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Diffstat (limited to '')
| -rw-r--r-- | lib/readline/signals.c | 754 |
1 files changed, 754 insertions, 0 deletions
diff --git a/lib/readline/signals.c b/lib/readline/signals.c new file mode 100644 index 0000000..9df365e --- /dev/null +++ b/lib/readline/signals.c @@ -0,0 +1,754 @@ +/* signals.c -- signal handling support for readline. */ + +/* Copyright (C) 1987-2021 Free Software Foundation, Inc. + + This file is part of the GNU Readline Library (Readline), a library + for reading lines of text with interactive input and history editing. + + Readline 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. + + Readline 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 Readline. If not, see <http://www.gnu.org/licenses/>. +*/ + +#define READLINE_LIBRARY + +#if defined (HAVE_CONFIG_H) +# include <config.h> +#endif + +#include <stdio.h> /* Just for NULL. Yuck. */ +#include <sys/types.h> +#include <signal.h> + +#if defined (HAVE_UNISTD_H) +# include <unistd.h> +#endif /* HAVE_UNISTD_H */ + +/* System-specific feature definitions and include files. */ +#include "rldefs.h" + +#if defined (GWINSZ_IN_SYS_IOCTL) +# include <sys/ioctl.h> +#endif /* GWINSZ_IN_SYS_IOCTL */ + +/* Some standard library routines. */ +#include "readline.h" +#include "history.h" + +#include "rlprivate.h" + +#if defined (HANDLE_SIGNALS) + +#define SIGHANDLER_RETURN return + +/* This typedef is equivalent to the one for Function; it allows us + to say SigHandler *foo = signal (SIGKILL, SIG_IGN); */ +typedef void SigHandler (int); + +#if defined (HAVE_POSIX_SIGNALS) +typedef struct sigaction sighandler_cxt; +# define rl_sigaction(s, nh, oh) sigaction(s, nh, oh) +#else +typedef struct { SigHandler *sa_handler; int sa_mask, sa_flags; } sighandler_cxt; +# define sigemptyset(m) +#endif /* !HAVE_POSIX_SIGNALS */ + +#ifndef SA_RESTART +# define SA_RESTART 0 +#endif + +static SigHandler *rl_set_sighandler (int, SigHandler *, sighandler_cxt *); +static void rl_maybe_set_sighandler (int, SigHandler *, sighandler_cxt *); +static void rl_maybe_restore_sighandler (int, sighandler_cxt *); + +static void rl_signal_handler (int); +static void _rl_handle_signal (int); + +/* Exported variables for use by applications. */ + +/* If non-zero, readline will install its own signal handlers for + SIGINT, SIGTERM, SIGHUP, SIGQUIT, SIGALRM, SIGTSTP, SIGTTIN, and SIGTTOU. */ +int rl_catch_signals = 1; + +/* If non-zero, readline will install a signal handler for SIGWINCH. */ +#ifdef SIGWINCH +int rl_catch_sigwinch = 1; +#else +int rl_catch_sigwinch = 0; /* for the readline state struct in readline.c */ +#endif + +/* Private variables. */ +int volatile _rl_caught_signal = 0; /* should be sig_atomic_t, but that requires including <signal.h> everywhere */ + +/* If non-zero, print characters corresponding to received signals as long as + the user has indicated his desire to do so (_rl_echo_control_chars). */ +int _rl_echoctl = 0; + +int _rl_intr_char = 0; +int _rl_quit_char = 0; +int _rl_susp_char = 0; + +static int signals_set_flag; +static int sigwinch_set_flag; + +#if defined (HAVE_POSIX_SIGNALS) +sigset_t _rl_orig_sigset; +#endif /* !HAVE_POSIX_SIGNALS */ + +/* **************************************************************** */ +/* */ +/* Signal Handling */ +/* */ +/* **************************************************************** */ + +static sighandler_cxt old_int, old_term, old_hup, old_alrm, old_quit; +#if defined (SIGTSTP) +static sighandler_cxt old_tstp, old_ttou, old_ttin; +#endif +#if defined (SIGWINCH) +static sighandler_cxt old_winch; +#endif + +_rl_sigcleanup_func_t *_rl_sigcleanup; +void *_rl_sigcleanarg; + +/* Readline signal handler functions. */ + +/* Called from RL_CHECK_SIGNALS() macro to run signal handling code. */ +void +_rl_signal_handler (int sig) +{ + _rl_caught_signal = 0; /* XXX */ + +#if defined (SIGWINCH) + if (sig == SIGWINCH) + { + RL_SETSTATE(RL_STATE_SIGHANDLER); + + rl_resize_terminal (); + /* XXX - experimental for now */ + /* Call a signal hook because though we called the original signal handler + in rl_sigwinch_handler below, we will not resend the signal to + ourselves. */ + if (rl_signal_event_hook) + (*rl_signal_event_hook) (); + + RL_UNSETSTATE(RL_STATE_SIGHANDLER); + } + else +#endif + _rl_handle_signal (sig); + + SIGHANDLER_RETURN; +} + +static void +rl_signal_handler (int sig) +{ + _rl_caught_signal = sig; + SIGHANDLER_RETURN; +} + +/* This is called to handle a signal when it is safe to do so (out of the + signal handler execution path). Called by _rl_signal_handler for all the + signals readline catches except SIGWINCH. */ +static void +_rl_handle_signal (int sig) +{ + int block_sig; + +#if defined (HAVE_POSIX_SIGNALS) + sigset_t set, oset; +#else /* !HAVE_POSIX_SIGNALS */ +# if defined (HAVE_BSD_SIGNALS) + long omask; +# else /* !HAVE_BSD_SIGNALS */ + sighandler_cxt dummy_cxt; /* needed for rl_set_sighandler call */ +# endif /* !HAVE_BSD_SIGNALS */ +#endif /* !HAVE_POSIX_SIGNALS */ + + RL_SETSTATE(RL_STATE_SIGHANDLER); + +#if !defined (HAVE_BSD_SIGNALS) && !defined (HAVE_POSIX_SIGNALS) + /* Since the signal will not be blocked while we are in the signal + handler, ignore it until rl_clear_signals resets the catcher. */ +# if defined (SIGALRM) + if (sig == SIGINT || sig == SIGALRM) +# else + if (sig == SIGINT) +# endif + rl_set_sighandler (sig, SIG_IGN, &dummy_cxt); +#endif /* !HAVE_BSD_SIGNALS && !HAVE_POSIX_SIGNALS */ + + /* If there's a sig cleanup function registered, call it and `deregister' + the cleanup function to avoid multiple calls */ + if (_rl_sigcleanup) + { + (*_rl_sigcleanup) (sig, _rl_sigcleanarg); + _rl_sigcleanup = 0; + _rl_sigcleanarg = 0; + } + +#if defined (HAVE_POSIX_SIGNALS) + /* Get the current set of blocked signals. If we want to block a signal for + the duration of the cleanup functions, make sure to add it to SET and + set block_sig = 1 (see the SIGHUP case below). */ + block_sig = 0; /* sentinel to block signals with sigprocmask */ + sigemptyset (&set); + sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &set); +#endif + + switch (sig) + { + case SIGINT: + /* We will end up blocking SIGTTOU while we are resetting the tty, so + watch out for this if it causes problems. We could prevent this by + setting block_sig to 1 without modifying SET. */ + _rl_reset_completion_state (); + rl_free_line_state (); +#if defined (READLINE_CALLBACKS) + rl_callback_sigcleanup (); +#endif + + /* FALLTHROUGH */ + +#if defined (SIGTSTP) + case SIGTSTP: + case SIGTTIN: + case SIGTTOU: +# if defined (HAVE_POSIX_SIGNALS) + /* Block SIGTTOU so we can restore the terminal settings to something + sane