/* Fork a Unix child process, and set up to debug it, for GDB.
- Copyright 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
+ Copyright 1990, 1991, 1992, 1993, 1994, 1996 Free Software Foundation, Inc.
Contributed by Cygnus Support.
This file is part of GDB.
#include "wait.h"
#include "gdbcore.h"
#include "terminal.h"
-#include "thread.h"
+#include "gdbthread.h"
#include <signal.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
-extern char **environ;
+#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.
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));
void (*init_trace_fun) PARAMS ((int));
+ void (*pre_trace_fun) PARAMS ((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;
+ 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);
- /* 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;
+ /* 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
shell_command = (char *) alloca (len);
shell_command[0] = '\0';
#endif
- strcat (shell_command, "exec ");
- /* Now add exec_file, quoting as necessary. */
- {
+ 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)
+ switch (*p)
{
case '\'':
case '"':
end_scan:
if (need_to_quote)
{
- strcat (shell_command, "'");
- for (p = exec_file; *p != '\0'; ++p)
+ strcat (shell_command, "'");
+ for (p = exec_file; *p != '\0'; ++p)
{
if (*p == '\'')
strcat (shell_command, "'\\''");
}
else
strcat (shell_command, exec_file);
- }
+
+ strcat (shell_command, " ");
+ strcat (shell_command, allargs);
- strcat (shell_command, " ");
- strcat (shell_command, allargs);
+ }
/* exec is said to fail if the executable is open. */
close_exec_file ();
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
/* "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
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) {
+#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. */
/* Now that we have a child process, make it our target, and
initialize anything target-vector-specific that needs initializing. */
- (*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
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
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
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 / deliverable / binutils-gdb.git / blobdiff