diff options
Diffstat (limited to 'src/basic/signal-util.c')
| -rw-r--r-- | src/basic/signal-util.c | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/src/basic/signal-util.c b/src/basic/signal-util.c new file mode 100644 index 0000000..5d948462 --- /dev/null +++ b/src/basic/signal-util.c @@ -0,0 +1,303 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <errno.h> +#include <stdarg.h> + +#include "errno-util.h" +#include "macro.h" +#include "missing_syscall.h" +#include "missing_threads.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 r = 0; + + for (int 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; + + return RET_NERRNO(sigprocmask(SIG_SETMASK, &ss, NULL)); +} + +int sigaction_many_internal(const struct sigaction *sa, ...) { + int sig, r = 0; + va_list ap; + + va_start(ap, sa); + + /* negative signal ends the list. 0 signal is skipped. */ + while ((sig = va_arg(ap, int)) >= 0) { + + if (sig == 0) + continue; + + if (sigaction(sig, sa, NULL) < 0) { + if (r >= 0) + r = -errno; + } + } + + 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 static_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(static_signal, int); + +const char *signal_to_string(int signo) { + static thread_local char buf[STRLEN("RTMIN+") + DECIMAL_STR_MAX(int)]; + const char *name; + + name = static_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 = static_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; + + return RET_NERRNO(sigismember(&ss, sig)); +} + +int pop_pending_signal_internal(int sig, ...) { + sigset_t ss; + va_list ap; + int r; + + if (sig < 0) /* Empty list? */ + return -EINVAL; + + if (sigemptyset(&ss) < 0) + return -errno; + + /* Add first signal (if the signal is zero, we'll silently skip it, to make it easier to build + * parameter lists where some element are sometimes off, similar to how sigset_add_many_ap() handles + * this.) */ + if (sig > 0 && sigaddset(&ss, sig) < 0) + return -errno; + + /* Add all other signals */ + va_start(ap, sig); + r = sigset_add_many_ap(&ss, ap); + va_end(ap); + if (r < 0) + return r; + + r = sigtimedwait(&ss, NULL, &(struct timespec) { 0, 0 }); + if (r < 0) { + if (errno == EAGAIN) + return 0; + + return -errno; + } + + return r; /* Returns the signal popped */ +} + +void propagate_signal(int sig, siginfo_t *siginfo) { + pid_t p; + + /* To be called from a signal handler. Will raise the same signal again, in our process + in our threads. + * + * Note that we use raw_getpid() instead of getpid_cached(). We might have forked with raw_clone() + * earlier (see PID 1), and hence let's go to the raw syscall here. In particular as this is not + * performance sensitive code. + * + * Note that we use kill() rather than raise() as fallback, for similar reasons. */ + + p = raw_getpid(); + + if (rt_tgsigqueueinfo(p, gettid(), sig, siginfo) < 0) + assert_se(kill(p, sig) >= 0); +} |