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Share fork_inferior et al with gdbserver

Browse source 
This is the most important (and the biggest, sorry) patch of the
series.  It moves fork_inferior from gdb/fork-child.c to
nat/fork-inferior.c and makes all the necessary adjustments to both
GDB and gdbserver to make sure everything works OK.

There is no "most important change" with this patch; all changes are
made in a progressive way, making sure that gdbserver had the
necessary features while not breaking GDB at the same time.

I decided to go ahead and implement a partial support for starting the
inferior with a shell on gdbserver, although the full feature comes in
the next patch.  The user won't have the option to disable the
startup-with-shell, and also won't be able to change which shell
gdbserver will use (other than setting the $SHELL environment
variable, that is).

Everything is working as expected, and no regressions were present
during the tests.

gdb/ChangeLog:
2017-06-07  Sergio Durigan Junior  <sergiodj@redhat.com>
	    Pedro Alves  <palves@redhat.com>

	* Makefile.in (HFILES_NO_SRCDIR): Add "common/common-inferior.h"
	and "nat/fork-inferior.h".
	* common/common-inferior.h: New file, with contents from
	"gdb/inferior.h".
	* commom/common-utils.c: Include "common-utils.h".
	(stringify_argv): New function.
	* common/common-utils.h (stringify_argv): New prototype.
	* configure.nat: Add "fork-inferior.o" as a dependency for
	"*linux*", "fbsd*" and "nbsd*" hosts.
	* corefile.c (get_exec_file): Update comment.
	* darwin-nat.c (darwin_ptrace_him): Call "gdb_startup_inferior"
	instead of "startup_inferior".
	(darwin_create_inferior): Call "add_thread_silent" after
	"fork_inferior".
	* fork-child.c: Cleanup unnecessary includes.
	(SHELL_FILE): Move to "common/common-fork-child.c".
	(environ): Likewise.
	(exec_wrapper): Initialize.
	(get_exec_wrapper): New function.
	(breakup_args): Move to "common/common-fork-child.c"; rename to
	"breakup_args_for_exec".
	(escape_bang_in_quoted_argument): Move to
	"common/common-fork-child.c".
	(saved_ui): New variable.
	(prefork_hook): New function.
	(postfork_hook): Likewise.
	(postfork_child_hook): Likewise.
	(gdb_startup_inferior): Likewise.
	(fork_inferior): Move to "common/common-fork-child.c".  Update
	function to support gdbserver.
	(startup_inferior): Likewise.
	* gdbcore.h (get_exec_file): Remove declaration.
	* gnu-nat.c (gnu_create_inferior): Call "gdb_startup_inferior"
	instead of "startup_inferior".  Call "add_thread_silent" after
	"fork_inferior".
	* inf-ptrace.c: Include "nat/fork-inferior.h" and "utils.h".
	(inf_ptrace_create_inferior): Call "gdb_startup_inferior"
	instead of "startup_inferior".  Call "add_thread_silent" after
	"fork_inferior".
	* inferior.h: Include "common-inferior.h".
	(trace_start_error): Move to "common/common-utils.h".
	(trace_start_error_with_name): Likewise.
	(fork_inferior): Move prototype to "nat/fork-inferior.h".
	(startup_inferior): Likewise.
	(gdb_startup_inferior): New prototype.
	* nat/fork-inferior.c: New file, with contents from "fork-child.c".
	* nat/fork-inferior.h: New file.
	* procfs.c (procfs_init_inferior): Call "gdb_startup_inferior"
	instead of "startup_inferior".  Call "add_thread_silent" after
	"fork_inferior".
	* target.h (target_terminal_init): Move prototype to
	"target/target.h".
	(target_terminal_inferior): Likewise.
	(target_terminal_ours): Likewise.
	* target/target.h (target_terminal_init): New prototype, moved
	from "target.h".
	(target_terminal_inferior): Likewise.
	(target_terminal_ours): Likewise.
	* utils.c (gdb_flush_out_err): New function.

gdb/gdbserver/ChangeLog:
2017-06-07  Sergio Durigan Junior  <sergiodj@redhat.com>
	    Pedro Alves  <palves@redhat.com>

	* Makefile.in (SFILES): Add "nat/fork-inferior.o".
	* configure: Regenerate.
	* configure.srv (srv_linux_obj): Add "fork-child.o" and
	"fork-inferior.o".
	(i[34567]86-*-lynxos*): Likewise.
	(spu*-*-*): Likewise.
	* fork-child.c: New file.
	* linux-low.c: Include "common-inferior.h", "nat/fork-inferior.h"
	and "environ.h".
	(linux_ptrace_fun): New function.
	(linux_create_inferior): Adjust function prototype to reflect
	change on "target.h".  Adjust function code to use
	"fork_inferior".
	(linux_request_interrupt): Delete "signal_pid".
	* lynx-low.c: Include "common-inferior.h" and "nat/fork-inferior.h".
	(lynx_ptrace_fun): New function.
	(lynx_create_inferior): Adjust function prototype to reflect
	change on "target.h".  Adjust function code to use
	"fork_inferior".
	* nto-low.c (nto_create_inferior): Adjust function prototype and
	code to reflect change on "target.h".  Update comments.
	* server.c: Include "common-inferior.h", "nat/fork-inferior.h",
	"common-terminal.h" and "environ.h".
	(terminal_fd): Moved to fork-child.c.
	(old_foreground_pgrp): Likewise.
	(restore_old_foreground_pgrp): Likewise.
	(last_status): Make it global.
	(last_ptid): Likewise.
	(our_environ): New variable.
	(startup_with_shell): Likewise.
	(program_name): Likewise.
	(program_argv): Rename to...
	(program_args): ...this.
	(wrapper_argv): New variable.
	(start_inferior): Delete function.
	(get_exec_wrapper): New function.
	(get_exec_file): Likewise.
	(get_environ): Likewise.
	(prefork_hook): Likewise.
	(post_fork_inferior): Likewise.
	(postfork_hook): Likewise.
	(postfork_child_hook): Likewise.
	(handle_v_run): Update code to deal with arguments coming from the
	remote host.  Update calls from "start_inferior" to
	"create_inferior".
	(captured_main): Likewise.  Initialize environment variable.  Call
	"have_job_control".
	* server.h (post_fork_inferior): New prototype.
	(get_environ): Likewise.
	(last_status): Declare.
	(last_ptid): Likewise.
	(signal_pid): Likewise.
	* spu-low.c: Include "common-inferior.h" and "nat/fork-inferior.h".
	(spu_ptrace_fun): New function.
	(spu_create_inferior): Adjust function prototype to reflect change
	on "target.h".  Adjust function code to use "fork_inferior".
	* target.c (target_terminal_init): New function.
	(target_terminal_inferior): Likewise.
	(target_terminal_ours): Likewise.
	* target.h: Include <vector>.
	(struct target_ops) <create_inferior>: Update prototype.
	(create_inferior): Update macro.
	* utils.c (gdb_flush_out_err): New function.
	* win32-low.c (win32_create_inferior): Adjust function prototype
	and code to reflect change on "target.h".

gdb/testsuite/ChangeLog:
2017-06-07  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.server/non-existing-program.exp: Update regex in order to
	reflect the fact that gdbserver is now using fork_inferior (with a
	shell) to startup the inferior.
This commit is contained in:
Sergio Durigan Junior 2016-12-22 21:11:11 -05:00
parent 043a49349c
commit 2090129c36
33 changed files with 1444 additions and 867 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

