/* Low level interface to ptrace, for GDB when running under Unix. Copyright (C) 1986-1996, 1998-2012 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 "defs.h" #include "frame.h" #include "inferior.h" #include "command.h" #include "serial.h" #include "terminal.h" #include "target.h" #include "gdbthread.h" #include "observer.h" #include "gdb_string.h" #include <signal.h> #include <fcntl.h> #include "gdb_select.h" #include "inflow.h" #include "gdbcmd.h" #ifdef HAVE_SYS_IOCTL_H #include <sys/ioctl.h> #endif #ifndef O_NOCTTY #define O_NOCTTY 0 #endif extern void _initialize_inflow (void); static void pass_signal (int); static void terminal_ours_1 (int); /* Record terminal status separately for debugger and inferior. */ static struct serial *stdin_serial; /* Terminal related info we need to keep track of. Each inferior holds an instance of this structure --- we save it whenever the corresponding inferior stops, and restore it to the foreground inferior when it resumes. */ struct terminal_info { /* The name of the tty (from the `tty' command) that we gave to the inferior when it was started. */ char *run_terminal; /* TTY state. We save it whenever the inferior stops, and restore it when it resumes. */ serial_ttystate ttystate; #ifdef PROCESS_GROUP_TYPE /* Process group. Saved and restored just like ttystate. */ PROCESS_GROUP_TYPE process_group; #endif /* fcntl flags. Saved and restored just like ttystate. */ int tflags; }; /* Our own tty state, which we restore every time we need to deal with the terminal. This is only set once, when GDB first starts. The settings of flags which readline saves and restores and unimportant. */ static struct terminal_info our_terminal_info; static struct terminal_info *get_inflow_inferior_data (struct inferior *); #ifdef PROCESS_GROUP_TYPE /* Return the process group of the current inferior. */ PROCESS_GROUP_TYPE inferior_process_group (void) { return get_inflow_inferior_data (current_inferior ())->process_group; } #endif /* While the inferior is running, we want SIGINT and SIGQUIT to go to the inferior only. If we have job control, that takes care of it. If not, we save our handlers in these two variables and set SIGINT and SIGQUIT to SIG_IGN. */ static void (*sigint_ours) (); static void (*sigquit_ours) (); /* The name of the tty (from the `tty' command) that we're giving to the inferior when starting it up. This is only (and should only be) used as a transient global by new_tty_prefork, create_tty_session, new_tty and new_tty_postfork, all called from fork_inferior, while forking a new child. */ static const char *inferior_thisrun_terminal; /* Nonzero if our terminal settings are in effect. Zero if the inferior's settings are in effect. Ignored if !gdb_has_a_terminal (). */ int terminal_is_ours; #ifdef PROCESS_GROUP_TYPE static PROCESS_GROUP_TYPE gdb_getpgrp (void) { int process_group = -1; #ifdef HAVE_TERMIOS process_group = tcgetpgrp (0); #endif #ifdef HAVE_TERMIO process_group = getpgrp (); #endif #ifdef HAVE_SGTTY ioctl (0, TIOCGPGRP, &process_group); #endif return process_group; } #endif enum { yes, no, have_not_checked } gdb_has_a_terminal_flag = have_not_checked; /* The value of the "interactive-mode" setting. */ static enum auto_boolean interactive_mode = AUTO_BOOLEAN_AUTO; /* Implement the "show interactive-mode" option. */ static void show_interactive_mode (struct ui_file *file, int from_tty, struct cmd_list_element *c, const char *value) { if (interactive_mode == AUTO_BOOLEAN_AUTO) fprintf_filtered (file, "Debugger's interactive mode " "is %s (currently %s).\n", value, gdb_has_a_terminal () ? "on" : "off"); else fprintf_filtered (file, "Debugger's interactive mode is %s.