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e16a7d8f3b
`et` means `expandtab`. ```sh rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\) :vi/vi: \1 xoet\2:vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2 :vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/' ```
79 lines
3.3 KiB
C
79 lines
3.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2023 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include <pthread.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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volatile sig_atomic_t signal_handled_count;
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void reentrant_signal_handler(int signum) {
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// waste stack memory to test raise() won't recurse
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volatile char burn_stack[3500];
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burn_stack[3000] = 0;
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burn_stack[0] = 3;
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// Increment the count to indicate the signal was handled
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if (++signal_handled_count == 10000) return;
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// Re-raise the signal to test reentrancy
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raise(signum | burn_stack[3000]);
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}
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void *child_thread_func(void *arg) {
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// Send SIGUSR2 to the main thread
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pthread_kill(*((pthread_t *)arg), SIGUSR2);
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return NULL;
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}
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int main() {
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pthread_t main_thread_id = pthread_self();
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pthread_t child_thread;
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struct sigaction sa;
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// Install the signal handler for SIGUSR2
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sa.sa_handler = reentrant_signal_handler;
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = 0;
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if (sigaction(SIGUSR2, &sa, NULL) == -1) {
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exit(1); // Failed to install signal handler
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}
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// Create the child thread
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if (pthread_create(&child_thread, NULL, &child_thread_func,
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&main_thread_id) != 0) {
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exit(2); // Failed to create child thread
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}
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// Wait for the signal to be handled
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while (signal_handled_count < 10000) {
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// Busy wait
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}
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// Wait for child thread to finish
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pthread_join(child_thread, NULL);
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// Check if the signal was handled reentrantly
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if (signal_handled_count == 10000) {
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exit(0); // Success
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} else {
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exit(3); // The signal was not handled twice as expected
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}
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}
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