63
gdb/ChangeLog
View file

@ -1,3 +1,66 @@
2017-06-07 Sergio Durigan Junior <sergiodj@redhat.com>
Pedro Alves <palves@redhat.com>
* Makefile.in (HFILES_NO_SRCDIR): Add "common/common-inferior.h"
and "nat/fork-inferior.h".
* common/common-inferior.h: New file, with contents from
"gdb/inferior.h".
* commom/common-utils.c: Include "common-utils.h".
(stringify_argv): New function.
* common/common-utils.h (stringify_argv): New prototype.
* configure.nat: Add "fork-inferior.o" as a dependency for
"*linux*", "fbsd*" and "nbsd*" hosts.
* corefile.c (get_exec_file): Update comment.
* darwin-nat.c (darwin_ptrace_him): Call "gdb_startup_inferior"
instead of "startup_inferior".
(darwin_create_inferior): Call "add_thread_silent" after
"fork_inferior".
* fork-child.c: Cleanup unnecessary includes.
(SHELL_FILE): Move to "common/common-fork-child.c".
(environ): Likewise.
(exec_wrapper): Initialize.
(get_exec_wrapper): New function.
(breakup_args): Move to "common/common-fork-child.c"; rename to
"breakup_args_for_exec".
(escape_bang_in_quoted_argument): Move to
"common/common-fork-child.c".
(saved_ui): New variable.
(prefork_hook): New function.
(postfork_hook): Likewise.
(postfork_child_hook): Likewise.
(gdb_startup_inferior): Likewise.
(fork_inferior): Move to "common/common-fork-child.c". Update
function to support gdbserver.
(startup_inferior): Likewise.
* gdbcore.h (get_exec_file): Remove declaration.
* gnu-nat.c (gnu_create_inferior): Call "gdb_startup_inferior"
instead of "startup_inferior". Call "add_thread_silent" after
"fork_inferior".
* inf-ptrace.c: Include "nat/fork-inferior.h" and "utils.h".
(inf_ptrace_create_inferior): Call "gdb_startup_inferior"
instead of "startup_inferior". Call "add_thread_silent" after
"fork_inferior".
* inferior.h: Include "common-inferior.h".
(trace_start_error): Move to "common/common-utils.h".
(trace_start_error_with_name): Likewise.
(fork_inferior): Move prototype to "nat/fork-inferior.h".
(startup_inferior): Likewise.
(gdb_startup_inferior): New prototype.
* nat/fork-inferior.c: New file, with contents from "fork-child.c".
* nat/fork-inferior.h: New file.
* procfs.c (procfs_init_inferior): Call "gdb_startup_inferior"
instead of "startup_inferior". Call "add_thread_silent" after
"fork_inferior".
* target.h (target_terminal_init): Move prototype to
"target/target.h".
(target_terminal_inferior): Likewise.
(target_terminal_ours): Likewise.
* target/target.h (target_terminal_init): New prototype, moved
from "target.h".
(target_terminal_inferior): Likewise.
(target_terminal_ours): Likewise.
* utils.c (gdb_flush_out_err): New function.
2017-06-07 Sergio Durigan Junior <sergiodj@redhat.com>
* Makefile.in (HFILES_NO_SRCDIR): Add "common/common-gdbthread.h".

2
gdb/Makefile.in
View file

@ -1525,6 +1525,7 @@ HFILES_NO_SRCDIR = \
common/gdb_termios.h \
common/gdb_vecs.h \
common/gdb_wait.h \
common/common-inferior.h \
common/host-defs.h \
common/print-utils.h \
common/ptid.h \
@ -1565,6 +1566,7 @@ HFILES_NO_SRCDIR = \
nat/amd64-linux-siginfo.h \
nat/gdb_ptrace.h \
nat/gdb_thread_db.h \
nat/fork-inferior.h \
nat/linux-btrace.h \
nat/linux-namespaces.h \
nat/linux-nat.h \

33
gdb/common/common-inferior.h Normal file
View file

@ -0,0 +1,33 @@
/* Functions to deal with the inferior being executed on GDB or
GDBserver.
Copyright (C) 1986-2017 Free Software Foundation, Inc.
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 3 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.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef COMMON_INFERIOR_H
#define COMMON_INFERIOR_H
/* Return the exec wrapper to be used when starting the inferior, or NULL
otherwise. */
extern const char *get_exec_wrapper ();
/* Return the name of the executable file as a string.
ERR nonzero means get error if there is none specified;
otherwise return 0 in that case. */
extern char *get_exec_file (int err);
#endif /* ! COMMON_INFERIOR_H */

24
gdb/common/common-utils.c
View file

@ -18,6 +18,7 @@
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "common-defs.h"
#include "common-utils.h"
#include "host-defs.h"
#include <ctype.h>
@ -328,3 +329,26 @@ free_vector_argv (std::vector<char *> &v)
v.clear ();
}
/* See common/common-utils.h. */
std::string
stringify_argv (const std::vector<char *> &args)
{
std::string ret;
if (!args.empty ())
{
for (auto s : args)
if (s != NULL)
{
ret += s;
ret += ' ';
}
/* Erase the last whitespace. */
ret.erase (ret.end () - 1);
}
return ret;
}

4
gdb/common/common-utils.h
View file

@ -108,4 +108,8 @@ extern const char *skip_to_space_const (const char *inp);
freeing all the elements. */
extern void free_vector_argv (std::vector<char *> &v);
/* Given a vector of arguments ARGV, return a string equivalent to
joining all the arguments with a whitespace separating them. */
extern std::string stringify_argv (const std::vector<char *> &argv);
#endif

8
gdb/configure.nat
View file

@ -54,7 +54,7 @@
case ${gdb_host} in
*linux*)
NAT_FILE='config/nm-linux.h'
NATDEPFILES='inf-ptrace.o fork-child.o proc-service.o \
NATDEPFILES='inf-ptrace.o fork-child.o fork-inferior.o proc-service.o \
linux-thread-db.o linux-nat.o linux-osdata.o linux-fork.o \
linux-procfs.o linux-ptrace.o linux-waitpid.o \
linux-personality.o linux-namespaces.o'
@ -62,15 +62,15 @@ case ${gdb_host} in
LOADLIBES='-ldl $(RDYNAMIC)'
;;
fbsd*)
NATDEPFILES='fork-child.o inf-ptrace.o fbsd-nat.o'
NATDEPFILES='fork-child.o fork-inferior.o inf-ptrace.o fbsd-nat.o'
HAVE_NATIVE_GCORE_HOST=1
LOADLIBES='-lkvm'
;;
nbsd*)
NATDEPFILES='fork-child.o inf-ptrace.o'
NATDEPFILES='fork-child.o fork-inferior.o inf-ptrace.o'
;;
obsd*)
NATDEPFILES='fork-child.o inf-ptrace.o'
NATDEPFILES='fork-child.o fork-inferior.o inf-ptrace.o'
;;
cygwin*)
NATDEPFILES='x86-nat.o x86-dregs.o windows-nat.o'

4
gdb/corefile.c
View file

@ -170,9 +170,7 @@ validate_files (void)
}
}
/* Return the name of the executable file as a string.
ERR nonzero means get error if there is none specified;
otherwise return 0 in that case. */
/* See common/common-inferior.h. */
char *
get_exec_file (int err)

18
gdb/darwin-nat.c
View file

@ -1790,7 +1790,7 @@ darwin_ptrace_him (int pid)
darwin_init_thread_list (inf);
startup_inferior (START_INFERIOR_TRAPS_EXPECTED);
gdb_startup_inferior (pid, START_INFERIOR_TRAPS_EXPECTED);
}
static void
@ -1833,13 +1833,23 @@ darwin_create_inferior (struct target_ops *ops,
const std::string &allargs,
char **env, int from_tty)
{
/* Do the hard work. */
fork_inferior (exec_file, allargs, env, darwin_ptrace_me, darwin_ptrace_him,
darwin_pre_ptrace, NULL, darwin_execvp);
pid_t pid;
ptid_t ptid;
/* Do the hard work. */
pid = fork_inferior (exec_file, allargs, env, darwin_ptrace_me,
darwin_ptrace_him, darwin_pre_ptrace, NULL,
darwin_execvp);
ptid = pid_to_ptid (pid);
/* Return now in case of error. */
if (ptid_equal (inferior_ptid, null_ptid))
return;
/* We have something that executes now. We'll be running through
the shell at this point (if startup-with-shell is true), but the
pid shouldn't change. */
add_thread_silent (ptid);
}

