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Diffstat (limited to 'tests/sighook.c')
| -rw-r--r-- | tests/sighook.c | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/tests/sighook.c b/tests/sighook.c new file mode 100644 index 0000000..82e0ae5 --- /dev/null +++ b/tests/sighook.c @@ -0,0 +1,228 @@ +// Copyright © Tavian Barnes <tavianator@tavianator.com> +// SPDX-License-Identifier: 0BSD + +#include "tests.h" + +#include "atomic.h" +#include "bfstd.h" +#include "sighook.h" +#include "thread.h" +#include "xtime.h" + +#include <errno.h> +#include <pthread.h> +#include <signal.h> +#include <stddef.h> +#include <stdlib.h> +#include <sys/wait.h> +#include <unistd.h> + +/** Counts SIGALRM deliveries. */ +static atomic size_t count = 0; + +/** SIGALRM handler. */ +static void alrm_hook(int sig, siginfo_t *info, void *arg) { + fetch_add(&count, 1, relaxed); +} + +/** SH_ONESHOT counter. */ +static atomic size_t shots = 0; + +/** SH_ONESHOT hook. */ +static void alrm_oneshot(int sig, siginfo_t *info, void *arg) { + fetch_add(&shots, 1, relaxed); +} + +/** Keeps the background thread alive. */ +static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; +static pthread_cond_t cond = PTHREAD_COND_INITIALIZER; +static bool done = false; + +/** Background thread that receives signals. */ +static void *hook_thread(void *ptr) { + mutex_lock(&mutex); + while (!done) { + cond_wait(&cond, &mutex); + } + mutex_unlock(&mutex); + return NULL; +} + +/** Block a signal in this thread. */ +static int block_signal(int sig, sigset_t *old) { + sigset_t set; + if (sigemptyset(&set) != 0) { + return -1; + } + if (sigaddset(&set, sig) != 0) { + return -1; + } + + errno = pthread_sigmask(SIG_BLOCK, &set, old); + if (errno != 0) { + return -1; + } + + return 0; +} + +/** Tests for sighook(). */ +static void check_hooks(void) { + struct sighook *hook = NULL; + struct sighook *oneshot = NULL; + + hook = sighook(SIGALRM, alrm_hook, NULL, SH_CONTINUE); + if (!bfs_echeck(hook, "sighook(SIGALRM)")) { + return; + } + + // Create a background thread to receive SIGALRM + pthread_t thread; + if (!bfs_echeck(thread_create(&thread, NULL, hook_thread, NULL) == 0)) { + goto unhook; + } + + // Block SIGALRM in this thread so the handler runs concurrently with + // sighook()/sigunhook() + sigset_t mask; + if (!bfs_echeck(block_signal(SIGALRM, &mask) == 0)) { + goto unthread; + } + + // Check that we can unregister and re-register a hook + sigunhook(hook); + hook = sighook(SIGALRM, alrm_hook, NULL, SH_CONTINUE); + if (!bfs_echeck(hook, "sighook(SIGALRM)")) { + goto unblock; + } + + // Test SH_ONESHOT + oneshot = sighook(SIGALRM, alrm_oneshot, NULL, SH_ONESHOT); + if (!bfs_echeck(oneshot, "sighook(SH_ONESHOT)")) { + goto unblock; + } + + // Create a timer that sends SIGALRM every 100 microseconds + const struct timespec ival = { .tv_nsec = 100 * 1000 }; + struct timer *timer = xtimer_start(&ival); + if (!bfs_echeck(timer, "xtimer_start()")) { + goto unblock; + } + + // Rapidly register/unregister SIGALRM hooks + size_t alarms; + while (alarms = load(&count, relaxed), alarms < 1000) { + size_t nshots = load(&shots, relaxed); + bfs_check(nshots <= 1); + if (alarms > 1) { + bfs_check(nshots == 1); + } + if (alarms >= 500) { + sigunhook(oneshot); + oneshot = NULL; + } + + struct sighook *next = sighook(SIGALRM, alrm_hook, NULL, SH_CONTINUE); + if (!bfs_echeck(next, "sighook(SIGALRM)")) { + break; + } + + sigunhook(hook); + hook = next; + } + + // Stop the timer + xtimer_stop(timer); +unblock: + // Restore the old signal mask + errno = pthread_sigmask(SIG_SETMASK, &mask, NULL); + bfs_echeck(errno == 0, "pthread_sigmask()"); +unthread: + // Quit the background thread + mutex_lock(&mutex); + done = true; + mutex_unlock(&mutex); + cond_signal(&cond); + thread_join(thread, NULL); +unhook: + // Unregister the SIGALRM hooks + sigunhook(oneshot); + sigunhook(hook); +} + +/** atsigexit() hook. */ +static void exit_hook(int sig, siginfo_t *info, void *arg) { + // Write the signal that's killing us to the pipe + int *pipes = arg; + if (xwrite(pipes[1], &sig, sizeof(sig)) != sizeof(sig)) { + abort(); + } +} + +/** Tests for atsigexit(). */ +static void check_sigexit(int sig) { + // To wait for the child to call atsigexit() + int ready[2]; + bfs_everify(pipe(ready) == 0); + + // Written in the atsigexit() handler + int killed[2]; + bfs_everify(pipe(killed) == 0); + + pid_t pid; + bfs_everify((pid = fork()) >= 0); + + if (pid > 0) { + // Parent + xclose(ready[1]); + xclose(killed[1]); + + // Wait for the child to call atsigexit() + char c; + bfs_everify(xread(ready[0], &c, 1) == 1); + + // Kill the child with the signal + bfs_everify(kill(pid, sig) == 0); + + // Check that the child died to the right signal + int wstatus; + if (bfs_echeck(xwaitpid(pid, &wstatus, 0) == pid)) { + bfs_check(WIFSIGNALED(wstatus) && WTERMSIG(wstatus) == sig); + } + + // Check that the signal hook wrote the signal number to the pipe + int hsig; + if (bfs_echeck(xread(killed[0], &hsig, sizeof(hsig)) == sizeof(hsig))) { + bfs_check(hsig == sig); + } + } else { + // Child + xclose(ready[0]); + xclose(killed[0]); + + // exit_hook() will write to killed[1] + bfs_everify(atsigexit(exit_hook, killed) != NULL); + + // Tell the parent we're ready + bfs_everify(xwrite(ready[1], "A", 1) == 1); + + // Wait until we're killed + const struct timespec dur = { .tv_nsec = 1 }; + while (true) { + nanosleep(&dur, NULL); + } + } +} + +void check_sighook(void) { + check_hooks(); + + check_sigexit(SIGINT); + check_sigexit(SIGQUIT); + check_sigexit(SIGPIPE); + + // macOS cannot distinguish between sync and async SIG{BUS,ILL,SEGV} +#if !__APPLE__ + check_sigexit(SIGSEGV); +#endif +} |