| 1 | /* Target-vector operations for controlling Unix child processes, for GDB. |
| 2 | Copyright 1990, 1991, 1992 Free Software Foundation, Inc. |
| 3 | Contributed by Cygnus Support. |
| 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 2 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, write to the Free Software |
| 19 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "frame.h" /* required by inferior.h */ |
| 23 | #include "inferior.h" |
| 24 | #include "target.h" |
| 25 | #include "wait.h" |
| 26 | #include "gdbcore.h" |
| 27 | #include "ieee-float.h" /* Required by REGISTER_CONVERT_TO_XXX */ |
| 28 | #include "terminal.h" /* For #ifdef TIOCGPGRP and new_tty */ |
| 29 | |
| 30 | #include <signal.h> |
| 31 | |
| 32 | #ifdef SET_STACK_LIMIT_HUGE |
| 33 | #include <sys/time.h> |
| 34 | #include <sys/resource.h> |
| 35 | |
| 36 | extern int original_stack_limit; |
| 37 | #endif /* SET_STACK_LIMIT_HUGE */ |
| 38 | |
| 39 | static void |
| 40 | child_prepare_to_store PARAMS ((void)); |
| 41 | |
| 42 | static int |
| 43 | child_wait PARAMS ((int *)); |
| 44 | |
| 45 | static void |
| 46 | child_open PARAMS ((char *, int)); |
| 47 | |
| 48 | static void |
| 49 | child_files_info PARAMS ((struct target_ops *)); |
| 50 | |
| 51 | static void |
| 52 | child_detach PARAMS ((char *, int)); |
| 53 | |
| 54 | static void |
| 55 | child_attach PARAMS ((char *, int)); |
| 56 | |
| 57 | static void |
| 58 | child_create_inferior PARAMS ((char *, char *, char **)); |
| 59 | |
| 60 | static void |
| 61 | child_mourn_inferior PARAMS ((void)); |
| 62 | |
| 63 | static int |
| 64 | child_can_run PARAMS ((void)); |
| 65 | |
| 66 | extern char **environ; |
| 67 | |
| 68 | /* Forward declaration */ |
| 69 | extern struct target_ops child_ops; |
| 70 | |
| 71 | /* Wait for child to do something. Return pid of child, or -1 in case |
| 72 | of error; store status through argument pointer STATUS. */ |
| 73 | |
| 74 | static int |
| 75 | child_wait (status) |
| 76 | int *status; |
| 77 | { |
| 78 | int pid; |
| 79 | |
| 80 | do { |
| 81 | #ifdef USE_PROC_FS |
| 82 | pid = proc_wait (status); |
| 83 | #else |
| 84 | pid = wait (status); |
| 85 | #endif |
| 86 | if (pid == -1) /* No more children to wait for */ |
| 87 | { |
| 88 | fprintf (stderr, "Child process unexpectedly missing.\n"); |
| 89 | *status = 42; /* Claim it exited with signal 42 */ |
| 90 | return -1; |
| 91 | } |
| 92 | } while (pid != inferior_pid); /* Some other child died or stopped */ |
| 93 | return pid; |
| 94 | } |
| 95 | |
| 96 | |
| 97 | /* Attach to process PID, then initialize for debugging it. */ |
| 98 | |
| 99 | static void |
| 100 | child_attach (args, from_tty) |
| 101 | char *args; |
| 102 | int from_tty; |
| 103 | { |
| 104 | char *exec_file; |
| 105 | int pid; |
| 106 | |
| 107 | if (!args) |
| 108 | error_no_arg ("process-id to attach"); |
| 109 | |
| 110 | #ifndef ATTACH_DETACH |
| 111 | error ("Can't attach to a process on this machine."); |
| 112 | #else |
| 113 | pid = atoi (args); |
| 114 | |
| 115 | if (pid == getpid()) /* Trying to masturbate? */ |
| 116 | error ("I refuse to debug myself!"); |
| 117 | |
| 118 | if (from_tty) |
| 119 | { |
| 120 | exec_file = (char *) get_exec_file (0); |
| 121 | |
| 122 | if (exec_file) |
