+++ /dev/null
-/* GStreamer
- * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
- * 2000 Wim Taymans <wtay@chello.be>
- *
- * cothreads.c: Cothreading routines
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
- */
-
-
-#include "gst_private.h"
-#include <glib.h>
-
-#include <sys/time.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <signal.h>
-#include <setjmp.h>
-#include <unistd.h>
-#include <errno.h>
-#include <sys/mman.h>
-
-#include "cothreads.h"
-#include "gstarch.h"
-#include "gstinfo.h"
-#include "gstutils.h"
-
-#ifdef HAVE_UCONTEXT_H
-#include <ucontext.h>
-#endif
-
-#ifndef MAP_ANONYMOUS
-#ifdef MAP_ANON
-/* older glibc's have MAP_ANON instead of MAP_ANONYMOUS */
-#define MAP_ANONYMOUS MAP_ANON
-#else
-/* make due without. If this fails, we need to open and map /dev/zero */
-#define MAP_ANONYMOUS 0
-#endif
-#endif
-
-#define STACK_SIZE 0x200000
-
-#define COTHREAD_MAGIC_NUMBER 0xabcdef
-
-#define COTHREAD_MAXTHREADS 16
-#define COTHREAD_STACKSIZE (STACK_SIZE/COTHREAD_MAXTHREADS)
-
-static void cothread_destroy (cothread_state * cothread);
-
-struct _cothread_context
-{
- cothread_state *cothreads[COTHREAD_MAXTHREADS]; /* array of cothread states */
- int ncothreads;
- int current;
- unsigned long stack_top;
- GHashTable *data;
- GThread *thread;
-};
-
-/* Disabling this define allows you to shut off a few checks in
- * cothread_switch. This likely will speed things up fractionally */
-#define COTHREAD_PARANOID
-
-
-/* this _cothread_ctx_key is used as a GThread key to the thread's context
- * a GThread key is a "pointer" to memory space that is/can be different
- * (ie. private) for each thread. The key itself is shared among threads,
- * so it only needs to be initialized once.
- */
-static GStaticPrivate _cothread_ctx_key = G_STATIC_PRIVATE_INIT;
-
-/*
- * This should only after context init, since we do checking.
- */
-static cothread_context *
-cothread_get_current_context (void)
-{
- cothread_context *ctx;
-
- ctx = g_static_private_get (&_cothread_ctx_key);
- g_assert (ctx);
-
-#ifdef COTHREAD_PARANOID
- g_assert (ctx->thread == g_thread_self ());
-#endif
-
- return ctx;
-}
-
-/**
- * cothread_context_init:
- *
- * Create and initialize a new cothread context
- *
- * Returns: the new cothread context
- */
-cothread_context *
-cothread_context_init (void)
-{
- char __csf;
- void *current_stack_frame = &__csf; /* Get pointer inside current stack frame */
- cothread_context *ctx;
-
- /* if there already is a cotread context for this thread,
- * just return it */
- ctx = g_static_private_get (&_cothread_ctx_key);
- if (ctx) {
- GST_CAT_INFO (GST_CAT_COTHREADS,
- "returning private _cothread_ctx_key %p", ctx);
- return ctx;
- }
-
- /*
- * initalize the whole of the cothreads context
- */
- ctx = (cothread_context *) g_malloc (sizeof (cothread_context));
-
- /* we consider the initiating process to be cothread 0 */
- ctx->ncothreads = 1;
- ctx->current = 0;
- ctx->data = g_hash_table_new (g_str_hash, g_str_equal);
- ctx->thread = g_thread_self ();
-
- GST_CAT_INFO (GST_CAT_COTHREADS, "initializing cothreads");
-
- /* set this thread's context pointer */
- GST_CAT_INFO (GST_CAT_COTHREADS,
- "setting private _cothread_ctx_key to %p in thread %p", ctx,
- g_thread_self ());
- g_static_private_set (&_cothread_ctx_key, ctx, NULL);
-
- g_assert (ctx == cothread_get_current_context ());
-
- /* clear the cothread data */
- memset (ctx->cothreads, 0, sizeof (ctx->cothreads));
-
- /* FIXME this may not be 64bit clean
- * could use casts to uintptr_t from inttypes.h
- * if only all platforms had inttypes.h
- */
