fish-shell/src/signal.cpp
Kurtis Rader 0aa7fd95b8 restyle signal module to match project style
Reduces lint errors from 15 to 15 (-0%). Line count from 754 to 438 (-42%).

Another step in resolving issue #2902.
2016-05-03 13:06:45 -07:00

396 lines
10 KiB
C++

// The library for various signal related issues.
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#ifdef HAVE_SIGINFO_H
#include <siginfo.h>
#endif
#include <pthread.h>
#include <stdbool.h>
#include "common.h"
#include "event.h"
#include "fallback.h" // IWYU pragma: keep
#include "proc.h"
#include "reader.h"
#include "signal.h"
#include "wutil.h" // IWYU pragma: keep
/// Struct describing an entry for the lookup table used to convert between signal names and signal
/// ids, etc.
struct lookup_entry {
/// Signal id.
int signal;
/// Signal name.
const wchar_t *name;
/// Signal description.
const wchar_t *desc;
};
/// The number of signal blocks in place. Increased by signal_block, decreased by signal_unblock.
static int block_count = 0;
/// Lookup table used to convert between signal names and signal ids, etc.
static const struct lookup_entry lookup[] = {
#ifdef SIGHUP
{SIGHUP, L"SIGHUP", N_(L"Terminal hung up")},
#endif
#ifdef SIGINT
{SIGINT, L"SIGINT", N_(L"Quit request from job control (^C)")},
#endif
#ifdef SIGQUIT
{SIGQUIT, L"SIGQUIT", N_(L"Quit request from job control with core dump (^\\)")},
#endif
#ifdef SIGILL
{SIGILL, L"SIGILL", N_(L"Illegal instruction")},
#endif
#ifdef SIGTRAP
{SIGTRAP, L"SIGTRAP", N_(L"Trace or breakpoint trap")},
#endif
#ifdef SIGABRT
{SIGABRT, L"SIGABRT", N_(L"Abort")},
#endif
#ifdef SIGBUS
{SIGBUS, L"SIGBUS", N_(L"Misaligned address error")},
#endif
#ifdef SIGFPE
{SIGFPE, L"SIGFPE", N_(L"Floating point exception")},
#endif
#ifdef SIGKILL
{SIGKILL, L"SIGKILL", N_(L"Forced quit")},
#endif
#ifdef SIGUSR1
{SIGUSR1, L"SIGUSR1", N_(L"User defined signal 1")},
#endif
#ifdef SIGUSR2
{SIGUSR2, L"SIGUSR2", N_(L"User defined signal 2")},
#endif
#ifdef SIGSEGV
{SIGSEGV, L"SIGSEGV", N_(L"Address boundary error")},
#endif
#ifdef SIGPIPE
{SIGPIPE, L"SIGPIPE", N_(L"Broken pipe")},
#endif
#ifdef SIGALRM
{SIGALRM, L"SIGALRM", N_(L"Timer expired")},
#endif
#ifdef SIGTERM
{SIGTERM, L"SIGTERM", N_(L"Polite quit request")},
#endif
#ifdef SIGCHLD
{SIGCHLD, L"SIGCHLD", N_(L"Child process status changed")},
#endif
#ifdef SIGCONT
{SIGCONT, L"SIGCONT", N_(L"Continue previously stopped process")},
#endif
#ifdef SIGSTOP
{SIGSTOP, L"SIGSTOP", N_(L"Forced stop")},
#endif
#ifdef SIGTSTP
{SIGTSTP, L"SIGTSTP", N_(L"Stop request from job control (^Z)")},
#endif
#ifdef SIGTTIN
{SIGTTIN, L"SIGTTIN", N_(L"Stop from terminal input")},
#endif
#ifdef SIGTTOU
{SIGTTOU, L"SIGTTOU", N_(L"Stop from terminal output")},
#endif
#ifdef SIGURG
{SIGURG, L"SIGURG", N_(L"Urgent socket condition")},
#endif
#ifdef SIGXCPU
{SIGXCPU, L"SIGXCPU", N_(L"CPU time limit exceeded")},
#endif
#ifdef SIGXFSZ
{SIGXFSZ, L"SIGXFSZ", N_(L"File size limit exceeded")},
#endif
#ifdef SIGVTALRM
{SIGVTALRM, L"SIGVTALRM", N_(L"Virtual timer expired")},
#endif
#ifdef SIGPROF
{SIGPROF, L"SIGPROF", N_(L"Profiling timer expired")},
#endif
#ifdef SIGWINCH
{SIGWINCH, L"SIGWINCH", N_(L"Window size change")},
#endif
#ifdef SIGWIND
{SIGWIND, L"SIGWIND", N_(L"Window size change")},
#endif
#ifdef SIGIO