632
gdb/fork-child.c
View file

@ -21,471 +21,64 @@
#include "defs.h"
#include "inferior.h"
#include "terminal.h"
#include "target.h"
#include "gdb_wait.h"
#include "gdb_vfork.h"
#include "gdbcore.h"
#include "gdbthread.h"
#include "command.h" /* for dont_repeat () */
#include "gdbcmd.h"
#include "solib.h"
#include "filestuff.h"
#include "terminal.h"
#include "gdbthread.h"
#include "top.h"
#include "signals-state-save-restore.h"
#include "job-control.h"
#include <signal.h>
#include <vector>
#include "filestuff.h"
#include "nat/fork-inferior.h"
#include "common/common-inferior.h"
/* This just gets used as a default if we can't find SHELL. */
#define SHELL_FILE "/bin/sh"
/* The exec-wrapper, if any, that will be used when starting the
inferior. */
extern char **environ;
static char *exec_wrapper = NULL;
static char *exec_wrapper;
/* See common/common-inferior.h. */
/* Build the argument vector for execv(3). */
class execv_argv
const char *
get_exec_wrapper ()
{
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 exec_wrapper;
}
/* 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. */
/* See nat/fork-inferior.h. */
void
execv_argv::init_for_no_shell (const char *exec_file,
const std::string &allargs)
gdb_flush_out_err ()
{
/* 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);
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. */
m_argv.push_back (NULL);
gdb_flush (main_ui->m_gdb_stdout);
gdb_flush (main_ui->m_gdb_stderr);
}
/* When executing a command under the given shell, return true if the
'!' character should be escaped when embedded in a quoted
command-line argument. */
/* The ui structure that will be saved on 'prefork_hook' and
restored on 'postfork_hook'. */
static struct ui *saved_ui = NULL;
static bool
escape_bang_in_quoted_argument (const char *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 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. */
/* See nat/fork-inferior.h. */
void
execv_argv::init_for_shell (const char *exec_file,
const std::string &allargs,
const char *shell_file)
prefork_hook (const char *args)
{
/* 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. */
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 (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;
static char default_shell_file[] = SHELL_FILE;
/* 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 const char *exec_file;
char **save_our_env;
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 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;
}
else
shell_file = NULL;
/* 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;
gdb_assert (saved_ui == NULL);
/* Retain a copy of our UI, since the child will replace this value
and if we're vforked, we have to restore it. */
saved_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 (main_ui->m_gdb_stdout);
gdb_flush (main_ui->m_gdb_stderr);
/* See nat/fork-inferior.h. */
/* 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. 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"));
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);
/* 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
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! */
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
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;
char **argv = child_argv.argv ();
if (exec_fun != NULL)
(*exec_fun) (argv[0], &argv[0], env);
else
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;
/* Likewise the current UI. */
current_ui = save_ui;
void
postfork_hook (pid_t pid)
{
struct inferior *inf;
if (!have_inferiors ())
init_thread_list ();
@ -494,147 +87,58 @@ fork_inferior (const char *exec_file_arg, const std::string &allargs,
inferior_appeared (inf, pid);
/* Needed for wait_for_inferior stuff below. */
/* Needed for wait_for_inferior stuff. */
inferior_ptid = pid_to_ptid (pid);
gdb_assert (saved_ui != NULL);
current_ui = saved_ui;
saved_ui = NULL;
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. */
return pid;
}
/* Accept NTRAPS traps from the inferior. */
/* See nat/fork-inferior.h. */
void
startup_inferior (int ntraps)
postfork_child_hook ()
{
int pending_execs = ntraps;
int terminal_initted = 0;
ptid_t resume_ptid;
/* 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;
if (startup_with_shell)
/* Make sure we switch to main_ui here in order to be able to
use the fprintf_unfiltered/warning/error functions. */
current_ui = main_ui;
/* 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)
{
/* One trap extra for exec'ing the shell. */
pending_execs++;
/* 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"));
}
if (target_supports_multi_process ())
resume_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
else
resume_ptid = minus_one_ptid;
/* Ask the tty subsystem to switch to the one we specified
earlier (or to share the current terminal, if none was
specified). */
new_tty ();
}
/* 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. */
/* See inferior.h. */
if (exec_wrapper)
pending_execs++;
while (1)
{
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 (resume_ptid, &ws, 0);
if (ws.kind == TARGET_WAITKIND_IGNORE)
/* The inferior didn't really stop, keep waiting. */
continue;
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;
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;
case TARGET_WAITKIND_STOPPED:
resume_signal = ws.value.sig;
switch_to_thread (event_ptid);
break;
}
if (resume_signal != GDB_SIGNAL_TRAP)
{
/* 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. */
/* Set up the "saved terminal modes" of the inferior
based on what modes we are starting it with. */
target_terminal_init ();
/* Install inferior's terminal modes. */
target_terminal_inferior ();
terminal_initted = 1;
}
if (--pending_execs == 0)
break;
/* Just make it go on. */
target_continue_no_signal (resume_ptid);
}
}
ptid_t
gdb_startup_inferior (pid_t pid, int num_traps)
{
ptid_t ptid = startup_inferior (pid, num_traps, NULL, NULL);
/* Mark all threads non-executing. */
set_executing (resume_ptid, 0);
set_executing (ptid, 0);
return ptid;
}
/* Implement the "unset exec-wrapper" command. */

6
gdb/gdbcore.h
View file

@ -29,12 +29,6 @@ struct regcache;
#include "exec.h"
#include "target.h"
/* Return the name of the executable file as a string.
ERR nonzero means get error if there is none specified;
otherwise return 0 in that case. */
extern char *get_exec_file (int err);
/* Nonzero if there is a core file. */
extern int have_core_file_p (void);

69
gdb/gdbserver/ChangeLog
View file

@ -1,3 +1,72 @@
2017-06-07 Sergio Durigan Junior <sergiodj@redhat.com>
Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add "nat/fork-inferior.o".
* configure: Regenerate.
* configure.srv (srv_linux_obj): Add "fork-child.o" and
"fork-inferior.o".
(i[34567]86-*-lynxos*): Likewise.
(spu*-*-*): Likewise.
* fork-child.c: New file.
* linux-low.c: Include "common-inferior.h", "nat/fork-inferior.h"
and "environ.h".
(linux_ptrace_fun): New function.
(linux_create_inferior): Adjust function prototype to reflect
change on "target.h". Adjust function code to use
"fork_inferior".
(linux_request_interrupt): Delete "signal_pid".
* lynx-low.c: Include "common-inferior.h" and "nat/fork-inferior.h".
(lynx_ptrace_fun): New function.
(lynx_create_inferior): Adjust function prototype to reflect
change on "target.h". Adjust function code to use
"fork_inferior".
* nto-low.c (nto_create_inferior): Adjust function prototype and
code to reflect change on "target.h". Update comments.
* server.c: Include "common-inferior.h", "nat/fork-inferior.h",
"common-terminal.h" and "environ.h".
(terminal_fd): Moved to fork-child.c.
(old_foreground_pgrp): Likewise.
(restore_old_foreground_pgrp): Likewise.
(last_status): Make it global.
(last_ptid): Likewise.
(our_environ): New variable.
(startup_with_shell): Likewise.
(program_name): Likewise.
(program_argv): Rename to...
(program_args): ...this.
(wrapper_argv): New variable.
(start_inferior): Delete function.
(get_exec_wrapper): New function.
(get_exec_file): Likewise.
(get_environ): Likewise.
(prefork_hook): Likewise.
(post_fork_inferior): Likewise.
(postfork_hook): Likewise.
(postfork_child_hook): Likewise.
(handle_v_run): Update code to deal with arguments coming from the
remote host. Update calls from "start_inferior" to
"create_inferior".
(captured_main): Likewise. Initialize environment variable. Call
"have_job_control".
* server.h (post_fork_inferior): New prototype.
(get_environ): Likewise.
(last_status): Declare.
(last_ptid): Likewise.
(signal_pid): Likewise.
* spu-low.c: Include "common-inferior.h" and "nat/fork-inferior.h".
(spu_ptrace_fun): New function.
(spu_create_inferior): Adjust function prototype to reflect change
on "target.h". Adjust function code to use "fork_inferior".
* target.c (target_terminal_init): New function.
(target_terminal_inferior): Likewise.
(target_terminal_ours): Likewise.
* target.h: Include <vector>.
(struct target_ops) <create_inferior>: Update prototype.
(create_inferior): Update macro.
* utils.c (gdb_flush_out_err): New function.
* win32-low.c (win32_create_inferior): Adjust function prototype
and code to reflect change on "target.h".
2017-06-07 Sergio Durigan Junior <sergiodj@redhat.com>
* inferiors.c (switch_to_thread): New function.

1
gdb/gdbserver/Makefile.in
View file

@ -218,6 +218,7 @@ SFILES = \
$(srcdir)/nat/linux-personality.c \
$(srcdir)/nat/mips-linux-watch.c \
$(srcdir)/nat/ppc-linux.c \
$(srcdir)/nat/fork-inferior.c \
$(srcdir)/target/waitstatus.c
DEPFILES = @GDBSERVER_DEPFILES@

6
gdb/gdbserver/configure.srv
View file

@ -43,7 +43,7 @@ srv_amd64_linux_xmlfiles="i386/amd64-linux.xml i386/amd64-avx-linux.xml i386/amd
# Linux object files. This is so we don't have to repeat
# these files over and over again.
srv_linux_obj="linux-low.o linux-osdata.o linux-procfs.o linux-ptrace.o linux-waitpid.o linux-personality.o linux-namespaces.o"
srv_linux_obj="linux-low.o linux-osdata.o linux-procfs.o linux-ptrace.o linux-waitpid.o linux-personality.o linux-namespaces.o fork-child.o fork-inferior.o"
# Input is taken from the "${target}" variable.
@ -131,7 +131,7 @@ case "${target}" in
ipa_obj="${ipa_i386_linux_regobj} linux-i386-ipa.o"
;;
i[34567]86-*-lynxos*) srv_regobj="i386.o"
srv_tgtobj="lynx-low.o lynx-i386-low.o"
srv_tgtobj="lynx-low.o lynx-i386-low.o fork-child.o fork-inferior.o"
srv_xmlfiles="i386/i386.xml"
srv_xmlfiles="${srv_xmlfiles} i386/32bit-core.xml"
srv_xmlfiles="${srv_xmlfiles} i386/32bit-sse.xml"
@ -338,7 +338,7 @@ case "${target}" in
srv_linux_thread_db=yes
;;
spu*-*-*) srv_regobj=reg-spu.o
srv_tgtobj="spu-low.o"
srv_tgtobj="spu-low.o fork-child.o fork-inferior.o"
;;
tic6x-*-uclinux) srv_regobj="tic6x-c64xp-linux.o"
srv_regobj="${srv_regobj} tic6x-c64x-linux.o"

