signal-util.c revision 93cc7779e0c121b75183920173f37cd1ee9d59cf
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2015 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include "macro.h"
#include "parse-util.h"
#include "signal-util.h"
#include "string-table.h"
#include "string-util.h"
int reset_all_signal_handlers(void) {
static const struct sigaction sa = {
.sa_handler = SIG_DFL,
.sa_flags = SA_RESTART,
};
int sig, r = 0;
for (sig = 1; sig < _NSIG; sig++) {
/* These two cannot be caught... */
if (sig == SIGKILL || sig == SIGSTOP)
continue;
/* On Linux the first two RT signals are reserved by
* glibc, and sigaction() will return EINVAL for them. */
if ((sigaction(sig, &sa, NULL) < 0))
if (errno != EINVAL && r >= 0)
r = -errno;
}
return r;
}
int reset_signal_mask(void) {
sigset_t ss;
if (sigemptyset(&ss) < 0)
return -errno;
if (sigprocmask(SIG_SETMASK, &ss, NULL) < 0)
return -errno;
return 0;
}
static int sigaction_many_ap(const struct sigaction *sa, int sig, va_list ap) {
int r = 0;
/* negative signal ends the list. 0 signal is skipped. */
if (sig < 0)
return 0;
if (sig > 0) {
if (sigaction(sig, sa, NULL) < 0)
r = -errno;
}
while ((sig = va_arg(ap, int)) >= 0) {
if (sig == 0)
continue;
if (sigaction(sig, sa, NULL) < 0) {
if (r >= 0)
r = -errno;
}
}
return r;
}
int sigaction_many(const struct sigaction *sa, ...) {
va_list ap;
int r;
va_start(ap, sa);
r = sigaction_many_ap(sa, 0, ap);
va_end(ap);
return r;
}
int ignore_signals(int sig, ...) {
static const struct sigaction sa = {
.sa_handler = SIG_IGN,
.sa_flags = SA_RESTART,
};
va_list ap;
int r;
va_start(ap, sig);
r = sigaction_many_ap(&sa, sig, ap);
va_end(ap);
return r;
}
int default_signals(int sig, ...) {
static const struct sigaction sa = {
.sa_handler = SIG_DFL,
.sa_flags = SA_RESTART,
};
va_list ap;
int r;
va_start(ap, sig);
r = sigaction_many_ap(&sa, sig, ap);
va_end(ap);
return r;
}
static int sigset_add_many_ap(sigset_t *ss, va_list ap) {
int sig, r = 0;
assert(ss);
while ((sig = va_arg(ap, int)) >= 0) {
if (sig == 0)
continue;
if (sigaddset(ss, sig) < 0) {
if (r >= 0)
r = -errno;
}
}
return r;
}
int sigset_add_many(sigset_t *ss, ...) {
va_list ap;
int r;
va_start(ap, ss);
r = sigset_add_many_ap(ss, ap);
va_end(ap);
return r;
}
int sigprocmask_many(int how, sigset_t *old, ...) {
va_list ap;
sigset_t ss;
int r;
if (sigemptyset(&ss) < 0)
return -errno;
va_start(ap, old);
r = sigset_add_many_ap(&ss, ap);
va_end(ap);
if (r < 0)
return r;
if (sigprocmask(how, &ss, old) < 0)
return -errno;
return 0;
}
static const char *const __signal_table[] = {
[SIGHUP] = "HUP",
[SIGINT] = "INT",
[SIGQUIT] = "QUIT",
[SIGILL] = "ILL",
[SIGTRAP] = "TRAP",
[SIGABRT] = "ABRT",
[SIGBUS] = "BUS",
[SIGFPE] = "FPE",
[SIGKILL] = "KILL",
[SIGUSR1] = "USR1",
[SIGSEGV] = "SEGV",
[SIGUSR2] = "USR2",
[SIGPIPE] = "PIPE",
[SIGALRM] = "ALRM",
[SIGTERM] = "TERM",
#ifdef SIGSTKFLT
[SIGSTKFLT] = "STKFLT", /* Linux on SPARC doesn't know SIGSTKFLT */
#endif
[SIGCHLD] = "CHLD",
[SIGCONT] = "CONT",
[SIGSTOP] = "STOP",
[SIGTSTP] = "TSTP",
[SIGTTIN] = "TTIN",
[SIGTTOU] = "TTOU",
[SIGURG] = "URG",
[SIGXCPU] = "XCPU",
[SIGXFSZ] = "XFSZ",
[SIGVTALRM] = "VTALRM",
[SIGPROF] = "PROF",
[SIGWINCH] = "WINCH",
[SIGIO] = "IO",
[SIGPWR] = "PWR",
[SIGSYS] = "SYS"
};
DEFINE_PRIVATE_STRING_TABLE_LOOKUP(__signal, int);
const char *signal_to_string(int signo) {
static thread_local char buf[sizeof("RTMIN+")-1 + DECIMAL_STR_MAX(int) + 1];
const char *name;
name = __signal_to_string(signo);
if (name)
return name;
if (signo >= SIGRTMIN && signo <= SIGRTMAX)
snprintf(buf, sizeof(buf), "RTMIN+%d", signo - SIGRTMIN);
else
snprintf(buf, sizeof(buf), "%d", signo);
return buf;
}
int signal_from_string(const char *s) {
int signo;
int offset = 0;
unsigned u;
signo = __signal_from_string(s);
if (signo > 0)
return signo;
if (startswith(s, "RTMIN+")) {
s += 6;
offset = SIGRTMIN;
}
if (safe_atou(s, &u) >= 0) {
signo = (int) u + offset;
if (signo > 0 && signo < _NSIG)
return signo;
}
return -EINVAL;
}
int signal_from_string_try_harder(const char *s) {
int signo;
assert(s);
signo = signal_from_string(s);
if (signo <= 0)
if (startswith(s, "SIG"))
return signal_from_string(s+3);
return signo;
}
void nop_signal_handler(int sig) {
/* nothing here */
}