/* Fork a Unix child process, and set up to debug it, for GDB.
- Copyright (C) 1990-2013 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 "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
+{
+public:
+ /* EXEC_FILE is the file to run. ALLARGS is a string containing the
+ arguments to the program. If starting with a shell, SHELL_FILE
+ is the shell to run. Otherwise, SHELL_FILE is NULL. */
+ execv_argv (const char *exec_file, const std::string &allargs,
+ const char *shell_file);
+
+ /* Return a pointer to the built argv, in the type expected by
+ execv. The result is (only) valid for as long as this execv_argv
+ object is live. We return a "char **" because that's the type
+ that the execv functions expect. Note that it is guaranteed that
+ the execv functions do not modify the argv[] array nor the
+ strings to which the array point. */
+ char **argv ()
+ {
+ return const_cast<char **> (&m_argv[0]);
+ }
+
+private:
+ /* Disable copying. */
+ execv_argv (const execv_argv &) = delete;
+ void operator= (const execv_argv &) = delete;
+
+ /* Helper methods for constructing the argument vector. */
+
+ /* Used when building an argv for a straight execv call, without
+ going via the shell. */
+ void init_for_no_shell (const char *exec_file,
+ const std::string &allargs);
+
+ /* Used when building an argv for execing a shell that execs the
+ child program. */
+ void init_for_shell (const char *exec_file,
+ const std::string &allargs,
+ const char *shell_file);
+
+ /* The argument vector built. Holds non-owning pointers. Elements
+ either point to the strings passed to the execv_argv ctor, or
+ inside M_STORAGE. */
+ std::vector<const char *> m_argv;
+
+ /* Storage. In the no-shell case, this contains a copy of the
+ arguments passed to the ctor, split by '\0'. In the shell case,
+ this contains the quoted shell command. I.e., SHELL_COMMAND in
+ {"$SHELL" "-c", SHELL_COMMAND, NULL}. */
+ std::string m_storage;
+};
+
+/* Create argument vector for straight call to execvp. Breaks up
+ ALLARGS into an argument vector suitable for passing to execvp and
+ stores it in M_ARGV. E.g., on "run a b c d" this routine would get
+ as input the string "a b c d", and as output it would fill in
+ M_ARGV with the four arguments "a", "b", "c", "d". Each argument
+ in M_ARGV points to a substring of a copy of ALLARGS stored in
+ M_STORAGE. */
+
+void
+execv_argv::init_for_no_shell (const char *exec_file,
+ const std::string &allargs)
{
- char *cp = scratch, *tmp;
- for (;;)
+ /* Save/work with a copy stored in our storage. The pointers pushed
+ to M_ARGV point directly into M_STORAGE, which is modified in
+ place with the necessary NULL terminators. This avoids N heap
+ allocations and string dups when 1 is sufficient. */
+ std::string &args_copy = m_storage = allargs;
+
+ m_argv.push_back (exec_file);
+
+ for (size_t cur_pos = 0; cur_pos < args_copy.size ();)
{
- /* 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. */
- tmp = strchr (cp, ' ');
- if (tmp == NULL)
- tmp = strchr (cp, '\t');
- if (tmp == NULL)
- tmp = strchr (cp, '\n');
-
- /* No separators => end of string => break. */
- if (tmp == NULL)
- break;
- cp = tmp;
-
- /* 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 += ' ';
+ }
- return 0;
+ /* 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
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))
{
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;
- }
-
- 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 **) alloca (argc * sizeof (*argv));
- argv[0] = exec_file;
- breakup_args (allargs, &argv[1]);
}
else
- {
- /* We're going to call a shell. */
- char *shell_command;
- int len;
- char *p;
- int need_to_quote;
- const int escape_bang = escape_bang_in_quoted_argument (shell_file);
-
- /* 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';
-
- 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);
-
- /* 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>". */
- argv = (char **) alloca (4 * sizeof (char *));
- argv[0] = shell_file;
- argv[1] = "-c";
- argv[2] = shell_command;
- argv[3] = (char *) 0;
- }
+ /* 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);
+ 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);
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;
+ char **argv = child_argv.argv ();
+
if (exec_fun != NULL)
- (*exec_fun) (argv[0], argv, env);
+ (*exec_fun) (argv[0], &argv[0], env);
else
- execvp (argv[0], argv);
+ execvp (argv[0], &argv[0]);
/* If we get here, it's an error. */
save_errno = errno;
- fprintf_unfiltered (gdb_stderr, "Cannot exec %s", exec_file);
+ 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");
/* Restore our environment in case a vforked child clob'd it. */
environ = save_our_env;
+ /* Likewise the current UI. */
+ current_ui = save_ui;
+
if (!have_inferiors ())
init_thread_list ();
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
case TARGET_WAITKIND_SIGNALLED:
target_terminal_ours ();
- target_mourn_inferior ();
+ 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));
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);
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, GDB_SIGNAL_0);
+ target_continue_no_signal (resume_ptid);
}
}
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;
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