113
gdb/gdbserver/fork-child.c Normal file
View file

@ -0,0 +1,113 @@
/* Fork a Unix child process, and set up to debug it, for GDBserver.
Copyright (C) 1989-2017 Free Software Foundation, Inc.
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 3 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.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "server.h"
#include "job-control.h"
#include "nat/fork-inferior.h"
#ifdef SIGTTOU
/* A file descriptor for the controlling terminal. */
static int terminal_fd;
/* TERMINAL_FD's original foreground group. */
static pid_t old_foreground_pgrp;
/* Hand back terminal ownership to the original foreground group. */
static void
restore_old_foreground_pgrp (void)
{
tcsetpgrp (terminal_fd, old_foreground_pgrp);
}
#endif
/* See nat/fork-inferior.h. */
void
prefork_hook (const char *args)
{
if (debug_threads)
{
debug_printf ("args: %s\n", args);
debug_flush ();
}
#ifdef SIGTTOU
signal (SIGTTOU, SIG_DFL);
signal (SIGTTIN, SIG_DFL);
#endif
/* Clear this so the backend doesn't get confused, thinking
CONT_THREAD died, and it needs to resume all threads. */
cont_thread = null_ptid;
}
/* See nat/fork-inferior.h. */
void
postfork_hook (pid_t pid)
{
}
/* See nat/fork-inferior.h. */
void
postfork_child_hook ()
{
/* 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;
debug_setpgrp = gdb_setpgid ();
if (debug_setpgrp == -1)
perror (_("setpgrp failed in child"));
}
/* See nat/fork-inferior.h. */
void
gdb_flush_out_err ()
{
fflush (stdout);
fflush (stderr);
}
/* See server.h. */
void
post_fork_inferior (int pid, const char *program)
{
#ifdef SIGTTOU
signal (SIGTTOU, SIG_IGN);
signal (SIGTTIN, SIG_IGN);
terminal_fd = fileno (stderr);
old_foreground_pgrp = tcgetpgrp (terminal_fd);
tcsetpgrp (terminal_fd, pid);
atexit (restore_old_foreground_pgrp);
#endif
startup_inferior (pid, START_INFERIOR_TRAPS_EXPECTED,
&last_status, &last_ptid);
current_thread->last_resume_kind = resume_stop;
current_thread->last_status = last_status;
signal_pid = pid;
target_post_create_inferior ();
fprintf (stderr, "Process %s created; pid = %d\n", program, pid);
fflush (stderr);
}

91
gdb/gdbserver/linux-low.c
View file

@ -47,6 +47,9 @@
#include "tracepoint.h"
#include "hostio.h"
#include <inttypes.h>
#include "common-inferior.h"
#include "nat/fork-inferior.h"
#include "environ.h"
#ifndef ELFMAG0
/* Don't include <linux/elf.h> here. If it got included by gdb_proc_service.h
then ELFMAG0 will have been defined. If it didn't get included by
@ -946,59 +949,57 @@ add_lwp (ptid_t ptid)
return lwp;
}
/* Callback to be used when calling fork_inferior, responsible for
actually initiating the tracing of the inferior. */
static void
linux_ptrace_fun ()
{
if (ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0,
(PTRACE_TYPE_ARG4) 0) < 0)
trace_start_error_with_name ("ptrace");
if (setpgid (0, 0) < 0)
trace_start_error_with_name ("setpgid");
/* If GDBserver is connected to gdb via stdio, redirect the inferior's
stdout to stderr so that inferior i/o doesn't corrupt the connection.
Also, redirect stdin to /dev/null. */
if (remote_connection_is_stdio ())
{
if (close (0) < 0)
trace_start_error_with_name ("close");
if (open ("/dev/null", O_RDONLY) < 0)
trace_start_error_with_name ("open");
if (dup2 (2, 1) < 0)
trace_start_error_with_name ("dup2");
if (write (2, "stdin/stdout redirected\n",
sizeof ("stdin/stdout redirected\n") - 1) < 0)
{
/* Errors ignored. */;
}
}
}
/* Start an inferior process and returns its pid.
ALLARGS is a vector of program-name and args. */
PROGRAM is the name of the program to be started, and PROGRAM_ARGS
are its arguments. */
static int
linux_create_inferior (char *program, char **allargs)
linux_create_inferior (const char *program,
const std::vector<char *> &program_args)
{
struct lwp_info *new_lwp;
int pid;
ptid_t ptid;
struct cleanup *restore_personality
= maybe_disable_address_space_randomization (disable_randomization);
std::string str_program_args = stringify_argv (program_args);
#if defined(__UCLIBC__) && defined(HAS_NOMMU)
pid = vfork ();
#else
pid = fork ();
#endif
if (pid < 0)
perror_with_name ("fork");
if (pid == 0)
{
close_most_fds ();
ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0);
setpgid (0, 0);
/* If gdbserver is connected to gdb via stdio, redirect the inferior's
stdout to stderr so that inferior i/o doesn't corrupt the connection.
Also, redirect stdin to /dev/null. */
if (remote_connection_is_stdio ())
{
close (0);
open ("/dev/null", O_RDONLY);
dup2 (2, 1);
if (write (2, "stdin/stdout redirected\n",
sizeof ("stdin/stdout redirected\n") - 1) < 0)
{
/* Errors ignored. */;
}
}
restore_original_signals_state ();
execv (program, allargs);
if (errno == ENOENT)
execvp (program, allargs);
fprintf (stderr, "Cannot exec %s: %s.\n", program,
strerror (errno));
fflush (stderr);
_exit (0177);
}
pid = fork_inferior (program,
str_program_args.c_str (),
environ_vector (get_environ ()), linux_ptrace_fun,
NULL, NULL, NULL, NULL);
do_cleanups (restore_personality);
@ -1008,6 +1009,8 @@ linux_create_inferior (char *program, char **allargs)
new_lwp = add_lwp (ptid);
new_lwp->must_set_ptrace_flags = 1;
post_fork_inferior (pid, program);
return pid;
}
@ -6055,8 +6058,6 @@ linux_look_up_symbols (void)
static void
linux_request_interrupt (void)
{
extern unsigned long signal_pid;
/* Send a SIGINT to the process group. This acts just like the user
typed a ^C on the controlling terminal. */
kill (-signal_pid, SIGINT);

51
gdb/gdbserver/lynx-low.c
View file

@ -28,6 +28,8 @@
#include "gdb_wait.h"
#include <signal.h>
#include "filestuff.h"
#include "common-inferior.h"
#include "nat/fork-inferior.h"
int using_threads = 1;
@ -224,36 +226,43 @@ lynx_add_process (int pid, int attached)
return proc;
}
/* Callback used by fork_inferior to start tracing the inferior. */
static void
lynx_ptrace_fun ()
{
int pgrp;
/* Switch child to its own process group so that signals won't
directly affect GDBserver. */
pgrp = getpid();
if (pgrp < 0)
trace_start_error_with_name ("pgrp");
if (setpgid (0, pgrp) < 0)
trace_start_error_with_name ("setpgid");
if (ioctl (0, TIOCSPGRP, &pgrp) < 0)
trace_start_error_with_name ("ioctl");
if (lynx_ptrace (PTRACE_TRACEME, null_ptid, 0, 0, 0) < 0)
trace_start_error_with_name ("lynx_ptrace");
}
/* Implement the create_inferior method of the target_ops vector. */
static int
lynx_create_inferior (char *program, char **allargs)
lynx_create_inferior (const char *program,
const std::vector<char *> &program_args)
{
int pid;
std::string str_program_args = stringify_argv (program_args);
lynx_debug ("lynx_create_inferior ()");
pid = fork ();
if (pid < 0)
perror_with_name ("fork");
pid = fork_inferior (program,
str_program_args.c_str (),
environ_vector (get_environ ()), lynx_ptrace_fun,
NULL, NULL, NULL, NULL);
if (pid == 0)
{
int pgrp;
close_most_fds ();
/* Switch child to its own process group so that signals won't
directly affect gdbserver. */
pgrp = getpid();
setpgid (0, pgrp);
ioctl (0, TIOCSPGRP, &pgrp);
lynx_ptrace (PTRACE_TRACEME, null_ptid, 0, 0, 0);
execv (program, allargs);
fprintf (stderr, "Cannot exec %s: %s.\n", program, strerror (errno));
fflush (stderr);
_exit (0177);
}
post_fork_inferior (pid, program);
lynx_add_process (pid, 0);
/* Do not add the process thread just yet, as we do not know its tid.