\n", value); } /* Does GDB have a terminal (on stdin)? */ int gdb_has_a_terminal (void) { if (interactive_mode != AUTO_BOOLEAN_AUTO) return interactive_mode == AUTO_BOOLEAN_TRUE; switch (gdb_has_a_terminal_flag) { case yes: return 1; case no: return 0; case have_not_checked: /* Get all the current tty settings (including whether we have a tty at all!). Can't do this in _initialize_inflow because serial_fdopen() won't work until the serial_ops_list is initialized. */ #ifdef F_GETFL our_terminal_info.tflags = fcntl (0, F_GETFL, 0); #endif gdb_has_a_terminal_flag = no; if (stdin_serial != NULL) { our_terminal_info.ttystate = serial_get_tty_state (stdin_serial); if (our_terminal_info.ttystate != NULL) { gdb_has_a_terminal_flag = yes; #ifdef PROCESS_GROUP_TYPE our_terminal_info.process_group = gdb_getpgrp (); #endif } } return gdb_has_a_terminal_flag == yes; default: /* "Can't happen". */ return 0; } } /* Macro for printing errors from ioctl operations */ #define OOPSY(what) \ if (result == -1) \ fprintf_unfiltered(gdb_stderr, "[%s failed in terminal_inferior: %s]\n", \ what, safe_strerror (errno)) static void terminal_ours_1 (int); /* Initialize the terminal settings we record for the inferior, before we actually run the inferior. */ void terminal_init_inferior_with_pgrp (int pgrp) { if (gdb_has_a_terminal ()) { struct inferior *inf = current_inferior (); struct terminal_info *tinfo = get_inflow_inferior_data (inf); xfree (tinfo->ttystate); tinfo->ttystate = serial_copy_tty_state (stdin_serial, our_terminal_info.ttystate); #ifdef PROCESS_GROUP_TYPE tinfo->process_group = pgrp; #endif /* Make sure that next time we call terminal_inferior (which will be before the program runs, as it needs to be), we install the new process group. */ terminal_is_ours = 1; } } /* Save the terminal settings again. This is necessary for the TUI when it switches to TUI or non-TUI mode; curses changes the terminal and gdb must be able to restore it correctly. */ void terminal_save_ours (void) { if (gdb_has_a_terminal ()) { xfree (our_terminal_info.ttystate); our_terminal_info.ttystate = serial_get_tty_state (stdin_serial); } } void terminal_init_inferior (void) { #ifdef PROCESS_GROUP_TYPE /* This is for Lynx, and should be cleaned up by having Lynx be a separate debugging target with a version of target_terminal_init_inferior which passes in the process group to a generic routine which does all the work (and the non-threaded child_terminal_init_inferior can just pass in inferior_ptid to the same routine). */ /* We assume INFERIOR_PID is also the child's process group. */ terminal_init_inferior_with_pgrp (PIDGET (inferior_ptid)); #endif /* PROCESS_GROUP_TYPE */ } /* Put the inferior's terminal settings into effect. This is preparation for starting or resuming the inferior. */ void terminal_inferior (void) { struct inferior *inf; struct terminal_info *tinfo; if (!terminal_is_ours) return; inf = current_inferior (); tinfo = get_inflow_inferior_data (inf); if (gdb_has_a_terminal () && tinfo->ttystate != NULL && tinfo->run_terminal == NULL) { int result; #ifdef F_GETFL /* Is there a reason this is being done twice? It happens both places we use F_SETFL, so I'm inclined to think perhaps there is some reason, however perverse. Perhaps not though... */ result = fcntl (0, F_SETFL, tinfo->tflags); result = fcntl (0, F_SETFL, tinfo->tflags); OOPSY ("fcntl F_SETFL"); #endif /* Because we were careful to not change in or out of raw mode in terminal_ours, we will not change in our out of raw mode with this call, so we don't flush any input. */ result = serial_set_tty_state (stdin_serial, tinfo->ttystate); OOPSY ("setting tty state"); if (!job_control) { sigint_ours = (void (*)()) signal (SIGINT, SIG_IGN); #ifdef SIGQUIT sigquit_ours = (void (*)()) signal (SIGQUIT, SIG_IGN); #endif } /* If attach_flag