diff options
Diffstat (limited to 'gdb/fork-child.c')
| -rw-r--r-- | gdb/fork-child.c | 616 |
1 files changed, 0 insertions, 616 deletions
diff --git a/gdb/fork-child.c b/gdb/fork-child.c deleted file mode 100644 index f3504bc..0000000 --- a/gdb/fork-child.c +++ /dev/null @@ -1,616 +0,0 @@ -/* Fork a Unix child process, and set up to debug it, for GDB. - Copyright 1990, 1991, 1992, 1993, 1994, 1996 Free Software Foundation, Inc. - Contributed by Cygnus Support. - -This file is part of GDB. - -This program is free software; you can redistribute it and/or modify -it under the terms of the GNU General Public License as published by -the Free Software Foundation; either version 2 of the License, or -(at your option) any later version. - -This program is distributed in the hope that it will be useful, -but WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -GNU General Public License for more details. - -You should have received a copy of the GNU General Public License -along with this program; if not, write to the Free Software -Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ - -#include "defs.h" -#include "gdb_string.h" -#include "frame.h" /* required by inferior.h */ -#include "inferior.h" -#include "target.h" -#include "wait.h" -#include "gdbcore.h" -#include "terminal.h" -#include "gdbthread.h" - -#include <signal.h> -#ifdef HAVE_UNISTD_H -#include <unistd.h> -#endif - -#define DEBUGGING 0 - -/* This just gets used as a default if we can't find SHELL */ -#ifndef SHELL_FILE -#define SHELL_FILE "/bin/sh" -#endif - -extern char **environ; - -/* This function breaks up an argument string into an argument - * vector suitable for passing to execvp(). - * E.g., on "run a b c d" this routine would get as input - * the string "a b c d", and as output it would fill in argv with - * the four arguments "a", "b", "c", "d". - */ -static void -breakup_args ( - scratch, - argv) - char *scratch; - char **argv; -{ - char *cp = scratch; - -#if DEBUGGING - printf ("breakup_args: input = %s\n", scratch); -#endif - for (;;) - { - - /* Scan past leading separators */ - while (*cp == ' ' || *cp == '\t' || *cp == '\n') - { - cp++; - } - - /* Break if at end of string */ - if (*cp == '\0') - break; - - /* Take an arg */ - *argv++ = cp; - - /* Scan for next arg separator */ - cp = strchr (cp, ' '); - if (cp == NULL) - cp = strchr (cp, '\t'); - if (cp == NULL) - cp = strchr (cp, '\n'); - - /* No separators => end of string => break */ - if (cp == NULL) - break; - - /* Replace the separator with a terminator */ - *cp++ = '\0'; - } - - /* execv requires a null-terminated arg vector */ - *argv = NULL; - -} - - -/* Start an inferior Unix child process and sets inferior_pid to its pid. - EXEC_FILE is the file to run. - ALLARGS is a string containing the arguments to the program. - ENV is the environment vector to pass. SHELL_FILE is the shell file, - or NULL if we should pick one. Errors reported with error(). */ - -void -fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun, - pre_trace_fun, shell_file) - char *exec_file; - char *allargs; - char **env; - void (*traceme_fun) PARAMS ((void)); - void (*init_trace_fun) PARAMS ((int)); - void (*pre_trace_fun) PARAMS ((void)); - char *shell_file; -{ - int pid; - char *shell_command; - static char default_shell_file[] = SHELL_FILE; - int len; - /* Set debug_fork then attach to the child while it sleeps, to debug. */ - static int debug_fork = 0; - /* This is set to the result of setpgrp, which if vforked, will be visible - to you in the parent process. It's only used by humans for debugging. */ - static int debug_setpgrp = 657473; - char **save_our_env; - int shell = 0; - char **argv; - char *tryname; - - /* If no exec file handed to us, get it from the exec-file command -- with - a good, common error message if none is specified. */ - if (exec_file == 0) - exec_file = get_exec_file (1); - - /* STARTUP_WITH_SHELL is defined in inferior.h. - * If 0, we'll just do a fork/exec, no shell, so don't - * bother figuring out what shell. - */ - if (STARTUP_WITH_SHELL) - { - /* Figure out what shell to start up the user program under. */ - if (shell_file == NULL) - shell_file = getenv ("SHELL"); - if (shell_file == NULL) - shell_file = default_shell_file; - shell = 1; - } - -#if DEBUGGING - printf ("shell is %s\n", shell_file); -#endif - - /* Multiplying