10
gdb/gdbserver/nto-low.c
View file

@ -347,14 +347,17 @@ nto_read_auxv_from_initial_stack (CORE_ADDR initial_stack,
return len_read;
}
/* Start inferior specified by PROGRAM passing arguments ALLARGS. */
/* Start inferior specified by PROGRAM, using PROGRAM_ARGS as its
arguments. */
static int
nto_create_inferior (char *program, char **allargs)
nto_create_inferior (const char *program,
const std::vector<char *> &program_args)
{
struct inheritance inherit;
pid_t pid;
sigset_t set;
std::string str_program_args = stringify_argv (program_args);
TRACE ("%s %s\n", __func__, program);
/* Clear any pending SIGUSR1's but keep the behavior the same. */
@ -367,7 +370,8 @@ nto_create_inferior (char *program, char **allargs)
memset (&inherit, 0, sizeof (inherit));
inherit.flags |= SPAWN_SETGROUP | SPAWN_HOLD;
inherit.pgroup = SPAWN_NEWPGROUP;
pid = spawnp (program, 0, NULL, &inherit, allargs, 0);
pid = spawnp (program, 0, NULL, &inherit,
(char *) str_program_args.c_str (), 0);
sigprocmask (SIG_BLOCK, &set, NULL);
if (pid == -1)

240
gdb/gdbserver/server.c
View file

@ -36,6 +36,19 @@
#include "dll.h"
#include "hostio.h"
#include <vector>
#include "common-inferior.h"
#include "job-control.h"
#include "environ.h"
/* The environment to pass to the inferior when creating it. */
struct gdb_environ *our_environ = NULL;
/* Start the inferior using a shell. */
/* We always try to start the inferior using a shell. */
int startup_with_shell = 1;
/* The thread set with an `Hc' packet. `Hc' is deprecated in favor of
`vCont'. Note the multi-process extensions made `vCont' a
@ -79,8 +92,9 @@ static int vCont_supported;
space randomization feature before starting an inferior. */
int disable_randomization = 1;
static std::vector<char *> program_argv;
static std::vector<char *> wrapper_argv;
static char *program_name = NULL;
static std::vector<char *> program_args;
static std::string wrapper_argv;
int pass_signals[GDB_SIGNAL_LAST];
int program_signals[GDB_SIGNAL_LAST];
@ -93,22 +107,6 @@ int program_signals_p;
unsigned long signal_pid;
#ifdef SIGTTOU
/* A file descriptor for the controlling terminal. */
int terminal_fd;
/* TERMINAL_FD's original foreground group. */
pid_t old_foreground_pgrp;
/* Hand back terminal ownership to the original foreground group. */
static void
restore_old_foreground_pgrp (void)
{
tcsetpgrp (terminal_fd, old_foreground_pgrp);
}
#endif
/* Set if you want to disable optional thread related packets support
in gdbserver, for the sake of testing GDB against stubs that don't
support them. */
@ -118,8 +116,8 @@ int disable_packet_qC;
int disable_packet_qfThreadInfo;
/* Last status reported to GDB. */
static struct target_waitstatus last_status;
static ptid_t last_ptid;
struct target_waitstatus last_status;
ptid_t last_ptid;
char *own_buf;
static unsigned char *mem_buf;
@ -238,94 +236,31 @@ target_running (void)
return get_first_thread () != NULL;
}
static int
start_inferior (char **argv)
/* See common/common-inferior.h. */
const char *
get_exec_wrapper ()
{
std::vector<char *> new_argv;
return !wrapper_argv.empty () ? wrapper_argv.c_str () : NULL;
}
if (!wrapper_argv.empty ())
new_argv.insert (new_argv.begin (),
wrapper_argv.begin (),
wrapper_argv.end ());
/* See common/common-inferior.h. */
for (int i = 0; argv[i] != NULL; ++i)
new_argv.push_back (argv[i]);
char *
get_exec_file (int err)
{
if (err && program_name == NULL)
error (_("No executable file specified."));
new_argv.push_back (NULL);
return program_name;
}
if (debug_threads)
{
for (int i = 0; i < new_argv.size (); ++i)
debug_printf ("new_argv[%d] = \"%s\"\n", i, new_argv[i]);
debug_flush ();
}
/* See server.h. */
#ifdef SIGTTOU
signal (SIGTTOU, SIG_DFL);
signal (SIGTTIN, SIG_DFL);
#endif
signal_pid = create_inferior (new_argv[0], &new_argv[0]);
/* FIXME: we don't actually know at this point that the create
actually succeeded. We won't know that until we wait. */
fprintf (stderr, "Process %s created; pid = %ld\n", argv[0],
signal_pid);
fflush (stderr);
#ifdef SIGTTOU
signal (SIGTTOU, SIG_IGN);
signal (SIGTTIN, SIG_IGN);
terminal_fd = fileno (stderr);
old_foreground_pgrp = tcgetpgrp (terminal_fd);
tcsetpgrp (terminal_fd, signal_pid);
atexit (restore_old_foreground_pgrp);
#endif
if (!wrapper_argv.empty ())
{
ptid_t ptid = pid_to_ptid (signal_pid);
last_ptid = mywait (pid_to_ptid (signal_pid), &last_status, 0, 0);
if (last_status.kind == TARGET_WAITKIND_STOPPED)
{
do
{
target_continue_no_signal (ptid);
last_ptid = mywait (pid_to_ptid (signal_pid), &last_status, 0, 0);
if (last_status.kind != TARGET_WAITKIND_STOPPED)
break;
current_thread->last_resume_kind = resume_stop;
current_thread->last_status = last_status;
}
while (last_status.value.sig != GDB_SIGNAL_TRAP);
}
target_post_create_inferior ();
return signal_pid;
}
/* Wait till we are at 1st instruction in program, return new pid
(assuming success). */
last_ptid = mywait (pid_to_ptid (signal_pid), &last_status, 0, 0);
/* At this point, the target process, if it exits, is stopped. Do not call
the function target_post_create_inferior if the process has already
exited, as the target implementation of the routine may rely on the
process being live. */
if (last_status.kind != TARGET_WAITKIND_EXITED
&& last_status.kind != TARGET_WAITKIND_SIGNALLED)
{
target_post_create_inferior ();
current_thread->last_resume_kind = resume_stop;
current_thread->last_status = last_status;
}
else
target_mourn_inferior (last_ptid);
return signal_pid;
struct gdb_environ *
get_environ ()
{
return our_environ;
}
static int
@ -2848,6 +2783,7 @@ handle_v_run (char *own_buf)
{
char *p, *next_p;
std::vector<char *> new_argv;
char *new_program_name = NULL;
int i, new_argc;
new_argc = 0;
@ -2866,42 +2802,94 @@ handle_v_run (char *own_buf)
if (i == 0 && p == next_p)
{
/* No program specified. */
new_argv.push_back (NULL);
new_program_name = NULL;
}
else if (p == next_p)
{
/* Empty argument. */
new_argv.push_back (xstrdup ("''"));
}
else
{
size_t len = (next_p - p) / 2;
/* ARG is the unquoted argument received via the RSP. */
char *arg = (char *) xmalloc (len + 1);
/* FULL_ARGS will contain the quoted version of ARG. */
char *full_arg = (char *) xmalloc ((len + 1) * 2);
/* These are pointers used to navigate the strings above. */
char *tmp_arg = arg;
char *tmp_full_arg = full_arg;
int need_quote = 0;
hex2bin (p, (gdb_byte *) arg, len);
arg[len] = '\0';
new_argv.push_back (arg);
}
while (*tmp_arg != '\0')
{
switch (*tmp_arg)
{
case '\n':
/* Quote \n. */
*tmp_full_arg = '\'';
++tmp_full_arg;
need_quote = 1;
break;
case '\'':
/* Quote single quote. */
*tmp_full_arg = '\\';
++tmp_full_arg;
break;
default:
break;
}
*tmp_full_arg = *tmp_arg;
++tmp_full_arg;
++tmp_arg;
}
if (need_quote)
*tmp_full_arg++ = '\'';
/* Finish FULL_ARG and push it into the vector containing
the argv. */
*tmp_full_arg = '\0';
if (i == 0)
new_program_name = full_arg;
else
new_argv.push_back (full_arg);
xfree (arg);
}
if (*next_p)
next_p++;
}
new_argv.push_back (NULL);
if (new_argv[0] == NULL)
if (new_program_name == NULL)
{
/* GDB didn't specify a program to run. Use the program from the
last run with the new argument list. */
if (program_argv.empty ())
if (program_name == NULL)
{
write_enn (own_buf);
free_vector_argv (new_argv);
return 0;
}
new_argv.push_back (xstrdup (program_argv[0]));
}
else
{
xfree (program_name);
program_name = new_program_name;
}
/* Free the old argv and install the new one. */
free_vector_argv (program_argv);
program_argv = new_argv;
free_vector_argv (program_args);
program_args = new_argv;
create_inferior (program_name, program_args);
start_inferior (&program_argv[0]);
if (last_status.kind == TARGET_WAITKIND_STOPPED)
{
prepare_resume_reply (own_buf, last_ptid, &last_status);
@ -3527,10 +3515,17 @@ captured_main (int argc, char *argv[])
tmp = next_arg;
while (*next_arg != NULL && strcmp (*next_arg, "--") != 0)
{
wrapper_argv.push_back (*next_arg);
wrapper_argv += *next_arg;
wrapper_argv += ' ';
next_arg++;
}
if (!wrapper_argv.empty ())
{
/* Erase the last whitespace. */
wrapper_argv.erase (wrapper_argv.end () - 1);
}
if (next_arg == tmp || *next_arg == NULL)
{
gdbserver_usage (stderr);
@ -3666,8 +3661,13 @@ captured_main (int argc, char *argv[])
exit (1);
}
/* Gather information about the environment. */
our_environ = make_environ ();
init_environ (our_environ);
initialize_async_io ();
initialize_low ();
have_job_control ();
initialize_event_loop ();
if (target_supports_tracepoints ())
initialize_tracepoint ();
@ -3681,12 +3681,13 @@ captured_main (int argc, char *argv[])
int i, n;
n = argc - (next_arg - argv);
for (i = 0; i < n; i++)
program_argv.push_back (xstrdup (next_arg[i]));
program_argv.push_back (NULL);
program_name = xstrdup (next_arg[0]);
for (i = 1; i < n; i++)
program_args.push_back (xstrdup (next_arg[i]));
program_args.push_back (NULL);
/* Wait till we are at first instruction in program. */
start_inferior (&program_argv[0]);
create_inferior (program_name, program_args);
/* We are now (hopefully) stopped at the first instruction of
the target process. This assumes that the target process was
@ -4301,9 +4302,10 @@ process_serial_event (void)
fprintf (stderr, "GDBserver restarting\n");
/* Wait till we are at 1st instruction in prog. */
if (!program_argv.empty ())
if (program_name != NULL)
{
start_inferior (&program_argv[0]);
create_inferior (program_name, program_args);
if (last_status.kind == TARGET_WAITKIND_STOPPED)
{
/* Stopped at the first instruction of the target