- /* stack_top is the address of the first byte past our stack segment. */
- /* FIXME: an assumption is made that the stack segment is STACK_SIZE
- * aligned. */
- ctx->stack_top = ((gulong) current_stack_frame | (STACK_SIZE - 1)) + 1;
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "stack top is 0x%08lx", ctx->stack_top);
-
- /*
- * initialize the 0th cothread
- */
- ctx->cothreads[0] = (cothread_state *) g_malloc0 (sizeof (cothread_state));
- ctx->cothreads[0]->ctx = ctx;
- ctx->cothreads[0]->cothreadnum = 0;
- ctx->cothreads[0]->func = NULL;
- ctx->cothreads[0]->argc = 0;
- ctx->cothreads[0]->argv = NULL;
- ctx->cothreads[0]->priv = NULL;
- ctx->cothreads[0]->flags = COTHREAD_STARTED;
- ctx->cothreads[0]->sp = (void *) current_stack_frame;
-
- GST_CAT_INFO (GST_CAT_COTHREADS, "0th cothread is %p at sp:%p",
- ctx->cothreads[0], ctx->cothreads[0]->sp);
-
- return ctx;
-}
-
-/**
- * cothread_context_free:
- * @ctx: the cothread context to free
- *
- * Free the cothread context.
- */
-void
-cothread_context_free (cothread_context * ctx)
-{
- gint i;
-
- g_return_if_fail (ctx != NULL);
- g_assert (ctx->thread == g_thread_self ());
- g_assert (ctx->current == 0);
-
- GST_CAT_INFO (GST_CAT_COTHREADS, "free cothread context");
-
- for (i = 1; i < COTHREAD_MAXTHREADS; i++) {
- if (ctx->cothreads[i]) {
- cothread_destroy (ctx->cothreads[i]);
- }
- }
- if (ctx->cothreads[0]) {
- g_free (ctx->cothreads[0]);
- ctx->cothreads[0] = NULL;
- }
- g_hash_table_destroy (ctx->data);
- /* make sure we free the private key for cothread context */
- GST_CAT_INFO (GST_CAT_COTHREADS,
- "setting private _cothread_ctx_key to NULL in thread %p",
- g_thread_self ());
- g_static_private_set (&_cothread_ctx_key, NULL, NULL);
- g_free (ctx);
-}
-
-/**
- * cothread_create:
- * @ctx: the cothread context
- *
- * Create a new cothread state in the given context
- *
- * Returns: the new cothread state or NULL on error
- */
-cothread_state *
-cothread_create (cothread_context * ctx)
-{
- cothread_state *cothread;
- void *mmaped = NULL;
- gint slot = 0;
- unsigned long page_size;
-
- g_return_val_if_fail (ctx != NULL, NULL);
-
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "manager sef %p, cothread self %p",
- ctx->thread, g_thread_self ());
-
- if (ctx->ncothreads == COTHREAD_MAXTHREADS) {
- /* this is pretty fatal */
- g_warning ("cothread_create: attempt to create > COTHREAD_MAXTHREADS");
- return NULL;
- }
- /* find a free spot in the stack, note slot 0 has the main thread */
- for (slot = 1; slot < ctx->ncothreads; slot++) {
- if (ctx->cothreads[slot] == NULL)
- break;
- else if (ctx->cothreads[slot]->flags & COTHREAD_DESTROYED &&
- slot != ctx->current) {
- cothread_destroy (ctx->cothreads[slot]);
- break;
- }
- }
-
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "Found free cothread slot %d", slot);
-
- /* cothread stack space of the thread is mapped in reverse, with cothread 0
- * stack space at the top */
- cothread =
- (cothread_state *) (ctx->stack_top - (slot + 1) * COTHREAD_STACKSIZE);
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "cothread pointer is %p", cothread);
-
-#if 0
- /* This tests to see whether or not we can grow down the stack */
- {
- unsigned long ptr;
-
- for (ptr = ctx->stack_top - 4096; ptr > (unsigned long) cothread;
- ptr -= 4096) {
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "touching location 0x%08lx", ptr);
- *(volatile unsigned int *) ptr = *(volatile unsigned int *) ptr;
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "ok (0x%08x)", *(unsigned int *) ptr);
- }
- }
-#endif
-
-#ifdef _SC_PAGESIZE
- page_size = sysconf (_SC_PAGESIZE);
