Archipelago » qemu

/*

 * QEMU System Emulator - managing I/O handler

 *

 * Copyright (c) 2003-2008 Fabrice Bellard

 *

 * 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.

 */

#include "config-host.h"

#include "qemu-common.h"

#include "qemu-char.h"

#include "qemu-queue.h"

#ifndef _WIN32

#include <sys/wait.h>

#endif

typedef struct IOHandlerRecord {

    int fd;

    IOCanReadHandler *fd_read_poll;

    IOHandler *fd_read;

    IOHandler *fd_write;

    int deleted;

    void *opaque;

    QLIST_ENTRY(IOHandlerRecord) next;

} IOHandlerRecord;

static QLIST_HEAD(, IOHandlerRecord) io_handlers =

    QLIST_HEAD_INITIALIZER(io_handlers);

/* XXX: fd_read_poll should be suppressed, but an API change is

   necessary in the character devices to suppress fd_can_read(). */

int qemu_set_fd_handler2(int fd,

                         IOCanReadHandler *fd_read_poll,

                         IOHandler *fd_read,

                         IOHandler *fd_write,

                         void *opaque)

{

    IOHandlerRecord *ioh;

    if (!fd_read && !fd_write) {

        QLIST_FOREACH(ioh, &io_handlers, next) {

            if (ioh->fd == fd) {

                ioh->deleted = 1;

                break;

            }

        }

    } else {

        QLIST_FOREACH(ioh, &io_handlers, next) {

            if (ioh->fd == fd)

                goto found;

        }

        ioh = g_malloc0(sizeof(IOHandlerRecord));

        QLIST_INSERT_HEAD(&io_handlers, ioh, next);

    found:

        ioh->fd = fd;

        ioh->fd_read_poll = fd_read_poll;

        ioh->fd_read = fd_read;

        ioh->fd_write = fd_write;

        ioh->opaque = opaque;

        ioh->deleted = 0;

    }

    return 0;

}

typedef struct IOTrampoline

{

    GIOChannel *chan;

    IOHandler *fd_read;

    IOHandler *fd_write;

    void *opaque;

    guint tag;

} IOTrampoline;

static gboolean fd_trampoline(GIOChannel *chan, GIOCondition cond, gpointer opaque)

{

    IOTrampoline *tramp = opaque;

    if ((cond & G_IO_IN) && tramp->fd_read) {

        tramp->fd_read(tramp->opaque);

    }

    if ((cond & G_IO_OUT) && tramp->fd_write) {

        tramp->fd_write(tramp->opaque);

    }

    return TRUE;

}

int qemu_set_fd_handler(int fd,

                        IOHandler *fd_read,

                        IOHandler *fd_write,

                        void *opaque)

{

    static IOTrampoline fd_trampolines[FD_SETSIZE];

    IOTrampoline *tramp = &fd_trampolines[fd];

    if (tramp->tag != 0) {

        g_io_channel_unref(tramp->chan);

        g_source_remove(tramp->tag);

        tramp->tag = 0;

    }

    if (fd_read || fd_write || opaque) {

        GIOCondition cond = 0;

        tramp->fd_read = fd_read;

        tramp->fd_write = fd_write;

        tramp->opaque = opaque;

        if (fd_read) {

            cond |= G_IO_IN | G_IO_ERR;

        }

        if (fd_write) {

            cond |= G_IO_OUT | G_IO_ERR;

        }

        tramp->chan = g_io_channel_unix_new(fd);

        tramp->tag = g_io_add_watch(tramp->chan, cond, fd_trampoline, tramp);

    }

    return 0;

}

void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds)

{

    IOHandlerRecord *ioh;

    QLIST_FOREACH(ioh, &io_handlers, next) {

        if (ioh->deleted)

            continue;

        if (ioh->fd_read &&

            (!ioh->fd_read_poll ||

             ioh->fd_read_poll(ioh->opaque) != 0)) {

            FD_SET(ioh->fd, readfds);

            if (ioh->fd > *pnfds)

                *pnfds = ioh->fd;

        }

        if (ioh->fd_write) {

            FD_SET(ioh->fd, writefds);

            if (ioh->fd > *pnfds)

                *pnfds = ioh->fd;

        }

    }

}

void qemu_iohandler_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds, int ret)

{

    if (ret > 0) {

        IOHandlerRecord *pioh, *ioh;

        QLIST_FOREACH_SAFE(ioh, &io_handlers, next, pioh) {

            if (!ioh->deleted && ioh->fd_read && FD_ISSET(ioh->fd, readfds)) {

                ioh->fd_read(ioh->opaque);

            }

            if (!ioh->deleted && ioh->fd_write && FD_ISSET(ioh->fd, writefds)) {

                ioh->fd_write(ioh->opaque);

            }

            /* Do this last in case read/write handlers marked it for deletion */

            if (ioh->deleted) {

                QLIST_REMOVE(ioh, next);

                g_free(ioh);

            }

        }

    }

}

/* reaping of zombies.  right now we're not passing the status to

   anyone, but it would be possible to add a callback.  */

#ifndef _WIN32

typedef struct ChildProcessRecord {

    int pid;

    QLIST_ENTRY(ChildProcessRecord) next;

} ChildProcessRecord;

static QLIST_HEAD(, ChildProcessRecord) child_watches =

    QLIST_HEAD_INITIALIZER(child_watches);

static QEMUBH *sigchld_bh;

static void sigchld_handler(int signal)

{

    qemu_bh_schedule(sigchld_bh);

}

static void sigchld_bh_handler(void *opaque)

{

    ChildProcessRecord *rec, *next;

    QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {

        if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {

            QLIST_REMOVE(rec, next);

            g_free(rec);

        }

    }

}

static void qemu_init_child_watch(void)

{

    struct sigaction act;

    sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);

    act.sa_handler = sigchld_handler;

    act.sa_flags = SA_NOCLDSTOP;

    sigaction(SIGCHLD, &act, NULL);

}

int qemu_add_child_watch(pid_t pid)

{

    ChildProcessRecord *rec;

    if (!sigchld_bh) {

        qemu_init_child_watch();

    }

    QLIST_FOREACH(rec, &child_watches, next) {

        if (rec->pid == pid) {

            return 1;

        }

    }

    rec = g_malloc0(sizeof(ChildProcessRecord));

    rec->pid = pid;

    QLIST_INSERT_HEAD(&child_watches, rec, next);

    return 0;

}

#endif