369 lines
9.7 KiB
C
369 lines
9.7 KiB
C
/*
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* QEMU I/O channels external command driver
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*
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* Copyright (c) 2015 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "qemu/osdep.h"
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#include "io/channel-command.h"
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#include "io/channel-watch.h"
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#include "qapi/error.h"
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#include "qemu/sockets.h"
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#include "trace.h"
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QIOChannelCommand *
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qio_channel_command_new_pid(int writefd,
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int readfd,
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pid_t pid)
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{
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QIOChannelCommand *ioc;
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ioc = QIO_CHANNEL_COMMAND(object_new(TYPE_QIO_CHANNEL_COMMAND));
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ioc->readfd = readfd;
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ioc->writefd = writefd;
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ioc->pid = pid;
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trace_qio_channel_command_new_pid(ioc, writefd, readfd, pid);
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return ioc;
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}
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#ifndef WIN32
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QIOChannelCommand *
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qio_channel_command_new_spawn(const char *const argv[],
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int flags,
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Error **errp)
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{
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pid_t pid = -1;
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int stdinfd[2] = { -1, -1 };
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int stdoutfd[2] = { -1, -1 };
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int devnull = -1;
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bool stdinnull = false, stdoutnull = false;
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QIOChannelCommand *ioc;
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flags = flags & O_ACCMODE;
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if (flags == O_RDONLY) {
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stdinnull = true;
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}
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if (flags == O_WRONLY) {
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stdoutnull = true;
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}
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if (stdinnull || stdoutnull) {
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devnull = open("/dev/null", O_RDWR);
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if (devnull < 0) {
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error_setg_errno(errp, errno,
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"Unable to open /dev/null");
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goto error;
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}
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}
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if ((!stdinnull && pipe(stdinfd) < 0) ||
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(!stdoutnull && pipe(stdoutfd) < 0)) {
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error_setg_errno(errp, errno,
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"Unable to open pipe");
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goto error;
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}
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pid = qemu_fork(errp);
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if (pid < 0) {
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goto error;
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}
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if (pid == 0) { /* child */
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dup2(stdinnull ? devnull : stdinfd[0], STDIN_FILENO);
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dup2(stdoutnull ? devnull : stdoutfd[1], STDOUT_FILENO);
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/* Leave stderr connected to qemu's stderr */
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if (!stdinnull) {
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close(stdinfd[0]);
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close(stdinfd[1]);
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}
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if (!stdoutnull) {
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close(stdoutfd[0]);
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close(stdoutfd[1]);
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}
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if (devnull != -1) {
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close(devnull);
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}
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execv(argv[0], (char * const *)argv);
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_exit(1);
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}
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if (!stdinnull) {
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close(stdinfd[0]);
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}
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if (!stdoutnull) {
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close(stdoutfd[1]);
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}
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ioc = qio_channel_command_new_pid(stdinnull ? devnull : stdinfd[1],
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stdoutnull ? devnull : stdoutfd[0],
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pid);
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trace_qio_channel_command_new_spawn(ioc, argv[0], flags);
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return ioc;
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error:
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if (devnull != -1) {
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close(devnull);
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}
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if (stdinfd[0] != -1) {
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close(stdinfd[0]);
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}
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if (stdinfd[1] != -1) {
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close(stdinfd[1]);
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}
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if (stdoutfd[0] != -1) {
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close(stdoutfd[0]);
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}
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if (stdoutfd[1] != -1) {
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close(stdoutfd[1]);
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}
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return NULL;
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}
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#else /* WIN32 */
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QIOChannelCommand *
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qio_channel_command_new_spawn(const char *const argv[],
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int flags,
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Error **errp)
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{
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error_setg_errno(errp, ENOSYS,
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"Command spawn not supported on this platform");
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return NULL;
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}
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#endif /* WIN32 */
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#ifndef WIN32
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static int qio_channel_command_abort(QIOChannelCommand *ioc,
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Error **errp)
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{
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pid_t ret;
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int status;
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int step = 0;
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/* See if intermediate process has exited; if not, try a nice
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* SIGTERM followed by a more severe SIGKILL.