-#else
- page_size = getpagesize ();
-#endif
-
- /* The mmap is necessary on Linux/i386, and possibly others, since the
- * kernel is picky about when we can expand our stack. */
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "mmaping %p, size 0x%08x", cothread,
- COTHREAD_STACKSIZE);
- /* Remap with a guard page. This decreases our stack size by 8 kB (for
- * 4 kB pages) and also wastes almost 4 kB for the cothreads
- * structure */
- munmap ((void *) cothread, COTHREAD_STACKSIZE);
- mmaped = mmap ((void *) cothread, page_size,
- PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
- mmaped = mmap (((void *) cothread) + page_size * 2,
- COTHREAD_STACKSIZE - page_size * 2,
- PROT_READ | PROT_WRITE | PROT_EXEC,
- MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "coming out of mmap");
- if (mmaped == MAP_FAILED) {
- perror ("mmap'ing cothread stack space");
- return NULL;
- }
- if (mmaped != (void *) cothread + page_size * 2) {
- g_warning ("could not mmap requested memory for cothread");
- return NULL;
- }
-
- cothread->magic_number = COTHREAD_MAGIC_NUMBER;
- GST_CAT_DEBUG (GST_CAT_COTHREADS,
- "create cothread %d with magic number 0x%x", slot,
- cothread->magic_number);
- cothread->ctx = ctx;
- cothread->cothreadnum = slot;
- cothread->flags = 0;
- cothread->priv = NULL;
- cothread->sp = ((guchar *) cothread + COTHREAD_STACKSIZE);
- cothread->stack_size = COTHREAD_STACKSIZE - page_size * 2;
- cothread->stack_base = (void *) cothread + 2 * page_size;
-
- GST_CAT_INFO (GST_CAT_COTHREADS,
- "created cothread #%d in slot %d: %p at sp:%p",
- ctx->ncothreads, slot, cothread, cothread->sp);
-
- ctx->cothreads[slot] = cothread;
- ctx->ncothreads++;
-
- return cothread;
-}
-
-/**
- * cothread_free:
- * @cothread: the cothread state
- *
- * Free the given cothread state
- */
-void
-cothread_free (cothread_state * cothread)
-{
- g_return_if_fail (cothread != NULL);
-
- GST_CAT_INFO (GST_CAT_COTHREADS, "flag cothread %d for destruction",
- cothread->cothreadnum);
-
- /* we simply flag the cothread for destruction here */
- if (cothread)
- cothread->flags |= COTHREAD_DESTROYED;
- else
- g_warning ("somebody set up us the bomb");
-}
-
-static void
-cothread_destroy (cothread_state * cothread)
-{
- cothread_context *ctx;
- gint cothreadnum;
-
- g_return_if_fail (cothread != NULL);
-
- cothreadnum = cothread->cothreadnum;
- ctx = cothread->ctx;
- g_assert (ctx->thread == g_thread_self ());
- g_assert (ctx == cothread_get_current_context ());
-
- GST_CAT_INFO (GST_CAT_COTHREADS, "destroy cothread %d %p %d",
- cothreadnum, cothread, ctx->current);
-
- /* cothread 0 needs to be destroyed specially */
- g_assert (cothreadnum != 0);
-
- /* doing cleanups of the cothread create */
- GST_CAT_DEBUG (GST_CAT_COTHREADS,
- "destroy cothread %d with magic number 0x%x", cothreadnum,
- cothread->magic_number);
- g_assert (cothread->magic_number == COTHREAD_MAGIC_NUMBER);
-
- g_assert (cothread->priv == NULL);
-
- memset (cothread, 0, sizeof (*cothread));
-
- ctx->cothreads[cothreadnum] = NULL;
- ctx->ncothreads--;
-}
-
-/**
- * cothread_setfunc:
- * @cothread: the cothread state
- * @func: the function to call
- * @argc: argument count for the cothread function
- * @argv: arguments for the cothread function
- *
- * Set the cothread function
- */
-void
-cothread_setfunc (cothread_state * cothread, cothread_func func, int argc,
- char **argv)
-{
- cothread->func = func;
- cothread->argc = argc;
- cothread->argv = argv;
-}
-
-/**
- * cothread_stop:
- * @cothread: the cothread to stop
- *
- * Stop the cothread and reset the stack and program counter.
