diff options
Diffstat (limited to 'linuxthreads/sysdeps/unix/sysv/linux/mq_notify.c')
| -rw-r--r-- | linuxthreads/sysdeps/unix/sysv/linux/mq_notify.c | 287 |
1 files changed, 0 insertions, 287 deletions
diff --git a/linuxthreads/sysdeps/unix/sysv/linux/mq_notify.c b/linuxthreads/sysdeps/unix/sysv/linux/mq_notify.c deleted file mode 100644 index e9c2b6e79a..0000000000 --- a/linuxthreads/sysdeps/unix/sysv/linux/mq_notify.c +++ /dev/null @@ -1,287 +0,0 @@ -/* Copyright (C) 2004 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Contribute by Ulrich Drepper <drepper@redhat.com>, 2004. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, write to the Free - Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA - 02111-1307 USA. */ - -#include <assert.h> -#include <errno.h> -#include <fcntl.h> -#include <mqueue.h> -#include <pthread.h> -#include <signal.h> -#include <stdlib.h> -#include <string.h> -#include <sysdep.h> -#include <unistd.h> -#include <sys/socket.h> -#include <not-cancel.h> - - -#ifdef __NR_mq_notify - -/* Defined in the kernel headers: */ -#define NOTIFY_COOKIE_LEN 32 /* Length of the cookie used. */ -#define NOTIFY_WOKENUP 1 /* Code for notifcation. */ -#define NOTIFY_REMOVED 2 /* Code for closed message queue - of de-notifcation. */ - - -/* Data structure for the queued notification requests. */ -union notify_data -{ - struct - { - void (*fct) (union sigval); /* The function to run. */ - union sigval param; /* The parameter to pass. */ - pthread_attr_t *attr; /* Attributes to create the thread with. */ - /* NB: on 64-bit machines the struct as a size of 24 bytes. Which means - byte 31 can still be used for returning the status. */ - }; - char raw[NOTIFY_COOKIE_LEN]; -}; - - -/* Keep track of the initialization. */ -static pthread_once_t once = PTHREAD_ONCE_INIT; - - -/* The netlink socket. */ -static int netlink_socket = -1; - - -/* Barrier used to make sure data passed to the new thread is not - resused by the parent. */ -static pthread_barrier_t notify_barrier; - - -/* Modify the signal mask. We move this into a separate function so - that the stack space needed for sigset_t is not deducted from what - the thread can use. */ -static int -__attribute__ ((noinline)) -change_sigmask (int how, sigset_t *oss) -{ - sigset_t ss; - sigfillset (&ss); - return pthread_sigmask (how, &ss, oss); -} - - -/* The function used for the notification. */ -static void * -notification_function (void *arg) -{ - /* Copy the function and parameter so that the parent thread can go - on with its life. */ - volatile union notify_data *data = (volatile union notify_data *) arg; - void (*fct) (union sigval) = data->fct; - union sigval param = data->param; - - /* Let the parent go. */ - (void) pthread_barrier_wait (¬ify_barrier); - - /* Make the thread detached. */ - (void) pthread_detach (pthread_self ()); - - /* The parent thread has all signals blocked. This is probably a - bit surprising for this thread. So we unblock all of them. */ - (void) change_sigmask (SIG_UNBLOCK, NULL); - - /* Now run the user code. */ - fct (param); - - /* And we are done. */ - return NULL; -} - - -/* Helper thread. */ -static void * -helper_thread (void *arg) -{ - while (1) - { - union notify_data data; - - ssize_t n = recv (netlink_socket, &data, sizeof (data), - MSG_NOSIGNAL | MSG_WAITALL); - if (n < NOTIFY_COOKIE_LEN) - continue; - - if (data.raw[NOTIFY_COOKIE_LEN - 1] == NOTIFY_WOKENUP) - { - /* Just create the thread as instructed. There is no way to - report a problem with creating a thread. */ - pthread_t th; - if (__builtin_expect (pthread_create (&th, data.attr, - notification_function, &data) - == 0, 0)) - /* Since we passed a pointer to DATA to the new thread we have - to wait until it is done with it. */ - (void) pthread_barrier_wait (¬ify_barrier); - } - else if (data.raw[NOTIFY_COOKIE_LEN - 1] == NOTIFY_REMOVED) - /* The