/* 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) 1990-2017 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 "frame.h" /* required by inferior.h */
#include "inferior.h"
+#include "terminal.h"
#include "target.h"
#include "gdb_wait.h"
#include "gdb_vfork.h"
#include "gdbcore.h"
-#include "terminal.h"
#include "gdbthread.h"
#include "command.h" /* for dont_repeat () */
-
+#include "gdbcmd.h"
+#include "solib.h"
+#include "filestuff.h"
+#include "top.h"
+#include "signals-state-save-restore.h"
#include <signal.h>
+#include <vector>
-/* This just gets used as a default if we can't find SHELL */
-#ifndef SHELL_FILE
+/* This just gets used as a default if we can't find SHELL. */
#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)
+static char *exec_wrapper;
+
+/* Build the argument vector for execv(3). */
+
+class execv_argv
+{
+public:
+ /* EXEC_FILE is the file to run. ALLARGS is a string containing the
+ arguments to the program. If starting with a shell, SHELL_FILE
+ is the shell to run. Otherwise, SHELL_FILE is NULL. */
+ execv_argv (const char *exec_file, const std::string &allargs,
+ const char *shell_file);
+
+ /* Return a pointer to the built argv, in the type expected by
+ execv. The result is (only) valid for as long as this execv_argv
+ object is live. We return a "char **" because that's the type
+ that the execv functions expect. Note that it is guaranteed that
+ the execv functions do not modify the argv[] array nor the
+ strings to which the array point. */
+ char **argv ()
+ {
+ return const_cast<char **> (&m_argv[0]);
+ }
+
+private:
+ /* Disable copying. */
+ execv_argv (const execv_argv &) = delete;
+ void operator= (const execv_argv &) = delete;
+
+ /* Helper methods for constructing the argument vector. */
+
+ /* Used when building an argv for a straight execv call, without
+ going via the shell. */
+ void init_for_no_shell (const char *exec_file,
+ const std::string &allargs);
+
+ /* Used when building an argv for execing a shell that execs the
+ child program. */
+ void init_for_shell (const char *exec_file,
+ const std::string &allargs,
+ const char *shell_file);
+
+ /* The argument vector built. Holds non-owning pointers. Elements
+ either point to the strings passed to the execv_argv ctor, or
+ inside M_STORAGE. */
+ std::vector<const char *> m_argv;
+
+ /* Storage. In the no-shell case, this contains a copy of the
+ arguments passed to the ctor, split by '\0'. In the shell case,
+ this contains the quoted shell command. I.e., SHELL_COMMAND in
+ {"$SHELL" "-c", SHELL_COMMAND, NULL}. */
+ std::string m_storage;
+};
+
+/* Create argument vector for straight call to execvp. Breaks up
+ ALLARGS into an argument vector suitable for passing to execvp and
+ stores it in M_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
+ M_ARGV with the four arguments "a", "b", "c", "d". Each argument
+ in M_ARGV points to a substring of a copy of ALLARGS stored in
+ M_STORAGE. */
+
+void
+execv_argv::init_for_no_shell (const char *exec_file,
+ const std::string &allargs)
{
- char *cp = scratch;
- for (;;)
+ /* Save/work with a copy stored in our storage. The pointers pushed
+ to M_ARGV point directly into M_STORAGE, which is modified in
+ place with the necessary NULL terminators. This avoids N heap
+ allocations and string dups when 1 is sufficient. */
+ std::string &args_copy = m_storage = allargs;
+
+ m_argv.push_back (exec_file);
+
+ for (size_t cur_pos = 0; cur_pos < args_copy.size ();)
{
+ /* Skip whitespace-like chars. */
+ std::size_t pos = args_copy.find_first_not_of (" \t\n", cur_pos);
+
+ if (pos != std::string::npos)
+ cur_pos = pos;
+
