIO_ENOSYS;
 396   return NULL;
 397 #endif
 398 }
 399
 400 static int
 401 inf_child_use_agent (struct target_ops *self, int use)
 402 {
 403   if (agent_loaded_p ())
 404     {
 405       use_agent = use;
 406       return 1;
 407     }
 408   else
 409     return 0;
 410 }
 411
 412 static int
 413 inf_child_can_use_agent (struct target_ops *self)
 414 {
 415   return agent_loaded_p ();
 416 }
 417
 418 /* Default implementation of the to_can_async_p and
 419    to_supports_non_stop methods.  */
 420
 421 static int
 422 return_zero (struct target_ops *ignore)
 423 {
 424   return 0;
 425 }
 426
 427 struct target_ops *
 428 inf_child_target (void)
 429 {
 430   struct target_ops *t = XCNEW (struct target_ops);
 431
 432   t->to_shortname = "native";
 433   t->to_longname = "Native process";
 434   t->to_doc = "Native process (started by the \"run\" command).";
 435   t->to_open = inf_child_open;
 436   t->to_close = inf_child_close;
 437   t->to_disconnect = inf_child_disconnect;
 438   t->to_post_attach = inf_child_post_attach;
 439   t->to_fetch_registers = inf_child_fetch_inferior_registers;
 440   t->to_store_registers = inf_child_store_inferior_registers;
 441   t->to_prepare_to_store = inf_child_prepare_to_store;
 442   t->to_insert_breakpoint = memory_insert_breakpoint;
 443   t->to_remove_breakpoint = memory_remove_breakpoint;
 444   t->to_terminal_init = child_terminal_init;
 445   t->to_terminal_inferior = child_terminal_inferior;
 446   t->to_terminal_ours_for_output = child_terminal_ours_for_output;
 447   t->to_terminal_ours = child_terminal_ours;
 448   t->to_terminal_info = child_terminal_info;
 449   t->to_post_startup_inferior = inf_child_post_startup_inferior;
 450   t->to_follow_fork = inf_child_follow_fork;
 451   t->to_can_run = inf_child_can_run;
 452   /* We must default these because they must be implemented by any
 453      target that can run.  */
 454   t->to_can_async_p = return_zero;
 455   t->to_supports_non_stop = return_zero;
 456   t->to_pid_to_exec_file = inf_child_pid_to_exec_file;
 457   t->to_stratum = process_stratum;
 458   t->to_has_all_memory = default_child_has_all_memory;
 459   t->to_has_memory = default_child_has_memory;
 460   t->to_has_stack = default_child_has_stack;
 461   t->to_has_registers = default_child_has_registers;
 462   t->to_has_execution = default_child_has_execution;
 463   t->to_fileio_open = inf_child_fileio_open;
 464   t->to_fileio_pwrite = inf_child_fileio_pwrite;
 465   t->to_fileio_pread = inf_child_fileio_pread;
 466   t->to_fileio_fstat = inf_child_fileio_fstat;
 467   t->to_fileio_close = inf_child_fileio_close;
 468   t->to_fileio_unlink = inf_child_fileio_unlink;
 469   t->to_fileio_readlink = inf_child_fileio_readlink;
 470   t->to_magic = OPS_MAGIC;
 471   t->to_use_agent = inf_child_use_agent;
 472   t->to_can_use_agent = inf_child_can_use_agent;
 473
 474   /* Store a pointer so we can push the most-derived target from
 475      inf_child_open.  */
 476   inf_child_ops = t;
 477
 478   return t;
 479 }