gdb/inf-child.c

   1 /* Base/prototype target for default child (native) targets.
   2
   3    Copyright (C) 1988-2014 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 <string.h>
  32 #include <sys/stat.h>
  33 #include "inf-child.h"
  34 #include "gdb/fileio.h"
  35 #include "agent.h"
  36 #include "gdb_wait.h"
  37 #include "filestuff.h"
  38
  39 #include <sys/types.h>
  40 #include <fcntl.h>
  41 #include <unistd.h>
  42
  43 /* Helper function for child_wait and the derivatives of child_wait.
  44    HOSTSTATUS is the waitstatus from wait() or the equivalent; store our
  45    translation of that in OURSTATUS.  */
  46 void
  47 store_waitstatus (struct target_waitstatus *ourstatus, int hoststatus)
  48 {
  49   if (WIFEXITED (hoststatus))
  50     {
  51       ourstatus->kind = TARGET_WAITKIND_EXITED;
  52       ourstatus->value.integer = WEXITSTATUS (hoststatus);
  53     }
  54   else if (!WIFSTOPPED (hoststatus))
  55     {
  56       ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
  57       ourstatus->value.sig = gdb_signal_from_host (WTERMSIG (hoststatus));
  58     }
  59   else
  60     {
  61       ourstatus->kind = TARGET_WAITKIND_STOPPED;
  62       ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (hoststatus));
  63     }
  64 }
  65
  66 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  67    for all registers.  */
  68
  69 static void
  70 inf_child_fetch_inferior_registers (struct target_ops *ops,
  71                                     struct regcache *regcache, int regnum)
  72 {
  73   if (regnum == -1)
  74     {
  75       for (regnum = 0;
  76            regnum < gdbarch_num_regs (get_regcache_arch (regcache));
  77            regnum++)
  78         regcache_raw_supply (regcache, regnum, NULL);
  79     }
  80   else
  81     regcache_raw_supply (regcache, regnum, NULL);
  82 }
  83
  84 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
  85    this for all registers (including the floating point registers).  */
  86
  87 static void
  88 inf_child_store_inferior_registers (struct target_ops *ops,
  89                                     struct regcache *regcache, int regnum)
  90 {
  91 }
  92
  93 static void
  94 inf_child_post_attach (struct target_ops *self, int pid)
  95 {
  96   /* This target doesn't require a meaningful "post attach" operation
  97      by a debugger.  */
  98 }
  99
 100 /* Get ready to modify the registers array.  On machines which store
 101    individual registers, this doesn't need to do anything.  On
 102    machines which store all the registers in one fell swoop, this
 103    makes sure that registers contains all the registers from the
 104    program being debugged.  */
 105
 106 static void
 107 inf_child_prepare_to_store (struct target_ops *self,
 108                             struct regcache *regcache)
 109 {
 110 }
 111
 112 static void
 113 inf_child_open (char *arg, int from_tty)
 114 {
 115   error (_("Use the \"run\" command to start a child process."));
 116 }
 117
 118 static void
 119 inf_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
 120 {
 121   /* This target doesn't require a meaningful "post startup inferior"
 122      operation by a debugger.  */
 123 }
 124
 125 static int
 126 inf_child_follow_fork (struct target_ops *ops, int follow_child,
 127                        int detach_fork)
 128 {
 129   /* This target doesn't support following fork or vfork events.  */
 130   return 0;
 131 }
 132
 133 static int
 134 inf_child_can_run (struct target_ops *self)
 135 {
 136   return 1;
 137 }
 138
 139 static char *
 140 inf_child_pid_to_exec_file (struct target_ops *self, int pid)
 141 {
 142   /* This target doesn't support translation of a process ID to the
 143      filename of the executable file.  */
 144   return NULL;
 145 }
 146
 147
 148 /* Target file operations.  */
 149
 150 static int
 151 inf_child_fileio_open_flags_to_host (int fileio_open_flags, int *open_flags_p)
 152 {
 153   int open_flags = 0;
 154
 155   if (fileio_open_flags & ~FILEIO_O_SUPPORTED)