| 123 | printf ("Attaching program `%s', pid %d\n", exec_file, pid); |
| 124 | else |
| 125 | printf ("Attaching pid %d\n", pid); |
| 126 | |
| 127 | fflush (stdout); |
| 128 | } |
| 129 | |
| 130 | attach (pid); |
| 131 | inferior_pid = pid; |
| 132 | push_target (&child_ops); |
| 133 | #endif /* ATTACH_DETACH */ |
| 134 | } |
| 135 | |
| 136 | |
| 137 | /* Take a program previously attached to and detaches it. |
| 138 | The program resumes execution and will no longer stop |
| 139 | on signals, etc. We'd better not have left any breakpoints |
| 140 | in the program or it'll die when it hits one. For this |
| 141 | to work, it may be necessary for the process to have been |
| 142 | previously attached. It *might* work if the program was |
| 143 | started via the normal ptrace (PTRACE_TRACEME). */ |
| 144 | |
| 145 | static void |
| 146 | child_detach (args, from_tty) |
| 147 | char *args; |
| 148 | int from_tty; |
| 149 | { |
| 150 | int siggnal = 0; |
| 151 | |
| 152 | #ifdef ATTACH_DETACH |
| 153 | if (from_tty) |
| 154 | { |
| 155 | char *exec_file = get_exec_file (0); |
| 156 | if (exec_file == 0) |
| 157 | exec_file = ""; |
| 158 | printf ("Detaching program: %s pid %d\n", |
| 159 | exec_file, inferior_pid); |
| 160 | fflush (stdout); |
| 161 | } |
| 162 | if (args) |
| 163 | siggnal = atoi (args); |
| 164 | |
| 165 | detach (siggnal); |
| 166 | inferior_pid = 0; |
| 167 | unpush_target (&child_ops); /* Pop out of handling an inferior */ |
| 168 | #else |
| 169 | error ("This version of Unix does not support detaching a process."); |
| 170 | #endif |
| 171 | } |
| 172 | |
| 173 | /* Get ready to modify the registers array. On machines which store |
| 174 | individual registers, this doesn't need to do anything. On machines |
| 175 | which store all the registers in one fell swoop, this makes sure |
| 176 | that registers contains all the registers from the program being |
| 177 | debugged. */ |
| 178 | |
| 179 | static void |
| 180 | child_prepare_to_store () |
| 181 | { |
| 182 | #ifdef CHILD_PREPARE_TO_STORE |
| 183 | CHILD_PREPARE_TO_STORE (); |
| 184 | #endif |
| 185 | } |
| 186 | |
| 187 | /* Print status information about what we're accessing. */ |
| 188 | |
| 189 | static void |
| 190 | child_files_info (ignore) |
| 191 | struct target_ops *ignore; |
| 192 | { |
| 193 | printf ("\tUsing the running image of %s process %d.\n", |
| 194 | attach_flag? "attached": "child", inferior_pid); |
| 195 | } |
| 196 | |
| 197 | /* ARGSUSED */ |
| 198 | static void |
| 199 | child_open (arg, from_tty) |
| 200 | char *arg; |
| 201 | int from_tty; |
| 202 | { |
| 203 | error ("Use the \"run\" command to start a Unix child process."); |
| 204 | } |
| 205 | |
| 206 | /* Start an inferior Unix child process and sets inferior_pid to its pid. |
| 207 | EXEC_FILE is the file to run. |
| 208 | ALLARGS is a string containing the arguments to the program. |
| 209 | ENV is the environment vector to pass. Errors reported with error(). */ |
| 210 | |
| 211 | #ifndef SHELL_FILE |
| 212 | #define SHELL_FILE "/bin/sh" |
| 213 | #endif |
| 214 | |
| 215 | static void |
| 216 | child_create_inferior (exec_file, allargs, env) |
| 217 | char *exec_file; |
| 218 | char *allargs; |
| 219 | char **env; |
| 220 | { |
| 221 | int pid; |
| 222 | char *shell_command; |
| 223 | char *shell_file; |