14
gdb/gdbserver/server.h
View file

@ -148,4 +148,18 @@ extern int in_queued_stop_replies (ptid_t ptid);
/* Definition for any syscall, used for unfiltered syscall reporting. */
#define ANY_SYSCALL (-2)
/* After fork_inferior has been called, we need to adjust a few
signals and call startup_inferior to start the inferior and consume
its first events. This is done here. PID is the pid of the new
inferior and PROGRAM is its name. */
extern void post_fork_inferior (int pid, const char *program);
/* Get the 'struct gdb_environ *' being used in the current
session. */
extern struct gdb_environ *get_environ ();
extern target_waitstatus last_status;
extern ptid_t last_ptid;
extern unsigned long signal_pid;
#endif /* SERVER_H */

44
gdb/gdbserver/spu-low.c
View file

@ -27,6 +27,7 @@
#include <sys/syscall.h>
#include "filestuff.h"
#include "hostio.h"
#include "nat/fork-inferior.h"
/* Some older glibc versions do not define this. */
#ifndef __WNOTHREAD
@ -261,36 +262,37 @@ spu_proc_xfer_spu (const char *annex, unsigned char *readbuf,
return ret;
}
/* Callback to be used when calling fork_inferior, responsible for
actually initiating the tracing of the inferior. */
static void
spu_ptrace_fun ()
{
if (ptrace (PTRACE_TRACEME, 0, 0, 0) < 0)
trace_start_error_with_name ("ptrace");
if (setpgid (0, 0) < 0)
trace_start_error_with_name ("setpgid");
}
/* Start an inferior process and returns its pid.
ALLARGS is a vector of program-name and args. */
PROGRAM is the name of the program to be started, and PROGRAM_ARGS
are its arguments. */
static int
spu_create_inferior (char *program, char **allargs)
spu_create_inferior (const char *program,
const std::vector<char *> &program_argv)
{
int pid;
ptid_t ptid;
struct process_info *proc;
std::string str_program_args = stringify_argv (program_args);
pid = fork ();
if (pid < 0)
perror_with_name ("fork");
pid = fork_inferior (program,
str_program_args.c_str (),
environ_vector (get_environ ()), spu_ptrace_fun,
NULL, NULL, NULL, NULL);
if (pid == 0)
{
close_most_fds ();
ptrace (PTRACE_TRACEME, 0, 0, 0);
setpgid (0, 0);
execv (program, allargs);
if (errno == ENOENT)
execvp (program, allargs);
fprintf (stderr, "Cannot exec %s: %s.\n", program,
strerror (errno));
fflush (stderr);
_exit (0177);
}
post_fork_inferior (pid, program);
proc = add_process (pid, 0);
proc->tdesc = tdesc_spu;

27
gdb/gdbserver/target.c
View file

@ -387,3 +387,30 @@ default_breakpoint_kind_from_pc (CORE_ADDR *pcptr)
(*the_target->sw_breakpoint_from_kind) (0, &size);
return size;
}
/* See target/target.h. */
void
target_terminal_init ()
{
/* Placeholder needed because of fork_inferior. Not necessary on
GDBserver. */
}
/* See target/target.h. */
void
target_terminal_inferior ()
{
/* Placeholder needed because of fork_inferior. Not necessary on
GDBserver. */
}
/* See target/target.h. */
void
target_terminal_ours ()
{
/* Placeholder needed because of fork_inferior. Not necessary on
GDBserver. */
}

13
gdb/gdbserver/target.h
View file

@ -28,6 +28,7 @@
#include "target/waitstatus.h"
#include "mem-break.h"
#include "btrace-common.h"
#include <vector>
struct emit_ops;
struct buffer;
@ -67,13 +68,13 @@ struct target_ops
/* Start a new process.
PROGRAM is a path to the program to execute.
ARGS is a standard NULL-terminated array of arguments,
to be passed to the inferior as ``argv''.
PROGRAM_ARGS is a standard NULL-terminated array of arguments,
to be passed to the inferior as ``argv'' (along with PROGRAM).
Returns the new PID on success, -1 on failure. Registers the new
process with the process list. */
int (*create_inferior) (char *program, char **args);
int (*create_inferior) (const char *program,
const std::vector<char *> &program_args);
/* Do additional setup after a new process is created, including
exec-wrapper completion. */
@ -480,8 +481,8 @@ extern struct target_ops *the_target;
void set_target_ops (struct target_ops *);
#define create_inferior(program, args) \
(*the_target->create_inferior) (program, args)
#define create_inferior(program, program_args) \
(*the_target->create_inferior) (program, program_args)
#define target_post_create_inferior() \
do \

23
gdb/gdbserver/win32-low.c
View file

@ -608,13 +608,13 @@ create_process (const char *program, char *args,
}
/* Start a new process.
PROGRAM is a path to the program to execute.
ARGS is a standard NULL-terminated array of arguments,
to be passed to the inferior as ``argv''.
PROGRAM is the program name.
PROGRAM_ARGS is the vector containing the inferior's args.
Returns the new PID on success, -1 on failure. Registers the new
process with the process list. */
static int
win32_create_inferior (char *program, char **program_args)
win32_create_inferior (const char *program,
const std::vector<char *> &program_args)
{
#ifndef USE_WIN32API
char real_path[PATH_MAX];
@ -622,11 +622,12 @@ win32_create_inferior (char *program, char **program_args)
#endif
BOOL ret;
DWORD flags;
char *args;
int argslen;
int argc;
PROCESS_INFORMATION pi;
DWORD err;
std::string str_program_args = stringify_argv (program_args);
char *args = (char *) str_program_args.c_str ();
/* win32_wait needs to know we're not attaching. */
attaching = 0;
@ -652,18 +653,6 @@ win32_create_inferior (char *program, char **program_args)
program = real_path;
#endif
argslen = 1;
for (argc = 1; program_args[argc]; argc++)
argslen += strlen (program_args[argc]) + 1;
args = (char *) alloca (argslen);
args[0] = '\0';
for (argc = 1; program_args[argc]; argc++)
{
/* FIXME: Can we do better about quoting? How does Cygwin
handle this? */
strcat (args, " ");
strcat (args, program_args[argc]);
}
OUTMSG2 (("Command line is \"%s\"\n", args));
#ifdef CREATE_NEW_PROCESS_GROUP