{SIGIO, L"SIGIO", N_(L"I/O on asynchronous file descriptor is possible")},
#endif
#ifdef SIGPWR
{SIGPWR, L"SIGPWR", N_(L"Power failure")},
#endif
#ifdef SIGSYS
{SIGSYS, L"SIGSYS", N_(L"Bad system call")},
#endif
#ifdef SIGINFO
{SIGINFO, L"SIGINFO", N_(L"Information request")},
#endif
#ifdef SIGSTKFLT
{SIGSTKFLT, L"SISTKFLT", N_(L"Stack fault")},
#endif
#ifdef SIGEMT
{SIGEMT, L"SIGEMT", N_(L"Emulator trap")},
#endif
#ifdef SIGIOT
{SIGIOT, L"SIGIOT", N_(L"Abort (Alias for SIGABRT)")},
#endif
#ifdef SIGUNUSED
{SIGUNUSED, L"SIGUNUSED", N_(L"Unused signal")},
#endif
{0, 0, 0}};
/// Test if \c name is a string describing the signal named \c canonical.
static int match_signal_name(const wchar_t *canonical, const wchar_t *name) {
if (wcsncasecmp(name, L"sig", 3) == 0) name += 3;
return wcscasecmp(canonical + 3, name) == 0;
}
int wcs2sig(const wchar_t *str) {
int i;
wchar_t *end = 0;
for (i = 0; lookup[i].desc; i++) {
if (match_signal_name(lookup[i].name, str)) {
return lookup[i].signal;
}
}
errno = 0;
int res = fish_wcstoi(str, &end, 10);
if (!errno && res >= 0 && !*end) return res;
return -1;
}
const wchar_t *sig2wcs(int sig) {
int i;
for (i = 0; lookup[i].desc; i++) {
if (lookup[i].signal == sig) {
return lookup[i].name;
}
}
return _(L"Unknown");
}
const wchar_t *signal_get_desc(int sig) {
int i;
for (i = 0; lookup[i].desc; i++) {
if (lookup[i].signal == sig) {
return _(lookup[i].desc);
}
}
return _(L"Unknown");
}
/// Standard signal handler.
static void default_handler(int signal, siginfo_t *info, void *context) {
if (event_is_signal_observed(signal)) {
event_fire_signal(signal);
}
}
/// Respond to a winch signal by checking the terminal size.
static void handle_winch(int sig, siginfo_t *info, void *context) {
common_handle_winch(sig);
default_handler(sig, 0, 0);
}
/// Respond to a hup signal by exiting, unless it is caught by a shellscript function, in which case
/// we do nothing.
static void handle_hup(int sig, siginfo_t *info, void *context) {
if (event_is_signal_observed(SIGHUP)) {
default_handler(sig, 0, 0);
} else {
reader_exit(1, 1);
}
}
/// Handle sigterm. The only thing we do is restore the front process ID, then die.
static void handle_term(int sig, siginfo_t *info, void *context) {
restore_term_foreground_process_group();
signal(SIGTERM, SIG_DFL);
raise(SIGTERM);
}
/// Interactive mode ^C handler. Respond to int signal by setting interrupted-flag and stopping all
/// loops and conditionals.
static void handle_int(int sig, siginfo_t *info, void *context) {
reader_handle_int(sig);
default_handler(sig, info, context);
}
/// sigchld handler. Does notification and calls the handler in proc.c.
static void handle_chld(int sig, siginfo_t *info, void *context) {
job_handle_signal(sig, info, context);
default_handler(sig, info, context);
}
void signal_reset_handlers() {
int i;
struct sigaction act;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
act.sa_handler = SIG_DFL;
for (i = 0; lookup[i].desc; i++) {
sigaction(lookup[i].signal, &act, 0);
}
}
/// Sets appropriate signal handlers.
void signal_set_handlers() {
struct sigaction act;
if (get_is_interactive() == -1) return;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
act.sa_sigaction = &default_handler;
// First reset everything to a use default_handler, a function whose sole action is to fire of
// an event.
