/* Fork a Unix child process, and set up to debug it, for GDB.
- Copyright 1990, 1991, 1992, 1993, 1994, 1996 Free Software Foundation, Inc.
+ Copyright 1990, 91, 92, 93, 94, 1996, 1999 Free Software Foundation, Inc.
Contributed by Cygnus Support.
-This file is part of GDB.
+ 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 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.
+ 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. */
+ 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 "frame.h" /* required by inferior.h */
#include "inferior.h"
#include "target.h"
-#include "wait.h"
+#include "gdb_wait.h"
#include "gdbcore.h"
#include "terminal.h"
#include "gdbthread.h"
+#include "command.h" /* for dont_repeat () */
#include <signal.h>
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-
-extern char **environ;
+/* 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 (char *scratch, char **argv)
+{
+ char *cp = scratch;
+
+ 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.
void
fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun,
- shell_file)
+ pre_trace_fun, shell_file)
char *exec_file;
char *allargs;
char **env;
- void (*traceme_fun) PARAMS ((void));
- int (*init_trace_fun) PARAMS ((int));
+ void (*traceme_fun) (void);
+ void (*init_trace_fun) (int);
+ void (*pre_trace_fun) (void);
char *shell_file;
{
int pid;
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;
/* 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);
-
- /* The user might want tilde-expansion, and in general probably wants
- the program to behave the same way as if run from
- his/her favorite shell. So we let the shell run it for us.
- FIXME-maybe, we might want a "set shell" command so the user can change
- the shell from within GDB (if so, change callers which pass in a non-NULL
- shell_file too). */
- if (shell_file == NULL)
- shell_file = getenv ("SHELL");
- if (shell_file == NULL)
- shell_file = default_shell_file;
+ 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;
+ }
/* 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;
+ 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 (len);
shell_command[0] = '\0';
#endif
- strcat (shell_command, "exec ");
-
- /* Now add exec_file, quoting as necessary. */
- {
- char *p;
- int need_to_quote;
-
- /* 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 '$':
- case '&':
- case ';':
- case '<':
- case '>':
- case ' ':
- case '\n':
- case '\t':
- need_to_quote = 1;
- goto end_scan;
-
- case '\0':
- need_to_quote = 0;
- goto end_scan;
-
- default:
- break;
- }
- ++p;
- }
- end_scan:
- if (need_to_quote)
- {
- strcat (shell_command, "'");
- for (p = exec_file; *p != '\0'; ++p)
- {
- if (*p == '\'')
- strcat (shell_command, "'\\''");
- else
- strncat (shell_command, p, 1);
- }
- strcat (shell_command, "'");
- }
- else
- strcat (shell_command, exec_file);
- }
-
- strcat (shell_command, " ");
- strcat (shell_command, allargs);
+
+ if (!shell)
+ {
+ /* We're going to call execvp. Create argv */
+ /* Largest case: every other character is a separate arg */
+ argv = (char **) xmalloc (((strlen (allargs) + 1) / (unsigned) 2 + 2) * sizeof (*argv));
+ argv[0] = exec_file;
+ breakup_args (allargs, &argv[1]);
+
+ }
+ else
+ {
+
+ /* We're going to call a shell */
+
+ /* Now add exec_file, quoting as necessary. */
+
+ char *p;
+ int need_to_quote;
+
+ strcat (shell_command, "exec ");
+
+ /* Quoting in this style is said to work with all shells. But csh
+ on IRIX 4.0.1 can't deal with it. So we only quote it if we need
+ to. */
+ p = exec_file;
+ while (1)
+ {
+ switch (*p)
+ {
+ case '\'':
+ case '"':
+ case '(':
+ case ')':
+ case '$':
+ 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
+ replace the value of environ and if we're vforked, we have to
restore it. */
save_our_env = environ;
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 (pid == 0)
{
- if (debug_fork)
+ 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");
+ 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). */
+ (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. */
+ 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. */
+ 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;
- execlp (shell_file, shell_file, "-c", shell_command, (char *)0);
- fprintf_unfiltered (gdb_stderr, "Cannot exec %s: %s.\n", shell_file,
- safe_strerror (errno));
- gdb_flush (gdb_stderr);
- _exit (0177);
+ /* 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)
+ {
+ execlp (shell_file, shell_file, "-c", shell_command, (char *) 0);
+
+ /* 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;
+
+ 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();
+ 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. */
- /* Note that pid may be modified by this function. */
- inferior_pid = pid = (*init_trace_fun)(pid);
+ (*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
#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 (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;
+startup_inferior (int ntraps)
{
int pending_execs = ntraps;
int terminal_initted;
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
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. */
+ 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. */
+ based on what modes we are starting it with. */
target_terminal_init ();
/* Install inferior's terminal modes. */
terminal_initted = 1;
}
- if (0 == --pending_execs)
+
+ pending_execs = pending_execs - 1;
+ if (0 == pending_execs)
break;
- resume (0, TARGET_SIGNAL_0); /* Just make it go on */
+
+ resume (0, TARGET_SIGNAL_0); /* Just make it go on */
}
}
#endif /* STARTUP_INFERIOR */
projects / thirdparty / binutils-gdb.git / blobdiff