LXR qemu/iohandler.c

   1/*
   2 * QEMU System Emulator - managing I/O handler
   3 *
   4 * Copyright (c) 2003-2008 Fabrice Bellard
   5 *
   6 * Permission is hereby granted, free of charge, to any person obtaining a copy
   7 * of this software and associated documentation files (the "Software"), to deal
   8 * in the Software without restriction, including without limitation the rights
   9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10 * copies of the Software, and to permit persons to whom the Software is
  11 * furnished to do so, subject to the following conditions:
  12 *
  13 * The above copyright notice and this permission notice shall be included in
  14 * all copies or substantial portions of the Software.
  15 *
  16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22 * THE SOFTWARE.
  23 */
  24
  25#include "qemu/osdep.h"
  26#include "qapi/error.h"
  27#include "qemu-common.h"
  28#include "qemu/queue.h"
  29#include "block/aio.h"
  30#include "qemu/main-loop.h"
  31
  32#ifndef _WIN32
  33#include <sys/wait.h>
  34#endif
  35
  36/* This context runs on top of main loop. We can't reuse qemu_aio_context
  37 * because iohandlers mustn't be polled by aio_poll(qemu_aio_context). */
  38static AioContext *iohandler_ctx;
  39
  40static void iohandler_init(void)
  41{
  42    if (!iohandler_ctx) {
  43        iohandler_ctx = aio_context_new(&error_abort);
  44    }
  45}
  46
  47AioContext *iohandler_get_aio_context(void)
  48{
  49    iohandler_init();
  50    return iohandler_ctx;
  51}
  52
  53GSource *iohandler_get_g_source(void)
  54{
  55    iohandler_init();
  56    return aio_get_g_source(iohandler_ctx);
  57}
  58
  59void qemu_set_fd_handler(int fd,
  60                         IOHandler *fd_read,
  61                         IOHandler *fd_write,
  62                         void *opaque)
  63{
  64    iohandler_init();
  65    aio_set_fd_handler(iohandler_ctx, fd, false,
  66                       fd_read, fd_write, opaque);
  67}
  68
  69/* reaping of zombies.  right now we're not passing the status to
  70   anyone, but it would be possible to add a callback.  */
  71#ifndef _WIN32
  72typedef struct ChildProcessRecord {
  73    int pid;
  74    QLIST_ENTRY(ChildProcessRecord) next;
  75} ChildProcessRecord;
  76
  77static QLIST_HEAD(, ChildProcessRecord) child_watches =
  78    QLIST_HEAD_INITIALIZER(child_watches);
  79
  80static QEMUBH *sigchld_bh;
  81
  82static void sigchld_handler(int signal)
  83{
  84    qemu_bh_schedule(sigchld_bh);
  85}
  86
  87static void sigchld_bh_handler(void *opaque)
  88{
  89    ChildProcessRecord *rec, *next;
  90
  91    QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
  92        if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
  93            QLIST_REMOVE(rec, next);
  94            g_free(rec);
  95        }
  96    }
  97}
  98
  99static void qemu_init_child_watch(void)
 100{
 101    struct sigaction act;
 102    sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
 103
 104    memset(&act, 0, sizeof(act));
 105    act.sa_handler = sigchld_handler;
 106    act.sa_flags = SA_NOCLDSTOP;
 107    sigaction(SIGCHLD, &act, NULL);
 108}
 109
 110int qemu_add_child_watch(pid_t pid)
 111{
 112    ChildProcessRecord *rec;
 113
 114    if (!sigchld_bh) {
 115        qemu_init_child_watch();
 116    }
 117
 118    QLIST_FOREACH(rec, &child_watches, next) {
 119        if (rec->pid == pid) {
 120            return 1;
 121        }
 122    }
 123    rec = g_malloc0(sizeof(ChildProcessRecord));
 124    rec->pid = pid;
 125    QLIST_INSERT_HEAD(&child_watches, rec, next);
 126    return 0;
 127}
 128#endif
 129