Add a QIOChannel subclass that is capable of performing I/O to/from a separate process, via a pair of pipes. The command can be used for unidirectional or bi-directional I/O.
Signed-off-by: Daniel P. Berrange <berra...@redhat.com> --- include/io/channel-command.h | 91 ++++++++++ io/Makefile.objs | 1 + io/channel-command.c | 369 ++++++++++++++++++++++++++++++++++++++++ tests/.gitignore | 2 + tests/Makefile | 3 + tests/test-io-channel-command.c | 129 ++++++++++++++ trace-events | 6 + 7 files changed, 601 insertions(+) create mode 100644 include/io/channel-command.h create mode 100644 io/channel-command.c create mode 100644 tests/test-io-channel-command.c diff --git a/include/io/channel-command.h b/include/io/channel-command.h new file mode 100644 index 0000000..bd3c599 --- /dev/null +++ b/include/io/channel-command.h @@ -0,0 +1,91 @@ +/* + * 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/>. + * + */ + +#ifndef QIO_CHANNEL_COMMAND_H__ +#define QIO_CHANNEL_COMMAND_H__ + +#include "io/channel.h" + +#define TYPE_QIO_CHANNEL_COMMAND "qio-channel-command" +#define QIO_CHANNEL_COMMAND(obj) \ + OBJECT_CHECK(QIOChannelCommand, (obj), TYPE_QIO_CHANNEL_COMMAND) + +typedef struct QIOChannelCommand QIOChannelCommand; + + +/** + * QIOChannelCommand: + * + * The QIOChannelCommand class provides a channel implementation + * that can transport data with an externally running command + * via its stdio streams. + */ + +struct QIOChannelCommand { + QIOChannel parent; + int writefd; + int readfd; + pid_t pid; +}; + + +/** + * qio_channel_command_new_pid: + * @writefd: the FD connected to the command's stdin + * @readfd: the FD connected to the command's stdout + * @pid: the PID of the running child command + * @errp: pointer to an uninitialized error object + * + * Create a channel for performing I/O with the + * previously spawned command identified by @pid. + * The two file descriptors provide the connection + * to command's stdio streams, either one or which + * may be -1 to indicate that stream is not open. + * + * The channel will take ownership of the process + * @pid and will kill it when closing the channel. + * Similarly it will take responsibility for + * closing the file descriptors @writefd and @readfd. + * + * Returns: the command channel object, or NULL on error + */ +QIOChannelCommand * +qio_channel_command_new_pid(int writefd, + int readfd, + pid_t pid); + +/** + * qio_channel_command_new_spawn: + * @argv: the NULL terminated list of command arguments + * @flags: the I/O mode, one of O_RDONLY, O_WRONLY, O_RDWR + * @errp: pointer to an uninitialized error object + * + * Create a channel for performing I/O with the + * command to be spawned with arguments @argv. + * + * Returns: the command channel object, or NULL on error + */ +QIOChannelCommand * +qio_channel_command_new_spawn(const char *const argv[], + int flags, + Error **errp); + + +#endif /* QIO_CHANNEL_COMMAND_H__ */ diff --git a/io/Makefile.objs b/io/Makefile.objs index e3771b1..1a58ccb 100644 --- a/io/Makefile.objs +++ b/io/Makefile.objs @@ -1,4 +1,5 @@ io-obj-y = channel.o +io-obj-y += channel-command.o io-obj-y += channel-file.o io-obj-y += channel-socket.o io-obj-y += channel-tls.o diff --git a/io/channel-command.c b/io/channel-command.c new file mode 100644 index 0000000..d735efb --- /dev/null +++ b/io/channel-command.c @@ -0,0 +1,369 @@ +/* + * 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; + + if (fds || nfds) { + error_setg_errno(errp, EINVAL, + "Channel does not support file descriptor passing"); + return -1; + } + + 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; + + if (fds || nfds) { + error_setg_errno(errp, EINVAL, + "Channel does not support file descriptor passing"); + return -1; + } + + 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); diff --git a/tests/.gitignore b/tests/.gitignore index 810b4f0..cc9aeec 100644 --- a/tests/.gitignore +++ b/tests/.gitignore @@ -24,6 +24,8 @@ test-cutils test-hbitmap test-int128 test-iov +test-io-channel-command +test-io-channel-command.fifo test-io-channel-file test-io-channel-file.txt test-io-channel-socket diff --git a/tests/Makefile b/tests/Makefile index 2919914..a0faebf 100644 --- a/tests/Makefile +++ b/tests/Makefile @@ -88,6 +88,7 @@ check-unit-y += tests/test-io-task$(EXESUF) check-unit-y += tests/test-io-channel-socket$(EXESUF) check-unit-y += tests/test-io-channel-file$(EXESUF) check-unit-$(CONFIG_GNUTLS) += tests/test-io-channel-tls$(EXESUF) +check-unit-y += tests/test-io-channel-command$(EXESUF) check-block-$(CONFIG_POSIX) += tests/qemu-iotests-quick.sh @@ -482,6 +483,8 @@ tests/test-io-channel-file$(EXESUF): tests/test-io-channel-file.o \ tests/test-io-channel-tls$(EXESUF): tests/test-io-channel-tls.o \ tests/crypto-tls-x509-helpers.o tests/pkix_asn1_tab.o \ tests/io-channel-helpers.o $(test-io-obj-y) +tests/test-io-channel-command$(EXESUF): tests/test-io-channel-command.o \ + tests/io-channel-helpers.o $(test-io-obj-y) libqos-obj-y = tests/libqos/pci.o tests/libqos/fw_cfg.o tests/libqos/malloc.o libqos-obj-y += tests/libqos/i2c.o tests/libqos/libqos.o diff --git a/tests/test-io-channel-command.c b/tests/test-io-channel-command.c new file mode 100644 index 0000000..03cac36 --- /dev/null +++ b/tests/test-io-channel-command.c @@ -0,0 +1,129 @@ +/* + * QEMU I/O channel command test + * + * 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-helpers.h" + +#ifndef WIN32 +static void test_io_channel_command_fifo(bool async) +{ +#define TEST_FIFO "tests/test-io-channel-command.fifo" + QIOChannel *src, *dst; + QIOChannelTest *test; + char *srcfifo = g_strdup_printf("PIPE:%s,wronly", TEST_FIFO); + char *dstfifo = g_strdup_printf("PIPE:%s,rdonly", TEST_FIFO); + const char *srcargv[] = { + "/bin/socat", "-", srcfifo, NULL, + }; + const char *dstargv[] = { + "/bin/socat", dstfifo, "-", NULL, + }; + + unlink(TEST_FIFO); + if (access("/bin/socat", X_OK) < 0) { + return; /* Pretend success if socat is not present */ + } + if (mkfifo(TEST_FIFO, 0600) < 0) { + abort(); + } + src = QIO_CHANNEL(qio_channel_command_new_spawn(srcargv, + O_WRONLY, + &error_abort)); + dst = QIO_CHANNEL(qio_channel_command_new_spawn(dstargv, + O_RDONLY, + &error_abort)); + + test = qio_channel_test_new(); + qio_channel_test_run_threads(test, async, src, dst); + qio_channel_test_validate(test); + + object_unref(OBJECT(src)); + object_unref(OBJECT(dst)); + + g_free(srcfifo); + g_free(dstfifo); + unlink(TEST_FIFO); +} + + +static void test_io_channel_command_fifo_async(void) +{ + test_io_channel_command_fifo(true); +} + +static void test_io_channel_command_fifo_sync(void) +{ + test_io_channel_command_fifo(false); +} + + +static void test_io_channel_command_echo(bool async) +{ + QIOChannel *ioc; + QIOChannelTest *test; + const char *socatargv[] = { + "/bin/socat", "-", "-", NULL, + }; + + if (access("/bin/socat", X_OK) < 0) { + return; /* Pretend success if socat is not present */ + } + + ioc = QIO_CHANNEL(qio_channel_command_new_spawn(socatargv, + O_RDWR, + &error_abort)); + test = qio_channel_test_new(); + qio_channel_test_run_threads(test, async, ioc, ioc); + qio_channel_test_validate(test); + + object_unref(OBJECT(ioc)); +} + + +static void test_io_channel_command_echo_async(void) +{ + test_io_channel_command_echo(true); +} + +static void test_io_channel_command_echo_sync(void) +{ + test_io_channel_command_echo(false); +} +#endif + +int main(int argc, char **argv) +{ + module_call_init(MODULE_INIT_QOM); + + g_test_init(&argc, &argv, NULL); + +#ifndef WIN32 + g_test_add_func("/io/channel/command/fifo/sync", + test_io_channel_command_fifo_sync); + g_test_add_func("/io/channel/command/fifo/async", + test_io_channel_command_fifo_async); + g_test_add_func("/io/channel/command/echo/sync", + test_io_channel_command_echo_sync); + g_test_add_func("/io/channel/command/echo/async", + test_io_channel_command_echo_async); +#endif + + return g_test_run(); +} diff --git a/trace-events b/trace-events index 01a3602..4933aa6 100644 --- a/trace-events +++ b/trace-events @@ -1842,3 +1842,9 @@ qio_channel_websock_handshake_pending(void *ioc, int status) "Websock handshake qio_channel_websock_handshake_reply(void *ioc) "Websock handshake reply ioc=%p" qio_channel_websock_handshake_fail(void *ioc) "Websock handshake fail ioc=%p" qio_channel_websock_handshake_complete(void *ioc) "Websock handshake complete ioc=%p" + +# io/channel-command.c +qio_channel_command_new_pid(void *ioc, int writefd, int readfd, int pid) "Command new pid ioc=%p writefd=%d readfd=%d pid=%d" +qio_channel_command_new_spawn(void *ioc, const char *binary, int flags) "Command new spawn ioc=%p binary=%s flags=%d" +qio_channel_command_abort(void *ioc, int pid) "Command abort ioc=%p pid=%d" +qio_channel_command_wait(void *ioc, int pid, int ret, int status) "Command abort ioc=%p pid=%d ret=%d status=%d" -- 2.5.0