+ /* Find the position of the next separator. */
+ std::size_t next_sep = args_copy.find_first_of (" \t\n", cur_pos);
- /* Scan past leading separators */
- while (*cp == ' ' || *cp == '\t' || *cp == '\n')
+ if (next_sep == std::string::npos)
+ {
+ /* No separator found, which means this is the last
+ argument. */
+ next_sep = args_copy.size ();
+ }
+ else
{
- cp++;
+ /* Replace the separator with a terminator. */
+ args_copy[next_sep++] = '\0';
}
- /* Break if at end of string */
- if (*cp == '\0')
- break;
+ m_argv.push_back (&args_copy[cur_pos]);
- /* Take an arg */
- *argv++ = cp;
+ cur_pos = next_sep;
+ }
+
+ /* NULL-terminate the vector. */
+ m_argv.push_back (NULL);
+}
- /* Scan for next arg separator */
- cp = strchr (cp, ' ');
- if (cp == NULL)
- cp = strchr (cp, '\t');
- if (cp == NULL)
- cp = strchr (cp, '\n');
+/* When executing a command under the given shell, return true if the
+ '!' character should be escaped when embedded in a quoted
+ command-line argument. */
+
+static bool
+escape_bang_in_quoted_argument (const char *shell_file)
+{
+ size_t shell_file_len = strlen (shell_file);
- /* No separators => end of string => break */
- if (cp == NULL)
- break;
+ /* 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. */
- /* Replace the separator with a terminator */
- *cp++ = '\0';
+ if (shell_file_len < 3)
+ return false;
+
+ if (shell_file[shell_file_len - 3] == 'c'
+ && shell_file[shell_file_len - 2] == 's'
+ && shell_file[shell_file_len - 1] == 'h')
+ return true;
+
+ return false;
+}
+
+/* See declaration. */
+
+execv_argv::execv_argv (const char *exec_file,
+ const std::string &allargs,
+ const char *shell_file)
+{
+ if (shell_file == NULL)
+ init_for_no_shell (exec_file, allargs);
+ else
+ init_for_shell (exec_file, allargs, shell_file);
+}
+
+/* See declaration. */
+
+void
+execv_argv::init_for_shell (const char *exec_file,
+ const std::string &allargs,
+ const char *shell_file)
+{
+ /* We're going to call a shell. */
+ bool escape_bang = escape_bang_in_quoted_argument (shell_file);
+
+ /* We need to build a new shell command string, and make argv point
+ to it. So build it in the storage. */
+ std::string &shell_command = m_storage;
+
+ shell_command = "exec ";
+
+ /* Add any exec wrapper. That may be a program name with arguments,
+ so the user must handle quoting. */
+ if (exec_wrapper)
+ {
+ shell_command += exec_wrapper;
+ shell_command += ' ';
}
- /* execv requires a null-terminated arg vector */
- *argv = NULL;
+ /* Now add exec_file, quoting as necessary. */
+ /* 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. */
+ bool need_to_quote;
+ const char *p = exec_file;
+ while (1)
+ {
+ switch (*p)
+ {
+ case '\'':
+ case '!':
+ case '"':
+ case '(':
+ case ')':
+ case '$':
+ case '&':
+ case ';':
+ case '<':
+ case '>':
+ case ' ':
+ case '\n':
+ case '\t':
+ need_to_quote = true;
+ goto end_scan;
+
+ case '\0':
+ need_to_quote = false;
+ goto end_scan;
+
+ default:
+ break;
+ }
+ ++p;
+ }
+ end_scan:
+ if (need_to_quote)
+ {
+ shell_command += '\'';
+ for (p = exec_file; *p != '\0'; ++p)
+ {
+ if (*p == '\'')
+ shell_command += "'\\''";
+ else if (*p == '!' && escape_bang)
+ shell_command += "\\!";
+ else
+ shell_command += *p;
+ }
+ shell_command += '\'';
+ }
+ else
+ shell_command += exec_file;
+
+ shell_command += ' ' + allargs;
+
+ /* 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>". */
+ m_argv.reserve (4);
+ m_argv.push_back (shell_file);
+ m_argv.push_back ("-c");
+ m_argv.push_back (shell_command.c_str ());
+ m_argv.push_back (NULL);
}
+/* See inferior.h. */
-/* 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(). */
+void
+trace_start_error (const char *fmt, ...)