without stopping on SIGTTOU if we have been placed into the + background. Even trying to get the current terminal pgrp with + tcgetpgrp() will generate SIGTTOU, so we don't bother. We still do + this even if we've been stopped on SIGTTOU, since we handle signals + when we have returned from the signal handler and the signal is no + longer blocked. */ + if (block_sig == 0) + { + sigaddset (&set, SIGTTOU); + block_sig = 1; + } +# endif +#endif /* SIGTSTP */ + /* Any signals that should be blocked during cleanup should go here. */ +#if defined (SIGHUP) + case SIGHUP: +# if defined (_AIX) + if (block_sig == 0) + { + sigaddset (&set, sig); + block_sig = 1; + } +# endif // _AIX +#endif + /* Signals that don't require blocking during cleanup should go here. */ + case SIGTERM: +#if defined (SIGALRM) + case SIGALRM: + if (sig == SIGALRM) + _rl_timeout_handle_sigalrm (); +#endif +#if defined (SIGQUIT) + case SIGQUIT: +#endif + +#if defined (HAVE_POSIX_SIGNALS) + if (block_sig) + sigprocmask (SIG_BLOCK, &set, &oset); +#endif + + rl_echo_signal_char (sig); + rl_cleanup_after_signal (); + + /* At this point, the application's signal handler, if any, is the + current handler. */ + +#if defined (HAVE_POSIX_SIGNALS) + /* Unblock any signal(s) blocked above */ + if (block_sig) + sigprocmask (SIG_UNBLOCK, &oset, (sigset_t *)NULL); +#endif + + /* We don't have to bother unblocking the signal because we are not + running in a signal handler context. */ + +#if defined (__EMX__) + signal (sig, SIG_ACK); +#endif + +#if defined (HAVE_KILL) + kill (getpid (), sig); +#else + raise (sig); /* assume we have raise */ +#endif + + /* We don't need to modify the signal mask now that this is not run in + a signal handler context. */ + + rl_reset_after_signal (); + } + + RL_UNSETSTATE(RL_STATE_SIGHANDLER); + SIGHANDLER_RETURN; +} + +#if defined (SIGWINCH) +static void +rl_sigwinch_handler (int sig) +{ + SigHandler *oh; + +#if defined (MUST_REINSTALL_SIGHANDLERS) + sighandler_cxt dummy_winch; + + /* We don't want to change old_winch -- it holds the state of SIGWINCH + disposition set by the calling application. We need this state + because we call the application's SIGWINCH handler after updating + our own idea of the screen size. */ + rl_set_sighandler (SIGWINCH, rl_sigwinch_handler, &dummy_winch); +#endif + + RL_SETSTATE(RL_STATE_SIGHANDLER); + _rl_caught_signal = sig; + + /* If another sigwinch handler has been installed, call it. */ + oh = (SigHandler *)old_winch.sa_handler; + if (oh && oh != (SigHandler *)SIG_IGN && oh != (SigHandler *)SIG_DFL) + (*oh) (sig); + + RL_UNSETSTATE(RL_STATE_SIGHANDLER); + SIGHANDLER_RETURN; +} +#endif /* SIGWINCH */ + +/* Functions to manage signal handling. */ + +#if !defined (HAVE_POSIX_SIGNALS) +static int +rl_sigaction (int sig, sighandler_cxt *nh, sighandler_cxt *oh) +{ + oh->sa_handler = signal (sig, nh->sa_handler); + return 0; +} +#endif /* !HAVE_POSIX_SIGNALS */ + +/* Set up a readline-specific signal handler, saving the old signal + information in OHANDLER. Return the old signal handler, like + signal(). */ +static SigHandler * +rl_set_sighandler (int sig, SigHandler *handler, sighandler_cxt *ohandler) +{ + sighandler_cxt old_handler; +#if defined (HAVE_POSIX_SIGNALS) + struct sigaction act; + + act.sa_handler = handler; +# if defined (SIGWINCH) + act.sa_flags = (sig == SIGWINCH) ? SA_RESTART : 0; +# else + act.sa_flags = 0; +# endif /* SIGWINCH */ + sigemptyset (&act.sa_mask); + sigemptyset (&ohandler->sa_mask); + sigaction (sig, &act, &old_handler); +#else + old_handler.sa_handler = (SigHandler *)signal (sig, handler); +#endif /* !HAVE_POSIX_SIGNALS */ + + /* XXX -- assume we have memcpy */ + /* If rl_set_signals is called twice in a row, don't set the old handler to + rl_signal_handler, because that would cause infinite recursion. */ + if (handler != rl_signal_handler || old_handler.sa_handler != rl_signal_handler) + memcpy (ohandler, &old_handler, sizeof (sighandler_cxt)); + + return (ohandler->sa_handler); +} + +/* Set disposition of SIG to HANDLER, returning old state in OHANDLER. Don't + change disposition if OHANDLER indicates the signal was ignored. */ +static void +rl_maybe_set_sighandler (int sig, SigHandler *handler, sighandler_cxt *ohandler) +{ + sighandler_cxt dummy; + SigHandler *oh; + + sigemptyset (&dummy.sa_mask); + dummy.sa_flags = 0; + oh = rl_set_sighandler (sig, handler, ohandler); + if (oh == (SigHandler *)SIG_IGN) + rl_sigaction (sig, ohandler, &dummy); +} + +/* Set the disposition of SIG to HANDLER, if HANDLER->sa_handler indicates the + signal was not being ignored. MUST only be called for signals whose + disposition was changed using rl_maybe_set_sighandler or for which the + SIG_IGN check was performed inline (e.g., SIGALRM below). */ +static void +rl_maybe_restore_sighandler (int sig, sighandler_cxt *handler) +{ + sighandler_cxt dummy; + + sigemptyset (&dummy.sa_mask); + dummy.sa_flags = 0; + if (handler->sa_handler != SIG_IGN) + rl_sigaction (sig, handler, &dummy); +} + +int +rl_set_signals (void) +{ + sighandler_cxt dummy; + SigHandler *oh; +#if defined (HAVE_POSIX_SIGNALS) + static int sigmask_set = 0; + static sigset_t bset, oset; +#endif + +#if defined (HAVE_POSIX_SIGNALS) + if (rl_catch_signals && sigmask_set == 0) + { + sigemptyset (&bset); + + sigaddset (&bset, SIGINT); + sigaddset (&bset, SIGTERM); +#if defined (SIGHUP) + sigaddset (&bset, SIGHUP); +#endif +#if defined (SIGQUIT) + sigaddset (&bset, SIGQUIT); +#endif +#if defined (SIGALRM) + sigaddset (&bset, SIGALRM); +#endif +#if defined (SIGTSTP) + sigaddset (&bset, SIGTSTP); +#endif +#if defined (SIGTTIN) + sigaddset (&bset, SIGTTIN); +#endif +#if defined (SIGTTOU) + sigaddset (&bset, SIGTTOU); +#endif + sigmask_set = 1; + } +#endif /* HAVE_POSIX_SIGNALS */ + + if (rl_catch_signals && signals_set_flag == 0) + { +#if defined (HAVE_POSIX_SIGNALS) + sigemptyset (&_rl_orig_sigset); + sigprocmask (SIG_BLOCK, &bset, &_rl_orig_sigset); +#endif + + rl_maybe_set_sighandler (SIGINT, rl_signal_handler, &old_int); + rl_maybe_set_sighandler (SIGTERM, rl_signal_handler, &old_term); +#if defined (SIGHUP) + rl_maybe_set_sighandler (SIGHUP, rl_signal_handler, &old_hup); +#endif +#if defined (SIGQUIT) + rl_maybe_set_sighandler (SIGQUIT, rl_signal_handler, &old_quit); +#endif + +#if defined (SIGALRM) + oh = rl_set_sighandler (SIGALRM, rl_signal_handler, &old_alrm); + if (oh == (SigHandler *)SIG_IGN) + rl_sigaction (SIGALRM, &old_alrm, &dummy); +#if defined (HAVE_POSIX_SIGNALS) && defined (SA_RESTART) + /* If the application using readline has already installed a signal + handler with SA_RESTART, SIGALRM will cause reads to be restarted + automatically, so