diff options
Diffstat (limited to 'io/channel-command.c')
| -rw-r--r-- | io/channel-command.c | 357 |
1 files changed, 357 insertions, 0 deletions
diff --git a/io/channel-command.c b/io/channel-command.c new file mode 100644 index 0000000..598fdab --- /dev/null +++ b/io/channel-command.c @@ -0,0 +1,357 @@ +/* + * QEMU I/O channels external command driver + * + * Copyright (c) 2015 Red Hat, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + * + */ + +#include "io/channel-command.h" +#include "io/channel-watch.h" +#include "qemu/sockets.h" +#include "trace.h" + + +QIOChannelCommand * +qio_channel_command_new_pid(int writefd, + int readfd, + pid_t pid) +{ + QIOChannelCommand *ioc; + + ioc = QIO_CHANNEL_COMMAND(object_new(TYPE_QIO_CHANNEL_COMMAND)); + + ioc->readfd = readfd; + ioc->writefd = writefd; + ioc->pid = pid; + + trace_qio_channel_command_new_pid(ioc, writefd, readfd, pid); + return ioc; +} + + +#ifndef WIN32 +QIOChannelCommand * +qio_channel_command_new_spawn(const char *const argv[], + int flags, + Error **errp) +{ + pid_t pid = -1; + int stdinfd[2] = { -1, -1 }; + int stdoutfd[2] = { -1, -1 }; + int devnull = -1; + bool stdinnull = false, stdoutnull = false; + QIOChannelCommand *ioc; + + flags = flags & O_ACCMODE; + + if (flags == O_RDONLY) { + stdinnull = true; + } + if (flags == O_WRONLY) { + stdoutnull = true; + } + + if (stdinnull || stdoutnull) { + devnull = open("/dev/null", O_RDWR); + if (!devnull) { + error_setg_errno(errp, errno, + "Unable to open /dev/null"); + goto error; + } + } + + if ((!stdinnull && pipe(stdinfd) < 0) || + (!stdoutnull && pipe(stdoutfd) < 0)) { + error_setg_errno(errp, errno, + "Unable to open pipe"); + goto error; + } + + pid = qemu_fork(errp); + if (pid < 0) { + goto error; + } + + if (pid == 0) { /* child */ + dup2(stdinnull ? devnull : stdinfd[0], STDIN_FILENO); + dup2(stdoutnull ? devnull : stdoutfd[1], STDOUT_FILENO); + /* Leave stderr connected to qemu's stderr */ + + if (!stdinnull) { + close(stdinfd[0]); + close(stdinfd[1]); + } + if (!stdoutnull) { + close(stdoutfd[0]); + close(stdoutfd[1]); + } + + execv(argv[0], (char * const *)argv); + _exit(1); + } + + if (!stdinnull) { + close(stdinfd[0]); + } + if (!stdoutnull) { + close(stdoutfd[1]); + } + + ioc = qio_channel_command_new_pid(stdinnull ? devnull : stdinfd[1], + stdoutnull ? devnull : stdoutfd[0], + pid); + trace_qio_channel_command_new_spawn(ioc, argv[0], flags); + return ioc; + + error: + if (stdinfd[0] != -1) { + close(stdinfd[0]); + } + if (stdinfd[1] != -1) { + close(stdinfd[1]); + } + if (stdoutfd[0] != -1) { + close(stdoutfd[0]); + } + if (stdoutfd[1] != -1) { + close(stdoutfd[1]); + } + return NULL; +} + +#else /* WIN32 */ +QIOChannelCommand * +qio_channel_command_new_spawn(const char *const argv[], + int flags, + Error **errp) +{ + error_setg_errno(errp, ENOSYS, + "Command spawn not supported on this platform"); + return NULL; +} +#endif /* WIN32 */ + +#ifndef WIN32 +static int qio_channel_command_abort(QIOChannelCommand *ioc, + Error **errp) +{ + pid_t ret; + int status; + int step = 0; + + /* See if intermediate process has exited; if not, try a nice + * SIGTERM followed by a more severe SIGKILL. + */ + rewait: + trace_qio_channel_command_abort(ioc, ioc->pid); + ret = waitpid(ioc->pid, &status, WNOHANG); + trace_qio_channel_command_wait(ioc, ioc->pid, ret, status); + if (ret == (pid_t)-1) { + if (errno == EINTR) { + goto rewait; + } else { + error_setg_errno(errp, errno, + "Cannot wait on pid %llu", + (unsigned long long)ioc->pid); + return -1; + } + } else if (ret == 0) { + if (step == 0) { + kill(ioc->pid, SIGTERM); + } else if (step == 1) { + kill(ioc->pid, SIGKILL); + } else { + error_setg(errp, + "Process %llu refused to die", + (unsigned long long)ioc->pid); + return -1; + } + usleep(10 * 1000); + goto rewait; + } + + return 0; +} +#endif /* ! WIN32 */ + + +static void qio_channel_command_init(Object *obj) +{ + QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj); + ioc->readfd = -1; + ioc->writefd = -1; + ioc->pid = -1; +} + +static void qio_channel_command_finalize(Object *obj) +{ + QIOChannelCommand *ioc = QIO_CHANNEL_COMMAND(obj); + if (ioc->readfd != -1) { + close(ioc->readfd); + ioc->readfd = -1; + } + if (ioc->writefd != -1) { + close(ioc->writefd); + ioc->writefd = -1; + } + if (ioc->pid > 0) { +#ifndef WIN32 + qio_channel_command_abort(ioc, NULL); +#endif + } +} + + +static ssize_t qio_channel_command_readv(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int **fds, + size_t *nfds, + Error **errp) +{ + QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); + ssize_t ret; + + retry: + ret = readv(cioc->readfd, iov, niov); + if (ret < 0) { + if (errno == EAGAIN || + errno == EWOULDBLOCK) { + return QIO_CHANNEL_ERR_BLOCK; + } + if (errno == EINTR) { + goto retry; + } + + error_setg_errno(errp, errno, + "Unable to read from command"); + return -1; + } + + return ret; +} + +static ssize_t qio_channel_command_writev(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + int *fds, + size_t nfds, + Error **errp) +{ + QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); + ssize_t ret; + + retry: + ret = writev(cioc->writefd, iov, niov); + if (ret <= 0) { + if (errno == EAGAIN || + errno == EWOULDBLOCK) { + return QIO_CHANNEL_ERR_BLOCK; + } + if (errno == EINTR) { + goto retry; + } + error_setg_errno(errp, errno, "%s", + "Unable to write to command"); + return -1; + } + return ret; +} + +static int qio_channel_command_set_blocking(QIOChannel *ioc, + bool enabled, + Error **errp) +{ + QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); + + if (enabled) { + qemu_set_block(cioc->writefd); + qemu_set_block(cioc->readfd); + } else { + qemu_set_nonblock(cioc->writefd); + qemu_set_nonblock(cioc->readfd); + } + + return 0; +} + + +static int qio_channel_command_close(QIOChannel *ioc, + Error **errp) +{ + QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); + int rv = 0; + + /* We close FDs before killing, because that + * gives a better chance of clean shutdown + */ + if (close(cioc->writefd) < 0) { + rv = -1; + } + if (close(cioc->readfd) < 0) { + rv = -1; + } +#ifndef WIN32 + if (qio_channel_command_abort(cioc, errp) < 0) { + return -1; + } +#endif + if (rv < 0) { + error_setg_errno(errp, errno, "%s", + "Unable to close command"); + } + return rv; +} + + +static GSource *qio_channel_command_create_watch(QIOChannel *ioc, + GIOCondition condition) +{ + QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc); + return qio_channel_create_fd_pair_watch(ioc, + cioc->readfd, + cioc->writefd, + condition); +} + + +static void qio_channel_command_class_init(ObjectClass *klass, + void *class_data G_GNUC_UNUSED) +{ + QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass); + + ioc_klass->io_writev = qio_channel_command_writev; + ioc_klass->io_readv = qio_channel_command_readv; + ioc_klass->io_set_blocking = qio_channel_command_set_blocking; + ioc_klass->io_close = qio_channel_command_close; + ioc_klass->io_create_watch = qio_channel_command_create_watch; +} + +static const TypeInfo qio_channel_command_info = { + .parent = TYPE_QIO_CHANNEL, + .name = TYPE_QIO_CHANNEL_COMMAND, + .instance_size = sizeof(QIOChannelCommand), + .instance_init = qio_channel_command_init, + .instance_finalize = qio_channel_command_finalize, + .class_init = qio_channel_command_class_init, +}; + +static void qio_channel_command_register_types(void) +{ + type_register_static(&qio_channel_command_info); +} + +type_init(qio_channel_command_register_types); |