| 224 | static char default_shell_file[] = SHELL_FILE; |
| 225 | int len; |
| 226 | int pending_execs; |
| 227 | /* Set debug_fork then attach to the child while it sleeps, to debug. */ |
| 228 | static int debug_fork = 0; |
| 229 | /* This is set to the result of setpgrp, which if vforked, will be visible |
| 230 | to you in the parent process. It's only used by humans for debugging. */ |
| 231 | static int debug_setpgrp = 657473; |
| 232 | char **save_our_env; |
| 233 | |
| 234 | /* If no exec file handed to us, get it from the exec-file command -- with |
| 235 | a good, common error message if none is specified. */ |
| 236 | if (exec_file == 0) |
| 237 | exec_file = get_exec_file(1); |
| 238 | |
| 239 | /* The user might want tilde-expansion, and in general probably wants |
| 240 | the program to behave the same way as if run from |
| 241 | his/her favorite shell. So we let the shell run it for us. |
| 242 | FIXME, this should probably search the local environment (as |
| 243 | modified by the setenv command), not the env gdb inherited. */ |
| 244 | shell_file = getenv ("SHELL"); |
| 245 | if (shell_file == NULL) |
| 246 | shell_file = default_shell_file; |
| 247 | |
| 248 | len = 5 + strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 10; |
| 249 | /* If desired, concat something onto the front of ALLARGS. |
| 250 | SHELL_COMMAND is the result. */ |
| 251 | #ifdef SHELL_COMMAND_CONCAT |
| 252 | shell_command = (char *) alloca (strlen (SHELL_COMMAND_CONCAT) + len); |
| 253 | strcpy (shell_command, SHELL_COMMAND_CONCAT); |
| 254 | #else |
| 255 | shell_command = (char *) alloca (len); |
| 256 | shell_command[0] = '\0'; |
| 257 | #endif |
| 258 | strcat (shell_command, "exec "); |
| 259 | strcat (shell_command, exec_file); |
| 260 | strcat (shell_command, " "); |
| 261 | strcat (shell_command, allargs); |
| 262 | |
| 263 | /* exec is said to fail if the executable is open. */ |
| 264 | close_exec_file (); |
| 265 | |
| 266 | /* Retain a copy of our environment variables, since the child will |
| 267 | replace the value of environ and if we're vforked, we have to |
| 268 | restore it. */ |
| 269 | save_our_env = environ; |
| 270 | |
| 271 | /* Tell the terminal handling subsystem what tty we plan to run on; |
| 272 | it will just record the information for later. */ |
| 273 | |
| 274 | new_tty_prefork (inferior_io_terminal); |
| 275 | |
| 276 | /* It is generally good practice to flush any possible pending stdio |
| 277 | output prior to doing a fork, to avoid the possibility of both the |
| 278 | parent and child flushing the same data after the fork. */ |
| 279 | |
| 280 | fflush (stdout); |
| 281 | fflush (stderr); |
| 282 | |
| 283 | #if defined(USG) && !defined(HAVE_VFORK) |
| 284 | pid = fork (); |
| 285 | #else |
| 286 | if (debug_fork) |
| 287 | pid = fork (); |
| 288 | else |
| 289 | pid = vfork (); |
| 290 | #endif |
| 291 | |
| 292 | if (pid < 0) |
| 293 | perror_with_name ("vfork"); |
| 294 | |
| 295 | if (pid == 0) |
| 296 | { |
| 297 | if (debug_fork) |
| 298 | sleep (debug_fork); |
| 299 | |
| 300 | #ifdef TIOCGPGRP |
| 301 | /* Run inferior in a separate process group. */ |
| 302 | #ifdef NEED_POSIX_SETPGID |
| 303 | debug_setpgrp = setpgid (0, 0); |
| 304 | #else |
| 305 | #if defined(USG) && !defined(SETPGRP_ARGS) |