+{
+ va_list ap;
-/* This function is NOT-REENTRANT. Some of the variables have been
- made static to ensure that they survive the vfork() call. */
+ va_start (ap, fmt);
+ fprintf_unfiltered (gdb_stderr, "Could not trace the inferior "
+ "process.\nError: ");
+ vfprintf_unfiltered (gdb_stderr, fmt, ap);
+ va_end (ap);
+
+ gdb_flush (gdb_stderr);
+ _exit (0177);
+}
+
+/* See inferior.h. */
void
-fork_inferior (char *exec_file_arg, char *allargs, char **env,
- void (*traceme_fun) (void), void (*init_trace_fun) (int),
- void (*pre_trace_fun) (void), char *shell_file_arg)
+trace_start_error_with_name (const char *string)
+{
+ trace_start_error ("%s: %s", string, safe_strerror (errno));
+}
+
+/* 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. EXEC_FUN is the exec(2) function to use, or NULL for the default
+ one. */
+
+/* This function is NOT reentrant. Some of the variables have been
+ made static to ensure that they survive the vfork call. */
+
+int
+fork_inferior (const char *exec_file_arg, const std::string &allargs,
+ char **env, void (*traceme_fun) (void),
+ void (*init_trace_fun) (int), void (*pre_trace_fun) (void),
+ char *shell_file_arg,
+ void (*exec_fun)(const char *file, char * const *argv,
+ char * const *env))
{
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. */
+ /* 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;
static char *shell_file;
- static char *exec_file;
+ static const char *exec_file;
char **save_our_env;
- int shell = 0;
- static 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. */
- exec_file = exec_file_arg;
- if (exec_file == 0)
+ const char *inferior_io_terminal = get_inferior_io_terminal ();
+ struct inferior *inf;
+ int i;
+ int save_errno;
+ struct ui *save_ui;
+
+ /* 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_arg == NULL)
exec_file = get_exec_file (1);
+ else
+ exec_file = exec_file_arg;
- /* 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.
- */
- shell_file = shell_file_arg;
- if (STARTUP_WITH_SHELL)
+ /* 'startup_with_shell' is declared in inferior.h and bound to the
+ "set startup-with-shell" option. 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. */
+ shell_file = shell_file_arg;
+ /* 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;
- /* 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 */
- 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. */
+ shell_file = NULL;
- 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 ();
+ /* Build the argument vector. */
+ execv_argv child_argv (exec_file, allargs, shell_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;
+ /* Likewise the current UI. */
+ save_ui = current_ui;
+
/* 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...
- */
+ 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 (main_ui->m_gdb_stdout);
+ gdb_flush (main_ui->m_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) ();
- /* 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)
{
+ /* Switch to the main UI, so that gdb_std{in/out/err} in the
+ child are mapped to std{in/out/err}. This makes it possible
+ to use fprintf_unfiltered/warning/error/etc. in the child
+ from here on. */
+ current_ui = main_ui;
+
+ /* Close all file descriptors except those that gdb inherited
+ (usually 0/1/2), so they don't leak to the inferior. Note
+ that this closes the file descriptors of all secondary
+ UIs. */
+ close_most_fds ();
+
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). */
+ /* Create a new session for the inferior process, if necessary.
+ It will also place the inferior in a separate process group. */
+ if (create_tty_session () <= 0)
+ {
+ /* No session was created, but we still want to run the 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
initialize_signals for how we get the right signal handlers
for the inferior. */
- /* "Trace me, Dr. Memory!" */
+ /* "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! */
+
+ restore_original_signals_state ();
/* 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 (shell)
- {
- execlp (shell_file, shell_file, "-c", shell_command, (char *) 0);
+ char **argv = child_argv.argv ();
- /* 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);
- }
+ if (exec_fun != NULL)
+ (*exec_fun) (argv[0], &argv[0], env);
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);
- }
+ execvp (argv[0], &argv[0]);
+
+ /* If we get here, it's an error. */
+ save_errno = errno;
+ fprintf_unfiltered (gdb_stderr, "Cannot exec %s", argv[0]);
+ for (i = 1; argv[i] != NULL; i++)
+ fprintf_unfiltered (gdb_stderr, " %s", argv[i]);
+ fprintf_unfiltered (gdb_stderr, ".\n");
+ fprintf_unfiltered (gdb_stderr, "Error: %s\n",
+ safe_strerror (save_errno));
+ gdb_flush (gdb_stderr);
+ _exit (0177);
}
/* Restore our environment in case a vforked child clob'd it. */
environ = save_our_env;
- init_thread_list ();
+ /* Likewise the current UI. */
+ current_ui = save_ui;
- inferior_ptid = pid_to_ptid (pid); /* Needed for wait_for_inferior stuff below */
+ if (!have_inferiors ())
+ init_thread_list ();
- /* Now that we have a child process, make it our target, and
- initialize anything target-vector-specific that needs initializing. */
+ inf = current_inferior ();
+
+ inferior_appeared (inf, pid);
- (*init_trace_fun) (pid);
+ /* Needed for wait_for_inferior stuff below. */
+ inferior_ptid = pid_to_ptid (pid);
+
+ new_tty_postfork ();
+
+ /* We have something that executes now. We'll be running through
+ the shell at this point, but the pid shouldn't change. Targets
+ supporting MT should fill this task's ptid with more data as soon
+ as they can. */
+ add_thread_silent (inferior_ptid);
+
+ /* Now that we have a child process, make it our target, and
+ initialize anything target-vector-specific that needs
+ initializing. */
+ if (init_trace_fun)
+ (*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
+ return pid;
}
-/* 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.