 156     return -1;
 157
 158   if (fileio_open_flags & FILEIO_O_CREAT)
 159     open_flags |= O_CREAT;
 160   if (fileio_open_flags & FILEIO_O_EXCL)
 161     open_flags |= O_EXCL;
 162   if (fileio_open_flags & FILEIO_O_TRUNC)
 163     open_flags |= O_TRUNC;
 164   if (fileio_open_flags & FILEIO_O_APPEND)
 165     open_flags |= O_APPEND;
 166   if (fileio_open_flags & FILEIO_O_RDONLY)
 167     open_flags |= O_RDONLY;
 168   if (fileio_open_flags & FILEIO_O_WRONLY)
 169     open_flags |= O_WRONLY;
 170   if (fileio_open_flags & FILEIO_O_RDWR)
 171     open_flags |= O_RDWR;
 172 /* On systems supporting binary and text mode, always open files in
 173    binary mode. */
 174 #ifdef O_BINARY
 175   open_flags |= O_BINARY;
 176 #endif
 177
 178   *open_flags_p = open_flags;
 179   return 0;
 180 }
 181
 182 static int
 183 inf_child_errno_to_fileio_error (int errnum)
 184 {
 185   switch (errnum)
 186     {
 187       case EPERM:
 188         return FILEIO_EPERM;
 189       case ENOENT:
 190         return FILEIO_ENOENT;
 191       case EINTR:
 192         return FILEIO_EINTR;
 193       case EIO:
 194         return FILEIO_EIO;
 195       case EBADF:
 196         return FILEIO_EBADF;
 197       case EACCES:
 198         return FILEIO_EACCES;
 199       case EFAULT:
 200         return FILEIO_EFAULT;
 201       case EBUSY:
 202         return FILEIO_EBUSY;
 203       case EEXIST:
 204         return FILEIO_EEXIST;
 205       case ENODEV:
 206         return FILEIO_ENODEV;
 207       case ENOTDIR:
 208         return FILEIO_ENOTDIR;
 209       case EISDIR:
 210         return FILEIO_EISDIR;
 211       case EINVAL:
 212         return FILEIO_EINVAL;
 213       case ENFILE:
 214         return FILEIO_ENFILE;
 215       case EMFILE:
 216         return FILEIO_EMFILE;
 217       case EFBIG:
 218         return FILEIO_EFBIG;
 219       case ENOSPC:
 220         return FILEIO_ENOSPC;
 221       case ESPIPE:
 222         return FILEIO_ESPIPE;
 223       case EROFS:
 224         return FILEIO_EROFS;
 225       case ENOSYS:
 226         return FILEIO_ENOSYS;
 227       case ENAMETOOLONG:
 228         return FILEIO_ENAMETOOLONG;
 229     }
 230   return FILEIO_EUNKNOWN;
 231 }
 232
 233 /* Open FILENAME on the target, using FLAGS and MODE.  Return a
 234    target file descriptor, or -1 if an error occurs (and set
 235    *TARGET_ERRNO).  */
 236 static int
 237 inf_child_fileio_open (struct target_ops *self,
 238                        const char *filename, int flags, int mode,
 239                        int *target_errno)
 240 {
 241   int nat_flags;
 242   int fd;
 243
 244   if (inf_child_fileio_open_flags_to_host (flags, &nat_flags) == -1)
 245     {
 246       *target_errno = FILEIO_EINVAL;
 247       return -1;
 248     }
 249
 250   /* We do not need to convert MODE, since the fileio protocol uses
 251      the standard values.  */
 252   fd = gdb_open_cloexec (filename, nat_flags, mode);
 253   if (fd == -1)
 254     *target_errno = inf_child_errno_to_fileio_error (errno);
 255
 256   return fd;
 257 }
 258
 259 /* Write up to LEN bytes from WRITE_BUF to FD on the target.
 260    Return the number of bytes written, or -1 if an error occurs
 261    (and set *TARGET_ERRNO).  */
 262 static int
 263 inf_child_fileio_pwrite (struct target_ops *self,
 264                          int fd, const gdb_byte *write_buf, int len,
 265                          ULONGEST offset, int *target_errno)
 266 {
 267   int ret;
 268
 269 #ifdef HAVE_PWRITE
 270   ret = pwrite (fd, write_buf, len, (long) offset);
 271 #else
 272   ret = -1;
 273 #endif
 274   /* If we have no pwrite or it failed for this file, use lseek/write.  */
 275   if (ret == -1)
 276     {
 277       ret = lseek (fd, (long) offset, SEEK_SET);
 278       if (ret != -1)
 279         ret = write (fd, write_buf, len);
 280     }
 281
 282   if (ret == -1)
 283     *target_errno = inf_child_errno_to_fileio_error (errno);
 284
 285   return ret;
 286 }
 287
 288 /* Read up to LEN bytes FD on the target into READ_BUF.
