gdb/inf-child.c

   1 /* Default child (native) target interface, for GDB when running under
   2    Unix.
   3
   4    Copyright (C) 1988-2013 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 "gdb_string.h"
  28 #include "gdb_stat.h"
  29 #include "inf-child.h"
  30 #include "gdb/fileio.h"
  31 #include "agent.h"
  32 #include "gdb_wait.h"
  33
  34 #ifdef HAVE_SYS_PARAM_H
  35 #include <sys/param.h>          /* for MAXPATHLEN */
  36 #endif
  37 #include <sys/types.h>
  38 #include <fcntl.h>
  39 #include <unistd.h>
  40
  41 /* Helper function for child_wait and the derivatives of child_wait.
  42    HOSTSTATUS is the waitstatus from wait() or the equivalent; store our
  43    translation of that in OURSTATUS.  */
  44 void
  45 store_waitstatus (struct target_waitstatus *ourstatus, int hoststatus)
  46 {
  47   if (WIFEXITED (hoststatus))
  48     {
  49       ourstatus->kind = TARGET_WAITKIND_EXITED;
  50       ourstatus->value.integer = WEXITSTATUS (hoststatus);
  51     }
  52   else if (!WIFSTOPPED (hoststatus))
  53     {
  54       ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
  55       ourstatus->value.sig = gdb_signal_from_host (WTERMSIG (hoststatus));
  56     }
  57   else
  58     {
  59       ourstatus->kind = TARGET_WAITKIND_STOPPED;
  60       ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (hoststatus));
  61     }
  62 }
  63
  64 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
  65    for all registers.  */
  66
  67 static void
  68 inf_child_fetch_inferior_registers (struct target_ops *ops,
  69                                     struct regcache *regcache, int regnum)
  70 {
  71   if (regnum == -1)
  72     {
  73       for (regnum = 0;
  74            regnum < gdbarch_num_regs (get_regcache_arch (regcache));
  75            regnum++)
  76         regcache_raw_supply (regcache, regnum, NULL);
  77     }
  78   else
  79     regcache_raw_supply (regcache, regnum, NULL);
  80 }
  81
  82 /* Store register REGNUM back into the inferior.  If REGNUM is -1, do
  83    this for all registers (including the floating point registers).  */
  84
  85 static void
  86 inf_child_store_inferior_registers (struct target_ops *ops,
  87                                     struct regcache *regcache, int regnum)
  88 {
  89 }
  90
  91 static void
  92 inf_child_post_attach (int pid)
  93 {
  94   /* This version of Unix doesn't require a meaningful "post attach"
  95      operation by a debugger.  */
  96 }
  97
  98 /* Get ready to modify the registers array.  On machines which store
  99    individual registers, this doesn't need to do anything.  On
 100    machines which store all the registers in one fell swoop, this
 101    makes sure that registers contains all the registers from the
 102    program being debugged.  */
 103
 104 static void
 105 inf_child_prepare_to_store (struct regcache *regcache)
 106 {
 107 }
 108
 109 static void
 110 inf_child_open (char *arg, int from_tty)
 111 {
 112   error (_("Use the \"run\" command to start a Unix child process."));
 113 }
 114
 115 static void
 116 inf_child_post_startup_inferior (ptid_t ptid)
 117 {
 118   /* This version of Unix doesn't require a meaningful "post startup
 119      inferior" operation by a debugger.  */
 120 }
 121
 122 static int
 123 inf_child_follow_fork (struct target_ops *ops, int follow_child)
 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 (void)
 132 {
 133   return 1;
 134 }
 135
 136 static char *
 137 inf_child_pid_to_exec_file (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 (const char *filename, int flags, int mode,
 235                        int *target_errno)
 236 {
 237   int nat_flags;
 238   int fd;
 239
 240   if (inf_child_fileio_open_flags_to_host (flags, &nat_flags) == -1)
 241     {
 242       *target_errno = FILEIO_EINVAL;
 243       return -1;
 244     }
 245
 246   /* We do not need to convert MODE, since the fileio protocol uses
 247      the standard values.  */
 248   fd = open (filename, nat_flags, mode);
 249   if (fd == -1)
 250     *target_errno = inf_child_errno_to_fileio_error (errno);
 251
 252   return fd;
 253 }
 254
 255 /* Write up to LEN bytes from WRITE_BUF to FD on the target.
 256    Return the number of bytes written, or -1 if an error occurs
 257    (and set *TARGET_ERRNO).  */
 258 static int
 259 inf_child_fileio_pwrite (int fd, const gdb_byte *write_buf, int len,
 260                          ULONGEST offset, int *target_errno)
 261 {
 262   int ret;
 263
 264 #ifdef HAVE_PWRITE
 265   ret = pwrite (fd, write_buf, len, (long) offset);
 266 #else
 267   ret = -1;
 268 #endif
 269   /* If we have no pwrite or it failed for this file, use lseek/write.  */
 270   if (ret == -1)
 271     {
 272       ret = lseek (fd, (long) offset, SEEK_SET);
 273       if (ret != -1)
 274         ret = write (fd, write_buf, len);
 275     }
 276
 277   if (ret == -1)
 278     *target_errno = inf_child_errno_to_fileio_error (errno);
 279
 280   return ret;
 281 }
 282
 283 /* Read up to LEN bytes FD on the target into READ_BUF.