the length of exec_file by 4 is to account for the fact - that it may expand when quoted; it is a worst-case number based on - every character being '. */ - len = 5 + 4 * strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 12; - /* If desired, concat something onto the front of ALLARGS. - SHELL_COMMAND is the result. */ -#ifdef SHELL_COMMAND_CONCAT - shell_command = (char *) alloca (strlen (SHELL_COMMAND_CONCAT) + len); - strcpy (shell_command, SHELL_COMMAND_CONCAT); -#else - shell_command = (char *) alloca (len); - shell_command[0] = '\0'; -#endif - - if (!shell) - { - /* We're going to call execvp. Create argv */ - /* Largest case: every other character is a separate arg */ -#if DEBUGGING - printf ("allocating argv, length = %d\n", - ( - (strlen (allargs) + 1) / (unsigned) 2 - + 2 - ) * sizeof (*argv) - ); -#endif - argv = (char **) xmalloc (((strlen (allargs) + 1) / (unsigned) 2 + 2) * sizeof (*argv)); - argv[0] = exec_file; - breakup_args (allargs, &argv[1]); - - } - else - { - - /* We're going to call a shell */ - - /* Now add exec_file, quoting as necessary. */ - - char *p; - int need_to_quote; - - strcat (shell_command, "exec "); - - /* Quoting in this style is said to work with all shells. But csh - on IRIX 4.0.1 can't deal with it. So we only quote it if we need - to. */ - p = exec_file; - while (1) - { - switch (*p) - { - case '\'': - case '"': - case '(': - case ')': - case '$': - case '&': - case ';': - case '<': - case '>': - case ' ': - case '\n': - case '\t': - need_to_quote = 1; - goto end_scan; - - case '\0': - need_to_quote = 0; - goto end_scan; - - default: - break; - } - ++p; - } - end_scan: - if (need_to_quote) - { - strcat (shell_command, "'"); - for (p = exec_file; *p != '\0'; ++p) - { - if (*p == '\'') - strcat (shell_command, "'\\''"); - else - strncat (shell_command, p, 1); - } - strcat (shell_command, "'"); - } - else - strcat (shell_command, exec_file); - - strcat (shell_command, " "); - strcat (shell_command, allargs); - - } - - /* exec is said to fail if the executable is open. */ - close_exec_file (); - - /* Retain a copy of our environment variables, since the child will - replace the value of environ and if we're vforked, we have to - restore it. */ - save_our_env = environ; - - /* Tell the terminal handling subsystem what tty we plan to run on; - it will just record the information for later. */ - - new_tty_prefork (inferior_io_terminal); - - /* It is generally good practice to flush any possible pending stdio - output prior to doing a fork, to avoid the possibility of both the - parent and child flushing the same data after the fork. */ - - gdb_flush (gdb_stdout); - gdb_flush (gdb_stderr); - - /* If there's any initialization of the target layers that must happen - to prepare to handle the child we're about fork, do it now... - */ - if (pre_trace_fun != NULL) - (*pre_trace_fun) (); - -#if defined(USG) && !defined(HAVE_VFORK) - pid = fork (); -#else - if (debug_fork) - pid = fork (); - else - pid = vfork (); -#endif - - if (pid < 0) - perror_with_name ("vfork"); - - if (pid == 0) - { - if (debug_fork) - sleep (debug_fork); - - /* Run inferior in a separate process group. */ - debug_setpgrp = gdb_setpgid (); - if (debug_setpgrp == -1) - perror ("setpgrp failed in child"); - - /* Ask the tty subsystem to switch to the one we specified earlier - (or to share the current terminal, if none was specified). */ - - new_tty (); - - /* Changing the signal handlers for the inferior after - a vfork can also change them for the superior, so we don't mess - with signals here. See comments in - initialize_signals for how we get the right signal handlers - for the inferior. */ - - /* "Trace me, Dr. Memory!" */ - (*traceme_fun) (); - /* The call above set this process (the "child") as debuggable - * by the original gdb process (the "parent"). Since processes - * (unlike people) can have only one parent, if you are - * debugging gdb itself (and your debugger is thus _already_ the - * controller/parent for this child), code from here on out - * is undebuggable. Indeed, you probably got an error message - * saying "not parent". Sorry--you'll have to use print statements! - */ - - /* There is no execlpe call, so we have to set the environment - for our child in the global variable. If we've vforked, this - clobbers the parent, but environ is restored a few lines down - in the parent. By the way, yes we do need to look down the - path to find $SHELL. Rich Pixley says so, and I agree. */ - environ = env; - - /* If we decided above to start up with a shell, - * we exec the shell, - * "-c" says to interpret the next arg as a shell command - * to execute, and this command is "exec <target-program> <args>". - * "-f" means "fast startup" to the c-shell, which means - * don't do .cshrc file. Doing .cshrc may cause fork/exec - * events which will confuse debugger start-up code. - */ - if (shell) - { -#if 0 - - /* HP change is problematic. The -f option has different meanings - for different shells. It is particularly inappropriate for - bourne shells. */ - execlp (shell_file, shell_file, "-f", "-c", shell_command, (char *) 0); -#else - execlp (shell_file, shell_file, "-c", shell_command, (char *) 0); -#endif - - - /* If we get here, it's an error */ - fprintf_unfiltered (gdb_stderr, "Cannot exec %s: %s.\n", shell_file, - safe_strerror (errno)); - gdb_flush (gdb_stderr); - _exit (0177); - } - else - { - /* Otherwise, we directly exec the target program with execvp. */ - int i; - char *errstring; -#if DEBUGGING - printf ("about to exec target, exec_file = %s\n", exec_file); - i = 0; - while (argv[i] != NULL) - { - printf ("strlen(argv[%d]) is %d\n", i, strlen (argv[i])); - printf ("argv[%d] is %s\n", i, argv[i]); - i++; - } -#endif - execvp (exec_file, argv); - - /* If we get here, it's an error */ - errstring = safe_strerror (errno); - fprintf_unfiltered (gdb_stderr, "Cannot exec %s ", exec_file); - - i = 1; - while (argv[i] != NULL) - { - if (i != 1) - fprintf_unfiltered (gdb_stderr, " "); - fprintf_unfiltered (gdb_stderr, "%s", argv[i]); - i++; - } - fprintf_unfiltered (gdb_stderr, ".\n"); - /* This extra info seems to be useless - fprintf_unfiltered (gdb_stderr, "Got error %s.\n", errstring); - */ - gdb_flush (gdb_stderr); - _exit (0177); - } - } - - /* Restore our environment in case a vforked child clob'd it. */ - environ = save_our_env; - - init_thread_list (); - - inferior_pid = pid; /* Needed for wait_for_inferior stuff below */ - - /* Now that we have a child process, make it our target, and - initialize anything target-vector-specific that needs initializing. */ - - (*init_trace_fun) (pid); - - /* We are now in the child process of interest, having exec'd the - correct program, and are poised at the first instruction of the - new program. */ - - /* Allow target dependant code to play with the new process. This might be - used to have target-specific code initialize a variable in the new process - prior to executing the first instruction. */ - TARGET_CREATE_INFERIOR_HOOK (pid); - -#ifdef SOLIB_CREATE_INFERIOR_HOOK - SOLIB_CREATE_INFERIOR_HOOK (pid); -#endif -} - -/* An inferior Unix process CHILD_PID has been created by a call to - fork() (or variants like vfork). It is presently stopped, and waiting - to be resumed. clone_and_follow_inferior will fork the debugger, - and that clone will "follow" (attach to) CHILD_PID. The original copy - of the debugger will not touch CHILD_PID again. - - Also, the original debugger will set FOLLOWED_CHILD FALSE, while the - clone will set it TRUE. - */ -void -clone_and_follow_inferior (child_pid, followed_child) - int child_pid; - int *followed_child; -{ - extern int auto_solib_add; - - int debugger_pid; - int status; - char pid_spelling[100]; /* Arbitrary but sufficient length. */ - - /* This semaphore is used to coordinate the two debuggers' handoff - of CHILD_PID. The original debugger will detach from CHILD_PID, - and then the clone debugger will attach to it. (It must be done - this way because on some targets, only one process at a time can - trace another. Thus, the original debugger must relinquish its - tracing rights before the clone can pick them up.) - */ -#define SEM_TALK (1) -#define SEM_LISTEN (0) - int handoff_semaphore[2]; /* Original "talks" to [1], clone "listens" to [0] */ - int talk_value = 99; - int listen_value; - - /* Set debug_fork then attach to the child while it sleeps, to debug. */ - static int debug_fork = 0; - - /* It is generally good practice to flush any possible pending stdio - output prior to doing a fork, to avoid the possibility of both the - parent and child flushing the same data after the fork. */ - - gdb_flush (gdb_stdout); - gdb_flush (gdb_stderr); - - /* Open the semaphore pipes. - */ - status = pipe (handoff_semaphore); - if (status < 0) - error ("error getting pipe for handoff semaphore"); - - /* Clone the debugger. */ -#if defined(USG) && !defined(HAVE_VFORK) - debugger_pid = fork (); -#else - if (debug_fork) - debugger_pid = fork (); - else - debugger_pid = vfork (); -#endif - - if (debugger_pid < 0) - perror_with_name ("fork"); - - /* Are we the original debugger? If so, we must relinquish all claims - to CHILD_PID. */ - if (debugger_pid != 0) - { - char signal_spelling[100];/* Arbitrary but sufficient length */ - - /* Detach from CHILD_PID. Deliver a "stop" signal when we do, though, - so that it remains stopped until the clone debugger can attach - to it. - */ - detach_breakpoints (child_pid); - - sprintf (signal_spelling, "%d", target_signal_to_host (TARGET_SIGNAL_STOP)); - target_require_detach (child_pid, signal_spelling, 1); - - /* Notify the clone debugger that it should attach to CHILD_PID. */ - write (handoff_semaphore[SEM_TALK], &talk_value, sizeof (talk_value)); - - *followed_child = 0; - } - - /* We're the child. */ - else - { - if (debug_fork) - sleep (debug_fork); - - /* The child (i.e., the cloned debugger) must now attach to - CHILD_PID. inferior_pid is presently set to the parent process - of the fork, while CHILD_PID should be the child process of the - fork. - - Wait until the original debugger relinquishes control of CHILD_PID, - though. - */ - read (handoff_semaphore[SEM_LISTEN], &listen_value, sizeof (listen_value)); - - /* Note that we DON'T want to actually detach from inferior_pid, - because that would allow it to run free. The original - debugger wants to retain control of the process. So, we - just reset inferior_pid to CHILD_PID, and then ensure that all - breakpoints are really set in CHILD_PID. - */ - target_mourn_inferior (); - - /* Ask the tty subsystem to switch to the one we specified earlier - (or to share the current terminal, if none was specified). */ - - new_tty (); - - dont_repeat (); - sprintf (pid_spelling, "%d", child_pid); - target_require_attach (pid_spelling, 1); - - /* Perform any necessary cleanup, after attachment. (This form - of attaching can behave differently on some targets than the - standard method, where a process formerly not under debugger - control was suddenly attached to..) - */ - target_post_follow_inferior_by_clone (); - - *followed_child = 1; - } - - /* Discard the handoff sempahore. */ - (void) close (handoff_semaphore[SEM_LISTEN]); - (void) close (handoff_semaphore[SEM_TALK]); -} - -/* Accept NTRAPS traps from the inferior. */ - -void -startup_inferior (ntraps) - int ntraps; -{ - int pending_execs = ntraps; - int terminal_initted; - - /* The process was started by the fork that created it, - but it will have stopped one instruction after execing the shell. - Here we must get it up to actual execution of the real program. */ - - clear_proceed_status (); - - init_wait_for_inferior (); - - terminal_initted = 0; - - if (STARTUP_WITH_SHELL) - inferior_ignoring_startup_exec_events = ntraps; - else - inferior_ignoring_startup_exec_events = 0; - inferior_ignoring_leading_exec_events = - target_reported_exec_events_per_exec_call () - 1; - -#ifdef STARTUP_INFERIOR - STARTUP_INFERIOR (pending_execs); -#else - while (1) - { - stop_soon_quietly = 1; /* Make wait_for_inferior be quiet */ - wait_for_inferior (); - if (stop_signal != TARGET_SIGNAL_TRAP) - { - /* Let shell child handle its own signals in its own way */ - /* FIXME, what if child has exit()ed? Must exit loop somehow */ - resume (0, stop_signal); - } - else - { - /* We handle SIGTRAP, however; it means child did an exec. */ - if (!terminal_initted) - { - /* Now that the child has exec'd we know it has already set its - process group. On POSIX systems, tcsetpgrp will fail with - EPERM if we try it before the child's setpgid. */ - - /* Set up the "saved terminal modes" of the inferior - based on what modes we are starting it with. */ - target_terminal_init (); - - /* Install inferior's terminal modes. */ - target_terminal_inferior (); - - terminal_initted = 1; - } - - pending_execs = pending_execs - 1; - if (0 == pending_execs) - break; - - resume (0, TARGET_SIGNAL_0); /* Just make it go on */ - } - } -#endif /* STARTUP_INFERIOR */ - stop_soon_quietly = 0; -} |