 289    Return the number of bytes read, or -1 if an error occurs
 290    (and set *TARGET_ERRNO).  */
 291 static int
 292 inf_child_fileio_pread (struct target_ops *self,
 293                         int fd, gdb_byte *read_buf, int len,
 294                         ULONGEST offset, int *target_errno)
 295 {
 296   int ret;
 297
 298 #ifdef HAVE_PREAD
 299   ret = pread (fd, read_buf, len, (long) offset);
 300 #else
 301   ret = -1;
 302 #endif
 303   /* If we have no pread or it failed for this file, use lseek/read.  */
 304   if (ret == -1)
 305     {
 306       ret = lseek (fd, (long) offset, SEEK_SET);
 307       if (ret != -1)
 308         ret = read (fd, read_buf, len);
 309     }
 310
 311   if (ret == -1)
 312     *target_errno = inf_child_errno_to_fileio_error (errno);
 313
 314   return ret;
 315 }
 316
 317 /* Close FD on the target.  Return 0, or -1 if an error occurs
 318    (and set *TARGET_ERRNO).  */
 319 static int
 320 inf_child_fileio_close (struct target_ops *self, int fd, int *target_errno)
 321 {
 322   int ret;
 323
 324   ret = close (fd);
 325   if (ret == -1)
 326     *target_errno = inf_child_errno_to_fileio_error (errno);
 327
 328   return ret;
 329 }
 330
 331 /* Unlink FILENAME on the target.  Return 0, or -1 if an error
 332    occurs (and set *TARGET_ERRNO).  */
 333 static int
 334 inf_child_fileio_unlink (struct target_ops *self,
 335                          const char *filename, int *target_errno)
 336 {
 337   int ret;
 338
 339   ret = unlink (filename);
 340   if (ret == -1)
 341     *target_errno = inf_child_errno_to_fileio_error (errno);
 342
 343   return ret;
 344 }
 345
 346 /* Read value of symbolic link FILENAME on the target.  Return a
 347    null-terminated string allocated via xmalloc, or NULL if an error
 348    occurs (and set *TARGET_ERRNO).  */
 349 static char *
 350 inf_child_fileio_readlink (struct target_ops *self,
 351                            const char *filename, int *target_errno)
 352 {
 353   /* We support readlink only on systems that also provide a compile-time
 354      maximum path length (PATH_MAX), at least for now.  */
 355 #if defined (HAVE_READLINK) && defined (PATH_MAX)
 356   char buf[PATH_MAX];
 357   int len;
 358   char *ret;
 359
 360   len = readlink (filename, buf, sizeof buf);
 361   if (len < 0)
 362     {
 363       *target_errno = inf_child_errno_to_fileio_error (errno);
 364       return NULL;
 365     }
 366
 367   ret = xmalloc (len + 1);
 368   memcpy (ret, buf, len);
 369   ret[len] = '\0';
 370   return ret;
 371 #else
 372   *target_errno = FILEIO_ENOSYS;
 373   return NULL;
 374 #endif
 375 }
 376
 377 static int
 378 inf_child_use_agent (struct target_ops *self, int use)
 379 {
 380   if (agent_loaded_p ())
 381     {
 382       use_agent = use;
 383       return 1;
 384     }
 385   else
 386     return 0;
 387 }
 388
 389 static int
 390 inf_child_can_use_agent (struct target_ops *self)
 391 {
 392   return agent_loaded_p ();
 393 }
 394
 395 /* Default implementation of the to_can_async_p and
 396    to_supports_non_stop methods.  */
 397
 398 static int
 399 return_zero (struct target_ops *ignore)
 400 {
 401   return 0;
 402 }
 403
 404 struct target_ops *
 405 inf_child_target (void)
 406 {
 407   struct target_ops *t = XCNEW (struct target_ops);
 408
 409   t->to_shortname = "child";
 410   t->to_longname = "Child process";
 411   t->to_doc = "Child process (started by the \"run\" command).";
 412   t->to_open = inf_child_open;
 413   t->to_post_attach = inf_child_post_attach;
 414   t->to_fetch_registers = inf_child_fetch_inferior_registers;
 415   t->to_store_registers = inf_child_store_inferior_registers;
 416   t->to_prepare_to_store = inf_child_prepare_to_store;
 417   t->to_insert_breakpoint = memory_insert_breakpoint;
 418   t->to_remove_breakpoint = memory_remove_breakpoint;
 419   t->to_terminal_init = child_terminal_init;
 420   t->to_terminal_inferior = child_terminal_inferior;
 421   t->to_terminal_ours_for_output = child_terminal_ours_for_output;
 422   t->to_terminal_save_ours = child_terminal_save_ours;
 423   t->to_terminal_ours = child_terminal_ours;
 424   t->to_terminal_info = child_terminal_info;
 425   t->to_post_startup_inferior = inf_child_post_startup_inferior;
 426   t->to_follow_fork = inf_child_follow_fork;
 427   t->to_can_run = inf_child_can_run;
 428   /* We must default these because they must be implemented by any
 429      target that can run.  */
 430   t->to_can_async_p = return_zero;
 431   t->to_supports_non_stop = return_zero;
 432   t->to_pid_to_exec_file = inf_child_pid_to_exec_file;
 433   t->to_stratum = process_stratum;
 434   t->to_has_all_memory = default_child_has_all_memory;
 435   t->to_has_memory = default_child_has_memory;
 436   t->to_has_stack = default_child_has_stack;
 437   t->to_has_registers = default_child_has_registers;
 438   t->to_has_execution = default_child_has_execution;
 439   t->to_fileio_open = inf_child_fileio_open;
 440   t->to_fileio_pwrite = inf_child_fileio_pwrite;
 441   t->to_fileio_pread = inf_child_fileio_pread;
 442   t->to_fileio_close = inf_child_fileio_close;
 443   t->to_fileio_unlink = inf_child_fileio_unlink;
 444   t->to_fileio_readlink = inf_child_fileio_readlink;
 445   t->to_magic = OPS_MAGIC;
 446   t->to_use_agent = inf_child_use_agent;
 447   t->to_can_use_agent = inf_child_can_use_agent;
 448   return t;
 449 }