 284    Return the number of bytes read, or -1 if an error occurs
 285    (and set *TARGET_ERRNO).  */
 286 static int
 287 inf_child_fileio_pread (int fd, gdb_byte *read_buf, int len,
 288                         ULONGEST offset, int *target_errno)
 289 {
 290   int ret;
 291
 292 #ifdef HAVE_PREAD
 293   ret = pread (fd, read_buf, len, (long) offset);
 294 #else
 295   ret = -1;
 296 #endif
 297   /* If we have no pread or it failed for this file, use lseek/read.  */
 298   if (ret == -1)
 299     {
 300       ret = lseek (fd, (long) offset, SEEK_SET);
 301       if (ret != -1)
 302         ret = read (fd, read_buf, len);
 303     }
 304
 305   if (ret == -1)
 306     *target_errno = inf_child_errno_to_fileio_error (errno);
 307
 308   return ret;
 309 }
 310
 311 /* Close FD on the target.  Return 0, or -1 if an error occurs
 312    (and set *TARGET_ERRNO).  */
 313 static int
 314 inf_child_fileio_close (int fd, int *target_errno)
 315 {
 316   int ret;
 317
 318   ret = close (fd);
 319   if (ret == -1)
 320     *target_errno = inf_child_errno_to_fileio_error (errno);
 321
 322   return ret;
 323 }
 324
 325 /* Unlink FILENAME on the target.  Return 0, or -1 if an error
 326    occurs (and set *TARGET_ERRNO).  */
 327 static int
 328 inf_child_fileio_unlink (const char *filename, int *target_errno)
 329 {
 330   int ret;
 331
 332   ret = unlink (filename);
 333   if (ret == -1)
 334     *target_errno = inf_child_errno_to_fileio_error (errno);
 335
 336   return ret;
 337 }
 338
 339 /* Read value of symbolic link FILENAME on the target.  Return a
 340    null-terminated string allocated via xmalloc, or NULL if an error
 341    occurs (and set *TARGET_ERRNO).  */
 342 static char *
 343 inf_child_fileio_readlink (const char *filename, int *target_errno)
 344 {
 345   /* We support readlink only on systems that also provide a compile-time
 346      maximum path length (MAXPATHLEN), at least for now.  */
 347 #if defined (HAVE_READLINK) && defined (MAXPATHLEN)
 348   char buf[MAXPATHLEN - 1];
 349   int len;
 350   char *ret;
 351
 352   len = readlink (filename, buf, sizeof buf);
 353   if (len < 0)
 354     {
 355       *target_errno = inf_child_errno_to_fileio_error (errno);
 356       return NULL;
 357     }
 358
 359   ret = xmalloc (len + 1);
 360   memcpy (ret, buf, len);
 361   ret[len] = '\0';
 362   return ret;
 363 #else
 364   *target_errno = FILEIO_ENOSYS;
 365   return NULL;
 366 #endif
 367 }
 368
 369 static int
 370 inf_child_use_agent (int use)
 371 {
 372   if (agent_loaded_p ())
 373     {
 374       use_agent = use;
 375       return 1;
 376     }
 377   else
 378     return 0;
 379 }
 380
 381 static int
 382 inf_child_can_use_agent (void)
 383 {
 384   return agent_loaded_p ();
 385 }
 386
 387 struct target_ops *
 388 inf_child_target (void)
 389 {
 390   struct target_ops *t = XZALLOC (struct target_ops);
 391
 392   t->to_shortname = "child";
 393   t->to_longname = "Unix child process";
 394   t->to_doc = "Unix child process (started by the \"run\" command).";
 395   t->to_open = inf_child_open;
 396   t->to_post_attach = inf_child_post_attach;
 397   t->to_fetch_registers = inf_child_fetch_inferior_registers;
 398   t->to_store_registers = inf_child_store_inferior_registers;
 399   t->to_prepare_to_store = inf_child_prepare_to_store;
 400   t->to_insert_breakpoint = memory_insert_breakpoint;
 401   t->to_remove_breakpoint = memory_remove_breakpoint;
 402   t->to_terminal_init = terminal_init_inferior;
 403   t->to_terminal_inferior = terminal_inferior;
 404   t->to_terminal_ours_for_output = terminal_ours_for_output;
 405   t->to_terminal_save_ours = terminal_save_ours;
 406   t->to_terminal_ours = terminal_ours;
 407   t->to_terminal_info = child_terminal_info;
 408   t->to_post_startup_inferior = inf_child_post_startup_inferior;
 409   t->to_follow_fork = inf_child_follow_fork;
 410   t->to_can_run = inf_child_can_run;
 411   t->to_pid_to_exec_file = inf_child_pid_to_exec_file;
 412   t->to_stratum = process_stratum;
 413   t->to_has_all_memory = default_child_has_all_memory;
 414   t->to_has_memory = default_child_has_memory;
 415   t->to_has_stack = default_child_has_stack;
 416   t->to_has_registers = default_child_has_registers;
 417   t->to_has_execution = default_child_has_execution;
 418   t->to_fileio_open = inf_child_fileio_open;
 419   t->to_fileio_pwrite = inf_child_fileio_pwrite;
 420   t->to_fileio_pread = inf_child_fileio_pread;
 421   t->to_fileio_close = inf_child_fileio_close;
 422   t->to_fileio_unlink = inf_child_fileio_unlink;
 423   t->to_fileio_readlink = inf_child_fileio_readlink;
 424   t->to_magic = OPS_MAGIC;
 425   t->to_use_agent = inf_child_use_agent;
 426   t->to_can_use_agent = inf_child_can_use_agent;
 427   return t;
 428 }