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-rw-r--r--src/basic/signal-util.c295
1 files changed, 295 insertions, 0 deletions
diff --git a/src/basic/signal-util.c b/src/basic/signal-util.c
new file mode 100644
index 0000000..63b833b
--- /dev/null
+++ b/src/basic/signal-util.c
@@ -0,0 +1,295 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <stdarg.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 (IN_SET(sig, SIGKILL, 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. */
+ for (; sig >= 0; sig = va_arg(ap, int)) {
+
+ 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[STRLEN("RTMIN+") + 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) {
+ const char *p;
+ int signo, r;
+
+ /* Check that the input is a signal number. */
+ if (safe_atoi(s, &signo) >= 0) {
+ if (SIGNAL_VALID(signo))
+ return signo;
+ else
+ return -ERANGE;
+ }
+
+ /* Drop "SIG" prefix. */
+ if (startswith(s, "SIG"))
+ s += 3;
+
+ /* Check that the input is a signal name. */
+ signo = __signal_from_string(s);
+ if (signo > 0)
+ return signo;
+
+ /* Check that the input is RTMIN or
+ * RTMIN+n (0 <= n <= SIGRTMAX-SIGRTMIN). */
+ p = startswith(s, "RTMIN");
+ if (p) {
+ if (*p == '\0')
+ return SIGRTMIN;
+ if (*p != '+')
+ return -EINVAL;
+
+ r = safe_atoi(p, &signo);
+ if (r < 0)
+ return r;
+
+ if (signo < 0 || signo > SIGRTMAX - SIGRTMIN)
+ return -ERANGE;
+
+ return signo + SIGRTMIN;
+ }
+
+ /* Check that the input is RTMAX or
+ * RTMAX-n (0 <= n <= SIGRTMAX-SIGRTMIN). */
+ p = startswith(s, "RTMAX");
+ if (p) {
+ if (*p == '\0')
+ return SIGRTMAX;
+ if (*p != '-')
+ return -EINVAL;
+
+ r = safe_atoi(p, &signo);
+ if (r < 0)
+ return r;
+
+ if (signo > 0 || signo < SIGRTMIN - SIGRTMAX)
+ return -ERANGE;
+
+ return signo + SIGRTMAX;
+ }
+
+ return -EINVAL;
+}
+
+void nop_signal_handler(int sig) {
+ /* nothing here */
+}
+
+int signal_is_blocked(int sig) {
+ sigset_t ss;
+ int r;
+
+ r = pthread_sigmask(SIG_SETMASK, NULL, &ss);
+ if (r != 0)
+ return -r;
+
+ r = sigismember(&ss, sig);
+ if (r < 0)
+ return -errno;
+
+ return r;
+}