gdb/inf-child.c

   1 /* Default child (native) target interface, for GDB when running under
   2    Unix.
   3
   4    Copyright (C) 1988-2014 Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "regcache.h"
  23 #include "memattr.h"
  24 #include "symtab.h"
  25 #include "target.h"
  26 #include "inferior.h"
  27 #include <string.h>
  28 #include <sys/stat.h>
  29 #include "inf-child.h"
  30 #include "gdb/fileio.h"
  31 #include "agent.h"
  32 #include "gdb_wait.h"
  33 #include "filestuff.h"
  34
  35 #include <sys/types.h>
  36 #include <fcntl.h>
  37 #include <unistd.h>
  38
  39 /* Helper function for child_wait and the derivatives of child_wait.
  40    HOSTSTATUS is the waitstatus from wait() or the equivalent; store our
  41    translation of that in OURSTATUS.  */
  42 void
  43 store_waitstatus (struct target_waitstatus *ourstatus, int hoststatus)
  44 {
  45   if (WIFEXITED (hoststatus))
  46     {
  47       ourstatus->kind = TARGET_WAITKIND_EXITED;
  48       ourstatus->value.integer = WEXITSTATUS (hoststatus);
  49     }
  50   else if (!WIFSTOPPED (hoststatus))
  51     {
  52       ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
  53       ourstatus->value.sig = gdb_signal_from_host (WTERMSIG (hoststatus));
  54     }
  55   else
  56     {
  57       ourstatus->kind = TARGET_WAITKIND_STOPPED;
  58       ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (hoststatus));
  59     }
  60 }
  61
  62 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  63    for all registers.  */
  64
  65 static void
  66 inf_child_fetch_inferior_registers (struct target_ops *ops,
  67                                     struct regcache *regcache, int regnum)
  68 {
  69   if (regnum == -1)
  70     {
  71       for (regnum = 0;
  72            regnum < gdbarch_num_regs (get_regcache_arch (regcache));
  73            regnum++)
  74         regcache_raw_supply (regcache, regnum, NULL);
  75     }
  76   else
  77     regcache_raw_supply (regcache, regnum, NULL);
  78 }
  79
  80 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
  81    this for all registers (including the floating point registers).  */
  82
  83 static void
  84 inf_child_store_inferior_registers (struct target_ops *ops,
  85                                     struct regcache *regcache, int regnum)
  86 {
  87 }
  88
  89 static void
  90 inf_child_post_attach (struct target_ops *self, int pid)
  91 {
  92   /* This version of Unix doesn't require a meaningful "post attach"
  93      operation by a debugger.  */
  94 }
  95
  96 /* Get ready to modify the registers array.  On machines which store
  97    individual registers, this doesn't need to do anything.  On
  98    machines which store all the registers in one fell swoop, this
  99    makes sure that registers contains all the registers from the
 100    program being debugged.  */
 101
 102 static void
 103 inf_child_prepare_to_store (struct target_ops *self,
 104                             struct regcache *regcache)
 105 {
 106 }
 107
 108 static void
 109 inf_child_open (char *arg, int from_tty)
 110 {
 111   error (_("Use the \"run\" command to start a Unix child process."));
 112 }
 113
 114 static void
 115 inf_child_post_startup_inferior (struct target_ops *self, ptid_t ptid)
 116 {
 117   /* This version of Unix doesn't require a meaningful "post startup
 118      inferior" operation by a debugger.  */
 119 }
 120
 121 static int
 122 inf_child_follow_fork (struct target_ops *ops, int follow_child,
 123                        int detach_fork)
 124 {
 125   /* This version of Unix doesn't support following fork or vfork
 126      events.  */
 127   return 0;
 128 }
 129
 130 static int
 131 inf_child_can_run (struct target_ops *self)
 132 {
 133   return 1;
 134 }
 135
 136 static char *
 137 inf_child_pid_to_exec_file (struct target_ops *self, int pid)
 138 {
 139   /* This version of Unix doesn't support translation of a process ID
 140      to the filename of the executable file.  */
 141   return NULL;
 142 }
 143
 144
 145 /* Target file operations.  */
 146
 147 static int
