/* Fork a Unix child process, and set up to debug it, for GDB.
- Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
- 2001 Free Software Foundation, Inc.
+
+ Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
+ 2001, 2004, 2005, 2006, 2007 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
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
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. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "gdb_string.h"
#include "terminal.h"
#include "gdbthread.h"
#include "command.h" /* for dont_repeat () */
+#include "solib.h"
#include <signal.h>
-/* This just gets used as a default if we can't find SHELL */
+/* 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".
- */
+/* Break up SCRATCH into an argument vector suitable for passing to
+ execvp and store it in ARGV. 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)
{
for (;;)
{
-
/* Scan past leading separators */
while (*cp == ' ' || *cp == '\t' || *cp == '\n')
- {
- cp++;
- }
+ cp++;
- /* Break if at end of string */
+ /* Break if at end of string. */
if (*cp == '\0')
break;
- /* Take an arg */
+ /* Take an arg. */
*argv++ = cp;
- /* Scan for next arg separator */
+ /* 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 */
+ /* No separators => end of string => break. */
if (cp == NULL)
break;
- /* Replace the separator with a terminator */
+ /* Replace the separator with a terminator. */
*cp++ = '\0';
}
- /* execv requires a null-terminated arg vector */
+ /* Null-terminate the vector. */
*argv = NULL;
-
}
+/* When executing a command under the given shell, return non-zero if
+ the '!' character should be escaped when embedded in a quoted
+ command-line argument. */
-/* Start an inferior Unix child process and sets inferior_ptid 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(). */
+static int
+escape_bang_in_quoted_argument (const char *shell_file)
+{
+ const int shell_file_len = strlen (shell_file);
-/* This function is NOT-REENTRANT. Some of the variables have been
- made static to ensure that they survive the vfork() call. */
+ /* Bang should be escaped only in C Shells. For now, simply check
+ that the shell name ends with 'csh', which covers at least csh
+ and tcsh. This should be good enough for now. */
+
+ if (shell_file_len < 3)
+ return 0;
+
+ if (shell_file[shell_file_len - 3] == 'c'
+ && shell_file[shell_file_len - 2] == 's'
+ && shell_file[shell_file_len - 1] == 'h')
+ return 1;
+
+ return 0;
+}
+
+/* Start an inferior Unix child process and sets inferior_ptid 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. */
+
+/* This function is NOT reentrant. Some of the variables have been
+ made static to ensure that they survive the vfork call. */
void
fork_inferior (char *exec_file_arg, char *allargs, char **env,
char **save_our_env;
int shell = 0;
static char **argv;
+ const char *inferior_io_terminal = get_inferior_io_terminal ();
- /* 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 no exec file handed to us, get it from the exec-file command
+ -- with a good, common error message if none is specified. */
exec_file = exec_file_arg;
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.
- */
+ /* STARTUP_WITH_SHELL is defined in inferior.h. If 0,e we'll just
+ do a fork/exec, no shell, so don't bother figuring out what
+ shell. */
shell_file = shell_file_arg;
if (STARTUP_WITH_SHELL)
{
- /* Figure out what shell to start up the user program under. */
+ /* Figure out what shell to start up the user program under. */
if (shell_file == NULL)
shell_file = getenv ("SHELL");
if (shell_file == NULL)
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 '. */
+ /* 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. */
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));
+ /* We're going to call execvp. Create argument vector.
+ Calculate an upper bound on the length of the vector by
+ assuming that every other character is a separate
+ argument. */
+ int argc = (strlen (allargs) + 1) / 2 + 2;
+ argv = (char **) xmalloc (argc * sizeof (*argv));
argv[0] = exec_file;
breakup_args (allargs, &argv[1]);
-
}
else
{
-
- /* We're going to call a shell */
+ /* We're going to call a shell. */
/* Now add exec_file, quoting as necessary. */
char *p;
int need_to_quote;
+ const int escape_bang = escape_bang_in_quoted_argument (shell_file);
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. */
+ /* 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)
{
{
if (*p == '\'')
strcat (shell_command, "'\\''");
- else if (*p == '!')
