/* Fork a Unix child process, and set up to debug it, for GDB.
- Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000,
- 2001, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 1990-2017 Free Software Foundation, Inc.
Contributed by Cygnus Support.
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. */
#define SHELL_FILE "/bin/sh"
static char *exec_wrapper;
-/* 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". */
+/* Build the argument vector for execv(3). */
-static void
-breakup_args (char *scratch, char **argv)
+class execv_argv
{
- char *cp = scratch;
+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)
+{
+
+ /* 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;
- for (;;)
+ m_argv.push_back (exec_file);
+
+ for (size_t cur_pos = 0; cur_pos < args_copy.size ();)
{
- /* 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';
+ /* 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);
+
+ if (next_sep == std::string::npos)
+ {
+ /* No separator found, which means this is the last
+ argument. */
+ next_sep = args_copy.size ();
+ }
+ else
+ {
+ /* Replace the separator with a terminator. */
+ args_copy[next_sep++] = '\0';
+ }
+
+ m_argv.push_back (&args_copy[cur_pos]);
+
+ cur_pos = next_sep;
}
- /* Null-terminate the vector. */
- *argv = NULL;
+ /* NULL-terminate the vector. */
+ m_argv.push_back (NULL);
}
-/* When executing a command under the given shell, return non-zero if
- the '!' character should be escaped when embedded in a quoted
+/* 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 int
+static bool
escape_bang_in_quoted_argument (const char *shell_file)
{
- const int shell_file_len = strlen (shell_file);
+ size_t shell_file_len = strlen (shell_file);
/* 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;
+ 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 1;
+ 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 += ' ';
+ }
+
+ /* 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. */
+
+void
+trace_start_error (const char *fmt, ...)
+{
+ va_list ap;
+
+ 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. */
- return 0;
+void
+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 (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)
+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;
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. */
- exec_file = exec_file_arg;
- if (exec_file == 0)
+ 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,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)
+ /* '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)
{
+ 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 (exec_wrapper)
- len += strlen (exec_wrapper) + 1;
-
- shell_command = (char *) alloca (len);
- shell_command[0] = '\0';
-
- if (!shell)
- {
- /* 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. */
-
- char *p;
- int need_to_quote;
- const int escape_bang = escape_bang_in_quoted_argument (shell_file);
-
- strcat (shell_command, "exec ");
-
- /* Add any exec wrapper. That may be a program name with arguments, so
- the user must handle quoting. */
- if (exec_wrapper)
- {
- strcat (shell_command, exec_wrapper);
- strcat (shell_command, " ");
- }
+ shell_file = 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. */
- 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 = 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 if (*p == '!' && escape_bang)
- 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);
- }
-
- /* On some systems an exec will 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
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);
+ 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
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);
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
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
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
clobbers the parent, but environ is restored a few lines down
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>". */
- 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");
-#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);
- }
+ 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;
- add_inferior (pid);
+ if (!have_inferiors ())
+ init_thread_list ();
+
+ inf = current_inferior ();
+
+ inferior_appeared (inf, 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
{
int pending_execs = ntraps;
int terminal_initted = 0;
+ ptid_t resume_ptid;
+
+ if (startup_with_shell)
+ {
+ /* One trap extra for exec'ing the shell. */
+ pending_execs++;
+ }
+
+ if (target_supports_multi_process ())
+ resume_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
+ else
+ resume_ptid = minus_one_ptid;
/* The process was started by the fork that created it, but it will
have stopped one instruction after execing the shell. Here we
while (1)
{
- int resume_signal = TARGET_SIGNAL_0;
- ptid_t resume_ptid;
+ enum gdb_signal resume_signal = GDB_SIGNAL_0;
ptid_t event_ptid;
struct target_waitstatus ws;
memset (&ws, 0, sizeof (ws));
- event_ptid = target_wait (pid_to_ptid (-1), &ws);
+ event_ptid = target_wait (resume_ptid, &ws, 0);
if (ws.kind == TARGET_WAITKIND_IGNORE)
/* The inferior didn't really stop, keep waiting. */
case TARGET_WAITKIND_SIGNALLED:
target_terminal_ours ();
- target_mourn_inferior ();
+ target_mourn_inferior (event_ptid);
error (_("During startup program terminated with signal %s, %s."),
- target_signal_to_name (ws.value.sig),
- target_signal_to_string (ws.value.sig));
+ 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 ();
+ target_mourn_inferior (event_ptid);
if (ws.value.integer)
error (_("During startup program exited with code %d."),
ws.value.integer);
case TARGET_WAITKIND_EXECD:
/* Handle EXEC signals as if they were SIGTRAP signals. */
xfree (ws.value.execd_pathname);
- resume_signal = TARGET_SIGNAL_TRAP;
+ resume_signal = GDB_SIGNAL_TRAP;
switch_to_thread (event_ptid);
break;
break;
}
- /* In all-stop mode, resume all threads. */
- if (!non_stop)
- resume_ptid = pid_to_ptid (-1);
- else
- resume_ptid = event_ptid;
-
- if (resume_signal != TARGET_SIGNAL_TRAP)
+ if (resume_signal != GDB_SIGNAL_TRAP)
{
/* Let shell child handle its own signals in its own way. */
- target_resume (resume_ptid, 0, resume_signal);
+ target_continue (resume_ptid, resume_signal);
}
else
{
break;
/* Just make it go on. */
- target_resume (resume_ptid, 0, TARGET_SIGNAL_0);
+ target_continue_no_signal (resume_ptid);
}
}
/* Mark all threads non-executing. */
- set_executing (pid_to_ptid (-1), 0);
-
- stop_pc = read_pc ();
+ set_executing (resume_ptid, 0);
}
/* Implement the "unset exec-wrapper" command. */
exec_wrapper = NULL;
}
+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);
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes. */
+extern initialize_file_ftype _initialize_fork_child;
+
void
_initialize_fork_child (void)
{
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