sigaction(SIGINT, &act, 0);
sigaction(SIGQUIT, &act, 0);
sigaction(SIGTSTP, &act, 0);
sigaction(SIGTTIN, &act, 0);
sigaction(SIGTTOU, &act, 0);
sigaction(SIGCHLD, &act, 0);
// Ignore sigpipe, which we may get from the universal variable notifier.
sigaction(SIGPIPE, &act, 0);
if (get_is_interactive()) {
// Interactive mode. Ignore interactive signals. We are a shell, we know whats best for the
// user.
act.sa_handler = SIG_IGN;
sigaction(SIGINT, &act, 0);
sigaction(SIGQUIT, &act, 0);
sigaction(SIGTSTP, &act, 0);
sigaction(SIGTTIN, &act, 0);
sigaction(SIGTTOU, &act, 0);
act.sa_sigaction = &handle_int;
act.sa_flags = SA_SIGINFO;
if (sigaction(SIGINT, &act, 0)) {
wperror(L"sigaction");
FATAL_EXIT();
}
act.sa_sigaction = &handle_chld;
act.sa_flags = SA_SIGINFO;
if (sigaction(SIGCHLD, &act, 0)) {
wperror(L"sigaction");
FATAL_EXIT();
}
#ifdef SIGWINCH
act.sa_flags = SA_SIGINFO;
act.sa_sigaction = &handle_winch;
if (sigaction(SIGWINCH, &act, 0)) {
wperror(L"sigaction");
FATAL_EXIT();
}
#endif
act.sa_flags = SA_SIGINFO;
act.sa_sigaction = &handle_hup;
if (sigaction(SIGHUP, &act, 0)) {
wperror(L"sigaction");
FATAL_EXIT();
}
// SIGTERM restores the terminal controlling process before dying.
act.sa_flags = SA_SIGINFO;
act.sa_sigaction = &handle_term;
if (sigaction(SIGTERM, &act, 0)) {
wperror(L"sigaction");
FATAL_EXIT();
}
} else {
// Non-interactive. Ignore interrupt, check exit status of processes to determine result
// instead.
act.sa_handler = SIG_IGN;
sigaction(SIGINT, &act, 0);
sigaction(SIGQUIT, &act, 0);
act.sa_handler = SIG_DFL;
act.sa_sigaction = &handle_chld;
act.sa_flags = SA_SIGINFO;
if (sigaction(SIGCHLD, &act, 0)) {
wperror(L"sigaction");
exit_without_destructors(1);
}
}
}
void signal_handle(int sig, int do_handle) {
struct sigaction act;
// These should always be handled.
if ((sig == SIGINT) || (sig == SIGQUIT) || (sig == SIGTSTP) || (sig == SIGTTIN) ||
(sig == SIGTTOU) || (sig == SIGCHLD))
return;
sigemptyset(&act.sa_mask);
if (do_handle) {
act.sa_flags = SA_SIGINFO;
act.sa_sigaction = &default_handler;
} else {
act.sa_flags = 0;
act.sa_handler = SIG_DFL;
}
sigaction(sig, &act, 0);
}
void get_signals_with_handlers(sigset_t *set) {
sigemptyset(set);
for (int i = 0; lookup[i].desc; i++) {
struct sigaction act = {};
sigaction(lookup[i].signal, NULL, &act);
if (act.sa_handler != SIG_DFL) sigaddset(set, lookup[i].signal);
}
}
void signal_block() {
ASSERT_IS_MAIN_THREAD();
sigset_t chldset;
if (!block_count) {
sigfillset(&chldset);
VOMIT_ON_FAILURE(pthread_sigmask(SIG_BLOCK, &chldset, NULL));
}
block_count++;
// debug( 0, L"signal block level increased to %d", block_count );
}
void signal_unblock() {
ASSERT_IS_MAIN_THREAD();
sigset_t chldset;
block_count--;
if (block_count < 0) {
debug(0, _(L"Signal block mismatch"));
bugreport();
FATAL_EXIT();
}
if (!block_count) {
sigfillset(&chldset);
VOMIT_ON_FAILURE(pthread_sigmask(SIG_UNBLOCK, &chldset, 0));
}
// debug( 0, L"signal block level decreased to %d", block_count );
}
bool signal_is_blocked() { return !!block_count; }