Mike Yuan
33db9f214b
This used to be relevant since in old versions of glibc an internal cache is maintained, while we might sidestep their invalidation with raw_clone(). After glibc 2.25 getpid() is a trivial wrapper for the syscall, and hence there's no need to have a separate raw_getpid().
325 lines
8.1 KiB
C
325 lines
8.1 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <errno.h>
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#include <stdarg.h>
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#include <threads.h>
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#include "errno-util.h"
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#include "macro.h"
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#include "missing_syscall.h"
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#include "parse-util.h"
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#include "signal-util.h"
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#include "stdio-util.h"
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#include "string-table.h"
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#include "string-util.h"
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int reset_all_signal_handlers(void) {
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int ret = 0, r;
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for (int sig = 1; sig < _NSIG; sig++) {
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/* These two cannot be caught... */
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if (IN_SET(sig, SIGKILL, SIGSTOP))
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continue;
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/* On Linux the first two RT signals are reserved by glibc, and sigaction() will return
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* EINVAL for them. */
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r = RET_NERRNO(sigaction(sig, &sigaction_default, NULL));
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if (r != -EINVAL)
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RET_GATHER(ret, r);
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}
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return ret;
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}
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int reset_signal_mask(void) {
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sigset_t ss;
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if (sigemptyset(&ss) < 0)
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return -errno;
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return RET_NERRNO(sigprocmask(SIG_SETMASK, &ss, NULL));
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}
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int sigaction_many_internal(const struct sigaction *sa, ...) {
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int sig, r = 0;
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va_list ap;
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va_start(ap, sa);
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/* negative signal ends the list. 0 signal is skipped. */
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while ((sig = va_arg(ap, int)) >= 0) {
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if (sig == 0)
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continue;
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RET_GATHER(r, RET_NERRNO(sigaction(sig, sa, NULL)));
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}
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va_end(ap);
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return r;
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}
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static int sigset_add_many_ap(sigset_t *ss, va_list ap) {
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int sig, r = 0;
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assert(ss);
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while ((sig = va_arg(ap, int)) >= 0) {
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if (sig == 0)
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continue;
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if (sigaddset(ss, sig) < 0) {
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if (r >= 0)
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r = -errno;
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}
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}
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return r;
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}
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int sigset_add_many_internal(sigset_t *ss, ...) {
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va_list ap;
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int r;
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va_start(ap, ss);
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r = sigset_add_many_ap(ss, ap);
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va_end(ap);
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return r;
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}
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int sigprocmask_many_internal(int how, sigset_t *old, ...) {
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va_list ap;
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sigset_t ss;
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int r;
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if (sigemptyset(&ss) < 0)
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return -errno;
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va_start(ap, old);
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r = sigset_add_many_ap(&ss, ap);
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va_end(ap);
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if (r < 0)
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return r;
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return RET_NERRNO(sigprocmask(how, &ss, old));
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}
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static const char *const static_signal_table[] = {
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[SIGHUP] = "HUP",
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[SIGINT] = "INT",
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[SIGQUIT] = "QUIT",
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[SIGILL] = "ILL",
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[SIGTRAP] = "TRAP",
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[SIGABRT] = "ABRT",
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[SIGBUS] = "BUS",
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[SIGFPE] = "FPE",
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[SIGKILL] = "KILL",
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[SIGUSR1] = "USR1",
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[SIGSEGV] = "SEGV",
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[SIGUSR2] = "USR2",
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[SIGPIPE] = "PIPE",
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[SIGALRM] = "ALRM",
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[SIGTERM] = "TERM",
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#ifdef SIGSTKFLT
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[SIGSTKFLT] = "STKFLT", /* Linux on SPARC doesn't know SIGSTKFLT */
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#endif
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[SIGCHLD] = "CHLD",
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[SIGCONT] = "CONT",
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[SIGSTOP] = "STOP",
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[SIGTSTP] = "TSTP",
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[SIGTTIN] = "TTIN",
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[SIGTTOU] = "TTOU",
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[SIGURG] = "URG",
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[SIGXCPU] = "XCPU",
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[SIGXFSZ] = "XFSZ",
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[SIGVTALRM] = "VTALRM",
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[SIGPROF] = "PROF",
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[SIGWINCH] = "WINCH",
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[SIGIO] = "IO",
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[SIGPWR] = "PWR",
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[SIGSYS] = "SYS"
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};
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DEFINE_PRIVATE_STRING_TABLE_LOOKUP(static_signal, int);
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const char* signal_to_string(int signo) {
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static thread_local char buf[STRLEN("RTMIN+") + DECIMAL_STR_MAX(int)];
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const char *name;
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name = static_signal_to_string(signo);
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if (name)
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return name;
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if (signo >= SIGRTMIN && signo <= SIGRTMAX)
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xsprintf(buf, "RTMIN+%d", signo - SIGRTMIN);
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else
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xsprintf(buf, "%d", signo);