- */
-void
-cothread_stop (cothread_state * cothread)
-{
- cothread->flags &= ~COTHREAD_STARTED;
-}
-
-/**
- * cothread_main:
- * @ctx: cothread context to find main cothread of.
- *
- * Gets the main thread.
- *
- * Returns: the #cothread_state of the main (0th) cothread.
- */
-cothread_state *
-cothread_main (cothread_context * ctx)
-{
- g_assert (ctx->thread == g_thread_self ());
-
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "returning %p, the 0th cothread",
- ctx->cothreads[0]);
- return ctx->cothreads[0];
-}
-
-/**
- * cothread_current_main:
- *
- * Get the main thread in the current GThread.
- *
- * Returns: the #cothread_state of the main (0th) thread in the current GThread
- */
-cothread_state *
-cothread_current_main (void)
-{
- cothread_context *ctx = cothread_get_current_context ();
-
- return ctx->cothreads[0];
-}
-
-/**
- * cothread_current:
- *
- * Get the currenttly executing cothread
- *
- * Returns: the #cothread_state of the current cothread
- */
-cothread_state *
-cothread_current (void)
-{
- cothread_context *ctx = cothread_get_current_context ();
-
- return ctx->cothreads[ctx->current];
-}
-
-static void
-cothread_stub (void)
-{
- cothread_context *ctx = cothread_get_current_context ();
- cothread_state *cothread = ctx->cothreads[ctx->current];
-
-#ifndef GST_DISABLE_GST_DEBUG
- char __csf;
- void *current_stack_frame = &__csf;
-#endif
-
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "stack addr %p", &ctx);
-
- cothread->flags |= COTHREAD_STARTED;
-
- while (TRUE) {
- cothread->func (cothread->argc, cothread->argv);
-
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "cothread[%d] thread->func exited",
- ctx->current);
-
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "sp=%p", current_stack_frame);
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "ctx=%p current=%p", ctx,
- cothread_get_current_context ());
- g_assert (ctx == cothread_get_current_context ());
-
- g_assert (ctx->current != 0);
-
- /* we do this to avoid ever returning, we just switch to 0th thread */
- cothread_switch (cothread_main (ctx));
- }
-}
-
-/**
- * cothread_getcurrent:
- *
- * Get the current cothread id
- *
- * Returns: the current cothread id
- */
-int
-cothread_getcurrent (void)
- G_GNUC_NO_INSTRUMENT;
-
- int cothread_getcurrent (void)
-{
- cothread_context *ctx = cothread_get_current_context ();
-
- if (!ctx)
- return -1;
-
- return ctx->current;
-}
-
-/**
- * cothread_set_private:
- * @cothread: the cothread state
- * @data: the data
- *
- * set private data for the cothread.
