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August 17, 2021 22:03
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SIGCHLD bug with macOS mach xnu posix_spawn
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/* Copyright libuv contributors. All rights reserved. | |
* | |
* Permission is hereby granted, free of charge, to any person obtaining a copy | |
* of this software and associated documentation files (the "Software"), to | |
* deal in the Software without restriction, including without limitation the | |
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or | |
* sell copies of the Software, and to permit persons to whom the Software is | |
* furnished to do so, subject to the following conditions: | |
* | |
* The above copyright notice and this permission notice shall be included in | |
* all copies or substantial portions of the Software. | |
* | |
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
* IN THE SOFTWARE. | |
*/ | |
/* | |
This test demonstrates a case in which the macOS xnu mach kernel will reliably | |
fail to deliver the SIGCHLD signal most of the time. | |
*/ | |
#include <unistd.h> | |
#include <sys/wait.h> | |
#include <stdio.h> | |
#include <string.h> | |
#include <spawn.h> | |
#include <errno.h> | |
#include "assert.h" | |
static volatile int exit_cb_called; | |
void sig_chld(int sig) { | |
const char* msg = "SIGCHLD\n"; | |
write(2, msg, strlen(msg)); | |
exit_cb_called++; | |
} | |
int main(void) { | |
pid_t pid; | |
char *args[4]; | |
int status; | |
signal(SIGCHLD, sig_chld); | |
args[0] = "sh"; | |
args[1] = "-c"; | |
args[2] = "exit 12"; | |
args[3] = NULL; | |
int r = posix_spawn(&pid, "/bin/sh", NULL, NULL, args, NULL); | |
assert(r == 0); | |
for (int i = 0; i < 1000; i++) { | |
pid_t pid; | |
int r = posix_spawn(&pid, "does not exist", NULL, NULL, args, NULL); | |
assert(r == ENOENT); | |
} | |
assert(sleep(2) >= 0); | |
assert(exit_cb_called); | |
printf("exit_cb_called: %d\n", exit_cb_called); | |
//do { | |
r = waitpid(pid, &status, 0); | |
//} while (r == -1 && errno == EINTR); | |
assert(r == pid); | |
r = WIFEXITED(status); | |
assert(r); | |
r = WEXITSTATUS(status); | |
assert(r == 12); | |
return 0; | |
} |
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