 148 inf_child_fileio_open_flags_to_host (int fileio_open_flags, int *open_flags_p)
 149 {
 150   int open_flags = 0;
 151
 152   if (fileio_open_flags & ~FILEIO_O_SUPPORTED)
 153     return -1;
 154
 155   if (fileio_open_flags & FILEIO_O_CREAT)
 156     open_flags |= O_CREAT;
 157   if (fileio_open_flags & FILEIO_O_EXCL)
 158     open_flags |= O_EXCL;
 159   if (fileio_open_flags & FILEIO_O_TRUNC)
 160     open_flags |= O_TRUNC;
 161   if (fileio_open_flags & FILEIO_O_APPEND)
 162     open_flags |= O_APPEND;
 163   if (fileio_open_flags & FILEIO_O_RDONLY)
 164     open_flags |= O_RDONLY;
 165   if (fileio_open_flags & FILEIO_O_WRONLY)
 166     open_flags |= O_WRONLY;
 167   if (fileio_open_flags & FILEIO_O_RDWR)
 168     open_flags |= O_RDWR;
 169 /* On systems supporting binary and text mode, always open files in
 170    binary mode. */
 171 #ifdef O_BINARY
 172   open_flags |= O_BINARY;
 173 #endif
 174
 175   *open_flags_p = open_flags;
 176   return 0;
 177 }
 178
 179 static int
 180 inf_child_errno_to_fileio_error (int errnum)
 181 {
 182   switch (errnum)
 183     {
 184       case EPERM:
 185         return FILEIO_EPERM;
 186       case ENOENT:
 187         return FILEIO_ENOENT;
 188       case EINTR:
 189         return FILEIO_EINTR;
 190       case EIO:
 191         return FILEIO_EIO;
 192       case EBADF:
 193         return FILEIO_EBADF;
 194       case EACCES:
 195         return FILEIO_EACCES;
 196       case EFAULT:
 197         return FILEIO_EFAULT;
 198       case EBUSY:
 199         return FILEIO_EBUSY;
 200       case EEXIST:
 201         return FILEIO_EEXIST;
 202       case ENODEV:
 203         return FILEIO_ENODEV;
 204       case ENOTDIR:
 205         return FILEIO_ENOTDIR;
 206       case EISDIR:
 207         return FILEIO_EISDIR;
 208       case EINVAL:
 209         return FILEIO_EINVAL;
 210       case ENFILE:
 211         return FILEIO_ENFILE;
 212       case EMFILE:
 213         return FILEIO_EMFILE;
 214       case EFBIG:
 215         return FILEIO_EFBIG;
 216       case ENOSPC:
 217         return FILEIO_ENOSPC;
 218       case ESPIPE:
 219         return FILEIO_ESPIPE;
 220       case EROFS:
 221         return FILEIO_EROFS;
 222       case ENOSYS:
 223         return FILEIO_ENOSYS;
 224       case ENAMETOOLONG:
 225         return FILEIO_ENAMETOOLONG;
 226     }
 227   return FILEIO_EUNKNOWN;
 228 }
 229
 230 /* Open FILENAME on the target, using FLAGS and MODE.  Return a
 231    target file descriptor, or -1 if an error occurs (and set
 232    *TARGET_ERRNO).  */
 233 static int
 234 inf_child_fileio_open (struct target_ops *self,
 235                        const char *filename, int flags, int mode,
 236                        int *target_errno)
 237 {
 238   int nat_flags;
 239   int fd;
 240
 241   if (inf_child_fileio_open_flags_to_host (flags, &nat_flags) == -1)
 242     {
 243       *target_errno = FILEIO_EINVAL;
 244       return -1;
 245     }
 246
 247   /* We do not need to convert MODE, since the fileio protocol uses
 248      the standard values.  */
 249   fd = gdb_open_cloexec (filename, nat_flags, mode);
 250   if (fd == -1)
 251     *target_errno = inf_child_errno_to_fileio_error (errno);
 252
 253   return fd;
 254 }
 255
 256 /* Write up to LEN bytes from WRITE_BUF to FD on the target.
 257    Return the number of bytes written, or -1 if an error occurs
 258    (and set *TARGET_ERRNO).  */
 259 static int
 260 inf_child_fileio_pwrite (int fd, const gdb_byte *write_buf, int len,
 261                          ULONGEST offset, int *target_errno)
 262 {
 263   int ret;
 264
 265 #ifdef HAVE_PWRITE
 266   ret = pwrite (fd, write_buf, len, (long) offset);
 267 #else
 268   ret = -1;
 269 #endif
 270   /* If we have no pwrite or it failed for this file, use lseek/write.  */
 271   if (ret == -1)
 272     {
 273       ret = lseek (fd, (long) offset, SEEK_SET);
 274       if (ret != -1)
 275         ret = write (fd, write_buf, len);
 276     }
 277
 278   if (ret == -1)
 279     *target_errno = inf_child_errno_to_fileio_error (errno);
 280
 281   return ret;
 282 }
 283
 284 /* Read up to LEN bytes FD on the target into READ_BUF.
