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Date: Sun, 24 Aug 2014 03:39:44 +0000 (GMT) From: Steven Stewart-Gallus <sstewartgallus00@...angara.bc.ca> To: Steven Stewart-Gallus <sstewartgallus00@...angara.bc.ca> Cc: akpm@...ux-foundation.org, davidlohr@...com, linux-kernel@...r.kernel.org, manfred@...orfullife.com, bfields@...hat.com, dledford@...hat.com Subject: Re: [PATCH] V1 2/2] ipc: let message queues use SIGEV_THREAD_ID with mq_notify Any one who wants a quick way to test the changes can use the following hacky program that works as an init program. Thank you, Steven Stewart-Gallus #include <assert.h> #include <errno.h> #include <fcntl.h> #include <mqueue.h> #include <pthread.h> #include <signal.h> #include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include <sys/reboot.h> #include <sys/syscall.h> #include <sys/wait.h> #include <unistd.h> /* GLibc does not expose sigev_notify_thread_id so we hack it in manually */ #ifndef __ARCH_SIGEV_PREAMBLE_SIZE #define __ARCH_SIGEV_PREAMBLE_SIZE (sizeof(int) * 2 + sizeof(sigval_t)) #endif #define SIGEV_MAX_SIZE 64 #define SIGEV_PAD_SIZE ((SIGEV_MAX_SIZE - __ARCH_SIGEV_PREAMBLE_SIZE) \ / sizeof(int)) struct my_sigevent { sigval_t sigev_value; int sigev_signo; int sigev_notify; union { int _pad[SIGEV_PAD_SIZE]; int _tid; struct { void (*_function)(sigval_t); void *_attribute; /* really pthread_attr_t */ } _sigev_thread; } _sigev_un; }; #define sigev_notify_function _sigev_un._sigev_thread._function #define sigev_notify_attributes _sigev_un._sigev_thread._attribute #define sigev_notify_thread_id _sigev_un._tid struct message { int number; }; static mqd_t mq; static pid_t gettid(void) { return syscall(__NR_gettid); } static void * start_routine(void * arg) { { struct message message = { .number = 4 }; if (-1 == mq_send(mq, (char*)&message, sizeof message, 0)) { perror("mq_send"); _Exit(EXIT_FAILURE); } } { struct message message = { .number = 5 }; if (-1 == mq_send(mq, (char*)&message, sizeof message, 0)) { perror("mq_send"); _Exit(EXIT_FAILURE); } } { struct message message = { .number = 0 }; if (-1 == mq_send(mq, (char*)&message, sizeof message, 0)) { perror("mq_send"); _Exit(EXIT_FAILURE); } } return NULL; } int main(int argc, char *argv[]) { int errnum; /* Fork to allow signals to be received */ { pid_t child = fork(); if (-1 == child) { perror("fork"); return EXIT_FAILURE; } if (child != 0) { siginfo_t info; do { errnum = -1 == waitid(P_PID, child, &info, WEXITED) ? errno : 0; } while (EINTR == errnum); if (errnum != 0) { assert(errnum != EINVAL); assert(errnum != ECHILD); assert(false); } reboot(RB_POWER_OFF); } } { struct mq_attr attr = { 0 }; attr.mq_maxmsg = 8U; attr.mq_msgsize = sizeof (struct message); mq = mq_open("/foo", O_RDWR | O_CREAT | O_EXCL | O_NONBLOCK, 0, &attr); } if (-1 == mq) { perror("mq_open"); return EXIT_FAILURE; } sigset_t rtset; sigemptyset(&rtset); sigaddset(&rtset, SIGRTMIN); pthread_sigmask(SIG_BLOCK, &rtset, NULL); pthread_t worker; if ((errnum = pthread_create(&worker, NULL, start_routine, NULL)) != 0) { errno = errnum; perror("pthread_create"); return EXIT_FAILURE; } for (;;) { { struct my_sigevent sev = { 0 }; sev.sigev_notify = SIGEV_THREAD_ID; sev.sigev_signo = SIGRTMIN; sev.sigev_notify_thread_id = gettid(); if (-1 == mq_notify(mq,(struct sigevent*) &sev)) { perror("mq_notify"); return EXIT_FAILURE; } } for (;;) { struct message message; if (-1 == mq_receive(mq, (char*)&message, sizeof message, 0)) { errnum = errno; } else { errnum = 0; } if (EAGAIN == errnum) { break; } if (errnum != 0) { errno = errnum; perror("mq_receive"); return EXIT_FAILURE; } printf("received: %u\n", message.number); if (0 == message.number) { goto exit_loop; } } { int xx; if (-1 == sigwait(&rtset, &xx)) { perror("sigwait"); return EXIT_FAILURE; } } /* Flush pending signals */ pthread_sigmask(SIG_UNBLOCK, &rtset, NULL); pthread_sigmask(SIG_BLOCK, &rtset, NULL); } exit_loop: return EXIT_SUCCESS; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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