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*/
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rewait:
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trace_qio_channel_command_abort(ioc, ioc->pid);
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ret = waitpid(ioc->pid, &status, WNOHANG);
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trace_qio_channel_command_wait(ioc, ioc->pid, ret, status);
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if (ret == (pid_t)-1) {
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if (errno == EINTR) {
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goto rewait;
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} else {
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error_setg_errno(errp, errno,
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"Cannot wait on pid %llu",
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(unsigned long long)ioc->pid);
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return -1;
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}
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} else if (ret == 0) {
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if (step == 0) {
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kill(ioc->pid, SIGTERM);
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} else if (step == 1) {
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kill(ioc->pid, SIGKILL);
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} else {
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error_setg(errp,
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"Process %llu refused to die",
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(unsigned long long)ioc->pid);
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return -1;
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}
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step++;
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usleep(10 * 1000);
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goto rewait;
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}
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return 0;
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}
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#endif /* ! WIN32 */
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static void qio_channel_command_init(Object *obj)
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{
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QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj);
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ioc->readfd = -1;
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ioc->writefd = -1;
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ioc->pid = -1;
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}
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static void qio_channel_command_finalize(Object *obj)
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{
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QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj);
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if (ioc->readfd != -1) {
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close(ioc->readfd);
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}
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if (ioc->writefd != -1 &&
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ioc->writefd != ioc->readfd) {
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close(ioc->writefd);
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}
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ioc->writefd = ioc->readfd = -1;
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if (ioc->pid > 0) {
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#ifndef WIN32
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qio_channel_command_abort(ioc, NULL);
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#endif
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}
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}
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static ssize_t qio_channel_command_readv(QIOChannel *ioc,
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const struct iovec *iov,
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size_t niov,
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int **fds,
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size_t *nfds,
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Error **errp)
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{
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QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
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ssize_t ret;
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retry:
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ret = readv(cioc->readfd, iov, niov);
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if (ret < 0) {
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if (errno == EAGAIN) {
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return QIO_CHANNEL_ERR_BLOCK;
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}
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if (errno == EINTR) {
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goto retry;
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}
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error_setg_errno(errp, errno,
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"Unable to read from command");
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return -1;
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}
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return ret;
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}
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static ssize_t qio_channel_command_writev(QIOChannel *ioc,
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const struct iovec *iov,
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size_t niov,
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int *fds,
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size_t nfds,
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Error **errp)
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{
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QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
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ssize_t ret;
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retry:
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ret = writev(cioc->writefd, iov, niov);
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if (ret <= 0) {
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if (errno == EAGAIN) {
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return QIO_CHANNEL_ERR_BLOCK;
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}
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if (errno == EINTR) {
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goto retry;
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}
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error_setg_errno(errp, errno, "%s",
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"Unable to write to command");
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return -1;
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}
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return ret;
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}
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static int qio_channel_command_set_blocking(QIOChannel *ioc,
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bool enabled,
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Error **errp)
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{
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QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
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if (enabled) {
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qemu_set_block(cioc->writefd);
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qemu_set_block(cioc->readfd);
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} else {
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qemu_set_nonblock(cioc->writefd);
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qemu_set_nonblock(cioc->readfd);
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}
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return 0;
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}
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static int qio_channel_command_close(QIOChannel *ioc,
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Error **errp)
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{
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QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
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int rv = 0;
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/* We close FDs before killing, because that
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* gives a better chance of clean shutdown
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*/
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if (cioc->readfd != -1 &&
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close(cioc->readfd) < 0) {
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rv = -1;
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}
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if (cioc->writefd != -1 &&
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cioc->writefd != cioc->readfd &&
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close(cioc->writefd) < 0) {
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rv = -1;
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}
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cioc->writefd = cioc->readfd = -1;
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#ifndef WIN32
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if (qio_channel_command_abort(cioc, errp) < 0) {
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return -1;
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}
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#endif
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if (rv < 0) {
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error_setg_errno(errp, errno, "%s",
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"Unable to close command");
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}
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return rv;
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}
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static GSource *qio_channel_command_create_watch(QIOChannel *ioc,
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GIOCondition condition)
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{
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QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
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return qio_channel_create_fd_pair_watch(ioc,
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cioc->readfd,
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cioc->writefd,
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condition);
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}
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static void qio_channel_command_class_init(ObjectClass *klass,
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void *class_data G_GNUC_UNUSED)
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{
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QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
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ioc_klass->io_writev = qio_channel_command_writev;
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ioc_klass->io_readv = qio_channel_command_readv;
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ioc_klass->io_set_blocking = qio_channel_command_set_blocking;
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ioc_klass->io_close = qio_channel_command_close;
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ioc_klass->io_create_watch = qio_channel_command_create_watch;
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}
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static const TypeInfo qio_channel_command_info = {
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.parent = TYPE_QIO_CHANNEL,
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.name = TYPE_QIO_CHANNEL_COMMAND,
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.instance_size = sizeof(QIOChannelCommand),
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.instance_init = qio_channel_command_init,
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.instance_finalize = qio_channel_command_finalize,
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.class_init = qio_channel_command_class_init,
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};
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static void qio_channel_command_register_types(void)
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{
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type_register_static(&qio_channel_command_info);
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}
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type_init(qio_channel_command_register_types);
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