8
gdb/gnu-nat.c
View file

@ -2143,6 +2143,11 @@ gnu_create_inferior (struct target_ops *ops,
pid = fork_inferior (exec_file, allargs, env, gnu_ptrace_me,
NULL, NULL, NULL, NULL);
/* We have something that executes now. We'll be running through
the shell at this point (if startup-with-shell is true), but the
pid shouldn't change. */
add_thread_silent (pid_to_ptid (pid));
/* Attach to the now stopped child, which is actually a shell... */
inf_debug (inf, "attaching to child: %d", pid);
@ -2162,7 +2167,8 @@ gnu_create_inferior (struct target_ops *ops,
thread_change_ptid (inferior_ptid,
ptid_build (inf->pid, inf_pick_first_thread (), 0));
startup_inferior (START_INFERIOR_TRAPS_EXPECTED);
gdb_startup_inferior (pid, START_INFERIOR_TRAPS_EXPECTED);
inf->pending_execs = 0;
/* Get rid of the old shell threads. */
prune_threads ();

15
gdb/inf-ptrace.c
View file

@ -31,6 +31,8 @@
#include "inf-ptrace.h"
#include "inf-child.h"
#include "gdbthread.h"
#include "nat/fork-inferior.h"
#include "utils.h"
@ -93,7 +95,8 @@ inf_ptrace_create_inferior (struct target_ops *ops,
const char *exec_file, const std::string &allargs,
char **env, int from_tty)
{
int pid;
pid_t pid;
ptid_t ptid;
/* Do not change either targets above or the same target if already present.
The reason is the target stack is shared across multiple inferiors. */
@ -110,13 +113,19 @@ inf_ptrace_create_inferior (struct target_ops *ops,
pid = fork_inferior (exec_file, allargs, env, inf_ptrace_me, NULL,
NULL, NULL, NULL);
ptid = pid_to_ptid (pid);
/* We have something that executes now. We'll be running through
the shell at this point (if startup-with-shell is true), but the
pid shouldn't change. */
add_thread_silent (ptid);
discard_cleanups (back_to);
startup_inferior (START_INFERIOR_TRAPS_EXPECTED);
gdb_startup_inferior (pid, START_INFERIOR_TRAPS_EXPECTED);
/* On some targets, there must be some explicit actions taken after
the inferior has been started up. */
target_post_startup_inferior (pid_to_ptid (pid));
target_post_startup_inferior (ptid);
}
#ifdef PT_GET_PROCESS_STATE

34
gdb/inferior.h
View file

@ -49,6 +49,8 @@ struct inferior;
#include "symfile-add-flags.h"
#include "common/refcounted-object.h"
#include "common-inferior.h"
struct infcall_suspend_state;
struct infcall_control_state;
@ -136,28 +138,10 @@ extern void child_terminal_init_with_pgrp (int pgrp);
/* From fork-child.c */
/* Report an error that happened when starting to trace the inferior
(i.e., when the "traceme_fun" callback is called on fork_inferior)
and bail out. This function does not return. */
extern void trace_start_error (const char *fmt, ...)
ATTRIBUTE_NORETURN;
/* Like "trace_start_error", but the error message is constructed by
combining STRING with the system error message for errno. This
function does not return. */
extern void trace_start_error_with_name (const char *string)
ATTRIBUTE_NORETURN;
extern int fork_inferior (const char *, const std::string &, char **,
void (*)(void),
void (*)(int), void (*)(void), char *,
void (*)(const char *,
char * const *, char * const *));
extern void startup_inferior (int);
/* Helper function to call STARTUP_INFERIOR with PID and NUM_TRAPS.
This function already calls set_executing. Return the ptid_t from
STARTUP_INFERIOR. */
extern ptid_t gdb_startup_inferior (pid_t pid, int num_traps);
extern char *construct_inferior_arguments (int, char **);
@ -282,12 +266,6 @@ enum stop_kind
#define ON_STACK 1
#define AT_ENTRY_POINT 4
/* Number of traps that happen between exec'ing the shell to run an
inferior and when we finally get to the inferior code, not counting
the exec for the shell. This is 1 on all supported
implementations. */
#define START_INFERIOR_TRAPS_EXPECTED 1
struct private_inferior;
/* Inferior process specific part of `struct infcall_control_state'.

595
gdb/nat/fork-inferior.c Normal file
View file

@ -0,0 +1,595 @@
/* Fork a Unix child process, and set up to debug it, for GDB and GDBserver.
Copyright (C) 1990-2017 Free Software Foundation, Inc.
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 3 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.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "common-defs.h"
#include "fork-inferior.h"
#include "target/waitstatus.h"
#include "filestuff.h"
#include "target/target.h"
#include "common-inferior.h"
#include "common-gdbthread.h"
#include "signals-state-save-restore.h"
#include <vector>
extern char **environ;
/* Default shell file to be used if 'startup-with-shell' is set but
$SHELL is not. */
#define SHELL_FILE "/bin/sh"
/* Build the argument vector for execv(3). */
class execv_argv
{
public:
/* EXEC_FILE is the file to run. ALLARGS is a string containing the
arguments to the program. If starting with a shell, SHELL_FILE
is the shell to run. Otherwise, SHELL_FILE is NULL. */
execv_argv (const char *exec_file, const std::string &allargs,
const char *shell_file);
/* Return a pointer to the built argv, in the type expected by
execv. The result is (only) valid for as long as this execv_argv
object is live. We return a "char **" because that's the type
that the execv functions expect. Note that it is guaranteed that
the execv functions do not modify the argv[] array nor the
strings to which the array point. */
char **argv ()
{
return const_cast<char **> (&m_argv[0]);
}
private:
/* Disable copying. */
execv_argv (const execv_argv &) = delete;
void operator= (const execv_argv &) = delete;
/* Helper methods for constructing the argument vector. */
/* Used when building an argv for a straight execv call, without
going via the shell. */
void init_for_no_shell (const char *exec_file,
const std::string &allargs);
/* Used when building an argv for execing a shell that execs the
child program. */
void init_for_shell (const char *exec_file,
const std::string &allargs,
const char *shell_file);
/* The argument vector built. Holds non-owning pointers. Elements
either point to the strings passed to the execv_argv ctor, or
inside M_STORAGE. */
std::vector<const char *> m_argv;
/* Storage. In the no-shell case, this contains a copy of the
arguments passed to the ctor, split by '\0'. In the shell case,
this contains the quoted shell command. I.e., SHELL_COMMAND in
{"$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)
{
/* 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);
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. */
m_argv.push_back (NULL);
}
/* 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);
/* 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 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)
{
const char *exec_wrapper = get_exec_wrapper ();
/* 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 != NULL)
{
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);
}
/* Return the shell that must be used to startup the inferior. The
first attempt is the environment variable SHELL; if it is not set,
then we default to SHELL_FILE. */
static const char *
get_startup_shell ()
{
static const char *ret;
ret = getenv ("SHELL");
if (ret == NULL)
ret = SHELL_FILE;
return ret;
}
/* See nat/fork-inferior.h. */
pid_t
fork_inferior (const char *exec_file_arg, const std::string &allargs,
char **env, void (*traceme_fun) (),
void (*init_trace_fun) (int), void (*pre_trace_fun) (),
const char *shell_file_arg,
void (*exec_fun)(const char *file, char * const *argv,
char * const *env))
{
pid_t pid;
/* Set debug_fork then attach to the child while it sleeps, to debug. */
int debug_fork = 0;
const char *shell_file;
const char *exec_file;
char **save_our_env;
int i;
int save_errno;
/* 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 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 = get_startup_shell ();
gdb_assert (shell_file != NULL);
}
else
shell_file = NULL;
/* 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;
/* Perform any necessary actions regarding to TTY before the
fork/vfork call. */
prefork_hook (allargs.c_str ());
/* 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_out_err ();
/* 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. 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 !(defined(__UCLIBC__) && defined(HAS_NOMMU))
if (pre_trace_fun || debug_fork)
pid = fork ();
else
#endif
pid = vfork ();
if (pid < 0)
perror_with_name (("vfork"));
if (pid == 0)
{
/* 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);
/* Execute any necessary post-fork actions before we exec. */
postfork_child_hook ();
/* 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. */
/* "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! */
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
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;
char **argv = child_argv.argv ();
if (exec_fun != NULL)
(*exec_fun) (argv[0], &argv[0], env);
else
execvp (argv[0], &argv[0]);
/* If we get here, it's an error. */
save_errno = errno;
warning ("Cannot exec %s", argv[0]);
for (i = 1; argv[i] != NULL; i++)
warning (" %s", argv[i]);
warning ("Error: %s\n", safe_strerror (save_errno));
_exit (0177);
}
/* Restore our environment in case a vforked child clob'd it. */
environ = save_our_env;
postfork_hook (pid);
/* 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. */
return pid;
}
/* See nat/fork-inferior.h. */
ptid_t
startup_inferior (pid_t pid, int ntraps,
struct target_waitstatus *last_waitstatus,
ptid_t *last_ptid)
{
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 (pid);
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
must get it up to actual execution of the real program. */
if (get_exec_wrapper () != NULL)
pending_execs++;
while (1)
{
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 (resume_ptid, &ws, 0);
if (last_waitstatus != NULL)
*last_waitstatus = ws;
if (last_ptid != NULL)
*last_ptid = event_ptid;
if (ws.kind == TARGET_WAITKIND_IGNORE)
/* The inferior didn't really stop, keep waiting. */
continue;
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;
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 resume_ptid;
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 resume_ptid;
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;
case TARGET_WAITKIND_STOPPED:
resume_signal = ws.value.sig;
switch_to_thread (event_ptid);
break;
}
if (resume_signal != GDB_SIGNAL_TRAP)
{
/* 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. */
/* Set up the "saved terminal modes" of the inferior
based on what modes we are starting it with. */
target_terminal_init ();
/* Install inferior's terminal modes. */
target_terminal_inferior ();
terminal_initted = 1;
}
if (--pending_execs == 0)
break;
/* Just make it go on. */
target_continue_no_signal (resume_ptid);
}
}
return resume_ptid;
}
/* See nat/fork-inferior.h. */
void
trace_start_error (const char *fmt, ...)
{
va_list ap;
va_start (ap, fmt);
warning ("Could not trace the inferior process.\nError: ");
vwarning (fmt, ap);
va_end (ap);
gdb_flush_out_err ();
_exit (0177);
}
/* See nat/fork-inferior.h. */
void
trace_start_error_with_name (const char *string)
{
trace_start_error ("%s: %s", string, safe_strerror (errno));
}