| 306 | debug_setpgrp = setpgrp (); |
| 307 | #else |
| 308 | debug_setpgrp = setpgrp (getpid (), getpid ()); |
| 309 | #endif /* USG */ |
| 310 | #endif /* NEED_POSIX_SETPGID */ |
| 311 | if (debug_setpgrp == -1) |
| 312 | perror("setpgrp failed in child"); |
| 313 | #endif /* TIOCGPGRP */ |
| 314 | |
| 315 | #ifdef SET_STACK_LIMIT_HUGE |
| 316 | /* Reset the stack limit back to what it was. */ |
| 317 | { |
| 318 | struct rlimit rlim; |
| 319 | |
| 320 | getrlimit (RLIMIT_STACK, &rlim); |
| 321 | rlim.rlim_cur = original_stack_limit; |
| 322 | setrlimit (RLIMIT_STACK, &rlim); |
| 323 | } |
| 324 | #endif /* SET_STACK_LIMIT_HUGE */ |
| 325 | |
| 326 | /* Ask the tty subsystem to switch to the one we specified earlier |
| 327 | (or to share the current terminal, if none was specified). */ |
| 328 | |
| 329 | new_tty (); |
| 330 | |
| 331 | /* Changing the signal handlers for the inferior after |
| 332 | a vfork can also change them for the superior, so we don't mess |
| 333 | with signals here. See comments in |
| 334 | initialize_signals for how we get the right signal handlers |
| 335 | for the inferior. */ |
| 336 | |
| 337 | #ifdef USE_PROC_FS |
| 338 | /* Use SVR4 /proc interface */ |
| 339 | proc_set_exec_trap (); |
| 340 | #else |
| 341 | /* "Trace me, Dr. Memory!" */ |
| 342 | call_ptrace (0, 0, (PTRACE_ARG3_TYPE) 0, 0); |
| 343 | #endif |
| 344 | |
| 345 | /* There is no execlpe call, so we have to set the environment |
| 346 | for our child in the global variable. If we've vforked, this |
| 347 | clobbers the parent, but environ is restored a few lines down |
| 348 | in the parent. By the way, yes we do need to look down the |
| 349 | path to find $SHELL. Rich Pixley says so, and I agree. */ |
| 350 | environ = env; |
| 351 | execlp (shell_file, shell_file, "-c", shell_command, (char *)0); |
| 352 | |
| 353 | fprintf (stderr, "Cannot exec %s: %s.\n", shell_file, |
| 354 | safe_strerror (errno)); |
| 355 | fflush (stderr); |
| 356 | _exit (0177); |
| 357 | } |
| 358 | |
| 359 | /* Restore our environment in case a vforked child clob'd it. */ |
| 360 | environ = save_our_env; |
| 361 | |
| 362 | /* Now that we have a child process, make it our target. */ |
| 363 | push_target (&child_ops); |
| 364 | |
| 365 | #ifdef CREATE_INFERIOR_HOOK |
| 366 | CREATE_INFERIOR_HOOK (pid); |
| 367 | #endif |
| 368 | |
| 369 | /* The process was started by the fork that created it, |
| 370 | but it will have stopped one instruction after execing the shell. |
| 371 | Here we must get it up to actual execution of the real program. */ |
| 372 | |
| 373 | inferior_pid = pid; /* Needed for wait_for_inferior stuff below */ |
| 374 | |
| 375 | clear_proceed_status (); |
| 376 | |
| 377 | /* We will get a trace trap after one instruction. |
| 378 | Continue it automatically. Eventually (after shell does an exec) |
| 379 | it will get another trace trap. Then insert breakpoints and continue. */ |
| 380 | |
| 381 | #ifdef START_INFERIOR_TRAPS_EXPECTED |
| 382 | pending_execs = START_INFERIOR_TRAPS_EXPECTED; |
| 383 | #else |
| 384 | pending_execs = 2; |
| 385 | #endif |
| 386 | |
| 387 | init_wait_for_inferior (); |
| 388 | |
| 389 | /* Set up the "saved terminal modes" of the inferior |
| 390 | based on what modes we are starting it with. */ |
