File:  [Qemu by Fabrice Bellard] / qemu / iohandler.c
Revision 1.1.1.2 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 19:17:28 2018 UTC (3 years, 1 month ago) by root
Branches: qemu, MAIN
CVS tags: qemu1001, HEAD
qemu 1.0.1

    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 "config-host.h"
   26: #include "qemu-common.h"
   27: #include "qemu-char.h"
   28: #include "qemu-queue.h"
   29: #include "main-loop.h"
   30: 
   31: #ifndef _WIN32
   32: #include <sys/wait.h>
   33: #endif
   34: 
   35: typedef struct IOHandlerRecord {
   36:     int fd;
   37:     IOCanReadHandler *fd_read_poll;
   38:     IOHandler *fd_read;
   39:     IOHandler *fd_write;
   40:     int deleted;
   41:     void *opaque;
   42:     QLIST_ENTRY(IOHandlerRecord) next;
   43: } IOHandlerRecord;
   44: 
   45: static QLIST_HEAD(, IOHandlerRecord) io_handlers =
   46:     QLIST_HEAD_INITIALIZER(io_handlers);
   47: 
   48: 
   49: /* XXX: fd_read_poll should be suppressed, but an API change is
   50:    necessary in the character devices to suppress fd_can_read(). */
   51: int qemu_set_fd_handler2(int fd,
   52:                          IOCanReadHandler *fd_read_poll,
   53:                          IOHandler *fd_read,
   54:                          IOHandler *fd_write,
   55:                          void *opaque)
   56: {
   57:     IOHandlerRecord *ioh;
   58: 
   59:     if (!fd_read && !fd_write) {
   60:         QLIST_FOREACH(ioh, &io_handlers, next) {
   61:             if (ioh->fd == fd) {
   62:                 ioh->deleted = 1;
   63:                 break;
   64:             }
   65:         }
   66:     } else {
   67:         QLIST_FOREACH(ioh, &io_handlers, next) {
   68:             if (ioh->fd == fd)
   69:                 goto found;
   70:         }
   71:         ioh = g_malloc0(sizeof(IOHandlerRecord));
   72:         QLIST_INSERT_HEAD(&io_handlers, ioh, next);
   73:     found:
   74:         ioh->fd = fd;
   75:         ioh->fd_read_poll = fd_read_poll;
   76:         ioh->fd_read = fd_read;
   77:         ioh->fd_write = fd_write;
   78:         ioh->opaque = opaque;
   79:         ioh->deleted = 0;
   80:     }
   81:     return 0;
   82: }
   83: 
   84: int qemu_set_fd_handler(int fd,
   85:                         IOHandler *fd_read,
   86:                         IOHandler *fd_write,
   87:                         void *opaque)
   88: {
   89:     return qemu_set_fd_handler2(fd, NULL, fd_read, fd_write, opaque);
   90: }
   91: 
   92: void qemu_iohandler_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds)
   93: {
   94:     IOHandlerRecord *ioh;
   95: 
   96:     QLIST_FOREACH(ioh, &io_handlers, next) {
   97:         if (ioh->deleted)
   98:             continue;
   99:         if (ioh->fd_read &&
  100:             (!ioh->fd_read_poll ||
  101:              ioh->fd_read_poll(ioh->opaque) != 0)) {
  102:             FD_SET(ioh->fd, readfds);
  103:             if (ioh->fd > *pnfds)
  104:                 *pnfds = ioh->fd;
  105:         }
  106:         if (ioh->fd_write) {
  107:             FD_SET(ioh->fd, writefds);
  108:             if (ioh->fd > *pnfds)
  109:                 *pnfds = ioh->fd;
  110:         }
  111:     }
  112: }
  113: 
  114: void qemu_iohandler_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds, int ret)
  115: {
  116:     if (ret > 0) {
  117:         IOHandlerRecord *pioh, *ioh;
  118: 
  119:         QLIST_FOREACH_SAFE(ioh, &io_handlers, next, pioh) {
  120:             if (!ioh->deleted && ioh->fd_read && FD_ISSET(ioh->fd, readfds)) {
  121:                 ioh->fd_read(ioh->opaque);
  122:             }
  123:             if (!ioh->deleted && ioh->fd_write && FD_ISSET(ioh->fd, writefds)) {
  124:                 ioh->fd_write(ioh->opaque);
  125:             }
  126: 
  127:             /* Do this last in case read/write handlers marked it for deletion */
  128:             if (ioh->deleted) {
  129:                 QLIST_REMOVE(ioh, next);
  130:                 g_free(ioh);
  131:             }
  132:         }
  133:     }
  134: }
  135: 
  136: /* reaping of zombies.  right now we're not passing the status to
  137:    anyone, but it would be possible to add a callback.  */
  138: #ifndef _WIN32
  139: typedef struct ChildProcessRecord {
  140:     int pid;
  141:     QLIST_ENTRY(ChildProcessRecord) next;
  142: } ChildProcessRecord;
  143: 
  144: static QLIST_HEAD(, ChildProcessRecord) child_watches =
  145:     QLIST_HEAD_INITIALIZER(child_watches);
  146: 
  147: static QEMUBH *sigchld_bh;
  148: 
  149: static void sigchld_handler(int signal)
  150: {
  151:     qemu_bh_schedule(sigchld_bh);
  152: }
  153: 
  154: static void sigchld_bh_handler(void *opaque)
  155: {
  156:     ChildProcessRecord *rec, *next;
  157: 
  158:     QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
  159:         if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
  160:             QLIST_REMOVE(rec, next);
  161:             g_free(rec);
  162:         }
  163:     }
  164: }
  165: 
  166: static void qemu_init_child_watch(void)
  167: {
  168:     struct sigaction act;
  169:     sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
  170: 
  171:     act.sa_handler = sigchld_handler;
  172:     act.sa_flags = SA_NOCLDSTOP;
  173:     sigaction(SIGCHLD, &act, NULL);
  174: }
  175: 
  176: int qemu_add_child_watch(pid_t pid)
  177: {
  178:     ChildProcessRecord *rec;
  179: 
  180:     if (!sigchld_bh) {
  181:         qemu_init_child_watch();
  182:     }
  183: 
  184:     QLIST_FOREACH(rec, &child_watches, next) {
  185:         if (rec->pid == pid) {
  186:             return 1;
  187:         }
  188:     }
  189:     rec = g_malloc0(sizeof(ChildProcessRecord));
  190:     rec->pid = pid;
  191:     QLIST_INSERT_HEAD(&child_watches, rec, next);
  192:     return 0;
  193: }
  194: #endif

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