+/* Accept NTRAPS traps from the inferior. */
- 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)
+startup_inferior (int ntraps)
{
- 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. 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)
- debugger_pid = fork ();
- else
- debugger_pid = vfork ();
-
- if (debugger_pid < 0)
- perror_with_name ("fork");
+ int pending_execs = ntraps;
+ int terminal_initted = 0;
+ ptid_t resume_ptid;
- /* Are we the original debugger? If so, we must relinquish all claims
- to CHILD_PID. */
- if (debugger_pid != 0)
+ if (startup_with_shell)
{
- 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;
+ /* One trap extra for exec'ing the shell. */
+ pending_execs++;
}
- /* We're the child. */
+ if (target_supports_multi_process ())
+ resume_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
else
- {
- if (debug_fork)
- sleep (debug_fork);
-
- /* The child (i.e., the cloned debugger) must now attach to
- CHILD_PID. inferior_ptid 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_ptid,
- because that would allow it to run free. The original
- debugger wants to retain control of the process. So, we
- just reset inferior_ptid 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 ();
+ resume_ptid = minus_one_ptid;
- dont_repeat ();
- sprintf (pid_spelling, "%d", child_pid);
- target_require_attach (pid_spelling, 1);
+ /* 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. */
- /* 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 ();
+ if (exec_wrapper)
+ pending_execs++;
- *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 (int ntraps)
-{
- int pending_execs = ntraps;
- int terminal_initted;
+ while (1)
+ {
+ enum gdb_signal resume_signal = GDB_SIGNAL_0;
+ ptid_t event_ptid;
- /* 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. */
+ struct target_waitstatus ws;
+ memset (&ws, 0, sizeof (ws));
+ event_ptid = target_wait (resume_ptid, &ws, 0);
- clear_proceed_status ();
+ if (ws.kind == TARGET_WAITKIND_IGNORE)
+ /* The inferior didn't really stop, keep waiting. */
+ continue;
- init_wait_for_inferior ();
+ switch (ws.kind)
+ {
+ case TARGET_WAITKIND_SPURIOUS:
+ case TARGET_WAITKIND_LOADED:
+ case TARGET_WAITKIND_FORKED:
+ case TARGET_WAITKIND_VFORKED:
+ case TARGET_WAITKIND_SYSCALL_ENTRY:
+ case TARGET_WAITKIND_SYSCALL_RETURN:
+ /* Ignore gracefully during startup of the inferior. */
+ switch_to_thread (event_ptid);
+ break;
- terminal_initted = 0;
+ case TARGET_WAITKIND_SIGNALLED:
+ target_terminal_ours ();
+ target_mourn_inferior (event_ptid);
+ error (_("During startup program terminated with signal %s, %s."),
+ gdb_signal_to_name (ws.value.sig),
+ gdb_signal_to_string (ws.value.sig));
+ return;
+
+ case TARGET_WAITKIND_EXITED:
+ target_terminal_ours ();
+ target_mourn_inferior (event_ptid);
+ if (ws.value.integer)
+ error (_("During startup program exited with code %d."),
+ ws.value.integer);
+ else
+ error (_("During startup program exited normally."));
+ return;
+
+ case TARGET_WAITKIND_EXECD:
+ /* Handle EXEC signals as if they were SIGTRAP signals. */
+ xfree (ws.value.execd_pathname);
+ resume_signal = GDB_SIGNAL_TRAP;
+ switch_to_thread (event_ptid);
+ break;
- 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;
+ case TARGET_WAITKIND_STOPPED:
+ resume_signal = ws.value.sig;
+ switch_to_thread (event_ptid);