106
gdb/nat/fork-inferior.h Normal file
View file

@ -0,0 +1,106 @@
/* Functions and data responsible for forking the inferior process.
Copyright (C) 1986-2017 Free Software Foundation, Inc.
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 3 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.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef FORK_INFERIOR_H
#define FORK_INFERIOR_H
#include <string>
/* Number of traps that happen between exec'ing the shell to run an
inferior and when we finally get to the inferior code, not counting
the exec for the shell. This is 1 on all supported
implementations. */
#define START_INFERIOR_TRAPS_EXPECTED 1
/* 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. */
extern pid_t fork_inferior (const char *exec_file_arg,
const std::string &allargs,
char **env, void (*traceme_fun) (),
void (*init_trace_fun) (int),
void (*pre_trace_fun) (),
const char *shell_file_arg,
void (*exec_fun) (const char *file,
char * const *argv,
char * const *env));
/* Accept NTRAPS traps from the inferior.
Return the ptid of the inferior being started. */
extern ptid_t startup_inferior (pid_t pid, int ntraps,
struct target_waitstatus *mystatus,
ptid_t *myptid);
/* Whether to start up the debuggee under a shell.
If startup-with-shell is set, GDB's "run" will attempt to start up
the debuggee under a shell. This also happens when using GDBserver
under extended remote mode.
This is in order for argument-expansion to occur. E.g.,
(gdb) run *
The "*" gets expanded by the shell into a list of files.
While this is a nice feature, it may be handy to bypass the shell
in some cases. To disable this feature, do "set startup-with-shell
false".
The catch-exec traps expected during start-up will be one more if
the target is started up with a shell. */
extern int startup_with_shell;
/* Perform any necessary tasks before a fork/vfork takes place. ARGS
is a string containing all the arguments received by the inferior.
This function is mainly used by fork_inferior. */
extern void prefork_hook (const char *args);
/* Perform any necessary tasks after a fork/vfork takes place. This
function is mainly used by fork_inferior. */
extern void postfork_hook (pid_t pid);
/* Perform any necessary tasks *on the child* after a fork/vfork takes
place. This function is mainly used by fork_inferior. */
extern void postfork_child_hook ();
/* Flush both stdout and stderr. This function needs to be
implemented differently on GDB and GDBserver. */
extern void gdb_flush_out_err ();
/* Report an error that happened when starting to trace the inferior
(i.e., when the "traceme_fun" callback is called on fork_inferior)
and bail out. This function does not return. */
extern void trace_start_error (const char *fmt, ...)
ATTRIBUTE_NORETURN;
/* Like "trace_start_error", but the error message is constructed by
combining STRING with the system error message for errno. This
function does not return. */
extern void trace_start_error_with_name (const char *string)
ATTRIBUTE_NORETURN;
#endif /* ! FORK_INFERIOR_H */

7
gdb/procfs.c
View file

@ -4377,7 +4377,7 @@ procfs_init_inferior (struct target_ops *ops, int pid)
thread_change_ptid (pid_to_ptid (pid),
ptid_build (pid, lwpid, 0));
startup_inferior (START_INFERIOR_TRAPS_EXPECTED);
gdb_startup_inferior (pid, START_INFERIOR_TRAPS_EXPECTED);
#ifdef SYS_syssgi
/* On mips-irix, we need to stop the inferior early enough during
@ -4604,6 +4604,11 @@ procfs_create_inferior (struct target_ops *ops, const char *exec_file,
pid = fork_inferior (exec_file, allargs, env, procfs_set_exec_trap,
NULL, NULL, shell_file, NULL);
/* We have something that executes now. We'll be running through
the shell at this point (if startup-with-shell is true), but the
pid shouldn't change. */
add_thread_silent (pid_to_ptid (pid));
procfs_init_inferior (ops, pid);
}

18
gdb/target.h
View file

@ -1538,16 +1538,8 @@ extern int target_terminal_is_inferior (void);
extern int target_terminal_is_ours (void);
/* Initialize the terminal settings we record for the inferior,
before we actually run the inferior. */
extern void target_terminal_init (void);
/* Put the inferior's terminal settings into effect. This is
preparation for starting or resuming the inferior. This is a no-op
unless called with the main UI as current UI. */
extern void target_terminal_inferior (void);
/* For target_terminal_init, target_terminal_inferior and
target_terminal_ours, see target/target.h. */
/* Put some of our terminal settings into effect, enough to get proper
results from our output, but do not change into or out of RAW mode
@ -1557,12 +1549,6 @@ extern void target_terminal_inferior (void);
extern void target_terminal_ours_for_output (void);
/* Put our terminal settings into effect. First record the inferior's
terminal settings so they can be restored properly later. This is
a no-op unless called with the main UI as current UI. */
extern void target_terminal_ours (void);
/* Return true if the target stack has a non-default
"to_terminal_ours" method. */

14
gdb/target/target.h
View file

@ -95,4 +95,18 @@ extern void target_mourn_inferior (ptid_t ptid);
extern int target_supports_multi_process (void);
/* Initialize the terminal settings we record for the inferior,
before we actually run the inferior. */
extern void target_terminal_init ();
/* Put the inferior's terminal settings into effect. This is
preparation for starting or resuming the inferior. This is a no-op
unless called with the main UI as current UI. */
extern void target_terminal_inferior ();
/* Put our terminal settings into effect. First record the inferior's
terminal settings so they can be restored properly later. This is
a no-op unless called with the main UI as current UI. */
extern void target_terminal_ours ();
#endif /* TARGET_COMMON_H */

6
gdb/testsuite/ChangeLog
View file

@ -1,3 +1,9 @@
2017-06-07 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.server/non-existing-program.exp: Update regex in order to
reflect the fact that gdbserver is now using fork_inferior (with a
shell) to startup the inferior.
2017-05-30 Simon Marchi <simon.marchi@ericsson.com>
* gdb.base/watch-cond-infcall.exp: Don't run if target doesn't

12
gdb/testsuite/gdb.server/non-existing-program.exp
View file

@ -39,8 +39,16 @@ set spawn_id [remote_spawn target "$gdbserver stdio non-existing-program"]
set msg "gdbserver exits cleanly"
set saw_exiting 0
expect {
# This is what we get on ptrace-based targets.
-re "stdin/stdout redirected.*No program to debug\r\nExiting\r\n$" {
# This is what we get on ptrace-based targets with
# startup-with-shell disabled (e.g., when the SHELL variable is
# unset).
-re "stdin/stdout redirected.*gdbserver: Cannot exec non-existing-program\r\ngdbserver: Error: No such file or directory\r\n\r\nDuring startup program exited with code 127\.\r\nExiting\r\n$" {
set saw_exiting 1
exp_continue
}
# Likewise, but with startup-with-shell enabled, which is the
# default behaviour.
-re "stdin/stdout redirected.*exec: non-existing-program: not found\r\nDuring startup program exited with code 127\.\r\nExiting\r\n$" {
set saw_exiting 1
exp_continue
}