- */
-void
-cothread_set_private (cothread_state * cothread, gpointer data)
-{
- cothread->priv = data;
-}
-
-/**
- * cothread_context_set_data:
- * @cothread: the cothread state
- * @key: a key for the data
- * @data: the data
- *
- * adds data to a cothread
- */
-void
-cothread_context_set_data (cothread_state * cothread, gchar * key,
- gpointer data)
-{
- cothread_context *ctx = cothread_get_current_context ();
-
- g_hash_table_insert (ctx->data, key, data);
-}
-
-/**
- * cothread_get_private:
- * @cothread: the cothread state
- *
- * get the private data from the cothread
- *
- * Returns: the private data of the cothread
- */
-gpointer
-cothread_get_private (cothread_state * cothread)
-{
- return cothread->priv;
-}
-
-/**
- * cothread_context_get_data:
- * @cothread: the cothread state
- * @key: a key for the data
- *
- * get data from the cothread
- *
- * Returns: the data associated with the key
- */
-gpointer
-cothread_context_get_data (cothread_state * cothread, gchar * key)
-{
- cothread_context *ctx = cothread_get_current_context ();
-
- return g_hash_table_lookup (ctx->data, key);
-}
-
-/**
- * cothread_switch:
- * @cothread: cothread state to switch to
- *
- * Switches to the given cothread state
- */
-void
-cothread_switch (cothread_state * cothread)
-{
- cothread_context *ctx;
- cothread_state *current;
- int enter;
-
-#ifdef COTHREAD_PARANOID
- if (cothread == NULL)
- goto nothread;
-#endif
- ctx = cothread->ctx;
-
- /* paranoia check to make sure we're in the right thread */
- g_assert (ctx->thread == g_thread_self ());
-
-#ifdef COTHREAD_PARANOID
- if (ctx == NULL)
- goto nocontext;
-#endif
-
- current = ctx->cothreads[ctx->current];
-#ifdef COTHREAD_PARANOID
- if (current == NULL)
- goto nocurrent;
-#endif
- if (current == cothread)
- goto selfswitch;
-
-
- /* find the number of the thread to switch to */
- GST_CAT_INFO (GST_CAT_COTHREAD_SWITCH,
- "switching from cothread #%d to cothread #%d",
- ctx->current, cothread->cothreadnum);
- ctx->current = cothread->cothreadnum;
-
- /* save the current stack pointer, frame pointer, and pc */
-#ifdef GST_ARCH_PRESETJMP
- GST_ARCH_PRESETJMP ();
-#endif
- enter = setjmp (current->jmp);
- if (enter != 0) {
- GST_CAT_DEBUG (GST_CAT_COTHREADS,
- "enter cothread #%d %d sp=%p jmpbuf=%p",
- current->cothreadnum, enter, current->sp, current->jmp);
- return;
- }
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "exit cothread #%d %d sp=%p jmpbuf=%p",
- current->cothreadnum, enter, current->sp, current->jmp);
- enter = 1;
-
- if (current->flags & COTHREAD_DESTROYED) {
- cothread_destroy (current);
- }
-
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "set stack to %p", cothread->sp);
- /* restore stack pointer and other stuff of new cothread */
- if (cothread->flags & COTHREAD_STARTED) {
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "via longjmp() jmpbuf %p", cothread->jmp);
- /* switch to it */
- longjmp (cothread->jmp, 1);
- } else {
-#ifdef HAVE_MAKECONTEXT
- ucontext_t ucp;
-
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "making context");
-
- g_assert (cothread != cothread_main (ctx));
-
- getcontext (&ucp);
- ucp.uc_stack.ss_sp = (void *) cothread->stack_base;
- ucp.uc_stack.ss_size = cothread->stack_size;
- makecontext (&ucp, cothread_stub, 0);
- setcontext (&ucp);
-#else
- GST_ARCH_SETUP_STACK ((char *) cothread->sp);
- GST_ARCH_SET_SP (cothread->sp);
- /* start it */
- GST_ARCH_CALL (cothread_stub);
-#endif
-
- GST_CAT_DEBUG (GST_CAT_COTHREADS, "exit thread ");
- ctx->current = 0;
- }
-
- return;
-
-#ifdef COTHREAD_PARANOID
-nothread:
- g_warning ("cothread: can't switch to NULL cothread!");
- return;
-nocontext:
- g_warning ("cothread: there's no context, help!");
- exit (2);
-nocurrent:
- g_warning ("cothread: there's no current thread, help!");
- exit (2);
-#endif /* COTHREAD_PARANOID */
-selfswitch:
- return;
-}
projects / platform / upstream / gstreamer.git / commitdiff