File:  [Qemu by Fabrice Bellard] / qemu / iohandler.c
Revision 1.1.1.1 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 18:56:22 2018 UTC (3 years, 1 month ago) by root
Branches: qemu, MAIN
CVS tags: qemu1000, qemu0151, HEAD
qemu 0.15.1

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

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