readline should just get out of the way. Since + we tested for SIG_IGN above, we can just test for SIG_DFL here. */ + if (oh != (SigHandler *)SIG_DFL && (old_alrm.sa_flags & SA_RESTART)) + rl_sigaction (SIGALRM, &old_alrm, &dummy); +#endif /* HAVE_POSIX_SIGNALS */ +#endif /* SIGALRM */ + +#if defined (SIGTSTP) + rl_maybe_set_sighandler (SIGTSTP, rl_signal_handler, &old_tstp); +#endif /* SIGTSTP */ + +#if defined (SIGTTOU) + rl_maybe_set_sighandler (SIGTTOU, rl_signal_handler, &old_ttou); +#endif /* SIGTTOU */ + +#if defined (SIGTTIN) + rl_maybe_set_sighandler (SIGTTIN, rl_signal_handler, &old_ttin); +#endif /* SIGTTIN */ + + signals_set_flag = 1; + +#if defined (HAVE_POSIX_SIGNALS) + sigprocmask (SIG_SETMASK, &_rl_orig_sigset, (sigset_t *)NULL); +#endif + } + else if (rl_catch_signals == 0) + { +#if defined (HAVE_POSIX_SIGNALS) + sigemptyset (&_rl_orig_sigset); + sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &_rl_orig_sigset); +#endif + } + +#if defined (SIGWINCH) + if (rl_catch_sigwinch && sigwinch_set_flag == 0) + { + rl_maybe_set_sighandler (SIGWINCH, rl_sigwinch_handler, &old_winch); + sigwinch_set_flag = 1; + } +#endif /* SIGWINCH */ + + return 0; +} + +int +rl_clear_signals (void) +{ + sighandler_cxt dummy; + + if (rl_catch_signals && signals_set_flag == 1) + { + /* Since rl_maybe_set_sighandler doesn't override a SIG_IGN handler, + we should in theory not have to restore a handler where + old_xxx.sa_handler == SIG_IGN. That's what rl_maybe_restore_sighandler + does. Fewer system calls should reduce readline's per-line + overhead */ + rl_maybe_restore_sighandler (SIGINT, &old_int); + rl_maybe_restore_sighandler (SIGTERM, &old_term); +#if defined (SIGHUP) + rl_maybe_restore_sighandler (SIGHUP, &old_hup); +#endif +#if defined (SIGQUIT) + rl_maybe_restore_sighandler (SIGQUIT, &old_quit); +#endif +#if defined (SIGALRM) + rl_maybe_restore_sighandler (SIGALRM, &old_alrm); +#endif + +#if defined (SIGTSTP) + rl_maybe_restore_sighandler (SIGTSTP, &old_tstp); +#endif /* SIGTSTP */ + +#if defined (SIGTTOU) + rl_maybe_restore_sighandler (SIGTTOU, &old_ttou); +#endif /* SIGTTOU */ + +#if defined (SIGTTIN) + rl_maybe_restore_sighandler (SIGTTIN, &old_ttin); +#endif /* SIGTTIN */ + + signals_set_flag = 0; + } + +#if defined (SIGWINCH) + if (rl_catch_sigwinch && sigwinch_set_flag == 1) + { + sigemptyset (&dummy.sa_mask); + rl_sigaction (SIGWINCH, &old_winch, &dummy); + sigwinch_set_flag = 0; + } +#endif + + return 0; +} + +/* Clean up the terminal and readline state after catching a signal, before + resending it to the calling application. */ +void +rl_cleanup_after_signal (void) +{ + _rl_clean_up_for_exit (); + if (rl_deprep_term_function) + (*rl_deprep_term_function) (); + rl_clear_pending_input (); + rl_clear_signals (); +} + +/* Reset the terminal and readline state after a signal handler returns. */ +void +rl_reset_after_signal (void) +{ + if (rl_prep_term_function) + (*rl_prep_term_function) (_rl_meta_flag); + rl_set_signals (); +} + +/* Free up the readline variable line state for the current line (undo list, + any partial history entry, any keyboard macros in progress, and any + numeric arguments in process) after catching a signal, before calling + rl_cleanup_after_signal(). */ +void +rl_free_line_state (void) +{ + register HIST_ENTRY *entry; + + rl_free_undo_list (); + + entry = current_history (); + if (entry) + entry->data = (char *)NULL; + + _rl_kill_kbd_macro (); + rl_clear_message (); + _rl_reset_argument (); +} + +int +rl_pending_signal (void) +{ + return (_rl_caught_signal); +} + +void +rl_check_signals (void) +{ + RL_CHECK_SIGNALS (); +} +#endif /* HANDLE_SIGNALS */ + +/* **************************************************************** */ +/* */ +/* SIGINT Management */ +/* */ +/* **************************************************************** */ + +#if defined (HAVE_POSIX_SIGNALS) +static sigset_t sigint_set, sigint_oset; +static sigset_t sigwinch_set, sigwinch_oset; +#else /* !HAVE_POSIX_SIGNALS */ +# if defined (HAVE_BSD_SIGNALS) +static int sigint_oldmask; +static int sigwinch_oldmask; +# endif /* HAVE_BSD_SIGNALS */ +#endif /* !HAVE_POSIX_SIGNALS */ + +static int sigint_blocked; +static int sigwinch_blocked; + +/* Cause SIGINT to not be delivered until the corresponding call to + release_sigint(). */ +void +_rl_block_sigint (void) +{ + if (sigint_blocked) + return; + + sigint_blocked = 1; +} + +/* Allow SIGINT to be delivered. */ +void +_rl_release_sigint (void) +{ + if (sigint_blocked == 0) + return; + + sigint_blocked = 0; + RL_CHECK_SIGNALS (); +} + +/* Cause SIGWINCH to not be delivered until the corresponding call to + release_sigwinch(). */ +void +_rl_block_sigwinch (void) +{ + if (sigwinch_blocked) + return; + +#if defined (SIGWINCH) + +#if defined (HAVE_POSIX_SIGNALS) + sigemptyset (&sigwinch_set); + sigemptyset (&sigwinch_oset); + sigaddset (&sigwinch_set, SIGWINCH); + sigprocmask (SIG_BLOCK, &sigwinch_set, &sigwinch_oset); +#else /* !HAVE_POSIX_SIGNALS */ +# if defined (HAVE_BSD_SIGNALS) + sigwinch_oldmask = sigblock (sigmask (SIGWINCH)); +# else /* !HAVE_BSD_SIGNALS */ +# if defined (HAVE_USG_SIGHOLD) + sighold (SIGWINCH); +# endif /* HAVE_USG_SIGHOLD */ +# endif /* !HAVE_BSD_SIGNALS */ +#endif /* !HAVE_POSIX_SIGNALS */ + +#endif /* SIGWINCH */ + + sigwinch_blocked = 1; +} + +/* Allow SIGWINCH to be delivered. */ +void +_rl_release_sigwinch (void) +{ + if (sigwinch_blocked == 0) + return; + +#if defined (SIGWINCH) + +#if defined (HAVE_POSIX_SIGNALS) + sigprocmask (SIG_SETMASK, &sigwinch_oset, (sigset_t *)NULL); +#else +# if defined (HAVE_BSD_SIGNALS) + sigsetmask (sigwinch_oldmask); +# else /* !HAVE_BSD_SIGNALS */ +# if defined (HAVE_USG_SIGHOLD) + sigrelse (SIGWINCH); +# endif /* HAVE_USG_SIGHOLD */ +# endif /* !HAVE_BSD_SIGNALS */ +#endif /* !HAVE_POSIX_SIGNALS */ + +#endif /* SIGWINCH */ + + sigwinch_blocked = 0; +} + +/* **************************************************************** */ +/* */ +/* Echoing special control characters */ +/* */ +/* **************************************************************** */ +void +rl_echo_signal_char (int sig) +{ + char cstr[3]; + int cslen, c; + + if (_rl_echoctl == 0 || _rl_echo_control_chars == 0) + return; + + switch (sig) + { + case SIGINT: c = _rl_intr_char; break; +#if defined (SIGQUIT) + case SIGQUIT: c = _rl_quit_char; break; +#endif +#if defined (SIGTSTP) + case SIGTSTP: c = _rl_susp_char; break; +#endif + default: return; + } + + if (CTRL_CHAR (c) || c == RUBOUT) + { + cstr[0] = '^'; + cstr[1] = CTRL_CHAR (c) ? UNCTRL (c) : '?'; + cstr[cslen = 2] = '\0'; + } + else + { + cstr[0] = c; + cstr[cslen = 1] = '\0'; + } + + _rl_output_some_chars (cstr, cslen); +} |