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author | Zack Weinberg <zackw@panix.com> | 2017-06-08 15:39:03 -0400 |
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committer | Zack Weinberg <zackw@panix.com> | 2017-06-08 15:39:03 -0400 |
commit | 5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch) | |
tree | 4470480d904b65cf14ca524f96f79eca818c3eaf /sysdeps/unix/sysv/linux/mq_notify.c | |
parent | 199fc19d3aaaf57944ef036e15904febe877fc93 (diff) | |
download | glibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.tar.gz glibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.tar.xz glibc-5046dbb4a7eba5eccfd258f92f4735c9ffc8d069.zip |
Prepare for radical source tree reorganization. zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage directory, REORG.TODO, except for files that will certainly still exist in their current form at top level when we're done (COPYING, COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which are moved to the new directory OldChangeLogs, instead), and the generated file INSTALL (which is just deleted; in the new order, there will be no generated files checked into version control).
Diffstat (limited to 'sysdeps/unix/sysv/linux/mq_notify.c')
-rw-r--r-- | sysdeps/unix/sysv/linux/mq_notify.c | 282 |
1 files changed, 0 insertions, 282 deletions
diff --git a/sysdeps/unix/sysv/linux/mq_notify.c b/sysdeps/unix/sysv/linux/mq_notify.c deleted file mode 100644 index 626430ccc7..0000000000 --- a/sysdeps/unix/sysv/linux/mq_notify.c +++ /dev/null @@ -1,282 +0,0 @@ -/* Copyright (C) 2004-2017 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, see - <http://www.gnu.org/licenses/>. */ - -#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> -#include <nptl/pthreadP.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 | SOCK_CLOEXEC, 0); - /* No need to do more if we have no socket. */ - if (netlink_socket == -1) - return; - } - - 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_get_minstack (&attr)); - - /* 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) - { - 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 (__glibc_unlikely (netlink_socket == -1)) - { - __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 (__glibc_unlikely (retval != 0)) - free (data.attr); - - return retval; -} - -#else -# include <rt/mq_notify.c> -#endif |