 285    Return the number of bytes read, or -1 if an error occurs
 286    (and set *TARGET_ERRNO).  */
 287 static int
 288 inf_child_fileio_pread (int fd, gdb_byte *read_buf, int len,
 289                         ULONGEST offset, int *target_errno)
 290 {
 291   int ret;
 292
 293 #ifdef HAVE_PREAD
 294   ret = pread (fd, read_buf, len, (long) offset);
 295 #else
 296   ret = -1;
 297 #endif
 298   /* If we have no pread or it failed for this file, use lseek/read.  */
 299   if (ret == -1)
 300     {
 301       ret = lseek (fd, (long) offset, SEEK_SET);
 302       if (ret != -1)
 303         ret = read (fd, read_buf, len);
 304     }
 305
 306   if (ret == -1)
 307     *target_errno = inf_child_errno_to_fileio_error (errno);
 308
 309   return ret;
 310 }
 311
 312 /* Close FD on the target.  Return 0, or -1 if an error occurs
 313    (and set *TARGET_ERRNO).  */
 314 static int
 315 inf_child_fileio_close (int fd, int *target_errno)
 316 {
 317   int ret;
 318
 319   ret = close (fd);
 320   if (ret == -1)
 321     *target_errno = inf_child_errno_to_fileio_error (errno);
 322
 323   return ret;
 324 }
 325
 326 /* Unlink FILENAME on the target.  Return 0, or -1 if an error
 327    occurs (and set *TARGET_ERRNO).  */
 328 static int
 329 inf_child_fileio_unlink (const char *filename, int *target_errno)
 330 {
 331   int ret;
 332
 333   ret = unlink (filename);
 334   if (ret == -1)
 335     *target_errno = inf_child_errno_to_fileio_error (errno);
 336
 337   return ret;
 338 }
 339
 340 /* Read value of symbolic link FILENAME on the target.  Return a
 341    null-terminated string allocated via xmalloc, or NULL if an error
 342    occurs (and set *TARGET_ERRNO).  */
 343 static char *
 344 inf_child_fileio_readlink (const char *filename, int *target_errno)
 345 {
 346   /* We support readlink only on systems that also provide a compile-time
 347      maximum path length (PATH_MAX), at least for now.  */
 348 #if defined (HAVE_READLINK) && defined (PATH_MAX)
 349   char buf[PATH_MAX];
 350   int len;
 351   char *ret;
 352
 353   len = readlink (filename, buf, sizeof buf);
 354   if (len < 0)
 355     {
 356       *target_errno = inf_child_errno_to_fileio_error (errno);
 357       return NULL;
 358     }
 359
 360   ret = xmalloc (len + 1);
 361   memcpy (ret, buf, len);
 362   ret[len] = '\0';
 363   return ret;
 364 #else
 365   *target_errno = FILEIO_ENOSYS;
 366   return NULL;
 367 #endif
 368 }
 369
 370 static int
 371 inf_child_use_agent (int use)
 372 {
 373   if (agent_loaded_p ())
 374     {
 375       use_agent = use;
 376       return 1;
 377     }
 378   else
 379     return 0;
 380 }
 381
 382 static int
 383 inf_child_can_use_agent (void)
 384 {
 385   return agent_loaded_p ();
 386 }
 387
 388 struct target_ops *
 389 inf_child_target (void)
 390 {
 391   struct target_ops *t = XCNEW (struct target_ops);
 392
 393   t->to_shortname = "child";
 394   t->to_longname = "Unix child process";
 395   t->to_doc = "Unix child process (started by the \"run\" command).";
 396   t->to_open = inf_child_open;
 397   t->to_post_attach = inf_child_post_attach;
 398   t->to_fetch_registers = inf_child_fetch_inferior_registers;
 399   t->to_store_registers = inf_child_store_inferior_registers;
 400   t->to_prepare_to_store = inf_child_prepare_to_store;
 401   t->to_insert_breakpoint = memory_insert_breakpoint;
 402   t->to_remove_breakpoint = memory_remove_breakpoint;
 403   t->to_terminal_init = terminal_init_inferior;
 404   t->to_terminal_inferior = terminal_inferior;
 405   t->to_terminal_ours_for_output = terminal_ours_for_output;
 406   t->to_terminal_save_ours = terminal_save_ours;
 407   t->to_terminal_ours = terminal_ours;
 408   t->to_terminal_info = child_terminal_info;
 409   t->to_post_startup_inferior = inf_child_post_startup_inferior;
 410   t->to_follow_fork = inf_child_follow_fork;
 411   t->to_can_run = inf_child_can_run;
 412   t->to_pid_to_exec_file = inf_child_pid_to_exec_file;
 413   t->to_stratum = process_stratum;
 414   t->to_has_all_memory = default_child_has_all_memory;
 415   t->to_has_memory = default_child_has_memory;
 416   t->to_has_stack = default_child_has_stack;
 417   t->to_has_registers = default_child_has_registers;
 418   t->to_has_execution = default_child_has_execution;
 419   t->to_fileio_open = inf_child_fileio_open;
 420   t->to_fileio_pwrite = inf_child_fileio_pwrite;
 421   t->to_fileio_pread = inf_child_fileio_pread;
 422   t->to_fileio_close = inf_child_fileio_close;
 423   t->to_fileio_unlink = inf_child_fileio_unlink;
 424   t->to_fileio_readlink = inf_child_fileio_readlink;
 425   t->to_magic = OPS_MAGIC;
 426   t->to_use_agent = inf_child_use_agent;
 427   t->to_can_use_agent = inf_child_can_use_agent;
 428   return t;
 429 }