only state we keep is the copy of the thread attributes. */ - free (data.attr); - } - return NULL; -} - - -static void -reset_once (void) -{ - once = PTHREAD_ONCE_INIT; -} - - -static void -init_mq_netlink (void) -{ - /* This code might be called a second time after fork(). The file - descriptor is inherited from the parent. */ - if (netlink_socket == -1) - { - /* Just a normal netlink socket, not bound. */ - netlink_socket = socket (AF_NETLINK, SOCK_RAW, 0); - /* No need to do more if we have no socket. */ - if (netlink_socket == -1) - return; - - /* Make sure the descriptor is closed on exec. */ - if (fcntl (netlink_socket, F_SETFD, FD_CLOEXEC) != 0) - goto errout; - } - - int err = 1; - - /* Initialize the barrier. */ - if (__builtin_expect (pthread_barrier_init (¬ify_barrier, NULL, 2) == 0, - 0)) - { - /* Create the helper thread. */ - pthread_attr_t attr; - (void) pthread_attr_init (&attr); - (void) pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); - /* We do not need much stack space, the bare minimum will be enough. */ - (void) pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN); - - /* Temporarily block all signals so that the newly created - thread inherits the mask. */ - sigset_t oss; - int have_no_oss = change_sigmask (SIG_BLOCK, &oss); - - pthread_t th; - err = pthread_create (&th, &attr, helper_thread, NULL); - - /* Reset the signal mask. */ - if (!have_no_oss) - pthread_sigmask (SIG_SETMASK, &oss, NULL); - - (void) pthread_attr_destroy (&attr); - - if (err == 0) - { - static int added_atfork; - - if (added_atfork == 0 - && pthread_atfork (NULL, NULL, reset_once) != 0) - { - /* The child thread will call recv() which is a - cancellation point. */ - (void) pthread_cancel (th); - err = 1; - } - else - added_atfork = 1; - } - } - - if (err != 0) - { - errout: - close_not_cancel_no_status (netlink_socket); - netlink_socket = -1; - } -} - - -/* Register notification upon message arrival to an empty message queue - MQDES. */ -int -mq_notify (mqd_t mqdes, const struct sigevent *notification) -{ - /* Make sure the type is correctly defined. */ - assert (sizeof (union notify_data) == NOTIFY_COOKIE_LEN); - - /* Special treatment needed for SIGEV_THREAD. */ - if (notification == NULL || notification->sigev_notify != SIGEV_THREAD) - return INLINE_SYSCALL (mq_notify, 2, mqdes, notification); - - /* The kernel cannot directly start threads. This will have to be - done at userlevel. Since we cannot start threads from signal - handlers we have to create a dedicated thread which waits for - notifications for arriving messages and creates threads in - response. */ - - /* Initialize only once. */ - pthread_once (&once, init_mq_netlink); - - /* If we cannot create the netlink socket we cannot provide - SIGEV_THREAD support. */ - if (__builtin_expect (netlink_socket == -1, 0)) - { - __set_errno (ENOSYS); - return -1; - } - - /* Create the cookie. It will hold almost all the state. */ - union notify_data data; - memset (&data, '\0', sizeof (data)); - data.fct = notification->sigev_notify_function; - data.param = notification->sigev_value; - - if (notification->sigev_notify_attributes != NULL) - { - /* The thread attribute has to be allocated separately. */ - data.attr = (pthread_attr_t *) malloc (sizeof (pthread_attr_t)); - if (data.attr == NULL) - return -1; - - memcpy (data.attr, notification->sigev_notify_attributes, - sizeof (pthread_attr_t)); - } - - /* Construct the new request. */ - struct sigevent se; - se.sigev_notify = SIGEV_THREAD; - se.sigev_signo = netlink_socket; - se.sigev_value.sival_ptr = &data; - - /* Tell the kernel. */ - int retval = INLINE_SYSCALL (mq_notify, 2, mqdes, &se); - - /* If it failed, free the allocated memory. */ - if (__builtin_expect (retval != 0, 0)) - free (data.attr); - - return retval; -} - -#else -# include <sysdeps/generic/mq_notify.c> -#endif |