+ else if (*p == '!' && escape_bang)
strcat (shell_command, "\\!");
else
strncat (shell_command, p, 1);
strcat (shell_command, " ");
strcat (shell_command, allargs);
-
}
- /* exec is said to fail if the executable is open. */
+ /* On some systems an exec will 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;
/* 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. */
-
+ 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 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) ();
- /* Create the child process. Note that the apparent call to vfork()
- below *might* actually be a call to fork() due to the fact that
- autoconf will ``#define vfork fork'' on certain platforms. */
- if (debug_fork)
+ /* Create the child process. Since the child process is going to
+ exec(3) shortly afterwards, try to reduce the overhead by
+ calling vfork(2). However, if PRE_TRACE_FUN is non-null, it's
+ likely that this optimization won't work since there's too much
+ work to do between the vfork(2) and the exec(3). This is known
+ to be the case on ttrace(2)-based HP-UX, where some handshaking
+ between parent and child needs to happen between fork(2) and
+ exec(2). However, since the parent is suspended in the vforked
+ state, this doesn't work. Also note that the vfork(2) call might
+ actually be a call to fork(2) due to the fact that autoconf will
+ ``#define vfork fork'' on certain platforms. */
+ if (pre_trace_fun || debug_fork)
pid = fork ();
else
pid = vfork ();
if (pid < 0)
- perror_with_name ("vfork");
+ perror_with_name (("vfork"));
if (pid == 0)
{
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). */
-
+ /* 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
/* "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!
- */
+ 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
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 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>". */
if (shell)
{
execlp (shell_file, shell_file, "-c", shell_command, (char *) 0);
- /* If we get here, it's an error */
+ /* 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);
}
else
{
- /* Otherwise, we directly exec the target program with execvp. */
+ /* 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 */
+ /* If we get here, it's an error. */
errstring = safe_strerror (errno);
fprintf_unfiltered (gdb_stderr, "Cannot exec %s ", exec_file);
i++;
}
fprintf_unfiltered (gdb_stderr, ".\n");
- /* This extra info seems to be useless
- fprintf_unfiltered (gdb_stderr, "Got error %s.\n", errstring);
- */
+#if 0
+ /* This extra info seems to be useless. */
+ fprintf_unfiltered (gdb_stderr, "Got error %s.\n", errstring);
+#endif
gdb_flush (gdb_stderr);
_exit (0177);
}
init_thread_list ();
- inferior_ptid = pid_to_ptid (pid); /* Needed for wait_for_inferior stuff below */
+ /* Needed for wait_for_inferior stuff below. */
+ inferior_ptid = pid_to_ptid (pid);
/* Now that we have a child process, make it our target, and
- initialize anything target-vector-specific that needs initializing. */
-
+ 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 dependent 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
}
/* Accept NTRAPS traps from the inferior. */
startup_inferior (int ntraps)
{
int pending_execs = ntraps;
- int terminal_initted;
+ int terminal_initted = 0;
- /* 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. */
+ /* 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 */
+ /* Make wait_for_inferior be quiet. */
+ stop_soon = STOP_QUIETLY;
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 */
+ /* Let shell child handle its own signals in its own way.
+ FIXME: what if child has exited? 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. */
+ /* 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. */
terminal_initted = 1;
}
- pending_execs = pending_execs - 1;
- if (0 == pending_execs)
+ if (--pending_execs == 0)
break;
- resume (0, TARGET_SIGNAL_0); /* Just make it go on */
+ resume (0, TARGET_SIGNAL_0); /* Just make it go on. */
}
}
-#endif /* STARTUP_INFERIOR */
- stop_soon_quietly = 0;
+ stop_soon = NO_STOP_QUIETLY;
}