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return buf;
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}
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int signal_from_string(const char *s) {
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const char *p;
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int signo, r;
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/* Check that the input is a signal number. */
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if (safe_atoi(s, &signo) >= 0) {
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if (SIGNAL_VALID(signo))
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return signo;
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else
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return -ERANGE;
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}
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/* Drop "SIG" prefix. */
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if (startswith(s, "SIG"))
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s += 3;
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/* Check that the input is a signal name. */
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signo = static_signal_from_string(s);
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if (signo > 0)
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return signo;
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/* Check that the input is RTMIN or
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* RTMIN+n (0 <= n <= SIGRTMAX-SIGRTMIN). */
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p = startswith(s, "RTMIN");
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if (p) {
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if (*p == '\0')
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return SIGRTMIN;
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if (*p != '+')
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return -EINVAL;
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r = safe_atoi(p, &signo);
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if (r < 0)
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return r;
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if (signo < 0 || signo > SIGRTMAX - SIGRTMIN)
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return -ERANGE;
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return signo + SIGRTMIN;
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}
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/* Check that the input is RTMAX or
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* RTMAX-n (0 <= n <= SIGRTMAX-SIGRTMIN). */
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p = startswith(s, "RTMAX");
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if (p) {
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if (*p == '\0')
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return SIGRTMAX;
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if (*p != '-')
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return -EINVAL;
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r = safe_atoi(p, &signo);
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if (r < 0)
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return r;
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if (signo > 0 || signo < SIGRTMIN - SIGRTMAX)
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return -ERANGE;
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return signo + SIGRTMAX;
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}
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return -EINVAL;
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}
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void nop_signal_handler(int sig) {
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/* nothing here */
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}
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int signal_is_blocked(int sig) {
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sigset_t ss;
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int r;
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r = pthread_sigmask(SIG_SETMASK, NULL, &ss);
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if (r != 0)
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return -r;
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return RET_NERRNO(sigismember(&ss, sig));
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}
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int pop_pending_signal_internal(int sig, ...) {
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sigset_t ss;
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va_list ap;
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int r;
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if (sig < 0) /* Empty list? */
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return -EINVAL;
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if (sigemptyset(&ss) < 0)
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return -errno;
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/* Add first signal (if the signal is zero, we'll silently skip it, to make it easier to build
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* parameter lists where some element are sometimes off, similar to how sigset_add_many_ap() handles
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* this.) */
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if (sig > 0 && sigaddset(&ss, sig) < 0)
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return -errno;
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/* Add all other signals */
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va_start(ap, sig);
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r = sigset_add_many_ap(&ss, ap);
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va_end(ap);
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if (r < 0)
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return r;
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r = sigtimedwait(&ss, NULL, &(const struct timespec) {});
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if (r < 0) {
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if (errno == EAGAIN)
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return 0;
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return -errno;
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}
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return r; /* Returns the signal popped */
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}
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void propagate_signal(int sig, siginfo_t *siginfo) {
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pid_t p;
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/* To be called from a signal handler. Will raise the same signal again, in our process + in our threads.
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*
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* Note that we use getpid() instead of getpid_cached(). We might have forked with raw_clone()
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* earlier (see PID 1), and hence let's go to the raw syscall here. In particular as this is not
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* performance sensitive code.
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*
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* Note that we use kill() rather than raise() as fallback, for similar reasons. */
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p = getpid();
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if (rt_tgsigqueueinfo(p, gettid(), sig, siginfo) < 0)
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assert_se(kill(p, sig) >= 0);
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}
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const struct sigaction sigaction_ignore = {
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.sa_handler = SIG_IGN,
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.sa_flags = SA_RESTART,
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};
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const struct sigaction sigaction_default = {
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.sa_handler = SIG_DFL,
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.sa_flags = SA_RESTART,
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};
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const struct sigaction sigaction_nop_nocldstop = {
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.sa_handler = nop_signal_handler,
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.sa_flags = SA_NOCLDSTOP|SA_RESTART,
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};
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int parse_signo(const char *s, int *ret) {
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int sig, r;
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r = safe_atoi(s, &sig);
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if (r < 0)
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return r;
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if (!SIGNAL_VALID(sig))
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return -EINVAL;
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if (ret)
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*ret = sig;
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return 0;
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}
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