+ break;
+ }
-#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)
+ if (resume_signal != GDB_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);
+ /* Let shell child handle its own signals in its own way. */
+ target_continue (resume_ptid, resume_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 */
+ /* Just make it go on. */
+ target_continue_no_signal (resume_ptid);
}
}
-#endif /* STARTUP_INFERIOR */
- stop_soon_quietly = 0;
-}
-/* Compute command-line string given argument vector. This does the
- same shell processing as fork_inferior. */
-/* ARGSUSED */
-char *
-construct_inferior_arguments (struct gdbarch *gdbarch, int argc, char **argv)
-{
- char *result;
+ /* Mark all threads non-executing. */
+ set_executing (resume_ptid, 0);
+}
- if (STARTUP_WITH_SHELL)
- {
- /* This holds all the characters considered special to the
- typical Unix shells. We include `^' because the SunOS
- /bin/sh treats it as a synonym for `|'. */
- char *special = "\"!#$&*()\\|[]{}<>?'\"`~^; \t\n";
- int i;
- int length = 0;
- char *out, *cp;
-
- /* We over-compute the size. It shouldn't matter. */
- for (i = 0; i < argc; ++i)
- length += 2 * strlen (argv[i]) + 1;
-
- result = (char *) xmalloc (length);
- out = result;
-
- for (i = 0; i < argc; ++i)
- {
- if (i > 0)
- *out++ = ' ';
+/* Implement the "unset exec-wrapper" command. */
- for (cp = argv[i]; *cp; ++cp)
- {
- if (strchr (special, *cp) != NULL)
- *out++ = '\\';
- *out++ = *cp;
- }
- }
- *out = '\0';
- }
- else
- {
- /* In this case we can't handle arguments that contain spaces,
- tabs, or newlines -- see breakup_args(). */
- int i;
- int length = 0;
+static void
+unset_exec_wrapper_command (char *args, int from_tty)
+{
+ xfree (exec_wrapper);
+ exec_wrapper = NULL;
+}
- for (i = 0; i < argc; ++i)
- {
- char *cp = strchr (argv[i], ' ');
- if (cp == NULL)
- cp = strchr (argv[i], '\t');
- if (cp == NULL)
- cp = strchr (argv[i], '\n');
- if (cp != NULL)
- error ("can't handle command-line argument containing whitespace");
- length += strlen (argv[i]) + 1;
- }
+static void
+show_startup_with_shell (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c, const char *value)
+{
+ fprintf_filtered (file,
+ _("Use of shell to start subprocesses is %s.\n"),
+ value);
+}
- result = (char *) xmalloc (length);
- result[0] = '\0';
- for (i = 0; i < argc; ++i)
- {
- if (i > 0)
- strcat (result, " ");
- strcat (result, argv[i]);
- }
- }
+/* Provide a prototype to silence -Wmissing-prototypes. */
+extern initialize_file_ftype _initialize_fork_child;
- return result;
+void
+_initialize_fork_child (void)
+{
+ add_setshow_filename_cmd ("exec-wrapper", class_run, &exec_wrapper, _("\
+Set a wrapper for running programs.\n\
+The wrapper prepares the system and environment for the new program."),
+ _("\
+Show the wrapper for running programs."), NULL,
+ NULL, NULL,
+ &setlist, &showlist);
+
+ add_cmd ("exec-wrapper", class_run, unset_exec_wrapper_command,
+ _("Disable use of an execution wrapper."),
+ &unsetlist);
+
+ add_setshow_boolean_cmd ("startup-with-shell", class_support,
+ &startup_with_shell, _("\
+Set use of shell to start subprocesses. The default is on."), _("\
+Show use of shell to start subprocesses."), NULL,
+ NULL,
+ show_startup_with_shell,
+ &setlist, &showlist);
}
projects / deliverable / binutils-gdb.git / blobdiff