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-rw-r--r--src/libbasic/signal-util.c278
1 files changed, 278 insertions, 0 deletions
diff --git a/src/libbasic/signal-util.c b/src/libbasic/signal-util.c
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--- /dev/null
+++ b/src/libbasic/signal-util.c
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+/***
+ 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 "stdio-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)
+ xsprintf(buf, "RTMIN+%d", signo - SIGRTMIN);
+ else
+ xsprintf(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 (SIGNAL_VALID(signo))
+ 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 */
+}