| 391 | target_terminal_init (); |
| 392 | |
| 393 | /* Install inferior's terminal modes. */ |
| 394 | target_terminal_inferior (); |
| 395 | |
| 396 | while (1) |
| 397 | { |
| 398 | stop_soon_quietly = 1; /* Make wait_for_inferior be quiet */ |
| 399 | wait_for_inferior (); |
| 400 | if (stop_signal != SIGTRAP) |
| 401 | { |
| 402 | /* Let shell child handle its own signals in its own way */ |
| 403 | /* FIXME, what if child has exit()ed? Must exit loop somehow */ |
| 404 | resume (0, stop_signal); |
| 405 | } |
| 406 | else |
| 407 | { |
| 408 | /* We handle SIGTRAP, however; it means child did an exec. */ |
| 409 | if (0 == --pending_execs) |
| 410 | break; |
| 411 | resume (0, 0); /* Just make it go on */ |
| 412 | } |
| 413 | } |
| 414 | stop_soon_quietly = 0; |
| 415 | |
| 416 | /* We are now in the child process of interest, having exec'd the |
| 417 | correct program, and are poised at the first instruction of the |
| 418 | new program. */ |
| 419 | #ifdef SOLIB_CREATE_INFERIOR_HOOK |
| 420 | SOLIB_CREATE_INFERIOR_HOOK (pid); |
| 421 | #endif |
| 422 | |
| 423 | /* Pedal to the metal. Away we go. */ |
| 424 | proceed ((CORE_ADDR) -1, 0, 0); |
| 425 | } |
| 426 | |
| 427 | static void |
| 428 | child_mourn_inferior () |
| 429 | { |
| 430 | unpush_target (&child_ops); |
| 431 | generic_mourn_inferior (); |
| 432 | } |
| 433 | |
| 434 | static int |
| 435 | child_can_run () |
| 436 | { |
| 437 | return(1); |
| 438 | } |
| 439 | \f |
| 440 | struct target_ops child_ops = { |
| 441 | "child", /* to_shortname */ |
| 442 | "Unix child process", /* to_longname */ |
| 443 | "Unix child process (started by the \"run\" command).", /* to_doc */ |
| 444 | child_open, /* to_open */ |
| 445 | 0, /* to_close */ |
| 446 | child_attach, /* to_attach */ |
| 447 | child_detach, /* to_detach */ |
| 448 | child_resume, /* to_resume */ |
| 449 | child_wait, /* to_wait */ |
| 450 | fetch_inferior_registers, /* to_fetch_registers */ |
| 451 | store_inferior_registers, /* to_store_registers */ |
| 452 | child_prepare_to_store, /* to_prepare_to_store */ |
| 453 | child_xfer_memory, /* to_xfer_memory */ |
| 454 | child_files_info, /* to_files_info */ |
| 455 | memory_insert_breakpoint, /* to_insert_breakpoint */ |
| 456 | memory_remove_breakpoint, /* to_remove_breakpoint */ |
| 457 | terminal_init_inferior, /* to_terminal_init */ |
| 458 | terminal_inferior, /* to_terminal_inferior */ |
| 459 | terminal_ours_for_output, /* to_terminal_ours_for_output */ |
| 460 | terminal_ours, /* to_terminal_ours */ |
| 461 | child_terminal_info, /* to_terminal_info */ |
| 462 | kill_inferior, /* to_kill */ |
| 463 | 0, /* to_load */ |
| 464 | 0, /* to_lookup_symbol */ |
| 465 | child_create_inferior, /* to_create_inferior */ |
| 466 | child_mourn_inferior, /* to_mourn_inferior */ |
| 467 | child_can_run, /* to_can_run */ |
| 468 | process_stratum, /* to_stratum */ |
| 469 | 0, /* to_next */ |
| 470 | 1, /* to_has_all_memory */ |
| 471 | 1, /* to_has_memory */ |
| 472 | 1, /* to_has_stack */ |
| 473 | 1, /* to_has_registers */ |
| 474 | 1, /* to_has_execution */ |
| 475 | 0, /* sections */ |
| 476 | 0, /* sections_end */ |
| 477 | OPS_MAGIC /* to_magic */ |
| 478 | }; |
| 479 | |
| 480 | void |
| 481 | _initialize_inftarg () |
| 482 | { |
| 483 | add_target (&child_ops); |
| 484 | } |