is set, we don't know whether we are sharing a terminal with the inferior or not. (attaching a process without a terminal is one case where we do not; attaching a process which we ran from the same shell as GDB via `&' is one case where we do, I think (but perhaps this is not `sharing' in the sense that we need to save and restore tty state)). I don't know if there is any way to tell whether we are sharing a terminal. So what we do is to go through all the saving and restoring of the tty state, but ignore errors setting the process group, which will happen if we are not sharing a terminal). */ if (job_control) { #ifdef HAVE_TERMIOS result = tcsetpgrp (0, tinfo->process_group); if (!inf->attach_flag) OOPSY ("tcsetpgrp"); #endif #ifdef HAVE_SGTTY result = ioctl (0, TIOCSPGRP, &tinfo->process_group); if (!inf->attach_flag) OOPSY ("TIOCSPGRP"); #endif } } terminal_is_ours = 0; } /* 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 so that no input is discarded. After doing this, either terminal_ours or terminal_inferior should be called to get back to a normal state of affairs. */ void terminal_ours_for_output (void) { terminal_ours_1 (1); } /* Put our terminal settings into effect. First record the inferior's terminal settings so they can be restored properly later. */ void terminal_ours (void) { terminal_ours_1 (0); } /* output_only is not used, and should not be used unless we introduce separate terminal_is_ours and terminal_is_ours_for_output flags. */ static void terminal_ours_1 (int output_only) { struct inferior *inf; struct terminal_info *tinfo; if (terminal_is_ours) return; terminal_is_ours = 1; /* Checking inferior->run_terminal is necessary so that if GDB is running in the background, it won't block trying to do the ioctl()'s below. Checking gdb_has_a_terminal avoids attempting all the ioctl's when running in batch. */ inf = current_inferior (); tinfo = get_inflow_inferior_data (inf); if (tinfo->run_terminal != NULL || gdb_has_a_terminal () == 0) return; { #ifdef SIGTTOU /* Ignore this signal since it will happen when we try to set the pgrp. */ void (*osigttou) () = NULL; #endif int result; #ifdef SIGTTOU if (job_control) osigttou = (void (*)()) signal (SIGTTOU, SIG_IGN); #endif xfree (tinfo->ttystate); tinfo->ttystate = serial_get_tty_state (stdin_serial); #ifdef PROCESS_GROUP_TYPE if (!inf->attach_flag) /* If setpgrp failed in terminal_inferior, this would give us our process group instead of the inferior's. See terminal_inferior for details. */ tinfo->process_group = gdb_getpgrp (); #endif /* Here we used to set ICANON in our ttystate, but I believe this was an artifact from before when we used readline. Readline sets the tty state when it needs to. FIXME-maybe: However, query() expects non-raw mode and doesn't use readline. Maybe query should use readline (on the other hand, this only matters for HAVE_SGTTY, not termio or termios, I think). */ /* Set tty state to our_ttystate. We don't change in our out of raw mode, to avoid flushing input. We need to do the same thing regardless of output_only, because we don't have separate terminal_is_ours and terminal_is_ours_for_output flags. It's OK, though, since readline will deal with raw mode when/if it needs to. */ serial_noflush_set_tty_state (stdin_serial, our_terminal_info.ttystate, tinfo->ttystate); if (job_control) { #ifdef HAVE_TERMIOS result = tcsetpgrp (0, our_terminal_info.process_group); #if 0 /* This fails on Ultrix with EINVAL if you run the testsuite in the background with nohup, and then log out. GDB never used to check for an error here, so perhaps there are other such situations as well. */ if (result == -1) fprintf_unfiltered (gdb_stderr, "[tcsetpgrp failed in terminal_ours: %s]\n", safe_strerror (errno)); #endif #endif /* termios */ #ifdef HAVE_SGTTY result = ioctl (0, TIOCSPGRP, &our_terminal_info.process_group); #endif } #ifdef SIGTTOU if (job_control) signal (SIGTTOU, osigttou); #endif if (!job_control) { signal (SIGINT, sigint_ours); #ifdef SIGQUIT signal (SIGQUIT, sigquit_ours); #endif } #ifdef F_GETFL tinfo->tflags = fcntl (0, F_GETFL, 0); /* Is there a reason this is being done twice? It happens both places we use F_SETFL, so I'm inclined to think perhaps there is some reason, however perverse. Perhaps not though... */ result = fcntl (0, F_SETFL, our_terminal_info.tflags); result = fcntl (0, F_SETFL, our_terminal_info.tflags); #endif } } /* Per-inferior data key. */ static const struct inferior_data *inflow_inferior_data; static void inflow_inferior_data_cleanup (struct inferior *inf, void *arg) { struct terminal_info *info; info = inferior_data (inf, inflow_inferior_data); if (info != NULL) { xfree (info->run_terminal); xfree (info->ttystate); xfree (info); } } /* Get the current svr4 data. If none is found yet, add it now. This function always returns a valid object. */ static struct terminal_info * get_inflow_inferior_data (struct inferior *inf) { struct terminal_info *info; info = inferior_data (inf, inflow_inferior_data); if (info == NULL) { info = XZALLOC (struct terminal_info); set_inferior_data (inf, inflow_inferior_data, info); } return info; } /* This is a "inferior_exit" observer. Releases the TERMINAL_INFO member of the inferior structure. This field is private to inflow.c, and its type is opaque to the rest of GDB. PID is the target pid of the inferior that is about to be removed from the inferior list. */ static void inflow_inferior_exit (struct inferior *inf) { struct terminal_info *info; info = inferior_data (inf, inflow_inferior_data); if (info != NULL) { xfree (info->run_terminal); xfree (info->ttystate); xfree (info); set_inferior_data (inf, inflow_inferior_data, NULL); } } void copy_terminal_info (struct inferior *to, struct inferior *from) { struct terminal_info *tinfo_to, *tinfo_from; tinfo_to = get_inflow_inferior_data (to); tinfo_from = get_inflow_inferior_data (from); xfree (tinfo_to->run_terminal); xfree (tinfo_to->ttystate); *tinfo_to = *tinfo_from; if (tinfo_from->run_terminal) tinfo_to->run_terminal = xstrdup (tinfo_from->run_terminal); if (tinfo_from->ttystate) tinfo_to->ttystate = serial_copy_tty_state (stdin_serial, tinfo_from->ttystate); } void term_info (char *arg, int from_tty) { target_terminal_info (arg, from_tty); } void child_terminal_info (char *args, int from_tty) { struct inferior *inf; struct terminal_info *tinfo; if (!gdb_has_a_terminal ()) { printf_filtered (_("This GDB does not control a terminal.\n")); return; } if (ptid_equal (inferior_ptid, null_ptid)) return; inf = current_inferior (); tinfo = get_inflow_inferior_data (inf); printf_filtered (_("Inferior's terminal status " "(currently saved by GDB):\n")); /* First the fcntl flags. */ { int flags; flags = tinfo->tflags; printf_filtered ("File descriptor flags = "); #ifndef O_ACCMODE #define O_ACCMODE (O_RDONLY | O_WRONLY | O_RDWR) #endif /* (O_ACCMODE) parens are to avoid Ultrix header file bug. */ switch (flags & (O_ACCMODE)) { case O_RDONLY: printf_filtered ("O_RDONLY"); break; case O_WRONLY: printf_filtered ("O_WRONLY"); break; case O_RDWR: printf_filtered ("O_RDWR"); break; } flags &= ~(O_ACCMODE); #ifdef O_NONBLOCK if (flags & O_NONBLOCK) printf_filtered (" | O_NONBLOCK"); flags &= ~O_NONBLOCK; #endif #if defined (O_NDELAY) /* If O_NDELAY and O_NONBLOCK are defined to the same thing, we will print it as O_NONBLOCK, which is good cause that is what POSIX has, and the flag will already be cleared by the time we get here. */ if (flags & O_NDELAY) printf_filtered (" | O_NDELAY"); flags &= ~O_NDELAY; #endif if (flags & O_APPEND) printf_filtered (" | O_APPEND"); flags &= ~O_APPEND; #if defined (O_BINARY) if (flags & O_BINARY) printf_filtered (" | O_BINARY"); flags &= ~O_BINARY; #endif if (flags) printf_filtered (" | 0x%x", flags); printf_filtered ("\n"); } #ifdef PROCESS_GROUP_TYPE printf_filtered ("Process group = %d\n", (int) tinfo->process_group); #endif serial_print_tty_state (stdin_serial, tinfo->ttystate, gdb_stdout); } /* NEW_TTY_PREFORK is called before forking a new child process, so we can record the state of ttys in the child to be formed. TTYNAME is null if we are to share the terminal with gdb; or points to a string containing the name of the desired tty. NEW_TTY is called in new child processes under Unix, which will become debugger target processes. This actually switches to the terminal specified in the NEW_TTY_PREFORK call. */ void new_tty_prefork (const char *ttyname) { /* Save the name for later, for determining whether we and the child are sharing a tty. */ inferior_thisrun_terminal = ttyname; } #if !defined(__GO32__) && !defined(_WIN32) /* If RESULT, assumed to be the return value from a system call, is negative, print the error message indicated by errno and exit. MSG should identify the operation that failed. */ static void check_syscall (const char *msg, int result) { if (result < 0) { print_sys_errmsg (msg, errno); _exit (1); } } #endif void new_tty (void) { int tty; if (inferior_thisrun_terminal == 0) return; #if !defined(__GO32__) && !defined(_WIN32) #ifdef TIOCNOTTY /* Disconnect the child process from our controlling terminal. On some systems (SVR4 for example), this may cause a SIGTTOU, so temporarily ignore SIGTTOU. */ tty = open ("/dev/tty", O_RDWR); if (tty > 0) { void (*osigttou) (); osigttou = (void (*)()) signal (SIGTTOU, SIG_IGN); ioctl (tty, TIOCNOTTY, 0); close (tty); signal (SIGTTOU, osigttou); } #endif /* Now open the specified new terminal. */ tty = open (inferior_thisrun_terminal, O_RDWR | O_NOCTTY); check_syscall (inferior_thisrun_terminal, tty); /* Avoid use of dup2; doesn't exist on all systems. */ if (tty != 0) { close (0); check_syscall ("dup'ing tty into fd 0", dup (tty)); } if (tty != 1) { close (1); check_syscall ("dup'ing tty into fd 1", dup (tty)); } if (tty != 2) { close (2); check_syscall ("dup'ing tty into fd 2", dup (tty)); } #ifdef TIOCSCTTY /* Make tty our new controlling terminal. */ if (ioctl (tty, TIOCSCTTY, 0) == -1) /* Mention GDB in warning because it will appear in the inferior's terminal instead of GDB's. */ warning (_("GDB: Failed to set controlling terminal: %s"), safe_strerror (errno)); #endif if (tty > 2) close (tty); #endif /* !go32 && !win32 */ } /* NEW_TTY_POSTFORK is called after forking a new child process, and adding it to the inferior table, to store the TTYNAME being used by the child, or null if it sharing the terminal with gdb. */ void new_tty_postfork (void) { /* Save the name for later, for determining whether we and the child are sharing a tty. */ if (inferior_thisrun_terminal) { struct inferior *inf = current_inferior (); struct terminal_info *tinfo = get_inflow_inferior_data (inf); tinfo->run_terminal = xstrdup (inferior_thisrun_terminal); } inferior_thisrun_terminal = NULL; } /* Call set_sigint_trap when you need to pass a signal on to an attached process when handling SIGINT. */ static void pass_signal (int signo) { #ifndef _WIN32 kill (PIDGET (inferior_ptid), SIGINT); #endif } static void (*osig) (); static int osig_set; void set_sigint_trap (void) { struct inferior *inf = current_inferior (); struct terminal_info *tinfo = get_inflow_inferior_data (inf); if (inf->attach_flag || tinfo->run_terminal) { osig = (void (*)()) signal (SIGINT, pass_signal); osig_set = 1; } else osig_set = 0; } void clear_sigint_trap (void) { if (osig_set) { signal (SIGINT, osig); osig_set = 0; } } /* Create a new session if the inferior will run in a different tty. A session is UNIX's way of grouping processes that share a controlling terminal, so a new one is needed if the inferior terminal will be different from GDB's. Returns the session id of the new session, 0 if no session was created or -1 if an error occurred. */ pid_t create_tty_session (void) { #ifdef HAVE_SETSID pid_t ret; if (!job_control || inferior_thisrun_terminal == 0) return 0; ret = setsid (); if (ret == -1) warning (_("Failed to create new terminal session: setsid: %s"), safe_strerror (errno)); return ret; #else return 0; #endif /* HAVE_SETSID */ } /* This is here because this is where we figure out whether we (probably) have job control. Just using job_control only does part of it because setpgid or setpgrp might not exist on a system without job control. It might be considered misplaced (on the other hand, process groups and job control are closely related to ttys). For a more clean implementation, in libiberty, put a setpgid which merely calls setpgrp and a setpgrp which does nothing (any system with job control will have one or the other). */ int gdb_setpgid (void) { int retval = 0; if (job_control) { #if defined (HAVE_TERMIOS) || defined (TIOCGPGRP) #ifdef HAVE_SETPGID /* The call setpgid (0, 0) is supposed to work and mean the same thing as this, but on Ultrix 4.2A it fails with EPERM (and setpgid (getpid (), getpid ()) succeeds). */ retval = setpgid (getpid (), getpid ()); #else #ifdef HAVE_SETPGRP #ifdef SETPGRP_VOID retval = setpgrp (); #else retval = setpgrp (getpid (), getpid ()); #endif #endif /* HAVE_SETPGRP */ #endif /* HAVE_SETPGID */ #endif /* defined (HAVE_TERMIOS) || defined (TIOCGPGRP) */ } return retval; } /* Get all the current tty settings (including whether we have a tty at all!). We can't do this in _initialize_inflow because serial_fdopen() won't work until the serial_ops_list is initialized, but we don't want to do it lazily either, so that we can guarantee stdin_serial is opened if there is a terminal. */ void initialize_stdin_serial (void) { stdin_serial = serial_fdopen (0); } void _initialize_inflow (void) { add_info ("terminal", term_info, _("Print inferior's saved terminal status.")); add_setshow_auto_boolean_cmd ("interactive-mode", class_support, &interactive_mode, _("\ Set whether GDB's standard input is a terminal."), _("\ Show whether GDB's standard input is a terminal."), _("\ If on, GDB assumes that standard input is a terminal. In practice, it\n\ means that GDB should wait for the user to answer queries associated to\n\ commands entered at the command prompt. If off, GDB assumes that standard\n\ input is not a terminal, and uses the default answer to all queries.\n\ If auto (the default), determine which mode to use based on the standard\n\ input settings."), NULL, show_interactive_mode, &setlist, &showlist); terminal_is_ours = 1; /* OK, figure out whether we have job control. If neither termios nor sgtty (i.e. termio or go32), leave job_control 0. */ #if defined (HAVE_TERMIOS) /* Do all systems with termios have the POSIX way of identifying job control? I hope so. */ #ifdef _POSIX_JOB_CONTROL job_control = 1; #else #ifdef _SC_JOB_CONTROL job_control = sysconf (_SC_JOB_CONTROL); #else job_control = 0; /* Have to assume the worst. */ #endif /* _SC_JOB_CONTROL */ #endif /* _POSIX_JOB_CONTROL */ #endif /* HAVE_TERMIOS */ #ifdef HAVE_SGTTY #ifdef TIOCGPGRP job_control = 1; #else job_control = 0; #endif /* TIOCGPGRP */ #endif /* sgtty */ observer_attach_inferior_exit (inflow_inferior_exit); inflow_inferior_data = register_inferior_data_with_cleanup (inflow_inferior_data_cleanup); }